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19-4421; Rev 0; 4/09
KIT ATION EVALU E AILABL AV
Adaptive Step-Up Converters with 1.5A Flash Driver
General Description Features
2.5V to 5.5V Operation Range Step-Up DC-DC Converter 1.5A Guaranteed Output Current Adaptive or I2C Programmable Output Voltage 2MHz and 4MHz Switching Frequency Options Two Flash/Movie LED Current Regulators I2C Programmable Flash and Movie Current Low-Dropout Voltage (110mV max) at 500mA LED Indicator Current Regulator I2C Programmable Output Current Ramp and Blink Timers for Indicator Mode Low-Dropout Voltage (130mV max) at 16mA I2C Programmable Safety and Watchdog Timers GSM Blank Logic Input MAXFLASH System Lockup Protection Remote Temperature Sensor Input Open/Short LED Detection Thermal Shutdown Protection < 1A Shutdown Current 20-Bump, 0.5mm Pitch, 2.5mm x 2.0mm WLP
MAX8834Y/MAX8834Z
The MAX8834Y/MAX8834Z flash drivers integrate a 1.5A PWM DC-DC step-up converter and three programmable low-side, low-dropout LED current regulators. The step-up converter features an internal switching MOSFET and synchronous rectifier to improve efficiency and minimize external component count. An I2C interface provides flexible control of stepup converter output voltage setting, movie/flash mode selection, flash timer duration settings, and current regulator settings. The MAX8834Y/MAX8834Z operate down to 2.5V, making them future proof for new battery technologies. The MAX8834Y/MAX8834Z consist of two current regulators for the flash/movie mode. Each current regulator can sink 750mA in flash mode and 125mA in movie mode. The MAX8834Y/MAX8834Z also integrate a 16mA lowcurrent regulator that can be used to indicate camera status. The indicator current regulator includes programmable ramp and blink timer settings. A programmable input current limit, invoked using the GSMB control, reduces the total current drawn from the battery during PA transmit events. This ensures the flash current is set to the maximum possible for any given operating condition. Additionally, the MAX8834Y/MAX8834Z include a MAXFLASH* function that adaptively reduces flash current during low battery conditions to help prevent system undervoltage lockup. Other features include an optional NTC input for fingerburn protection and open/short LED detection. The MAX8834Y switches at 2MHz, providing best overall efficiency. The MAX8834Z switches at 4MHz, providing smallest overall solution size. The MAX8834Y/ MAX8834Z are available in a 20-bump, 0.5mm pitch WLP package (2.5mm x 2.0mm).
*Patent pending.
Applications
Cell Phones and Smart Phones PDAs, Digital Cameras, and Camcorders
Typical Operating Circuit
1H OR 2.2H PROGRAMMABLE OUTPUT 3.7V TO 5.2V OUT 10F AGND
INPUT 2.5V TO 5.5V IN 10F
LX
Ordering Information
PART SWITCHING TEMP PIN-PACKAGE FREQUENCY RANGE (MHz) 2 4
PA_TXON FLASH ON I2C VLOGIC 0.1F
PGND COMP FLED1 1.5A TOTAL FLASH FLED2
MAX8834Y MAX8834Z
-40C to 20 WLP MAX8834YEWP+T +85C (2.5mm x 2.0mm) MAX8834ZEWP+T -40C to 20 WLP +85C (2.5mm x 2.0mm)
GSMB LED_EN SCL SDA
INDLED 16mA INDICATOR FGND NTC FINGER-BURN PROTECTION
+Denotes a lead(Pb)-free/RoHS-compliant package. T = Tape and reel.
VDD
Pin Configuration appears at end of data sheet.
________________________________________________________________ Maxim Integrated Products 1
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim's website at www.maxim-ic.com.
Adaptive Step-Up Converters with 1.5A Flash Driver MAX8834Y/MAX8834Z
ABSOLUTE MAXIMUM RATINGS
IN, OUT, NTC to AGND .........................................-0.3V to +6.0V VDD to AGND.........................................................-0.3V to +4.0V SCL, SDA, LED_EN, GSMB to AGND ........-0.3V to (VDD + 0.3V) FLED1, FLED2, INDLED to FGND ............-0.3V to (VOUT + 0.3V) COMP to AGND ...........................................-0.3V to (VIN + 0.3V) PGND, FGND to AGND .........................................-0.3V to +0.3V ILX Current (rms) ......................................................................3A Continuous Power Dissipation (TA = +70C) (derate 17.5mW/C above +70C) .............................1410mW Operating Temperature Range ...........................-40C to +85C Junction Temperature ......................................................+150C Storage Temperature Range .............................-65C to +150C Bump Temperature* (soldering) ......................................+260C
*This device is constructed using a unique set of packaging techniques that impose a limit on the thermal profile the device can be exposed to during board level solder attach and rework. This limit permits only the use of the solder profiles recommended in the industry-standard specification, JEDEC 020A, paragraph 7.6, Table 3 for IR/VPR and Convection reflow. Preheating is required. Hand or wave soldering is not allowed.
Stresses beyond those listed under "Absolute Maximum Ratings" may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.
ELECTRICAL CHARACTERISTICS
(VIN = 3.6V, VAGND = VPGND = VFGND = 0V, VDD = 1.8V, TA = -40C to +85C, unless otherwise noted. Typical values are at TA = +25C.) (Note 1)
PARAMETER IN Operating Voltage VDD Operating Range VDD Undervoltage Lockout (UVLO) Threshold VDD UVLO Hysteresis IN UVLO Threshold IN UVLO Hysteresis IN Standby Supply Current VDD Standby Supply Current (All Outputs Off, I2C Enabled) LOGIC INTERFACE LED_EN, GSMB Logic Input-High Voltage VDD = 1.62V to 3.6V SCL, SDA LED_EN, GSMB Logic Input-Low Voltage VDD = 1.62V to 3.6V SCL, SDA 1.4 0.7 x VDD 0.4 0.3 x VDD 1 From LED_EN going high to rising edge on current regulator 400 VIL = 0V or VIH = 3.6V TA = +25C TA = +85C -1 V V VSCL = VSDA = VDD, VIN = 5.5V, I2C ready VSCL = VSDA = VDD = 3.6V, I2C ready 4 VIN falling 2.15 VDD falling CONDITIONS MIN 2.5 1.62 1.25 1.4 50 2.3 50 1 7 2.45 TYP MAX 5.5 3.6 1.55 UNITS V V V mV V mV A A
LED_EN Minimum High Time (LED_EN is Internally Sampled by a 1MHz Clock) LED_EN Propagation Delay LED_EN and GSMB Pulldown Resistor Logic Input Current (SCL, SDA)
s
3 800 0.01 0.1 1600 +1
s k A
2
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Adaptive Step-Up Converters with 1.5A Flash Driver
ELECTRICAL CHARACTERISTICS (continued)
(VIN = 3.6V, VAGND = VPGND = VFGND = 0V, VDD = 1.8V, TA = -40C to +85C, unless otherwise noted. Typical values are at TA = +25C.) (Note 1)
PARAMETER Shutdown Leakage Current I2C INTERFACE SDA Output Low Voltage I2C Clock Frequency Bus-Free Time Between STOP and START Hold Time Repeated START Condition SCL Low Period SCL High Period Setup Time Repeated START Condition SDA Hold Time SDA Setup Time Setup Time for STOP Condition STEP-UP DC-DC CONVERTER OUT Voltage Range OUT Voltage Accuracy OUT Overvoltage Protection Adaptive Output Voltage Regulation Threshold PGOOD Window Comparator Line Regulation Load Regulation nFET Current Limit LX nFET On-Resistance LX pFET On-Resistance LX Leakage Input Current Limit Range During GSMB Trigger Input Current Limit Step Size During GSMB Trigger Input Current Limit Accuracy I ILIM = 100mA, in dropout mode MAX8834Y Operating Frequency, No Load MAX8834Z TA = +25C TA = -40C to +85C TA = +25C TA = -40C to +85C -15 1.8 1.6 3.6 3.2 4 2 LX to PGND, ILX = 200mA LX to OUT, ILX = 200mA VLX = 5.5V TA = +25C TA = +85C 50 50 +15 2.2 2.4 4.4 4.8 MHz 100mV steps No load, VOUT = 5V When running in adaptive mode IFLED1 = IFLED2 = 492.24mA setting, IINDLED = 16mA VOUT = 5V, in programmable mode VIN = 2.5V to 4.2V I OUT = 0mA to 1500mA -15 3.7 -2.75 5.2 0.5 5.35 150 -12.5 0.1 0.5 3.6 0.055 0.12 0.1 0.1 800 0.130 0.200 1 A mA mA % -10 5.2 +2.75 5.5 V % V mV % %/V %/A A tBUF tHD_STA tLOW tHIGH t SU_STA tHD_DAT t SU_DAT t SU_STO 1.3 0.6 1.3 0.6 0.6 0 100 0.6 0.1 0.2 0.2 0.1 -0.01 50 0.1 I SDA = 3mA 0.03 0.4 400 V kHz s s s s s s ns s CONDITIONS IN and VDD in UVLO, VLED_EN = VGSMB = 0V TA = +25C TA = +85C MIN -1 TYP 0.01 0.1 MAX +1 UNITS A
MAX8834Y/MAX8834Z
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3
Adaptive Step-Up Converters with 1.5A Flash Driver MAX8834Y/MAX8834Z
ELECTRICAL CHARACTERISTICS (continued)
(VIN = 3.6V, VAGND = VPGND = VFGND = 0V, VDD = 1.8V, TA = -40C to +85C, unless otherwise noted. Typical values are at TA = +25C.) (Note 1)
PARAMETER Maximum Duty Cycle Minimum Duty Cycle COMP Transconductance COMP Discharge Resistance OUT Discharge Resistance VOUT = 4.5V VOUT = 4.5V VCOMP = 1.5V During shutdown or UVLO, from COMP to AGND During shutdown or UVLO, from OUT to LX Step-up off, FLED1/FLED2 on, supply current for each current source Flash Movie 23.44mA setting Current Accuracy 492.24mA setting 750mA setting Current Regulator Dropout (Note 2) FLED1/FLED2 Leakage in Shutdown 492.24mA setting 93.75mA setting VFLED1 = VFLED2 = 5.5V TA = +25C TA = +85C -1 50 0.01 0.1 0.6 16 0.5mA setting Current Accuracy Current Regulator Dropout INDLED Leakage in Shutdown PROTECTION CIRCUITS NTC BIAS Current NTC Overtemperature Detection Threshold NTC Short Detection Threshold Flash Duration Timer Range Flash Duration Timer Accuracy (400ms Setting) Minimum Flash Duration Flash Safety Timer Reset Inhibit Period Watchdog Timer Range VNTC falling, 100mV hysteresis, NTC_CNTL[2:0] = 100 VNTC falling In 50ms steps (Note 3) TA = +25C TA = -40C to +85C FLASH_EN[2:0] = 1XX From falling edge of LED_EN until flash safety timer is reset In 4s steps 4 50 360 320 2 30 16 400 19.4 388 20 400 100 800 440 480 20.6 412 A mV mV ms ms ms ms s 16mA setting 16mA setting (Note 2) VINDLED = 5.5V TA = +25C TA = +85C -1 TA = +25C TA = +25C TA = -40C to +85C -10 -3 -5 55 0.01 0.1 0.5 +10 +3 +5 130 +1 TA = +25C TA = +25C TA = -40C to +85C TA = -40C to +85C -5 -2.5 -4 -10 0.5 CONDITIONS MIN 69 TYP 75 7.5 55 120 10 k MAX UNITS % % S
FLED1/FLED2 CURRENT REGULATOR IN Supply Current Maximum Current Setting 0.6 750 125 +20 +2.5 +4 +5 110 100 +1 mA mA % % % mV A
INDLED CURRENT REGULATOR IN Supply Current Step-up converter off, INDLED on Maximum Current Setting
mA mA % % % mV A
4
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Adaptive Step-Up Converters with 1.5A Flash Driver
ELECTRICAL CHARACTERISTICS (continued)
(VIN = 3.6V, VAGND = VPGND = VFGND = 0V, VDD = 1.8V, TA = -40C to +85C, unless otherwise noted. Typical values are at TA = +25C.) (Note 1)
PARAMETER Watchdog Timer Accuracy (4s setting) Open LED Detection Threshold TA = +25C TA = -40C to +85C FLED1, FLED2, INDLED enabled VOUT 1V 30 20 +160 CONDITIONS MIN 3.6 3.2 TYP 4 MAX 4.4 4.8 100 UNITS s mV V ms C C
MAX8834Y/MAX8834Z
Shorted LED Detection Threshold FLED1, FLED2, INDLED enabled Open and Short Debounce Timer Thermal-Shutdown Hysteresis Thermal Shutdown MAXFLASH Low-Battery Detect Threshold Range Low-Battery Voltage Threshold Accuracy Low-Battery Voltage Hysteresis Programmable Range Low-Battery Voltage Hysteresis Step Size Low-Battery Reset Time LB_TMR[1:0] = 00 LB_TMR[1:0] = 01 200 400 100 33mV steps 2.5 From LED open or short detected until LED current regulator is disabled
3.4 2.5 200 100 250 500 300 600
V % mV mV s
Note 1: All devices are 100% production tested at TA = +25C. Limits over the operating temperature range are guaranteed by design. Note 2: LED current regulator dropout voltage is defined as the voltage when current drops 10% from the current level measured at 0.6V. Note 3: Flash duration is from rising edge of LED_EN until IFLED = 0A (safety time in one-shot mode). Note 4: The adaptive output voltage regulation threshold is individually set on each device to 75mV above the dropout voltage of the LED current regulators. This ensures minimum power dissipation on the IC during a flash event. The dropout voltage chosen is the highest measured dropout voltage of FLED1, FLED2, and INDLED.
