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MIC2827
Triple Output PMIC with HyperLight LoadTM DCDC, two LDOs, and I2C Control
General Description
The Micrel MIC2827 is a three output, programmable Power Management IC, optimized for high efficiency power support in Mobile Application Processors, CoProcessors, DSPs, GPS and Media Player chipsets. The device integrates a single 500mA PWM/PFM synchronous buck (step-down) regulator with two Low Dropout Regulators and a 400kHz IC interface that provides programmable Dynamic Voltage Scaling (DVS), Power Sequencing, and individual output Enable/Disable controls allowing the user to optimally control all three outputs. The 4MHz synchronous buck regulator features a patented HyperLight LoadTM (HLL) architecture which minimizes switching losses and provides low quiescent current operation for high efficiency at light loads. Additional benefits of this proprietary architecture are low output ripple voltage and fast transient response throughout the entire load range with the use of small output capacitors, reducing the overall system size. Two high performance LDOs are integrated into the MIC2827 to provide additional system voltages for I/O, memory and other analog functions. Each LDO is capable of sourcing 150mA output current with high PSRR and low output noise. A 2% output voltage accuracy, low dropout voltage (150mV @ 150mA), and low ground current of 83A (both LDOs operating) makes this device ideally suited for mobile applications. The MIC2827 is available in a tiny 14-pin 2.5mm x 2.5mm Thin MLF(R) with a junction operating range from -40C to +125C. Data sheets and support documentation can be found on Micrel's web site at: www.micrel.com.
Features
* * * * * * * Fast-mode I2C control interface Tiny 14-pin 2.5mm x 2.5mm MLF(R) package Default start-up voltage states and sequencing Fault indication processor flag - IRQb -40C to 125C junction temperature range Thermal shutdown and current-limit protection Power On After Fault (POAF) function
DC-DC Synchronous Buck * 2.7V to 5.5V input voltage range * 500mA continuous output current * HyperLight LoadTM mode - 25A quiescent current * 90% peak efficiency; 85% at 1mA * Ultra-fast transient response * Dynamic Voltage Scaling (DVS) range: 0.8V to 1.8V - 0.8V to 1.2V in 25mV steps - 1.2V to 1.8V in 50mV steps * 3% over temperature * Low output voltage ripple: 20mVpp in HyperLight LoadTM mode, 3mV in full PWM mode LDOs * 1.8V to VDVIN input voltage range * 150mA output current (each LDO) * Dynamic Voltage Scaling (each LDO) - DVS range: 0.8V to 3.3V in 50mV steps * 3% over temperature * Low quiescent current - 50A (each LDO) * Low dropout voltage - 50mV @ 50mA * Low output noise - 45VRMS * Stable with ceramic output capacitors * 65dB PSRR at 1kHz
Applications
* * * * * * Application processors GPS subsystems General purpose PMIC Mobile phones / PDAs Portable media players Mobile television receivers
HyperLight Load is a trademark of Micrel, Inc MLF and MicroLeadFrame are registered trademarks of Amkor Technology, Inc. Micrel Inc. * 2180 Fortune Drive * San Jose, CA 95131 * USA * tel +1 (408) 944-0800 * fax + 1 (408) 474-1000 * http://www.micrel.com
July 2009
M9999-072709-A
Micrel, Inc.
MIC2827
Typical Application
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MIC2827
Ordering Information
Part Number Marking Code (2) 827B2 Default Start Up Voltages (1)
DC-DC LDO1 1.2V LDO2 2.8V
Default Start Up Sequence (1)
DC-DC 1 LDO1 2 LDO2 3
Junction Temp. Range -40C to +125C
Package
(3)
MIC2827-B2YMT
Note:
1.8V
14-Pin 2.5x2.5mm Thin MLF(R)
1. Other Default voltages and sequences are available on request (Voltages: 0.8V to 3.3VOUT LDOs, and 0.8V to 1.8VOUT PWM). Please contact Micrel Marketing for other voltage ranges. 2. Thin MLF Pin 1 Identifier symbol is "". 3. Thin MLF is a Green RoHS compliant package. Lead finish is NiPdAu. Mold compound is Halogen Free.
