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19-1254; Rev 0; 7/97
L MANUA ION KIT ALUAT DATA SHEET EV WS FOLLO
3.3V/5V or Adjustable, Step-Up/Down DC-DC Converters
____________________________Features
o Step-Up/Down Voltage Conversion o +1.8V to +11V Input Range o Output: 5V/250mA at VIN = 1.8V 5V/500mA at VIN = 3.6V o No External FETs Required o Load Disconnected from Input in Shutdown o Battery Drain: 200A No-Load (VIN = 4V) 7A in Standby 0.2A when Off o Low-Noise and High-Efficiency Modes
_______________General Description
The MAX710/MAX711 integrate a step-up DC-DC converter with a linear regulator to provide step-up/down voltage conversion. They are optimized for battery applications where the input varies above and below the regulated output voltage. They have an input range from +1.8V to +11V. Typical efficiency when boosting battery inputs is 85%. The MAX710/MAX711 can be configured for minimum noise or optimum efficiency. Shutdown control turns off the part completely, disconnecting the input from the output (ISHDN = 0.2A). Standby control turns off only the step-up converter and leaves the low-power linear regulator active (IQ = 7A). The MAX710 has a preset 3.3V or 5V output voltage. The MAX711 has an adjustable output that can be set from +2.7V to +5.5V with two resistors. Both devices come in 16-pin narrow SO packages.
MAX710/MAX711
________________________Applications
Single-Cell, Lithium-Powered Portable Devices Digital Cameras 2- to 4-Cell AA Alkaline Hand-Held Equipment 3.3V and Other Low-Voltage Systems 2-, 3-, and 4-Cell Battery-Powered Equipment Battery-Powered Devices with AC Input Adapters
______________Ordering Information
PART MAX710C/D MAX710ESE MAX711C/D MAX711ESE TEMP. RANGE 0C to +70C -40C to +85C 0C to +70C -40C to +85C PIN-PACKAGE Dice 16 Narrow SO Dice 16 Narrow SO
__________Typical Operating Circuit
+1.8V TO +11V INPUT C1 LBI+ ON STBY 3.3V OFF ON 5V SHDN STBY PS 3/5 OUT LBIREF C3 0.1F PGND GND ILIM C4 OUTPUT 3.3V/5V N/E LBO L1
__________________Pin Configuration
TOP VIEW
LX 1 PGND 2 C2 ILIM 3 SHDN 4 STBY 5 3/5 (FB) 6 N/E 7 LBO 8
16 LX 15 PGND 14 GND
MAX710
LX
MAX710 MAX711
13 REF 12 PS 11 LBI+ 10 LBI9 OUT
SO
( ) IS FOR THE MAX711.
________________________________________________________________ Maxim Integrated Products
1
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3.3V/5V or Adjustable, Step-Up/Down DC-DC Converters MAX710/MAX711
ABSOLUTE MAXIMUM RATINGS
PS, LX, OUT to GND............................................-0.3V to +11.5V ILIM, SHDN, STBY, FB, 3/5, N/E, LBO, LBI-, LBI+, REF to GND ...........................-0.3V to (VPS + 0.3V) PGND to GND .......................................................-0.3V to +0.3V REF Short Circuit to GND ...........................................Continuous IOUT ...................................................................................700mA Continuous Power Dissipation (TA = +70C) SO (derate 8.70mW/C above +70C) ..........................696mW Operating Temperature Range ...........................-40C to +85C Storage Temperature Range .............................-65C to +160C Junction Temperature ......................................................+150C Lead Temperature (soldering, 10sec) .............................+300C