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5
Adaptive Step-Up Converters with 1.5A Flash Driver MAX8834Y/MAX8834Z
Typical Operating Characteristics
(Circuit of Figure 1, VIN = 3.6V, VOUT = 3.8V, VDD = 3.0V, TA = +25C, unless otherwise noted.)
STEP-UP CONVERTER EFFICIENCY vs. INPUT VOLTAGE (MAX8834Y)
MAX8834Y/Z toc01
STEP-UP CONVERTER EFFICIENCY vs. INPUT VOLTAGE (MAX8834Z)
MAX8834Y/Z toc02
STEP-UP CONVERTER EFFICIENCY vs. OUTPUT CURRENT (MAX8834Y)
VIN = 3.6V VIN = 3.2V VIN = 2.5V
MAX8834Y/Z toc03
100 90 80 EFFICIENCY (%) 70 60 50 40 30 20 10 0 VOUT = 3.8V IOUT = 750mA VOUT = 5V IOUT = 250mA VOUT = 3.8V IOUT = 250mA VOUT = 5V IOUT = 16mA VOUT = 3.8V IOUT = 16mA
100 90 80 EFFICIENCY (%) 70 60 50 40 30 20 10 0 VOUT = 5V IOUT = 250mA VOUT = 3.8V IOUT = 250mA VOUT = 5V VOUT = 3.8V IOUT = 16mA IOUT = 16mA VOUT = 3.8V IOUT = 750mA VOUT = 5V IOUT = 750mA
100
80 EFFICIENCY (%)
60
VOUT = 5V IOUT = 750mA
40
FOR VIN > VOUT, VOUT INCREASES ABOVE THE PROGRAMMED VALUE DUE TO THE MINIMUM DUTY CYCLE CONSTRAINT. 2.5 3.0 3.5 4.0 4.5 5.0
FOR VIN > VOUT, VOUT INCREASES ABOVE THE PROGRAMMED VALUE DUE TO THE MINIMUM DUTY CYCLE CONSTRAINT. 2.5 3.0 3.5 4.0 4.5 5.0
20
0 1 10 100 1000 10,000 OUTPUT CURRENT (mA)
INPUT VOLTAGE (V)
INPUT VOLTAGE (V)
STEP-UP CONVERTER EFFICIENCY vs. OUTPUT CURRENT (MAX8834Z)
MAX8834Y/Z toc04
STEP-UP CONVERTER SUPPLY CURRENT vs. SUPPLY VOLTAGE
VOUT = 3.8V 12 SUPPLY CURRENT (mA) MAX8834Z
MAX8834Y/Z toc05
STEP-UP CONVERTER SUPPLY CURRENT vs. TEMPERATURE
VOUT = 5V SUPPLY CURRENT (mA) 15 MAX8834Z
MAX8834Y/Z toc06
100
VIN = 3.6V VIN = 3.2V VIN = 2.5V
15
20
80 EFFICIENCY (%)
60
9
10 MAX8834Y 5
40
6
MAX8834Y
20
3 0 2.5 3.0 3.5 4.0 4.5 5.0 -40 -15 10 35 60 85 SUPPLY VOLTAGE (V) TEMPERATURE (C)
0 1 10 100 1000 10,000 OUTPUT CURRENT (mA)
0
LED CURRENT ACCURACY vs. INPUT VOLTAGE
MAX8834Y/Z toc07
LED CURRENT ACCURACY vs. TEMPERATURE
8 LED CURRENT ACCURACY (%) 6 4 2 0 -2 -4 -6 -8 -10 5.5 -40 IFLED2 = 492.19mA VOUT = 5V -15 10 35 60 85 IFLED2 = 750mA IINDLED = 16mA IFLED1 = 750mA IFLED1 = 125mA
MAX8834Y/Z toc08
10 LED CURRENT ACCURACY (%) IFLED1 = 125mA 5 IFLED1 = 492.19mA 0 IFLED2 = 492.19mA IFLED1 = 750mA -5 IFLED2 = 750mA VOUT = 5V -10 2.5 3.0 3.5 4.0 4.5 5.0 INPUT VOLTAGE (V) IINDLED = 16mA IFLED2 = 125mA
10 IFLED2 = 125mA IFLED1 = 492.19mA
TEMPERATURE (C)
6
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Adaptive Step-Up Converters with 1.5A Flash Driver
Typical Operating Characteristics (continued)
(Circuit of Figure 1, VIN = 3.6V, VOUT = 3.8V, VDD = 3.0V, TA = +25C, unless otherwise noted.)
OUTPUT VOLTAGE ACCURACY vs. TEMPERATURE
MAX8834Y/Z toc09
MAX8834Y/MAX8834Z
INTERNAL OSCILLATOR FREQUENCY vs. SUPPLY VOLTAGE
MAX8834Y/Z toc10
0.6 OUTPUT VOLTAGE ACCURACY (%) MAX8834Z, NO LOAD 0.4 0.2 0 -0.2 -0.4 -0.6 -40 -15 10 35 MAX8834Z, IOUT = 250mA
VOUT = 5V MAX8834Y, NO LOAD
5 OSCILLATOR FREQUENCY (MHz) MAX8834Z
4
3
MAX8834Y, IOUT = 250mA
2 MAX8834Y 1
0 60 85 2.5 3.0 3.5 4.0 4.5 5.0 5.5 TEMPERATURE (C) SUPPLY VOLTAGE (V)
STARTUP WAVEFORM (MAX8834Y, VOUT = 5V)
MAX8834Y/Z toc11
STARTUP WAVEFORM (MAX8834Y, ADAPTIVE MODE)
MAX8834Y/Z toc12
VOUT
5V
2V/div
VOUT
2V/div
VLX
2V/div
VLX ADAPTIVE MODE ILED1 = 31.25mA
2V/div
ILX
VOUT = 5V ILED1 = 31.25mA 500mA/div
ILX
500mA/div
VCOMP 1ms/div
1V/div
VCOMP 1ms/div
1V/div
STARTUP WAVEFORM (MAX8834Z, VOUT = 5V)
MAX8834Y/Z toc13
STARTUP WAVEFORM (MAX8834Z, ADAPTIVE MODE)
MAX8834Y/Z toc14
VOUT
5V
2V/div
VOUT
2V/div
VLX VOUT = 5V ILED1 = 31.25mA
2V/div
VLX
2V/div
ILX
ILX 500mA/div 1V/div VCOMP 1ms/div
ADAPTIVE MODE ILED1 = 31.25mA
500mA/div
VCOMP 1ms/div
1V/div
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7
Adaptive Step-Up Converters with 1.5A Flash Driver MAX8834Y/MAX8834Z
Typical Operating Characteristics (continued)
(Circuit of Figure 1, VIN = 3.6V, VOUT = 3.8V, VDD = 3.0V, TA = +25C, unless otherwise noted.)