(R) (R)
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Pin Configuration
14-Pin 2.5mm x 2.5mm Thin MLF (MT) (Top View)
(R)
Pin Description
Pin Number 1 2 3 4 5 6 7 8 9 10 11 12 13 Pin Name LDO1OUT LDO2OUT LDO2IN N/C IRQb SW DGND DVIN SDA SCL FB AGND EN Fault Output (open drain). Switch (Output): Internal power MOSFET output switches. Switch Ground Pin. Input Voltage: Requires a close minimum 2.2F ceramic capacitor to DGND. Fast-mode 400kHz IC Data Input/Output pin. Fast-mode 400kHz IC Clock Input pin. Feedback Pin Connected to VOUT to sense output voltage. Analog Ground. Must be connected externally to DGND. Enable (Input): Executes default startup sequence. Active High. HIGH = ON, LOW = OFF. Do not leave floating. The EN pin function is optional if I2C control is used for startup and shutdown. External Input Supply Rail to LDO1. Requires a minimum 1F ceramic capacitor to AGND. Exposed Heat-Sink Pad. Pin Function Output of LDO1: Requires a minimum 1F ceramic capacitor-to-AGND. Output of LDO2: Requires a minimum 1F ceramic capacitor-to-AGND. External Input Supply Rail to LDO2. Requires a minimum 1F ceramic capacitor to AGND.
14 EP
LDO1IN HS PAD
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Absolute Maximum Ratings(1)
Supply Voltage (VDVIN, VLDO1IN, VLDO2IN)............ -0.3V to +6V Enable Voltage (VEN) ....................................... -0.3V to +6V I2C Voltage (VSDA, VSCL) ................................... -0.3V to +6V Power Dissipation ................................. Internally Limited(3) Lead Temperature (Soldering, 10 sec.) ..................... 260C Storage Temperature (TS)...................-65C TJ +150C ESD Rating(4) ................................................................. 2kV
Operating Ratings(2)
DVIN Supply voltage (VDVIN)......................... +2.7V to +5.5V LDO Supply voltage (VLDO1IN, VLDO2IN) ............+1.8V to VDVIN Enable Input Voltage (VEN)..................................0V to VDVIN I2C Voltage (VSDA, VSCL) .................................... 0V to +5.5V Junction Temperature Range (TJ)............. -40C to +125C Junction Thermal Resistance 2.5mm x 2.5mm Thin MLF-14 (JA) ...................89C/W
Electrical Characteristics(5) - DC/DC Converter
DVIN = EN = 3.6V; LDO1, LDO2 disabled; L=1H, COUT =4.7F, IOUT= 20mA, TA = 25C, unless otherwise specified. Bold values indicate -40CTJ+125C.
Parameter Supply Voltage Range Under-Voltage Lockout Threshold Switcher Quiescent Current, HLL Shutdown Current Output Voltage Accuracy Current Limit in PWM Mode Output Voltage Line Regulation Output Voltage Load Regulation PWM Switch ON-Resistance Frequency SoftStart Time Enable Voltage Enable Input Current Over-temperature Shutdown Over-temperature Shutdown Hysteresis VPOR Threshold % of VOUT below Nominal Auto-Discharge NFET resistance
Notes: 1. Exceeding the absolute maximum rating may damage the device. 2. The device is not guaranteed to function outside its operating rating. 3. The maximum allowable power dissipation of any TA (ambient temperature) is PD(max) = (TJ(max) - TA) / JA. Exceeding the maximum allowable power dissipation will result in excessive die temperature, and the regulator will go into thermal shutdown. 4. Devices are ESD sensitive. Handling precautions recommended. Human body model, 1.5k in series with 100pF. 5. Specification for packaged product only.