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
(VPS = 5.6V, STBY = PS, CREF = 0.1F, COUT = 4.7F, TA = -40C to +85C, unless otherwise noted. Typical values are at TA = +25C.) (Note 1) PARAMETER Input Voltage Full Load Start-Up Voltage 3/5 = low, IOUT = 0 to 250mA 3/5 = high, IOUT = 0 to 250mA, VPS = 4.7V Output Voltage-Adjustment Range Output Voltage Load Regulation Output Voltage Line Regulation Quiescent Current Standby Quiescent Current Shutdown Quiescent Current Reference Voltage Standby Output Current FB Voltage Load Regulation FB Input Current LX On-Resistance LX Leakage Current LX Current Limit MAX711 0 < IOUT < 250mA, STBY = PS STBY = PS, 1.8V to 5V V STBY = V SHDN = logic high, current measured into PS pin; ILOAD = 0 V STBY = 0V V SHDN = 0V TA = 0C to +85C, IREF = 0 TA = -40C to +85C, IREF = 0 V STBY = 0V, linear regulator MAX711, OUT = FB MAX711, OUT = FB FB = 1.25V VPS = 5.6V MAX710, VPS = 3.7V MAX711, VPS = 2.7V VLX = 5.6V ILIM = PS ILIM = GND 0.5 1.1 TA = 0C to +85C TA = -40C to +85C 0mA ILOAD 250mA 1.20 1.18 1.25 1.25 0.1 1 0.2 0.3 0.6 0.1 0.8 1.5 1.24 1.23 TA = 0C to +85C TA = -40C to +85C TA = 0C to +85C TA = -40C to +85C 4.8 4.6 3.17 3.05 FB 0.5 0.3 100 7 0.1 1.28 1.28 140 16 5 1.31 1.32 10 1.29 1.31 1 50 0.6 0.9 1.2 1 1.3 1.95 A A N/E = PS N/E = GND (Note 2) CONDITIONS MIN 1.8 1.8 0.9 5.0 5.0 3.3 3.3 5.2 5.3 3.43 3.55 5.5 V % %/V A A A V mA mV % nA V TYP MAX 11.0 7.0 UNITS V V
Output Voltage (MAX710)
2
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3.3V/5V or Adjustable, Step-Up/Down DC-DC Converters
ELECTRICAL CHARACTERISTICS (continued)
(VPS = 5.6V, STBY = PS, CREF = 0.1F, COUT = 4.7F, TA = -40C to +85C, unless otherwise noted. Typical values are at TA = +25C.) (Note 1) PARAMETER VOUT = 5.0V Output PFET Resistance Output PFET Leakage Thermal Shutdown Thermal Shutdown Hysteresis LOGIC Input Low Voltage Input High Voltage Input Bias Current LBI/LBO COMPARATOR Input Range LBI-, LBI+ Input Bias Current LBI-, LBI+ Hysteresis LBI/LBO Offset Voltage LBO Output Voltage VLBI- = 1.25V ILBO = 2mA, VLBI- = 1.25V, VLBI+ = 1V ILBO = -300A, VLBI- = 1.25V, VLBI+ = 2V VPS - 0.2V (Note 3) VLBI-, VLBI+ = 1.25V 6 -25 1.2 1 40 10 50 100 +25 0.4 V nA mV mV V STBY, SHDN, N/E, 3/5, ILIM STBY, SHDN, N/E, 3/5, ILIM STBY, SHDN, N/E, 3/5, ILIM 1.6 1 50 0.4 V V nA MAX710, VOUT = 3.0V MAX711, VOUT = 2.7V VPS = 3V, VOUT = 0V STBY = PS STBY = PS CONDITIONS MIN TYP 0.7 1.3 1.6 0.4 150 20 MAX 1.3 2.4 3.0 3 A C C UNITS
MAX710/MAX711
Note 1: Specifications at -40C are guaranteed by design, not production tested. Note 2: Guaranteed by design (see Table 1). Note 3: The LBO comparator provides the correct result as long as one input is within the specified input range.
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3.3V/5V or Adjustable, Step-Up/Down DC-DC Converters MAX710/MAX711
__________________________________________Typical Operating Characteristics
(TA = +25C, unless otherwise noted.)