SHUTDOWN WAVEFORM (MAX8834Y, VOUT = 5V)
MAX8834Y/Z toc15
SHUTDOWN WAVEFORM (MAX8834Y, ADAPTIVE MODE)
MAX8834Y/Z toc16
VOUT
5V
2V/div
VOUT
2V/div
VLX
2V/div
VLX
2V/div
VOUT = 5V ILED1 = 31.25mA ILX VCOMP 400s/div
ILX 500mA/div 1V/div
ADAPTIVE MODE ILED1 = 31.25mA
500mA/div
VCOMP 400s/div
1V/div
SHUTDOWN WAVEFORM (MAX8834Z, VOUT = 5V)
MAX8834Y/Z toc17
SHUTDOWN WAVEFORM (MAX8834Z, ADAPTIVE MODE)
MAX8834Y/Z toc18
VOUT
5V
2V/div
VOUT
2V/div
VLX
2V/div
VLX
2V/div
ILX VCOMP
VOUT = 5V ILED1 = 31.25mA
500mA/div
ILX
ADAPTIVE MODE ILED1 = 31.25mA
500mA/div
1V/div
VCOMP 1V/div
400s/div
400s/div
LIGHT-LOAD SWITCHING WAVEFORMS (MAX8834Y)
MAX8834Y/Z toc19
LIGHT-LOAD SWITCHING WAVEFORMS (MAX8834Z)
MAX8834Y/Z toc20
VLX
2V/div 0V
VLX
2V/div 0V
ILX VOUT = 5V IOUT = 16mA
0mA 200mA/div
ILX VOUT = 5V IOUT = 16mA
0mA 200mA/div
VOUT AC RIPPLE 400ns/div
20mV/div
VOUT AC RIPPLE 400ns/div
20mV/div
8
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Adaptive Step-Up Converters with 1.5A Flash Driver
Typical Operating Characteristics (continued)
(Circuit of Figure 1, VIN = 3.6V, VOUT = 3.8V, VDD = 3.0V, TA = +25C, unless otherwise noted.)
HEAVY-LOAD SWITCHING WAVEFORMS (MAX8834Y)
MAX8834Y/Z toc21
MAX8834Y/MAX8834Z
HEAVY-LOAD SWITCHING WAVEFORMS (MAX8834Z)
MAX8834Y/Z toc22
VLX
2V/div 0V
VLX
2V/div 0V 500mA/div 1.5A VOUT = 5V IOUT = 1A
ILX VOUT = 5V IOUT = 1A VOUT AC RIPPLE 400ns/div
1.5A 500mA/div
ILX
50mV/div
VOUT AC RIPPLE 400ns/div
50mV/div
GSMB WAVEFORM
MAX8834Y/Z toc23
MAXFLASH FUNCTION
MAX8834Y/Z toc24
VGSMB
VOUT = 5V ILIM = 500mA IFLED1 = IFLED2 = 515.63mA tHC_TRM = 80s
2V/div VIN 1A/div
3.6V
VIN DROPS BELOW THE THRESHOLD VOLTAGE
3.6V 200mV/div
IIN
VIN INCREASES TO THE THRESHOLD IFLED1 500mA/div IFLED1 IFLED2 1ms/div 500mA/div 0mA VOUT = 5V IFLED1 = 750mA VLB_TH = 3.0V VLB_HYS DISABLED tTMR_DUR = 50ms 10ms/div
200mV/div
OUTPUT VOLTAGE LINE REGULATION (MAX8834Y)
MAX8834Y/Z toc25
OUTPUT VOLTAGE LINE REGULATION (MAX8834Z)
VOUT = 5V 5.01 OUTPUT VOLTAGE (V) IOUT = 16mA
MAX8834Y/Z toc26
5.02 VOUT = 5V 5.01 OUTPUT VOLTAGE (V) IOUT = 16mA 5.00
5.02
5.00
4.99 IOUT = 250mA IOUT = 750mA 4.98
4.99
IOUT = 250mA
IOUT = 750mA
4.98
4.97 2.5 3.0 3.5 INPUT VOLTAGE (V) 4.0 4.5
4.97 2.5 3.0 3.5 INPUT VOLTAGE (V) 4.0 4.5
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9
Adaptive Step-Up Converters with 1.5A Flash Driver MAX8834Y/MAX8834Z
Typical Operating Characteristics (continued)
(Circuit of Figure 1, VIN = 3.6V, VOUT = 3.8V, VDD = 3.0V, TA = +25C, unless otherwise noted.)
OUTPUT VOLTAGE LOAD REGULATION (MAX8834Y)
MAX8834Y/Z toc27
OUTPUT VOLTAGE LOAD REGULATION (MAX8834Z)
MAX8834Y/Z toc28
5.02 5.01 OUTPUT VOLTAGE (V) 5.00 4.99 4.98 4.97 VOUT = 5V 4.96 1 10 100 1000
5.02 5.01 OUTPUT VOLTAGE (V) 5.00 4.99 4.98 4.97 VOUT = 5V 4.96
10,000
1
10
100
1000
10,000
OUTPUT CURRENT (mA)
OUTPUT CURRENT (mA)
INPUT CURRENT LIMIT vs. PROGRAMMED OUTPUT VOLTAGE
ILIM = 500mA
MAX8834Y/Z toc29
INPUT CURRENT LIMIT vs. PROGRAMMED VALUE
VOUT = 5V INPUT CURRENT LIMIT (mA) 800
MAX8834Y/Z toc30
580 570 INPUT CURRENT LIMIT (mA) 560 550 540 530 520 510 500 3.7 4.0 4.3 4.6
1000
600 IDEAL LINE 400
200
0 4.9 5.2 0 200 400 600 800 PROGRAMMED OUTPUT VOLTAGE (V) PROGRAMMED VALUE (mA)
10
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Adaptive Step-Up Converters with 1.5A Flash Driver
Pin Description
PIN A1, B1 NAME OUT FUNCTION Regulator Output. Connect OUT to the anodes of the external LEDs. Bypass OUT to PGND with a 10F ceramic capacitor. OUT is connected to LX through an internal 10k resistor during shutdown. Inductor Connection. Connect LX to the switched side of the inductor. LX is internally connected to the drains of the internal MOSFETs. LX is connected to OUT through an internal 10k resistor during shutdown. Power Ground. Connect PGND to AGND and to the input capacitor ground. Connect PGND to the PCB ground plane. Analog Supply Voltage Input. The input voltage range is 2.5V to 5.5V. Bypass IN to AGND and PGND with a 10F ceramic capacitor as close as possible to the IC. IN is high impedance during shutdown. Logic Input Supply Voltage. Connect VDD to the logic supply driving SCL, SDA, LED_EN, and GSMB. Bypass VDD to AGND with a 0.1F ceramic capacitor. When VDD is below the UVLO, the I2C registers reset and the step-up converter turns off. I2C Clock Input. Data is read on the rising edge of SCL. Analog Ground. Connect AGND to PGND and to the input capacitor ground. Connect AGND to the PCB ground plane. Compensation Input. See the Compensation Network Selection section for details. COMP is internally pulled to AGND through a 180 resistor in shutdown. FLED1/FLED2 and INDLED Power Ground. Connect FGND to PGND. LED Enable Logic Input. LED_EN controls FLED1, FLED2, and INDLED, depending on control bits written into the LED_CNTL register. See the LED_EN Control register description for an explanation of this input function. LED_EN has an internal 800k pulldown resistor to AGND. GSM Blank Signal. Assert GSMB to reduce the current regulator settings according to the values programmed into the GSMB_CUR register. The status of the flash safety timer and the flash/movie mode values in the current regulator registers are not affected by the GSMB state. Connect GSMB to the PA module enable signal or other suitable logic signal that indicates a GSM transmit is in process. Polarity of this signal is set by a bit in the GSMB_CUR register (default is active-high). GSMB has an internal 800k pulldown resistor to AGND. I2C Data Input. Data is read on the rising edge of SCL and data is clocked out on the falling edge of SCL. FLED2 Current Regulator. Current flowing into FLED2 is based on the internal I2C registers FLASH2_CUR and MOVIE_CUR. Connect FLED2 to the cathode of an external flash LED or LED module. FLED2 is high impedance during shutdown. If unused, connect FLED2 to ground. FLED1 Current Regulator. Current flowing into FLED1 is based on the internal I2C registers FLASH1_CUR and MOVIE_CUR. Connect FLED1 to the cathode of an external flash LED or LED module. FLED1 is high impedance during shutdown. If unused, connect FLED1 to ground. INDLED Current Regulator. Current flowing into INDLED is based on the internal I2C registers IND_CUR. Connect INDLED to the cathode of an external indicator LED. INDLED is high impedance during shutdown. If unused, connect INDLED to ground. NTC Bias Output. NTC provides 20A to bias the NTC thermistor. The NTC voltage is compared to the trip threshold programmed by the NTC_CNTL register. NTC is high impedance during shutdown. Connect NTC to IN if not used. See the Finger-Burn Protection (NTC) section for details.
MAX8834Y/MAX8834Z
A2, B2
LX
A3, B3 A4
PGND IN
A5 B4 B5 C1 C2, D2 C3
VDD SCL AGND COMP FGND LED_EN
C4
GSMB
C5
SDA
D1
FLED2
D3
FLED1
D4
INDLED
D5
NTC
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Adaptive Step-Up Converters with 1.5A Flash Driver MAX8834Y/MAX8834Z
Detailed Description
The MAX8834Y/MAX8834Z flash drivers integrate an adaptive 1.5A PWM step-up DC-DC converter, two 750mA white LED camera flash/movie current regulators, and a 16mA indicator LED current regulator. An I2C interface controls individual output on/off, the stepup output voltage setting, the movie/flash current, and the flash timer duration settings. see Tables 3 and 4). The movie mode provides continuous lighting when enabled through I 2C or LED_EN. When the flash mode is enabled, a flash safety timer, programmable from 50ms to 800ms through I2C, limits the duration of the flash mode. Once the flash safety timer expires, the current regulators return to movie mode if movie mode was active when a flash event was triggered. The flash mode has priority over the movie mode.
Step-Up Converter (LX, OUT, COMP, PGND)
The MAX8834Y/MAX8834Z include a fixed-frequency, PWM step-up converter that supplies power to the flash LEDs. The output voltage is programmable from 3.7V to 5.2V (in 100mV steps) through the I2C interface. The output voltage can also be set adaptively based on the LED forward voltage. The step-up converter switches an internal power MOSFET and synchronous rectifier at a constant 2MHz or 4MHz frequency, with varying duty cycle up to 75%, to maintain constant output voltage as the input voltage and load vary. Internal circuitry prevents any unwanted subharmonic switching by forcing a minimum 7% (typ) duty cycle. When the step-up converter is set to dropout mode, the internal synchronous rectifier is driven fully on, keeping the voltage at OUT equal to the LX input. This mode provides the lowest current consumption when driving LEDs with low forward voltage. The output voltage is internally monitored for a fault condition. If the output voltage drops below 8% (typ) of the nominal programmed value, a POK fault is indicated in STATUS1 register bit 5. This feature is disabled if the step-up converter is set to operate in adaptive mode.