Conditions Rising IOUT = 0mA, FB > 1.2 * VOUT Nominal EN = 0V, DVIN = 5.5V DVIN = 3.6V; ILOAD = 20mA FB = 0.9* VOUT(NOM) DVIN = 3.0V to 5.5V, ILOAD = 20mA 20mA < ILOAD < 500mA, DVIN = 3.6V ISW = 100mA PMOS ISW = -100mA NMOS ILOAD = 120mA VOUT = 90% OFF ON
Min 2.7 2.45
Typ
Max 5.5
Units V V A A % A %/V % MHz s
2.55 25 2
2.65 35 5 +3
-3 0.55 1 0.4 0.5 0.55 0.6 4 300
0.2 1.2 0.1 160 20 2
V A C C % %
VOUT Ramping Up VOUT Ramping Down
91 89 280
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Electrical Characteristics - LDO1, LDO2
DVIN = EN = LDO1IN = LDO2IN = 3.6V; DC-DC disabled; LDO COUT =1F, LDO IOUT = 100A, TA = 25C, unless otherwise specified. Bold values indicate -40CTJ+125C.
Parameter Output Voltage Accuracy Input voltage Output Voltage DVS Range Line Regulation Load Regulation Dropout Voltage Conditions Variation from nominal VOUT IOUT = 100A to 150mA; IOUT = 100A to 100mA; -20C to +100C Adjustable through IC Registers LDO1IN, LDO2IN = VOUT +1V to 5.5V; IOUT = 100A IOUT = 100A to 75mA IOUT = 50mA; VOUT = 2V IOUT = 150mA; VOUT = 2V IOUT = 50mA; VOUT = 3V IOUT = 150mA; VOUT = 3V Ground Pin Current EN = DVIN 1 LDO enabled 2 LDOs enabled Ripple Rejection Current Limit Output Voltage Noise Auto-Discharge NFET resistance f = up to 1kHz; COUT = 1F; VOUT = 2.5V f = 1kHz - 10kHz; COUT = 1F VOUT = 2.5V VOUT = 0V COUT = 1F,10Hz to 100kHz 190 50 83 65 45 400 45 280 550 A A dB dB mA VRMS Min -3.0 2 1.74 0.8 0.014 4 70 200 50 150 350 3.3 0.1 Typ Max +3.0 Units % V V V %/V mV mV mV mV mV
Electrical Characteristics - I2C Interface
DVIN = EN = 3.6V, TA = 25C, unless otherwise specified. Bold values indicate -40CTJ+125C.
Parameter LOW-Level Input Voltage HIGH-Level Input Voltage SDA Pull-down resistance IRQb Pull-down resistance Open drain pull-down on SDA during read back Open drain pull-down 1.2 80 55 Conditions Min Typ Max 0.2 Units V V
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Typical Characteristics
Thermal Shutdown
2.0 1.8 1.6 OUTPUT VOLTAGE (V) 1.4 1.2 1.0 0.8 0.6 0.4 0.2 0.0 -40 0 40 80 120 160 T EM PERAT URE (C) 200 0.9 0.8 ENABLE THRESHOLD (V)
ENABLE THRESHOLD (V)
Enable Threshold v s. Temperature
0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0 2.7 3.1
Enable Threshold v s. Input Voltage
0.7 0.6 0.5 0.4 0.3 0.2 0.1 0 -40 -20 0 20 40 60 80 T EM PERAT URE (C) 100 120
DVIN = 3.6V VIN = 3.6V VOUT = 1.8V
DVIN = VIN = 3.6V
3.5 3.9 4.3 4.7 INPUT VO LT AGE (V)
5.1
5.5
LDO Input Voltage PSRR
90 80
10
LDO Output Noise Spectral Density
250
Dropout Voltage v s. Load Current
DROPOUT VOLTAGE (mV)
70
1
200
NO ISE (V/Hz)
60
VLDO = 2V
150
PSRR (dB)
50 40 30 20 10 0
0.1
VLDO = 3V
100
DVIN = 5.5V VIN = 3.6V VOUT = 1.2V COUT = 1F Load = 150mA
FREQ UENCY (Hz)
0.01
DVIN = VIN = 5.5V VOUT = 1.0V COUT = 1F Load = 10mA
Noise = (10Hz to 100kHz)=44.77VRMS
50
0.001
1.E+01 1.E+02 1.E+03 1.E+04 1.E+05 1.E+06 1.E+07
DVIN = 5.5V COUT = 1F
0 0 25 50 75 100 125 150