EFFICIENCY vs. OUTPUT CURRENT-- HIGH-EFFICIENCY MODE (VOUT = 5V)
VIN = 5.6V 80 EFFICIENCY (%) VIN = 3.6V 70 VIN = 2.5V VIN = 1.8V 60 VIN = 1V VOUT = 5V N/E = GND 50 0.1 1 10 100 1000 OUTPUT CURRENT (mA) 50 0.1 1 10 100 1000 OUTPUT CURRENT (mA)
MAX710/711 TOC01
EFFICIENCY vs. OUTPUT CURRENT-- HIGH-EFFICIENCY MODE (VOUT = 3.3V)
MAX710/711 TOC02
MINIMUM START-UP INPUT VOLTAGE vs. LOAD CURRENT
1.8 1.6 INPUT VOLTAGE (V) 1.4 1.2 1.0 0.8 0.6 0.4 0.2 0 0 50 100 150 200 250 LOAD CURRENT (mA) VOUT = 5V N/E = PS
MAX710/711 TOC03
90
90 VIN = 2.5V 80 EFFICIENCY (%) VIN = 1.8V 70 VIN = 1V 60 VOUT = 3.3V N/E = GND
2.0
EFFICIENCY vs. LOAD CURRENT-- HIGH-EFFICIENCY AND LOW-NOISE MODES (VOUT = 5V)
MAX710/711 TOC04
EFFICIENCY vs. LOAD CURRENT-- HIGH-EFFICIENCY AND LOW-NOISE MODES (VOUT = 3.3V)
HIGH-EFFICIENCY MODE ILIM = 0.8A 80 EFFICIENCY (%) ILIM = 1.5A ILIM = 0.8A 70 ILIM = 1.5A 60 LOW-NOISE MODE VOUT = 3.3V VIN = 2.5V 50
MAX710/711 TOC05
NO-LOAD BATTERY CURRENT vs. INPUT VOLTAGE
1400 SUPPLY CURRENT (A) 1200 1000 800 ILIM = GND (1.5A) 600 400 200 0 0 ILIM = PS (0.8A) 2 4 6 8 10 12 N/E = GND
MAX710/711 TOC06 MAX710/711 TOC09
90 N/E = GND 80 EFFICIENCY (%) ILIM = 1.5A ILIM = 0.8A
90
1600
70 N/E = PS 60 VOUT = 5V VIN = 2.5V 50 0.1 1 10 100 1000 LOAD CURRENT (mA)
0.1
1
10
100
1000
LOAD CURRENT (mA)
INPUT VOLTAGE (V)
MAXIMUM OUTPUT CURRENT vs. INPUT VOLTAGE
MAX710/711 TOC07
LINEAR-REGULATOR POWER-SUPPLY REJECTION RATIO vs. FREQUENCY
55 50 45 PSRR (dB) 40 35 30 25
MAX710/711 TOC08
SHUTDOWN CURRENT vs. INPUT VOLTAGE
1.0
1000 ILIM = GND MAXIMUM OUTPUT CURRENT (mA)
60
ILIM = PS 100
SHUTDOWN CURRENT (A)
0.8
0.6
0.4
N/E = GND N/E = PS 10 1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4 2.6 INPUT VOLTAGE (V)
20 15 10 0.01 0.1 1 10 100 1000 FREQUENCY (kHz)
0.2
0 1 2 3 4 5 6 7 8 9 10 11 INPUT VOLTAGE (V)
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3.3V/5V or Adjustable, Step-Up/Down DC-DC Converters
____________________________Typical Operating Characteristics (continued)
(TA = +25C, unless otherwise noted.) LINE-TRANSIENT RESPONSE
MAX710/711 TOC10
MAX710/MAX711
LOAD-TRANSIENT RESPONSE
MAX710/711 TOC11
A
A
B B
2ms/div A: VOUT = 3.3V (100mV/div, AC COUPLED), N/E = GND B: VIN = 2V TO 4V, IOUT = 100mA
1ms/div A: VOUT = 3.3V (50mV/div, AC COUPLED), N/E = PS B: IOUT = 10mA TO 100mA
OUTPUT RIPPLE (HIGH-EFFICIENCY MODE)
MAX710/711 TOC12
OUTPUT RIPPLE (LOW-NOISE MODE)
MAX710/711 TOC13
200s/div VIN = 2.5V, IOUT = 20mA, N/E = GND VOUT = 5V (20mV/div, AC COUPLED), IOUT = 20mA
200s/div VIN = 2.5V, IOUT = 20mA, N/E = PS VOUT = 5V (20mV/div, AC COUPLED), IOUT = 20mA
START-UP DELAY
MAX710/711 TOC14
TURN-OFF DELAY
MAX710/711 TOC15
A
A
B
B
20s/div A: VOUT (2V/div), IOUT = 100mA B: VSHDN (2V/div)
200s/div A: VOUT (2V/div), IOUT = 100mA B: VSHDN (2V/div)
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3.3V/5V or Adjustable, Step-Up/Down DC-DC Converters MAX710/MAX711
______________________________________________________________Pin Description
PIN MAX710 1 2 3 4 5 6 -- 7 8 9 10 11 12 13 14 15 16 MAX711 1 2 3 4 5 -- 6 7 8 9 10 11 12 13 14 15 16 NAME LX PGND ILIM SHDN STBY 3/5 FB N/E LBO OUT LBILBI+ PS REF GND PGND LX FUNCTION Drain Connection for internal N-channel power MOSFET Power Ground Inductor Current-Limit-Select Input. Connect to GND for 1.5A limit and to PS for 0.8A limit. Shutdown Input. When low, the entire circuit is off and OUT is actively pulled to GND. Standby Input. Connect to GND to disable boost circuit. Connect to PS for normal operation. Selects the output voltage. Connect to GND for 5V output and to OUT for 3.3V output. Feedback Input Selects low-noise or high-efficiency mode. Connect to GND for high efficiency and to PS for lowest noise. See Operating Configurations section. Low-Battery Comparator Output Linear-Regulator Output. Bypass with a 4.7F capacitor to GND. Negative Input to Low-Battery Comparator Positive Input to Low-Battery Comparator Source of internal PFET regulator. The IC is powered from PS. 1.28V Reference Voltage Output. Bypass with a 0.1F capacitor to GND. Analog Ground. Must be low impedance. Solder directly to ground plane. Power Ground Drain Connection for internal N-channel power MOSFET
_______________Detailed Description
The MAX710/MAX711 integrate a step-up DC-DC converter with a linear regulator to provide step-up/down voltage conversion. The step-up switch-mode regulator contains an N-channel power MOSFET switch. It also shares a precision voltage reference with a linear regulator that contains a P-channel MOSFET pass element (Figure 1).