Flash Safety Timer The flash safety timer is activated any time flash mode is selected, either with LED_EN or through the I2C interface. The flash safety timer, programmable from 50ms to 800ms through I2C, limits the duration of the flash mode in case LED_EN is stuck high or the I2C command to turn off has not been sent within the programmed flash safety timer duration. This timer can be configured to operate either in one-shot mode or maximum flash duration mode (see Table 9). In one-shot mode, the flash function is initiated on the rising edge of LED_EN (or I2C bit) and terminated based on the programmed value of the safety timer (see Figure 1). In the maximum flash timer mode, flash function remains enabled as long as LED_EN (or I2C bit) is high, unless the preprogrammed safety timer times out (see Figure 2). Once the flash mode is disabled, by either LED_EN, I2C, or flash safety timer, the flash has to be off for a minimum time (flash safety timer reset inhibit period), before it can be reinitiated (see Figure 3). This prevents spurious events from re-enabling the flash mode.
Indicator Current Regulator (INDLED)
A low-dropout linear current regulator from INDLED to FGND sinks current from the cathode terminal of the indicator LED. The INDLED current is regulated to I2C programmable levels up to 16mA. Programmable control is provided for ramp-up (OFF to ON) and rampdown (ON to OFF) times, as well as blink rate and duty cycle. The user can choose to enable or disable the ramp time and blink rate features. See Tables 6, 7, and 8 for more information.
Overvoltage Protection
The MAX8834Y/MAX8834Z include a comparator to monitor the output voltage (V OUT ) during adaptive mode operation of the step-up converter. If at anytime the output voltage exceeds a maximum threshold of 5.5V, the COMP capacitor is discharged until the output voltage is reduced by the 200mV (typ) hysteresis. Once the output voltage drops below this threshold, normal charging of the COMP capacitor is resumed.
Flash Current Regulator (FLED1 and FLED2)
A low-dropout linear current regulator from FLED1/ FLED2 to FGND sinks current from the cathode terminal of the flash LED(s). The FLED1/FLED2 current is regulated to I2C programmable levels for movie mode (up to 125mA, see Table 5) and flash mode (up to 750mA,
INDLED Blink Function INDLED current regulator is able to generate a blink function. The OFF and ON time for INDLED are set using the I2C interface. See Figure 4. INDLED Ramp Function The INDLED current regulator output provides ramp-up/ down for smooth transition between different brightness settings. The ramp-up/down times are controlled by the
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Adaptive Step-Up Converters with 1.5A Flash Driver MAX8834Y/MAX8834Z
ENABLING OF FLASH MODE BY LED_EN OR I2C CONTROL
ONE-SHOT FLASH TIMER ONE-SHOT FLASH TIMER
Figure 1. One-Shot Flash-Timer Mode
ENABLING OF FLASH MODE BY LED_EN OR I2C CONTROL
MAXIMUM FLASH SAFETY TIMER MAXIMUM FLASH TIMER
Figure 2. Maximum Flash-Timer Mode
ENABLING OF FLASH MODE BY LED_EN OR I2C CONTROL 30ms
Figure 3. Flash Safety Timer Reset Inhibit Period
IIND[4:0]
tIND_OFF
tIND_ON
Figure 4. Blink Function Timing
IND_RU and IND_RD control bits, and the ramp function is enabled/disabled by the IND_RP_EN bit. The current regulator increases/decreases the current onestep every tRAMP/32 until 0mA or IND[4:0] current is reached. See Figures 5 and 6.
Combining BLINK Timer and Ramp Function When using the ramp function for INDLED together with the blink timer, keep the ramp-up timer shorter than the ON blink timer and the ramp-down timer shorter than the OFF timer. Failing to comply with this results in the
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13
Adaptive Step-Up Converters with 1.5A Flash Driver MAX8834Y/MAX8834Z
IINDLED = FULL SCALE IINDLED = 1/2 SCALE 0mA 128ms 256ms 512ms 1024ms
Figure 5. Ramp-Up Behavior
IINDLED = FULL SCALE IINDLED = 1/2 SCALE 0mA 128ms 256ms 512ms 1024ms
Figure 6. Ramp-Down Behavior
tIND_OFF
tIND_ON
tIND_OFF
tIND_ON
tIND_OFF
IIND_LED = IND_LED[4:0] IIND_LED = CODE 0111 IIND_LED = CODE 0011 IIND_LED = OFF t= tIND_RU 32 t= tIND_RD 32
Figure 7. Combining RAMP Function and Blink Timer
programmed current not being reached during the ON time, or the INDLED current not returning to 0mA during the OFF time. See Figure 7. tIND _ ON tIND _ RU 32 32 (IND _ LED + 1) (IND _ LED + 1)
If FLED1/FLED2 is enabled for both movie and flash modes at the same time, flash mode has priority. Once the safety timer expires, the current regulator then returns to the movie mode.
Watchdog Timer
The MAX8834Y/MAX8834Z include a watchdog timer function that can be programmed using the I2C interface from 4 seconds to 16 seconds with a 4-second step. If the watchdog timer expires, the MAX8834Y/ MAX8834Z interpret it as an indication that the system is no longer responding and enters safe mode. In safe mode, the MAX8834Y/MAX8834Z disable all current regulators and the step-up DC-DC converter to prevent potential damage to the system. The I2C setting for the respective registers does not change, therefore, resetting the watchdog timer reverts the MAX8834Y/ MAX8834Z back to the state present before entering safe mode.
tIND _ OFF
tIND _ RD
where IND_LED is the code from 0 to 31 specified in the IND_LED[4:0].
LED Enable Input (LED_EN)
The LED_EN logic input can enable/disable the FLED1, FLED2, and INDLED current regulators. It can be programmed to control movie mode, flash mode, and indicator mode by using the IND_EN, MOVIE_EN, and FLASH_EN bits, respectively. See Table 8 for more information.
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Adaptive Step-Up Converters with 1.5A Flash Driver MAX8834Y/MAX8834Z
WATCHDOG TIMEOUT SUSPENDING ALL CURRENT REGULATIONS WDT_RST IS CLEARED
WATCHDOG TIMER ENABLED
WATCHDOG TIMER RESET
WATCHDOG TIMER RESET
WATCHDOG TIMER RESET
(I2C) WDT_EN (I2C) WDT_RST
WATCHDOG TIMER
LED_EN
IFLED_ OR IINDLED
t < WDT_DUR[1:0]
t < WDT_DUR[1:0]
t > WDT_DUR[1:0]
t < WDT_DUR[1:0]
Figure 8. Watchdog Timer Timing Diagram 1
WATCHDOG TIMER ENABLED
WATCHDOG TIMER RESET
WATCHDOG TIMER RESET WDT_RST IS CLEARED
WATCHDOG TIMEOUT SUSPENDING ALL CURRENT REGULATIONS
WATCHDOG TIMER RESET
(I2C) WDT_EN (I2C) WDT_RST
WATCHDOG TIMER
LED_EN
IFLED_ OR IINDLED
t < WDT_DUR[1:0]
t < WDT_DUR[1:0]
t > WDT_DUR[1:0]
t < WDT_DUR[1:0]
Figure 9. Watchdog Timer Timing Diagram 2
Setting the WDT_EN bit to 1 in the TMR_DUR register (Table 9) enables the watchdog timer. Resetting the watchdog timer is achieved by the rising or falling edge
of LED_EN or by setting bit 0 in the WDT_RST register (Table 14). See Figures 8 and 9 for two examples of watchdog timer timing diagrams.
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Adaptive Step-Up Converters with 1.5A Flash Driver MAX8834Y/MAX8834Z
GSMB EVENT GSMB (ACTIVE-HIGH)
INPUT CURRENT PREDEFINED INPUT CURRENT LIMIT DURING GSMB
FLED1/FLED2 DECREASED ONE LSB SINCE IIN > ILIM[3:0] FLED1/FLED2 INCREASED ONE LSB SINCE IIN < ILIM[3:0]
FLED2 OUTPUT CURRENT
FLED1 OUTPUT CURRENT
FLASH1_CUR SETTING
TIME HC_TMR[1:0] 1s AFTER GSMB ACTIVATED, FLED_ GOES TO THE MINIMUM SETTING 1s AFTER GSMB DEACTIVATED, FLED_ GOES TO THE PREVIOUS SETTING
Figure 10. Input Current Limit During GSMB Event
GSM Blank Function (GSMB)
The GSMB input is provided to allow the flash current to be momentarily reduced during a GSM transmit to reduce the peak current drawn from the battery. The input current limit ensures that the maximum possible output current is always provided, regardless of the input voltage and the LED forward voltages. When a GSMB event is triggered, the FLED1 and FLED2 current regulators go to the lowest setting to ensure the current drawn from the battery is quickly reduced to a safe level. The MAX8834Y/MAX8834Z
then start increasing the FLED1 and FLED2 current by one LSB steps, at a time interval set by HC_TMR[1:0] (see Table 11). The increasing continues until either the predefined FLED1/FLED2 current setting is reached or the input current exceeds the maximum predefined input current limit during a GSMB event. When the input current exceeds the predefined input current limit, the FLED1/FLED2 current is reduced by one LSB. The MAX8834Y/MAX8834Z continue to adjust the FLED1 and FLED2 up and down depending on the input current limit as long as the GSMB event is present. See Figure 10 for more detailed information.
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Adaptive Step-Up Converters with 1.5A Flash Driver
To use this feature, connect the logic signal used to enable the PA, or equivalent, to the GSMB input. Assertion of this signal does not change the current status of the flash safety timer or the flash current values stored in the I2C registers. Once the signal is deasserted, the current regulators change back to their previously programmed values. Polarity of this signal is controlled through bit 6 in the GSMB_CUR register (Table 11). The default is active-high. plus a predefined hysteresis (V LB_HYS ). If it is still below VLB_TH + VLB_HYS, the FLED1/FLED2 current regulators reduce their output current again to ensure that minimum input voltage is available for the system. If the input voltage is above VLB_TH + VLB_HYS, the current regulator increases the output current by one step (if it is less than the user-defined output current). To disable the hysteresis, set LB_HYS[1:0] to 11. In this case, after the FLED1/FLED2 current is reduced, it stays at the current setting. Figures 12, 13, and 14 show examples of MAXFLASH function operation. See Tables 12 and 13 for control register details. The MAXFLASH function continues for the entire duration of the FLASH/MOVIE event to ensure that the FLASH/MOVIE output current is always maximized for the specific operating conditions.
MAX8834Y/MAX8834Z
Finger-Burn Protection (NTC)
An NTC input is provided for the (optional) finger-burn protection feature. To use this feature, connect a 100k NTC with B = 4550 between NTC and AGND. NTC sources 20A current and the voltage established by this current and the NTC resistance is compared internally to a voltage threshold in the range of 200mV to 550mV, programmed through bits [2:0] of the NTC Control register (see Table 10). If the voltage on the NTC pin falls below the programmed threshold during a flash event, the flash cycle is immediately terminated, and an indication is latched through bit 3 in the STATUS1 register (see Table 15). To disable this function, clear bit 3 (enable bit) in the NTC Control register.