1.E+01 1.E+02 1.E+03 1.E+04 1.E+05 1.E+06 1.E+07
FREQ UENCY (Hz)
LO AD CURRENT (mA)
Dropout Voltage v s. Temperature
250 225 DROPOUT VOLTAG E (mV) 200 175 150 125 100 75 50 25 0 -40 -20
Dropout Voltage v s. Tem perature
200
1.25
LDO Output Voltage v s. Temperature
1.24 LDO OUTPUT VOLTAGE (V) 1.23 1.22 1.21 1.20 1.19 1.18 1.17 1.16 1.15 -40 -20 0 20
L = 150mA
DRO POUT VOLTAGE (mV)
175 150 125 100 75 50 25 0
L = 150mA
L = 100mA
L = 100mA DVIN = 5.5V VLDO = 3V COUT = 1F
100 120
L = 50mA
DVIN = 5.5V VLDO = 2V COUT = 1F
100 120
L = 50mA
-40 -20
DVIN = VIN = 3.6V VOUT = 1.2V COUT = 1F Load = 100A
40 60 80 100 120
0 20 40 60 80 T EM PERAT URE (C)
0 20 40 60 80 T EM PERAT URE (C)
TEM PERATURE (C)
LDO Output Voltage v s. Load Current
1.250 1.240 1.230 OUTPUT VOLTAGE (V)
OUTPUT VO LTAGE (V) 2.0 1.8 1.6 1.4 1.2 1.0 0.8 0.6 0.4 0.2 0.0
LDO Output Voltage v s. Input Voltage
700 650 600 550 500 450 400 350 300 250 200 150 100 50 0 2 2.5
LDO Current Limit v s. Input Voltage
1.220 1.210 1.200 1.190 1.180 1.170 1.160 1.150 0 25
DVIN = 5.0 VIN = 3.6V COUT = 1F
50 75 100 125 LOAD CURRENT (mA) 150
DVIN = 5.5V VLDO = 1.8V COUT = 1F Load = 100A
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 INPUT VO LT AG E (V)
CURRENT LIM IT (mA)
DVIN =5.5V COUT = 1F
3 3.5 4 4.5 INPUT VOLT AGE (V) 5 5.5
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Typical Characteristics (continued)
LDO Current Limit v s. Temperature
450 440 430
GROUND CURRENT (A)
LDO Ground Current v s. Temperature
55 53
GROUND CURRENT (A) 120 100 80 60 40 20 0
LDO Ground Current v s. Input Voltage
51 49 47 45 43 41 39 37 35
120
CURRENT LIMIT (mA)
420 410 400 390 380 370 360 350 -40 -20 0 20 40 60 80 TEM PERATURE (C) 100
2 LDOs
DVIN = VIN = 3.6V
DVIN = VIN = 3.6V VOUT = 1.2V COUT = 1F Load = 150mA
-40 -20 0 20 40 60 80 T EM PERAT URE (C) 100 120
1 LDO VOUT = 1.2V COUT = 1F Load = 100A
2.7 3.1 3.5 3.9 4.3 4.7 INPUT VOLT AGE (V) 5.1 5.5
LDO Ground Current v s. Load Current
51.6 51.2 G ROUND CURRENT (A) 50.8 EFFICIENCY (%) 50.4 50.0 49.6 49.2 48.8 48.4 48.0 0 25 50 75 100 125 LO AD CURRENT (mA) 150 90 85 80 75 70 65 60 55 50 1
DC-DC Efficiency VOUT=1.0V
90 85
DC-DC Efficiency VOUT=1.2V
VIN=3.6V VIN=2.7V
VIN=2.7V
EFFICIENCY (%)
80 75 70 65 60
VIN=4.2V
VIN=3.6V VIN=4.2V L = 1H C = 4.7F
10 100 LO AD CURRENT (mA) 1000
DVIN = VIN = 3.6V VOUT = 1.2V COUT = 1F
55 50 1 10
L = 1H C = 4.7F
100 1000
LOAD CURRENT (mA)
DC-DC Efficiency VOUT=1.5V
90 85 80 EFFICIENCY (%) 75 70 65 60 55 50 1 10 100 LOAD CURRENT (mA) 1000
EFFICIENCY (%) 80
DC-DC Efficiency VOUT=1.8V
100
10
DC-DC Switching Frequency v s. Load Current
VIN=2.7V
VIN=3.6V
VIN=2.7V
90
VIN=3.6V
SW FREQUENCY (M Hz)
1
VIN=3.0V
VIN=4.2V
VIN=4.2V
70 60 50 40 1 10 100 LOAD CURRENT (mA) 1000
0.1
VIN=3.6V VOUT = 1.8V L = 1H
1000
L = 1H C = 4.7F
L = 1H C = 4.7F
0.01 1
VIN=4.2V
10 100 LOAD CURRENT (mA)
DC-DC Switching Frequency v s. Load Current
10
5.0
DC-DC Switching Frequency v s. Temperature