input. The error amplifier compares this reference with the selected feedback voltage and amplifies the difference. The difference is conditioned and applied to the P-channel pass transistor's gate.
Operating Configurations
The MAX710/MAX711 have several operating configurations to minimize noise and optimize efficiency for different input voltage ranges. These configurations are accomplished via the N/E input, which controls operation of the on-chip linear regulator. With N/E low, the linear regulator behaves as a 0.7 (at 5V output) PFET switch when the IC is boosting, and as a conventional linear regulator when VIN > VOUT. This provides optimum boost efficiency, but the PFET does little to reject boost-converter output ripple. With N/E high, boost ripple rejection is optimized by maintaining headroom (VFV, typically 0.5V at 5V output) across the linear regulator. Boost mode efficiency is then about 10% lower than with N/E high.
Step-Up Operation
A pulse-frequency-modulation (PFM) control scheme with a constant 1s off-time and variable on-time controls the N-channel MOSFET switch. The N-channel switch turns off when the part reaches the peak current limit or the 4s maximum on-time. The ripple frequency is a function of load current and input voltage.
Step-Down Operation
The low-dropout linear regulator consists of a reference, an error amplifier, and a P-channel MOSFET. The reference is connected to the error amplifier's inverting
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3.3V/5V or Adjustable, Step-Up/Down DC-DC Converters MAX710/MAX711
N/E VIN
VOUT REF1
ERROR AMP2
PS LX tON FIXED tOFF GENERATOR OFF PS ILIM N
VFV
DRV
100mV
MAX710
PGND PGND
CURRENTLIMIT COMPARATOR
REF1 REF2
ERROR AMP1
PS
OUT
(FB)
SHDN REF
REFA
REF2 3.3/5
STBY
REFB
REF1
LBI+
GND
LBI-
LBO
( ) IS FOR MAX711.
Figure 1. Functional Diagram
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3.3V/5V or Adjustable, Step-Up/Down DC-DC Converters MAX710/MAX711
In high-efficiency mode (N/E = low), the maximum input voltage is limited to 7V. This voltage limitation is easily overcome, however, by configuring the LBO output to change modes based on input voltage, allowing an 11V maximum input with high-efficiency configurations. Four operating configurations are described in Table 1 and in the following subsections.
Configuration 1: High Efficiency, 7V Max VIN With N/E connected to GND, when the IC boosts, the linear regulator operates only as a switch, with minimum forward drop, until VIN > VOUT (where linear regulation begins). This configuration is limited to no more than 7V input, but provides best efficiency for batteryonly operation or low-voltage AC adapter usage. Configuration 2: High Efficiency, VBATT < VOUT In this configuration, N/E is driven high by LBO when V IN > V OUT (Figure 2a). When V IN < V OUT , the IC boosts, and the linear regulator operates as a switch, with minimum forward drop. When VIN > VOUT, the linear regulator operates with VFV forward drop, while VPS increases by VFV so that OUT maintains regulation. VFV is set inside the IC to approximately 0.5V (at 5V VOUT). When VIN is only slightly higher than VOUT, conversion efficiency is poorer than in configuration 1, so configuration 2 is most suitable when the battery voltage is less than VOUT, but the AC adapter output is greater than VOUT.