Undervoltage Lockout
The MAX8834Y/MAX8834Z contain undervoltage lockout (UVLO) circuitry that disables the IC until VIN is greater than 2.3V (typ). Once V IN rises above 2.3V (typ), the UVLO circuitry does not disable the IC until VIN falls below the UVLO threshold minus the hysteresis voltage. The MAX8834Y/MAX8834Z also contain a VDD UVLO circuitry that monitors the VDD voltage. When the VDD voltage falls below 1.4V (typ), the contents of all the logic registers are reset to their default states. The logic registers are only reset in a VDD UVLO condition and not an IN UVLO condition.
MAXFLASH Function
During high load currents, the battery voltage momentarily drops due to its internal ESR, together with the serial impedance from the battery to the load. For equipment requiring a minimum voltage for stable operation, the battery ESR needs to be calculated to estimate the maximum battery current that maintains the battery voltage above the critical threshold. Due to the complicated measurement of the battery ESR, the MAX8834Y/MAX8834Z feature the MAXFLASH function to prevent the battery voltage from dropping below the threshold voltage. See Figure 11 for details. The MAX8834Y/MAX8834Z input voltage is monitored during a FLASH/MOVIE event. If the input voltage drops below a predefined threshold (VLB_TH), it indicates that the FLASH/MOVIE event is drawing more current than the battery can support. As a result, the FLED1/FLED2 current regulators start decreasing their output currents by one step. Therefore, the input current is reduced and the input voltage starts to rise due to the internal battery ESR. The input voltage is then sampled again after tLB_TMR and compared to VLB_TH
tLB_TMR IN
IOUT_MAX
DOWN
VLB_TH
CURRENT REGULATOR UP
VLB_HYS VLB_TH
Figure 11. Block Diagram of MAXFLASH Function
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Adaptive Step-Up Converters with 1.5A Flash Driver MAX8834Y/MAX8834Z
VLB_TH + VLB_HYS
VLB_TH
tLB_TMR TIME
Figure 12. Example 1 of MAXFLASH Function Operation
REDUCTION IN BATTERY CURRENT CAUSED BY OTHER SYSTEM
VLB_TH + VLB_HYS
VLB_TH
IMAX
tLB_TMR
TIME
Figure 13. Example 2 of MAXFLASH Function Operation
REDUCTION IN BATTERY CURRENT CAUSED BY OTHER SYSTEM
FLASH CURRENT IS NOT INCREASED AGAIN SINCE LB_HYS = 11
VLB_TH + VLB_HYS
VLB_TH
IMAX
tLB_TMR TIME
Figure 14. Example 3 of MAXFLASH Function Operation with Hysteresis Disabled
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FLASH/MOVIE CURRENT
BATTERY VOLTAGE
FLASH/MOVIE CURRENT
BATTERY VOLTAGE
FLASH/MOVIE CURRENT
BATTERY VOLTAGE
Adaptive Step-Up Converters with 1.5A Flash Driver
Soft-Start
The step-up converter implements a soft-start to control inrush current when it turns on. It soft-starts by charging CCOMP with a 100A current source. During this time, the internal MOSFET is switching at the minimum duty cycle. Once V COMP rises above 1V, the duty cycle increases until the output voltage reaches the desired regulation level. COMP is pulled to AGND with a 180 (typ) internal resistor during IN, UVLO, dropout mode, or shutdown. See the Typical Operating Characteristics for an example of soft-start operation. Soft-start is reinitiated after UVLO or if the step-up converter is reenabled after shutdown or dropout mode. FLED2 regulators must be disabled through I 2 C to avoid a fault detection from an open or short.
MAX8834Y/MAX8834Z
Open/Short Detection
The MAX8834Y/MAX8834Z monitor the FLED1, FLED2, and INDLED voltage to detect any open or short LEDs. A short fault is detected when the voltage rises above VOUT - 1V (typ), and an open fault is detected when the voltage falls below 100mV. The fault detection circuitry is only activated when the corresponding current regulator is enabled and provides a continuous monitor of the current regulator condition. Once a fault is detected, the corresponding current regulator is disabled and the status is latched into the corresponding fault register bit (see Table 15). This allows the processor to determine the MAX8834Y/MAX8834Z operating condition.
Shutdown and Standby
The MAX8834Y/MAX8834Z are in shutdown when either VIN or VDD are in UVLO. In shutdown, supply current is reduced to 0.1A (typ). When VIN is above its UVLO threshold, but VDD is below its UVLO threshold, the IC disables its internal reference, keeps all registers reset, turns the step-up converter off, and turns the FLED1/FLED2 current regulators off (high impedance). Once a logic-level voltage is supplied to VDD, the IC enters standby condition and is ready to accept I2C commands. The internal MOSFET, synchronous rectifier, and FLED1/FLED2 are also high impedance in standby. Typical shutdown timing characteristics are shown in the Typical Operating Characteristics.
Thermal Shutdown
Thermal shutdown limits total power dissipation in the MAX8834Y/MAX8834Z. When the junction temperature exceeds +160C (typ), the IC turns off, allowing itself to cool. The IC turns on and begins soft-start after the junction temperature cools by 20C. This results in a pulsed output during continuous thermal overload conditions.
Parallel Connection of Current Regulators
The FLED1/FLED2 current regulators can be connected in parallel as long as the system software properly sets the current levels for each regulator. Unused current regulators may be connected to ground. The FLED1/
I2C Serial Interface An I2C-compatible, 2-wire serial interface controls the step-up converter output voltage, flash, movie, and indicator current settings, flash duration, and other parameters. The serial bus consists of a bidirectional serial-data line (SDA) and a serial-clock input (SCL). The MAX8834Y/MAX8834Z are slave-only devices, relying upon a master to generate a clock signal. The master initiates data transfer to and from the MAX8834Y/
SDA tSU,STA tHD,DAT tHIGH tBUF tHD,STA tSU,STO
tLOW
tSU,DAT
SCL tHD,STA tR START CONDITION
tF REPEATED START CONDITION STOP CONDITION START CONDITION
Figure 15. 2-Wire Serial Interface Timing Detail
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Adaptive Step-Up Converters with 1.5A Flash Driver MAX8834Y/MAX8834Z
SCL
SDA
START CONDITION (S)
DATA LINE STABLE DATA VALID
DATA ALLOWED TO CHANGE
STOP CONDITION (P)
Figure 16. Bit Transfer
MAX8834Z and generates SCL to synchronize the data transfer (Figure 15). I2C is an open-drain bus. Both SDA and SCL are bidirectional lines, connected to a positive supply voltage through a pullup resistor. They both have Schmitt triggers and filter circuits to suppress noise spikes on the bus to assure proper device operation. A bus master initiates communication with the MAX8834Y/MAX8834Z as a slave device by issuing a START (S) condition followed by the MAX8834Y/ MAX8834Z address. The MAX8834Y/MAX8834Z address byte consists of 7 address bits and a read/ write bit (R/W). After receiving the proper address, the MAX8834Y/MAX8834Z issue an acknowledge bit by pulling SDA low during the ninth clock cycle.
START and STOP Conditions Both SCL and SDA remain high when the bus is not busy. The master signals the beginning of a transmission with a START (S) condition by transitioning SDA from high to low while SCL is high. When the master has finished communicating with the MAX8834Y/ MAX8834Z, it issues a STOP (P) condition by transitioning SDA from low to high while SCL is high. The bus is then free for another transmission (Figure 17). Both START and STOP conditions are generated by the bus master. Acknowledge The acknowledge bit is used by the recipient to handshake the receipt of each byte of data (Figure 18). After data transfer, the master generates the acknowledge clock pulse and the recipient pulls down the SDA line during this acknowledge clock pulse so the SDA line stays low during the high duration of the clock pulse. When the master transmits the data to the MAX8834Y/MAX8834Z, it releases the SDA line and the MAX8834Y/MAX8834Z take control of the SDA line and generate the acknowledge bit. When SDA remains high during this 9th clock pulse, this is defined as the not acknowledge signal. The master can then generate either a STOP condition to abort the transfer, or a repeated START condition to start a new transfer.
Slave Address The MAX8834Y/MAX8834Z act as a slave transmitter/ receiver. Its slave address is 0x94 for write operations and 0x95 for read operations. Bit Transfer Each data bit, from the most significant bit to the least significant bit, is transferred one by one during each clock cycle. During data transfer, the SDA signal is allowed to change only during the low period of the SCL clock and it must remain stable during the high period of the SCL clock (Figure 16).
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Adaptive Step-Up Converters with 1.5A Flash Driver MAX8834Y/MAX8834Z
SDA BY MASTER D7 SDA NOT ACKNOWLEDGE SDA BY SLAVE D6 D0
SCL
SCL 1 2
ACKNOWLEDGE 8 9
START CONDITION
STOP CONDITION
START CONDITION
CLOCK PULSE FOR ACKNOWLEDGEMENT
Figure 17. START and STOP Conditions
Figure 18. Acknowledge
Write Operations The MAX8834Y/MAX8834Z recognize the write byte protocol as defined in the SMBusTM specification and shown in section A of Figure 19. The write byte protocol allows the I2C master device to send 1 byte of data to the slave device. The write-byte protocol requires a register pointer address for the subsequent write. The MAX8834Y/MAX8834Z acknowledge any register pointer even though only a subset of those registers actually exists in the device. The write byte protocol is as follows: 1) The master sends a start command.
2) The master sends the 7-bit slave address followed by a write bit. 3) The addressed slave asserts an acknowledge by pulling SDA low. 4) The master sends an 8-bit register pointer. 5) The slave acknowledges the register pointer. 6) The master sends a data byte. 7) The slave updates with the new data. 8) The slave acknowledges the data byte. 9) The master sends a STOP (P) condition. In addition to the write-byte protocol, the MAX8834Y/ MAX8834Z can write to multiple registers as shown in section B of Figure 19. This protocol allows the I2C master device to address the slave only once and then send data to a sequential block of registers starting at the specified register pointer.
Use the following procedure to write to a sequential block of registers: 1) The master sends a start command. 2) The master sends the 7-bit slave address followed by a write bit. 3) The addressed slave asserts an acknowledge by pulling SDA low. 4) The master sends the 8-bit register pointer of the first register to write. 5) The slave acknowledges the register pointer. 6) The master sends a data byte. 7) The slave updates with the new data. 8) The slave acknowledges the data byte. 9) Steps 6 to 8 are repeated for as many registers in the block, with the register pointer automatically incremented each time. 10) The master sends a STOP condition.
Read Operations The method for reading a single register (byte) is shown in section A of Figure 20. To read a single register: 1) The master sends a start command.
2) The master sends the 7-bit slave address followed by a write bit. 3) The addressed slave asserts an acknowledge by pulling SDA low. 4) The master sends an 8-bit register pointer.