5.0 4.5 4.0 SW FREQUENCY (M Hz) 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0.0 2.7
DC-DC Switching Frequency v s. Input Voltage
L=4.7H
4.8 4.6
SW FREQUENCY (M Hz)
SW FREQ UENCY (M Hz)
1
4.4 4.2 4.0 3.8 3.6 3.4 3.2 3.0 -40 -20
L=2.2H
0.1
L=1H
DVIN = 3.6V VOUT = 1.8V
0.01 1 10 100 LOAD CURRENT (mA) 1000
DVIN = 3.6V VOUT = 1.8V L = 1H C= 4.7F Load = 120mA
0 20 40 60 80 T EM PERAT URE (C) 100 120
VOUT = 1.8V L = 1H C= 4.7F Load = 120mA
3.1 3.5 3.9 4.3 4.7 INPUT VOLT AGE (V) 5.1 5.5
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Typical Characteristics (continued)
DC-DC Output Voltage v s. Load Current
1.92 1.90 1.88
OUTPUT VOLTAGE (V) 1.9 1.88 1.86 1.84 1.82 1.8 1.78 1.76 1.74 1.72 1.7 -40 -20
DC-DC Output Voltage v s. Tem perature
2.10 2.06 2.02 1.98 1.94 1.90 1.86 1.82 1.78 1.74 1.70 1.66 1.62 1.58 1.54 1.50 2.7
DC-DC Output Voltage v s. Input Voltage
O UTPUT VOLTAGE (V)
1.84 1.82 1.80 1.78 1.76 1.74 1.72 1.70 1.68 0 100 200 300 400 LOAD CURRENT (mA) 500
VIN = 3.6V L = 1H C= 4.7F
DVIN = 3.6V VOUT = 1.8V Load = 20mA
0 20 40 60 80 T EM PERAT URE (C) 100 120
OUTPUT VOLTAGE (V)
1.86
L = 1H C= 4.7F Load = 20mA
3.1 3.5 3.9 4.3 4.7 INPUT VOLT AGE (V) 5.1 5.5
DC-DC Current Lim it v s. Input Voltage
1.2 1.1 1.0 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0.0 2.7 3.1
Current Limit v s. Tem perature
1.40 1.20 CURRENT LIM IT (A) 1.00 0.80 0.60 0.40 0.20 0.00
5.5
RDSON (PMOS) v s. Temperature
800 700 600 RDS (m) 500 400 300 200
CURRENT LIM IT (A)
VOUT = 1.8V L = 1H C= 4.7F
3.5 3.9 4.3 4.7 INPUT VO LT AGE (V) 5.1
DVIN = 3.6V VOUT = 1.8V
-40 -20 0 20 40 60 80 T EM PERAT URE (C) 100 120
100 0 -40 -20 0 20 40 60 80 T EM PERAT URE (C) 100 120
RDSON (NMOS) v s. Temperature
900 800 700 600 RDS (m) 500 400 300 200 100 0 -40 -20 0 20 40 60 80 T EM PERAT URE (C) 100 120
RDS (m)
RDSON (PMOS) v s. Input Voltage
800 700 600
RDS (m) 800 700 600 500 400 300 200 100 0
RDSON (NMOS) v s. Input Voltage
500 400 300 200 100 0 2.7 3.1 3.5 3.9 4.3 4.7 5.1 5.5
INPUT VOLTAGE (V)
2.7
3.1
3.5 3.9 4.3 4.7 INPUT VOLT AGE (V)
5.1
5.5
Quiescent Current v s. Tem perature
40 35 QUIESCENT CURRENT (A) 30 25 20 15 10 5 0 -40 -20 0 20 40 60 80 T EM PERAT URE (C) 100 120
Q UIESCENT CURRENT (A)
29 28 27 26 25 24 23 22 21 20 19 2.7
Quiescent Current v s. Input Voltage
DVIN = 3.6V VOUT = 1.8V IOUT = 0mA
VOUT = 1.8V IOUT = 0mA
3.1 3.5 3.9 4.3 4.7 INPUT VO LT AG E (V) 5.1 5.5
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Functional Characteristics
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Functional Characteristics (continued)
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Functional Block Diagram
MIC2827 Block Diagram