Table 1. Operating Configurations
NO. 1 DESCRIPTION High efficiency, 7V max VIN High efficiency, VBATT < VOUT (Figure 2a) High efficiency, 11V, VBATT < 6.5V (Figure 2b) Low noise INPUT VOLTAGE Up to 7V CONNECTIONS N/E = GND LBO = N/E LBI- = VOUT LBI+ = VIN LBO = N/E LBI- = REF LBI+ = R5, R6 N/E = PS
2
Up to 11V
3 4
Up to 11V Up to 11V
VIN = +1.8V TO +11V
VIN = +1.8V TO +11V
100F
L1
100F
L1
SHDN STBY N/E LBO LBI+ LBIREF PGND 0.1F GND
LX PS OUT 4.7F 100F
SHDN STBY R5 N/E LBO LBI+ R6 LBIREF PGND GND
LX PS OUT 4.7F 100F
MAX710
MAX710
3/5 ILIM 0.1F
3/5 ILIM
R5 = R6
(VIN - VREF) VREF R5 = R6 (4.08) WHEN VREF = 1.28V AND VIN = 6.5V
Figure 2a. High-Efficiency Operating Configuration for VBATT < VOUT
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Figure 2b. High-Efficiency Operating Configuration for VBATT < 6.5V
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3.3V/5V or Adjustable, Step-Up/Down DC-DC Converters
Configuration 3: High Efficiency, 11V, VBATT < 6.5V In this configuration, N/E is driven high by LBO when V IN > 6.5V (Figure 2b). When V IN < V OUT , the IC boosts, and the linear regulator operates as a switch, with minimum forward drop. When VIN > VOUT, linear regulation begins. When VIN > 6.5V (set by R5 and R6), the linear regulator forces a minimum forward drop of VFV (typically 0.5V at 5V VOUT) as LBO drives N/E high. This transition is not seen at the output, since the linear regulator already has an input-output voltage difference of 6.5V - 5V. Efficiency with VIN slightly higher than VOUT is equal to that of configuration 1, so configuration 3 is most suitable when the battery voltage may be near VOUT. This hookup has no functional shortcomings compared with configuration 2, except that two additional resistors (R5 and R6) are needed. Configuration 4: Low Noise With N/E connected to PS, when the IC is boosting, the linear regulator operates with VFV forward voltage (typically 0.5V at 5V VOUT) for optimum noise rejection. Linear regulation occurs when VIN > VOUT + VFV. The VFV voltage differential results in boost efficiency typically 10% lower than with the high-efficiency configurations.
MAX710/MAX711
IN C1 ON OFF SHDN STBY R3 N/E LBO LBI+ R4 LBIR2 REF PGND GND ILIM LX PS OUT C2 L1
MAX711
FB
R1
C4
Figure 3. MAX711 Adjustable Output Voltage
ILIM
The current-limit-select input, ILIM, selects between the two peak current limits: 1.5A (ILIM = GND) and 0.8A (ILIM = PS). If the application requires 200mA or less from the MAX710/MAX711, select 0.8A. The lower peak current limit permits the use of smaller, low-cost inductors. The ILIM input is internally diode clamped to GND and PS, and should not be connected to signals outside this range. MAX710/MAX711 typically start up with a 1V input. If the battery voltage exceeds the programmed output voltage, the output will linear regulate down to the selected output voltage. The MAX711's adjustable output voltage is set by two resistors, R1 and R2 (Figure 3), which form a voltage divider between the output and FB. Use the following equation to determine the resistor values: R1 = R2 [(VOUT / VREF) - 1] where VREF = 1.25V. Since the input bias current at FB has a maximum value of 50nA, R1 and R2 can be large with no significant accuracy loss. Choose R2 in the 100k to 1M range and calculate R1 using the formula above. For 1% error, the current through R1 should be at least 100 times FB's bias current.
Shutdown and Standby Modes
Grounding SHDN turns off the MAX710/MAX711 completely, disconnecting the input from the output. Tie SHDN to PS for normal operation. The MAX710/MAX711 have a standby mode that shuts down the step-up converter. The linear regulator remains on with a 7A (typ) LDO quiescent current. Connect STBY to ground to enter standby mode; otherwise, connect STBY to PS.