SMBus is a trademark of Intel Corp.
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Adaptive Step-Up Converters with 1.5A Flash Driver MAX8834Y/MAX8834Z
LEGEND MASTER TO SLAVE SLAVE TO MASTER
A. WRITING TO A SINGLE REGISTER WITH THE WRITE BYTE PROTOCOL
1 S
7 SLAVE ADDRESS R/W
1 0
1 A
8 REGISTER POINTER
1 A
8 DATA
1 A
1 P
NUMBER OF BITS
B. WRITING TO MULTIPLE REGISTERS
1 S
7 SLAVE ADDRESS R/W
1 0
1 A
8 REGISTER POINTER X
1 A
8 DATA X
1 A
8 DATA X+1
1 A ...
NUMBER OF BITS
8 ... DATA X+n-1
1 A
8 DATA X+n
1 AP
NUMBER OF BITS
Figure 19. Writing to the MAX8834Y/MAX8834Z
5) The slave acknowledges the register pointer. 6) The master sends a REPEATED START (Sr) condition. 7) The master sends the 7-bit slave address followed by a read bit. 8) The slave asserts an acknowledge by pulling SDA low. 9) The slave sends the 8-bit data (contents of the register). 10) The master asserts an acknowledge by pulling SDA low. 11) The master sends a STOP (P) condition. In addition, the MAX8834Y/MAX8834Z can read a block of multiple sequential registers as shown in section B of Figure 20. Use the following procedure to read a sequential block of registers: 1) The master sends a start command. 2) The master sends the 7-bit slave address followed by a write bit.
3) The addressed slave asserts an acknowledge by pulling SDA low. 4) The master sends an 8-bit register pointer of the first register in the block. 5) The slave acknowledges the register pointer. 6) The master sends a REPEATED START condition. 7) The master sends the 7-bit slave address followed by a read bit. 8) The slave asserts an acknowledge by pulling SDA low. 9) The slave sends the 8-bit data (contents of the register). 10) The master asserts an acknowledge by pulling SDA low. 11) Steps 9 and 10 are repeated for as many registers in the block, with the register pointer automatically incremented each time. 12) The master sends a STOP condition.
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Adaptive Step-Up Converters with 1.5A Flash Driver MAX8834Y/MAX8834Z
LEGEND MASTER TO SLAVE SLAVE TO MASTER
A. READING A SINGLE REGISTER
1 S
7 SLAVE ADDRESS R/W
1 0
1 A
8 REGISTER POINTER
1
1
8 SLAVE ADDRESS
1 1
1 A
8 DATA
1 A
1 P
NUMBER OF BITS
A Sr
B. READING MULTIPLE REGISTERS
1 S
7 SLAVE ADDRESS R/W
1 0
1 A
8 REGISTER POINTER X
1 A
1 Sr
8 SLAVE ADDRESS R/W
11 1 A
8 DATA X+1
1 A ...
NUMBER OF BITS
8 ... DATA X+1
1 A ...
8 DATA X+n-1
1 A
8 DATA X+n
1
1
NUMBER OF BITS
AP
Figure 20. Reading from the MAX8834Y/MAX8834Z
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23
Adaptive Step-Up Converters with 1.5A Flash Driver MAX8834Y/MAX8834Z
Table 1. Register Map
NAME BOOST_CNTL FLASH1_CUR FLASH2_CUR MOVIE_CUR Reserved for future use IND_CUR Reserved for future use IND_CNTL Reserved for future use LED_CNTL TMR_DUR NTC_CNTL GSMB_CUR MAXFLASH1 MAXFLASH2 WDT_RST STATUS1 STATUS2 Reserved for future use CHIP_ID1 CHIP_ID2 TABLE Table 2 Table 3 Table 4 Table 5 -- Table 6 -- Table 7 -- Table 8 Table 9 Table 10 Table 11 Table 12 Table 13 Table 14 Table 15 Table 16 -- Table 17 Table 18 REGISTER ADDRESS (hex) 00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 16 17 18 19 1A 1B TYPE R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R R R/W R R DESCRIPTION Step-up converter control FLED1 flash current control FLED2 flash current control FLED1 and FLED2 movie current control Reserved for future use Indicator LED current control Reserved for future use Indicator LED ramp and blink control Reserved for future use FLED1, FLED2, and INDLED on/off and mode control, and definition of LED_EN logic input function Watchdog timer and flash safety timer control NTC function control FLED1 and FLED2 current control during GSM transmit MAXFLASH function register 1 MAXFLASH function register 2 Watchdog timer reset Status register Status register Reserved for future use Die type information Die type and mask revision information
24
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Adaptive Step-Up Converters with 1.5A Flash Driver MAX8834Y/MAX8834Z
Table 2. BOOST_CNTL
This register contains step-up converter control values.
REGISTER NAME Address Reset Value Type Special Features BOOST_CNTL 0x00 0x00 Read/write --
BIT B7 (MSB) B6 B5
NAME -- BOOST_EN Reserved for future use 0 = Step-up converter off 1 = Step-up converter on
DESCRIPTION
DEFAULT VALUE 0 0
BOOST_MODE B4
00 = Step-up voltage set adaptively 01 = Step-up voltage set programmatically according to BOOST_CNTL[3:0] 10 = Step-up converter runs in dropout 11 = Step-up converter automatically changes between adaptive regulation and dropout mode depending on operating conditions 0000 0001 0010 0011 0100 0101 0110 0111 1000 1001 1010 1011 1100 1101 1110 1111 = = = = = = = = = = = = = = = = 3.7V 3.8V 3.9V 4.0V 4.1V 4.2V 4.3V 4.4V 4.5V 4.6V 4.7V 4.8V 4.9V 5.0V 5.1V 5.2V
00
B3
B2 BOOST_CNTL[3:0] B1
0000
B0 (LSB)
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25
Adaptive Step-Up Converters with 1.5A Flash Driver MAX8834Y/MAX8834Z
Table 3. FLASH1_CUR
This register contains FLED1 flash current control values.
REGISTER NAME Address Reset Value Type Special Features FLASH1_CUR 0x01 0x00 Read/write --
BIT
NAME
DESCRIPTION FLED1 Flash Mode Current Setting 00000 = 23.44mA 00001 = 46.88mA 00010 = 70.32mA 00011 = 93.76mA 00100 = 117.20mA 00101 = 140.64mA 00110 = 164.08mA 00111 = 187.52mA 01000 = 210.96mA 01001 = 234.40mA 01010 = 257.84mA 01011 = 281.28mA 01100 = 304.72mA 01101 = 328.16mA 01110 = 351.60mA 01111 = 375.04mA 10000 = 398.48mA 10001 = 421.92mA 10010 = 445.36mA 10011 = 468.80mA 10100 = 492.24mA 10101 = 515.68mA 10110 = 539.12mA 10111 = 562.56mA 11000 = 586.00mA 11001 = 609.44mA 11010 = 632.88mA 11011 = 656.32mA 11100 = 679.76mA 11101 = 703.20mA 11110 = 726.56mA 11111 = 750.00mA Reserved for future use Reserved for future use Reserved for future use
DEFAULT VALUE
B7 (MSB)
B6
B5
FLASH1[4:0]
00000
B4
B3
B2 B1 B0 (LSB)
-- -- --
-- -- --
26
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Adaptive Step-Up Converters with 1.5A Flash Driver MAX8834Y/MAX8834Z
Table 4. FLASH2_CUR
This register contains FLED2 flash current control values.
REGISTER NAME Address Reset Value Type Special Features FLASH2_CUR 0x02 0x00 Read/write --
BIT
NAME
DESCRIPTION FLED2 Flash Mode Current Setting 00000 = 23.44mA 00001 = 46.88mA 00010 = 70.32mA 00011 = 93.76mA 00100 = 117.20mA 00101 = 140.64mA 00110 = 164.08mA 00111 = 187.52mA 01000 = 210.96mA 01001 = 234.40mA 01010 = 257.84mA 01011 = 281.28mA 01100 = 304.72mA 01101 = 328.16mA 01110 = 351.60mA 01111 = 375.04mA 10000 = 398.48mA 10001 = 421.92mA 10010 = 445.36mA 10011 = 468.80mA 10100 = 492.24mA 10101 = 515.68mA 10110 = 539.12mA 10111 = 562.56mA 11000 = 586.00mA 11001 = 609.44mA 11010 = 632.88mA 11011 = 656.32mA 11100 = 679.76mA 11101 = 703.20mA 11110 = 726.56mA 11111 = 750.00mA Reserved for future use Reserved for future use Reserved for future use
DEFAULT VALUE
B7 (MSB)
B6
B5
FLASH2[4:0]
00000
B4
B3
B2 B1 B0 (LSB)
-- -- --
-- -- --
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27
Adaptive Step-Up Converters with 1.5A Flash Driver MAX8834Y/MAX8834Z
Table 5. MOVIE_CUR
This register contains FLED1 and FLED2 movie current control values.
REGISTER NAME Address Reset Value Type Special Features MOVIE_CUR 0x03 0x00 Read/write --
BIT B7 (MSB) B6
NAME -- Reserved for future use
DESCRIPTION FLED1 Movie Mode Current Setting 000 = 15.625mA 001 = 31.250mA 010 = 49.875mA 011 = 62.500mA 100 = 78.125mA 101 = 93.750mA 110 = 109.375mA 111 = 125.000mA Reserved for future use FLED2 Movie Mode Current Setting 000 = 15.625mA 001 = 31.250mA 010 = 49.875mA 011 = 62.500mA 100 = 78.125mA 101 = 93.750mA 110 = 109.375mA 111 = 125.000mA
DEFAULT NAME --
B5
MOVIE1[2:0]
000
B4 B3 B2 --
--
B1
MOVIE2[2:0]
000
B0 (LSB)
28
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Adaptive Step-Up Converters with 1.5A Flash Driver
Table 6. IND_CUR
This register contains indicator LED current control values.