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MIC2827 Power-Up via the EN Pin The EN pin is transition sensitive and not level sensitive (with the exception of hot enable--please see the description below). If the EN pin is toggled low-to-high, the MIC2827 will execute the default startup sequence. During the startup sequence, the appropriate set of supply enables is loaded into the Enable Register. This allows the part to present a consistent interface to the IC host; if the host reads the Enable Control register, it will see one or more enables on, which is consistent with one or more active supplies. Individual control of the supplies is now possible via the IC interface. "Hot Enable" Startup Some systems may choose to tie the EN pin to DVIN, so that the MIC2827 registers an active EN pin as it completes power-on. This is perfectly legal and produces a default startup immediately after power is applied. Depending on the rise time of the input power being applied, the UVLO flag may be set. Power-Down via the EN Pin If the EN pin is toggled high-to-low, then the MIC2827 will shut down all outputs simultaneously. For reasons similar to those above, at the conclusion of the shutdown sequence, all three individual supply enables will be clear in the Enable Control register and the bias will be switched off. If the MIC2827 startup is initiated by asserting EN and later shutdown is initiated by clearing the Enable Register bits, the part will be quiescent (with all bias currents disabled) but EN will still be high. In this case, de-asserting EN will have no effect, since the part has already completed its shutdown. Power-Up and Power-Down via the Enable Register The three individual power supply enable bits in the Enable Register (LDO2-EN, LDO1-EN, and DC-EN) may be used to enable and disable individual supplies. If the part is sequenced-enabled, and sequencing is permitted by the Sequence Control bit, enabled supplies are turned on in sequence. Any disabled outputs will not participate in the sequence and will be ignored. See also the "Ensuring Clean Switching in SequenceEnabled Parts" section. Under no circumstances should the EN and IC control be used simultaneously. The results would not be deterministic. If a supply output is enabled and its Voltage Control register is written with a new value, the output voltage changes immediately at the IC acknowledge.
Functional Description - Power Control and Sequencing
Two Types of Part: Sequence-Enabled and NoSequence * Sequence-Enabled parts support automatic sequencing of the three supplies. SequenceEnabled parts all have a default sequence (activated by asserting the EN pin). These parts also allow sequencing to be disabled. While very flexible, sequence-enabled parts require more care in operation. See the later section "Ensuring Clean Switching in Sequence-Enabled Parts". No-Sequence parts have no built-in sequencing capability. Their default startup turns on only one supply, which requires no sequencing. If the host needs more supplies to come on, this can be accomplished with IC writes which allows a sequence activated by software to be performed.