__________________Design Procedure
Output Voltage Selection
For the MAX710, you can obtain a 3.3V or 5V output voltage by tying 3/5 to GND or PS. Efficiency is typically 85% over a 2mA to 250mA load range. The device is bootstrapped, with power derived from the step-up voltage output (at PS). Under all load conditions, the
Low-Battery Comparator
The MAX710/MAX711 contain a comparator for lowbattery detection. If the voltage at LBI+ falls below that at LBI- (typically connected to REF), LBO goes low. Hysteresis is typically 50mV. Set the low-battery monitor's threshold with two resistors, R3 and R4 (Figure 2), using the following equation: R3 = R4 [(VLBT / VLBI-) - 1]
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3.3V/5V or Adjustable, Step-Up/Down DC-DC Converters MAX710/MAX711
Table 2. Component Selection
INDUCTORS (L1) Sumida CD75-220 (1.5A), CDRH-74-220 (1.23A), or CD54-220 Coilcraft DO33-08P-223 CAPACITORS 100F, 16V low-ESR tantalum capacitor AVX TPSE107M016R0100 or Sprague 593D107X0016E2W 4.7F, 16V tantalum capacitor Sprague 595D475X0016A2T RECTIFIERS (D1)
Schottky diode Motorola MBRS130T3
where VLBT is the desired threshold of the low-battery detector and VLBI- is the voltage applied to the inverting input of the low-battery comparator. Since LBI current is less than 50nA, R3 and R4 can be large (typically 100k to 1M), minimizing input supply loading. If the low-battery comparator is not used, connect LBI+ to PS and LBI- to REF, leaving LBO unconnected.
useful for operation at cold temperatures. The output capacitor, C3, needs to be only 4.7F to maintain linear regulator stability. See Tables 2 and 3 for a list of suggested capacitors and suppliers.
Rectifier Diode
For optimum performance, use a switching Schottky diode. Refer to Tables 2 and 3 for the suggested diode and supplier.
Inductor Selection
A 22H inductor value performs well in most MAX710/MAX711 applications. The inductance value is not critical, however, since the MAX710/MAX711 work with inductors in the 18H to 100H range. Smaller inductance values typically offer a smaller size for a given series resistance, allowing the smallest overall circuit dimensions. Circuits using larger inductance values exhibit higher output current capability and larger physical dimensions for a given series resistance. The inductor's incremental saturation current rating should be greater than the peak switch-current limit, which is 1.5A for ILIM = GND and 0.8A for ILIM = PS. However, it is generally acceptable to bias most inductors into saturation by as much as 20%, although this slightly reduces efficiency. The inductor's DC resistance significantly affects efficiency. See Tables 2 and 3 for a list of suggested inductors and suppliers.
__________Applications Information
The MAX710/MAX711 high-frequency operation makes PC layout important for minimizing ground bounce and noise. Keep the IC's GND pin and the ground leads of C1 and C2 (Figure 1) less than 0.2in. (5mm) apart. Also keep all connections to the FB and LX pins as short as possible. To maximize output power and efficiency and minimize output ripple voltage, use a ground plane and solder the IC's GND pin directly to the ground plane.
Table 3. Component Suppliers
SUPPLIER AVX Coilcraft Motorola Sanyo Sprague Sumida PHONE (803) 946-0690 (847) 639-6400 (602) 303-5454 (619) 661-6835 (603) 224-1961 (847) 956-0666 FAX (803) 626-3123 (847) 639-1469 (602) 994-6430 (619) 661-1055 (603) 224-1430 (847) 956-0702
Capacitor Selection
A 100F, 16V, 0.1 equivalent series resistance (ESR), surface-mount tantalum (SMT) output filter capacitor, C2, typically exhibits 50mV output ripple when stepping up from 2V to 5V at 100mA. Smaller capacitors (down to 10F with higher ESRs) are acceptable for light loads or in applications that can tolerate higher output ripple. The ESR of both bypass and filter capacitors affects efficiency and output ripple. Output voltage ripple is the product of the peak inductor current and the output capacitor's ESR. Use low-ESR capacitors for best performance, or connect two or more filter capacitors in parallel. Low-ESR, SMT capacitors are currently available from Sprague (595D series) and AVX (TPS series). Sanyo OS-CON organic-semiconductor through-hole capacitors also exhibit very low ESR and are especially
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___________________Chip Information
TRANSISTOR COUNT: 661 SUBSTRATE CONNECTED TO GND
______________________________________________________________________________________
3.3V/5V or Adjustable, Step-Up/Down DC-DC Converters
________________________________________________________Package Information
SOICN.EPS
MAX710/MAX711
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11
3.3V/5V or Adjustable, Step-Up/Down DC-DC Converters MAX710/MAX711
NOTES
12
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