REGISTER NAME Address Reset Value Type Special Features BIT B7 (MSB) B6 NAME -- IND_BL_EN Reserved for future use INDLED Indicator Blink Timer Enable 0 = Indicator blink is disabled 1 = Indicator blink is enabled INDLED Indicator Ramp-Up/Down Enable 0 = Indicator ramp-up/down is disabled 1= Indicator ramp-up/down is enabled INDLED Indicator Mode Current Setting 00000 = 0.5mA 00001 = 1.0mA 00010 = 1.5mA 00011 = 2.0mA 00100 = 2.5mA 00101 = 3.0mA 00110 = 3.5mA 00111 = 4.0mA 01000 = 4.5mA 01001 = 5.0mA 01010 = 5.5mA 01011 = 6.0mA 01100 = 6.5mA 01101 = 7.0mA 01110 = 7.5mA 01111 = 8.0mA 10000 = 8.5mA 10001 = 9.0mA 10010 = 9.5mA 10011 = 10.0mA 10100 = 10.5mA 10101 = 11.0mA 10110 = 11.5mA 10111 = 12.0mA 11000 = 12.5mA 11001 = 13.0mA 11010 = 13.5mA 11011 = 14.0mA 11100 = 14.5mA 11101 = 15.0mA 11110 = 15.5mA 11111 = 16.0mA IND_CUR 0x05 0x00 Read/write -- DESCRIPTION DEFAULT VALUE 0 0
MAX8834Y/MAX8834Z
B5
IND_RP_EN
0
B4
B3
B2
IND[4:0]
00000
B1
B0 (LSB)
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29
Adaptive Step-Up Converters with 1.5A Flash Driver MAX8834Y/MAX8834Z
Table 7. IND_CNTL
This register contains indicator LED ramp and blink timer control.
REGISTER NAME Address Reset Value Type Special Features BIT B7 (MSB) IND_OFF B6 B5 IND_ON B4 NAME IND_CNTL 0x07 0x00 Read/write -- DESCRIPTION INDLED Indicator Off Blink Timer Control 00 = 512ms 01 = 1024ms 10 = 2048ms 11 = 4096ms INDLED Indicator On Blink Timer Control 00 = 128ms 01 = 256ms 10 = 512ms 11 = 1024ms INDLED Indicator Ramp-Up Timer Control 00 = 128ms 01 = 256ms 10 = 512ms 11 = 1024ms INDLED Indicator Ramp-Down Timer Control 00 = 128ms 01 = 256ms 10 = 512ms 11 = 1024ms DEFAULT VALUE
00
00
B3 IND_RU[1:0] B2
00
B1 IND_RD[1:0] B0 (LSB)
00
30
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Adaptive Step-Up Converters with 1.5A Flash Driver MAX8834Y/MAX8834Z
Table 8. LED_CNTL
This register contains FLED1, FLED2 and INDLED on/off and mode control.
REGISTER NAME Address Reset Value Type Special Features BIT B7 (MSB) B6 IND_EN[1:0] NAME LED_CNTL 0x09 0x00 Read/write -- DESCRIPTION INDLED Indicator Current Regulator Enable 00 = INDLED indicator LED is disabled 01 = INDLED indicator LED is disabled 10 = INDLED indicator LED is enabled 11 = INDLED indicator LED is controlled by LED_EN input FLED1/FLED2 MOVIE Mode Current Regulator Enable 000 = FLED1 and FLED2 movie mode disabled 001 = FLED1 movie mode is enabled, FLED2 movie mode is disabled 010 = FLED2 movie mode is enabled, FLED1 movie mode is disabled 011 = FLED1 and FLED2 movie mode is enabled 101 = FLED1 movie mode is controlled by LED_EN, FLED2 movie mode is disabled 110 = FLED2 movie mode is controlled by LED_EN, FLED1 movie mode is disabled 111 = FLED1 and FLED2 movie mode is controlled by LED_EN FLED1/FLED2 Flash Mode Current Regulator Enable 000 = FLED1 and FLED2 flash mode disabled 001 = FLED1 flash mode is enabled, FLED2 flash mode is disabled 010 = FLED2 flash mode is enabled, FLED1 flash mode is disabled 011 = FLED1 and FLED2 flash mode is enabled 101 = FLED1 flash mode is controlled by LED_EN, FLED2 flash mode is disabled 110 = FLED2 flash mode is controlled by LED_EN, FLED1 flash mode is disabled 111 = FLED1 and FLED2 flash mode is controlled by LED_EN DEFAULT VALUE
00
B5
B4
MOVIE_EN[2:0]
000
B3
B2
B1
FLASH_EN[2:0]
000
B0 (LSB)
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31
Adaptive Step-Up Converters with 1.5A Flash Driver MAX8834Y/MAX8834Z
Table 9. TMR_DUR
This register contains watchdog timer and flash safety time-control values.
REGISTER NAME Address Reset Value Type Special Features BIT B7 (MSB) B6 B5 WDT_DUR[1:0] NAME WDT_EN TMR_DUR 0x0A 0x00 Read/write -- DESCRIPTION Enable/Disable Of Watchdog Timer Function 0 = WDT is disabled 1 = WDT is enabled Watchdog Timer Duration 00 = 4s 01 = 8s 10 = 12s 11 = 16s Safety Timer Control 0 = One-shot mode--generates a flash with a duration of TMR_DUR regardless of LED:EN and I2C setting; pulling VDD low in this condition terminates flash operating and puts the IC into power-down mode 1 = Maximum timer mode--ensures that flash duration does not exceed the timer defined in TMR:DUR Safety Timer Duration Control 0000 = 50ms 0001 = 100ms 0010 = 150ms 0011 = 200ms 0100 = 250ms 0101 = 300ms 0110 = 350ms 0111 = 400ms 1000 = 450ms 1001 = 500ms 1010 = 550ms 1011 = 600ms 1100 = 650ms 1101 = 700ms 1110 = 750ms 1111 = 800ms DEFAULT VALUE 0
00
B4
TMR_MODE
0
B3
B2 TMR_DUR [3:0] B1
0000
B0 (LSB)
32
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Adaptive Step-Up Converters with 1.5A Flash Driver MAX8834Y/MAX8834Z
Table 10. NTC_CNTL
This register contains NTC function control values.
REGISTER NAME Address Reset Value Type Special Features BIT NAME NTC_CNTL 0x0B 0x00 Read/write -- DESCRIPTION DEFAULT VALUE
B7 (MSB)
B6 B5 B4 B3
Flash Safety Timer Reset Control 0 = Enable FLASH reset timer, only valid when FLASH mode is enabled using the LED_EN; LED_EN needs to be pulled low for FLASH_TMR_CNTL minimum 30ms (typ) to reset the flash safety 1 = Disable FLASH reset timer; flash safety timer is reset as soon as LED_EN is pulled low -- Reserved for future use -- -- NTC_EN Reserved for future use Reserved for future use Finger-Burn Feature Enable 0 = Disable NTC function 1 = Enable NTC function Finger-Burn Threshold Control 000 = 200mV 001 = 250mV 010 = 300mV 011 = 350mV 100 = 400mV 101 = 450mV 110 = 500mV 111 = 550mV
0
0 0 0 0
B2
B1
NTC[2:0]
000
B0 (LSB)
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33
Adaptive Step-Up Converters with 1.5A Flash Driver MAX8834Y/MAX8834Z
Table 11. GSMB_CUR
This register contains FLED1 and FLED2 current control values for the GSMB function.
REGISTER NAME Address Reset Value Type Special Features BIT B7 (MSB) NAME GSMB_EN GSM Blank Enable 0 = GSMB input is disabled 1 = GSMB input is enabled GSM Blank Polarity Control 0 = GSMB is active-low 1 = GSMB is active-high Input Current Limit During GSMB 0000 = 50mA 0001 = 100mA 0010 = 150mA 0011 = 200mA 0100 = 250mA 0101 = 300mA 0110 = 350mA 0111 = 400mA 1000 = 450mA 1001 = 500mA 1010 = 550mA 1011 = 600mA 1100 = 650mA 1101 = 700mA 1110 = 750mA 1111 = 800mA GSMB Reset Timer 00 = 10s 01 = 20s 10 = 40s 11 = 80s GSMB_CUR 0x0C 0xC0 Read/write -- DESCRIPTION DEFAULT VALUE 1
B6
GSMB_POL
1
B5
B4 ILIM[3:0] B3
0000
B2
B1 HC_TMR[1:0] B0 (LSB)
00
34
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Adaptive Step-Up Converters with 1.5A Flash Driver
Table 12. MAXFLASH1
This register contains MAXFLASH control function.
REGISTER NAME Address Reset Value Type Special Features BIT B7 (MSB) NAME LB_EN MAXFLASH1 0x0D 0x00 Read/write -- DESCRIPTION MAXFLASH Function Enable 0 = Disabled 1 = Low-battery function is enabled Low-Battery Detection Threshold 00000 = 2.400V [Do not use] 00001 = 2.433V [Do not use] 00010 = 2.466V [Do not use] 00011 = 2.500V 00100 = 2.533V 00101 = 2.566V 00110 = 2.600V 00111 = 2.633V 01000 = 2.666V 01001 = 2.700V 01010 = 2.733V 01011 = 2.766V 01100 = 2.800V 01101 = 2.833V 01110 = 2.866V 01111 = 2.900V 10000 = 2.933V 10001 = 2.966V 10010 = 3.000V 10011 = 3.033V 10100 = 3.066V 10101 = 3.100V 10110 = 3.133V 10111 = 3.166V 11000 = 3.200V 11001 = 3.233V 11010 = 3.266V 11011 = 3.300V 11100 = 3.333V 11101 = 3.366V 11110 = 3.400V 11111 = 3.400V Low-Battery Detection Hysteresis 00 = 100mV 01 = 200mV 10 = Reserved for future use 11 = Hysteresis is disabled--flash current is only reduced DEFAULT VALUE 0
MAX8834Y/MAX8834Z
B6
B5
B4
LB_TH[4:0]
00000
B3
B2
B1 LB_HYS[1:0] B0 (LSB)
00
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35
Adaptive Step-Up Converters with 1.5A Flash Driver MAX8834Y/MAX8834Z
Table 13. MAXFLASH2
This register contains MAXFLASH control function.
REGISTER NAME Address Reset Value Type Special Features BIT B7 (MSB) B6 B4 B3 B3 B2 B1 LB_TMR[1:0] B0 (LSB) NAME -- -- -- -- -- -- Reserved for future use Reserved for future use Reserved for future use Reserved for future use Reserved for future use Reserved for future use Low-Battery Reset Timer 00 = 0.250ms 01 = 0.500ms 10 = Reserved for future use 11 = Reserved for future use MAXFLASH2 0x0E 0x00 Read/write -- DESCRIPTION DEFAULT VALUE 0 0 0 0 0 0
00
Table 14. WDT_RST
This register contains watchdog reset function.
REGISTER NAME Address Reset Value Type Special Features BIT B7 (MSB) B6 B4 B3 B3 B2 B1 NAME -- -- -- -- -- -- -- Reserved for future use Reserved for future use Reserved for future use Reserved for future use Reserved for future use Reserved for future use Reserved for future use Watchdog Reset 0 = Default 1 = Writing a 1 resets the watchdog timer; after writing a 1, this bit is cleared upon watchdog timer reset WDT_RST 0x16 0x00 Read/write -- DESCRIPTION DEFAULT VALUE 0 0 0 0 0 0 0
B0 (LSB)
--
--
36
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Adaptive Step-Up Converters with 1.5A Flash Driver MAX8834Y/MAX8834Z
Table 15. STATUS1
This register contains status information.
REGISTER NAME Address Reset Value Type Special Features BIT B7 (MSB) NAME NTC_FLT STATUS1 0x17 N/A Read -- DESCRIPTION NTC Status Readback 0 = NTC status OK 1 = Fault (short) occurred on NTC GSMB Status Readback 0 = No GSMB event has occurred 1 = GSMB event has occurred POK Window Cooperator Status Readback 0 = Output voltage is within POK window 1 = POK fault has occurred Die Temperature Overload Condition Status Readback 0 = Die temp is within spec 1 = Die overtemp event has occurred NTC Status Readback 0 = NTC temperature is within spec 1 = NTC temperature threshold has tripped INDLED Status Readback 0 = INDLED status is OK 1 = Fault (open/short) has occurred on INDLED FLED2 Status Readback 0 = FLED2 status is OK 1 = Fault (open/short) has occurred on FLED2 FLED1 Status Readback 0 = FLED1 status is OK 1 = Fault (open/short) has occurred on FLED1 DEFAULT VALUE 0
B6
GSMB
0
B5
POK_FLT
0
B4
OVER_TEMP
0
B3
NTC_OVT
0
B2
INDLED_FLT
0
B1
FLED2_FLT
0
B0 (LSB)
FLED1_FLT
0
Note: All faults are latched. Bit(s) are cleared after reading register contents. If the fault is still present, the bit is set again.
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37
Adaptive Step-Up Converters with 1.5A Flash Driver MAX8834Y/MAX8834Z
Table 16. STATUS2
This register contains status information.
REGISTER NAME Address Reset Value Type Special Features BIT NAME STATUS2 0x18 N/A Read -- DESCRIPTION Indication of if MAXFLASH Function Has Been Triggered Since Last Read Operation of This Register 0 = MAXFLASH event has not occurred 1 = MAXFLASH event has occurred Indication of if Input Current Limit Has Been Reached During GSMB Since Last Read Operation of This Register 0 = Input current limit not reached 1 = Input current limit reached Reserved for future use Reserved for future use Reserved for future use Reserved for future use Reserved for future use Reserved for future use DEFAULT VALUE
B7 (MSB)
MAXFLASH_STAT
0
B6 B5 B4 B3 B2 B1 B0 (LSB)
GSMB_ILIM -- -- -- -- -- --
0 0 0 0 0 0 0
Table 17. CHIP_ID1
This register contains the MAX8834Y/MAX8834Z die type number.
REGISTER NAME Address Reset Value Type Special Features BIT B7 (MSB) B6 B5 B4 B3 B2 B1 B0 (LSB) DIE_TYPE[3:0] BCD Character 1 [0001] DIE_TYPE[7:4] BCD Character 1 [0001] NAME CHIP_ID1 0x1A N/A Read -- DESCRIPTION DEFAULT VALUE
Note: This register value is fixed in metal.
38
______________________________________________________________________________________
Adaptive Step-Up Converters with 1.5A Flash Driver MAX8834Y/MAX8834Z
Table 18. CHIP_ID2
This register contains the die type dash number (0 = plain) and mask revision level.
REGISTER NAME Address Reset Value Type Special Features BIT B7 (MSB) B6 B5 B4 B3 B2 B1 B0 (LSB) MASK_REV BCD Character representing die revision -- DASH BCD Character representing dash number -- NAME CHIP_ID2 0x1B N/A Read -- DESCRIPTION DEFAULT VALUE
Applications Information
Inductor Selection
See Table 19 for a list of recommended inductors. To prevent core saturation, ensure that the inductor saturation current rating exceeds the peak inductor current for the application. Calculate the worst-case peak inductor current as follows: IPEAK = VOUT x IOUT(MAX) 0.9 x VIN(MIN) + VIN(MIN) 2 x fSW x L
most situations, but a 4.7F ceramic capacitor is acceptable for lower load currents.
Compensation Network Selection
The step-up converter is compensated for stability through an external compensation network from COMP to AGND. See Table 20 for recommended compensation networks.
PCB Layout
Due to fast-switching waveforms and high-current paths, careful PCB layout is required. Connect AGND, FGND, and PGND directly to the ground plane. The IN bypass capacitor should be placed as close as possible to the IC. RCOMP and CCOMP should be connected between COMP and AGND as close as possible to the IC. Minimize trace lengths between the IC and the inductor, the input capacitor, and the output capacitor; keep these traces short, direct, and wide. The ground connections of C IN and C OUT should be as close together as possible and connected to PGND. The traces from the input to the inductor and from the output capacitor to the LEDs may be longer. Figure 21 illustrates an example PCB layout and routing scheme. Refer to the MAX8834Y/MAX8834Z Evaluation Kit for a PCB layout example.
where fSW is the switching frequency.
Capacitor Selection
Bypass IN to AGND and PGND with a ceramic capacitor. Ceramic capacitors with X5R and X7R dielectrics are recommended for their low ESR and tighter tolerances over wide temperature ranges. Place the capacitor as close as possible to the IC. The recommended minimum value for the input capacitor is 10F; however, larger value capacitors can be used to reduce input ripple at the expense of size and higher cost. The output capacitance required depends on the output current. A 10F ceramic capacitor works well in
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39
Adaptive Step-Up Converters with 1.5A Flash Driver MAX8834Y/MAX8834Z
Table 19. Suggested Inductors
MANUFACTURER PART/SERIES LPS4012-222ML LPS4018-222ML LPS5030-220ML LPS6225-222ML LPO3310-102ML LPS3015-102ML Coilcraft LPO3010-102NLC DO3314-102ML LPS3314-102ML DP1605T-102ML LPS4012-102ML LPS4018-102ML LPS5015-102ML NR4018T2R2M NR3012T1R0N NR4010T1R0N Taiyo Yuden NR3015T1R0N NR4012T1R0N NP03SB1R0M NP04SZB1R0N NR4018T1R0N 1117AS-1R2N 1098AS-1R2N TOKO A997AS-1R0N 1072AS-1R0N 1071AS-1R0N INDUCTANCE (H) 2.2 2.2 2.2 2.2 1 1 1 1 1 1 1 1 1 2.2 1 1 1 1 1 1 1 1.2 1.2 1 1 1 DCR (m ) 100 70 57 45 76 75 140 110 45 40 60 40 50 72 60 120 36 72 27 30 36 65 56 40 30 40 ISAT (A) 2.3 2.7 3.1 3.9 1.6 1.6 1.7 2.1 2.3 2.5 2.8 2.8 3.8 2.7 1.5 1.8 2.1 2.5 2.6 4 4 1.2 1.8 1.8 1.95 2.1 DIMENSIONS (lTYP x W TYP x HMAX) (mm) 4 x 4 x 1.1 4 x 4 x 1.7 5 x 5 x 2.9 6.2 x 6.2 x 2.5 3x3x1 3x3x1 3x3x1 3 x 3 x 1.4 3 x 3 x 1.4 4 x 4 x 1.8 4 x 4 x 1.1 4 x 4 x 1.7 5 x 5 x 1.5 4 x 4 x 1.8 3 x 3 x 1.2 4x4x1 3 x 3 x 1.5 4 x 4 x 1.2 4 x 4 x 1.8 5x5x2 4 x 4 x 1.8 3x3x1 3 x 3 x 1.2 4 x 4 x 1.8 3 x 3 x 1.8 3 x 3 x 1.5
Table 20. Suggested Compensation Networks
INDUCTANCE 1.0H Inductor (dynamic loads) 2.2H Inductor (dynamic loads) 4.7H Inductor (dynamic loads) 10H Inductor (dynamic loads) Other (non-LED) Loads (1H to 10H) RCOMP (k ) 5.5 4.3 3 3 0 (short) CCOMP (pF) 2200 2200 4700 6800 22000
40
______________________________________________________________________________________
Adaptive Step-Up Converters with 1.5A Flash Driver MAX8834Y/MAX8834Z
L
6.0mm
COUT
CIN
OUT A1 OUT B1 COMP CCOMP C1 FLED2 FLASH2 LED CATHODE D1
LX A2 LX B2 FGND C2 FGND D2
PGND A3 PGND B3 LED_EN C3 FLED1 D3
IN A4 SCL B4 GSMB C4 INDLED D4
VDD A5 AGND B5 SDA C5 NTC D5 CVDD
FLASH1 LED CATHODE INDICATOR LED CATHODE
3.8mm
Figure 21. Recommended PCB Layout
______________________________________________________________________________________
41
Adaptive Step-Up Converters with 1.5A Flash Driver MAX8834Y/MAX8834Z
Block Diagram and Typical Application Circuit
1H
LX IN INPUT CURRENT LIMIT
OUT
PROGRAMMABLE OUTPUT 3.7V TO 5.2V COUT 10F
VIN 2.5V TO 5.5V
CIN 10F AGND PGND COMP CCOMP RCOMP
UVLO AND POWER
PWM STEP-UP CONVERTER ADAPTIVE/ FIXED OUTPUT SELECT VREF SELECT MIN
2MHz OR 4MHz
VREG
FLASH TIMER WATCHDOG TIMER REGISTERS AND CONTROL LOGIC SAMPLING LOGIC
VPOK 750mA FLED1
NTC RNTC 100k VLOGIC 1.62V TO 3.6V FLASH/MOVIE LED_EN STROBE VDD CVDD 0.1F SDA SCL GSMB PA_EN 1MHz
750mA
FLED2
16mA INDLED
FGND
I2 C INTERFACE
I2C INTERFACE
MAX8834Y MAX8834Z
42
______________________________________________________________________________________
Adaptive Step-Up Converters with 1.5A Flash Driver
Pin Configuration
PROCESS: BiCMOS
TOP VIEW (BUMPS ON BOTTOM) 1 2 3 4 5
Chip Information Package Information
For the latest package outline information and land patterns, go to www.maxim-ic.com/packages.
MAX8834Y/MAX8834Z
MAX8834Y/MAX8834Z
A A1 OUT A2 LX A3 PGND A4 IN A5 VDD
PACKAGE TYPE 20 WLP
PACKAGE CODE W202A2+2
DOCUMENT NO. 21-0059
B
B1 OUT
B2 LX
B3 PGND
B4 SCL
B5 AGND
C
C1 COMP
C2 FGND
C3 LED_EN
C4 GSMB
C5 SDA
D
D1 FLED2
D2 FGND
D3 FLED1 WLP (2.5mm x 2.0mm)
D4 INDLED
D5 NTC
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 ____________________ 43
(c) 2009 Maxim Integrated Products Maxim is a registered trademark of Maxim Integrated Products, Inc.

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