*
Power-up State When battery power is first applied to the MIC2827, all IC registers are loaded with their default (POR) values. If EN is high, a default startup is executed; otherwise, the part remains in a quiescent state waiting to be started by EN or an IC command. Enable Pin-Initiated Default Startup When EN is asserted, a default startup is executed. This is defined below: * * The voltage registers are loaded with their default values. In sequence-enabled parts, the Sequence Control bit is set to low (to allow sequencing to occur). Nosequence parts always have zero for the Sequence Control bit The correct set of supply enable bits is loaded into the Enable Register, and the appropriate sequence is then executed. The Power-On After Fault (POAF) bit is set to its default state, high.
*
*
Turning on the Power Supplies After power is applied, the MIC2827 offers two methods of turning the three supply outputs on and off: 1. Default startup sequencing or shutdown via the EN pin; 2. Flexible startup sequencing or shutdown via the IC interface
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Micrel, Inc. Fault Handling A fault is generated from either a thermal shutdown or under-voltage lockout event. If a fault occurs, the activation of the fault condition immediately turns off all output supplies, sets the fault flag bit(s) in the Status Register, and loads default values in the Enable and Voltage Registers. The sequence Control bit SEQ CNT is cleared to enable sequencing for sequence-enabled parts. The POAF bit is unaffected. The default state of the Enable Register's POAF (Power On After Fault) bit is high, indicating that the MIC2827 will perform a default start up when the fault goes away. If the user instead prefers that the part does not automatically attempt re-start after a fault, the POAF can be programmed to a "0". The EN pin can be toggled high-to-low at any time to clear the supply enables in the Enable Register and shut down the part. The same can be achieved through I2C at any time by disabling all enables in the enable register. Either method can be used to shut down the part during a fault. Shutdown after a fault will maintain the fault flags in the status register. Only Power-on-Reset or an echo reset of the status register will clear these flags. Thermal Shutdown (TSD) If the MIC2827's on-chip thermal shutdown detects that the die is too hot, the part will immediately turn off all outputs but maintain the bias to internal circuitry. The thermal event is logged in the Status register which can be read via IC. When the thermal shutdown event is removed, a default startup is executed if POAF is high. Under Voltage Lock Out (UVLO) If the MIC2827's on-chip voltage monitor detects a low voltage on the DVIN supply, the part will immediately turn off all outputs but maintain the bias to internal circuitry. When the UVLO event is removed, the outputs will turn on using the default startup if POAF is high. The UVLO event is logged in the status register which can be read via IC. If the power on DVIN drops too low, the MIC2827 will no longer be able to function reliably and will enter its power-on reset (POR) state. Any previously raised TSD or UVLO flags will now be cleared at startup Power Good Indication and Hysteresis The status of all three outputs can be read via IC in the status register. A register flag is set for each output when it reaches 90% of its regulated value and cleared when the output falls to about 85%.
MIC2827 Interrupt Operation If interrupts are enabled (INT-EN = 1), then the MIC2827's IRQb output will be asserted (driven low) whenever either of the two fault bits, UVLO or TSD, are asserted. Clearing the fault status bit by writing a one to it will clear the interrupt if the fault condition is no longer present. If the fault is still present, the status bit will be asserted again, together with the IRQb output. This operation does not depend on the state of the POAF bit. The default state of the INT_EN bit is zero, so the interrupt output is disabled. This is done so that the interrupt pin does not transition in MIC2827 systems which use only the EN pin and not the IC interface. Ensuring Clean Switching in Sequence-Enabled Parts In no-sequence parts, no sequencing ever occurs, and no special rules are required. However, in sequenceenabled parts, care must be taken when using automatic supply startup sequencing. The sequence-enabled MIC2827 accomplishes supply sequencing by asynchronously using one supply's power good signal to enable the next supply in line. As a consequence "downstream" supplies can momentarily switch off their outputs when "upstream" supplies are switched in and out of the sequencing chain. Example: Suppose the sequence [DC, 1, 2] is enabled and LDO1 is off, the others are enabled and their status is valid. If LDO1 is now enabled through IC, LDO2 will turn momentarily off, until LDO1 is valid, which then starts LDO2. To avoid this, the following rules should be observed, which apply only to sequence-enabled parts: 1. If all supplies are to be turned on, it is fine to use sequencing. This is what happens naturally as part of the EN-initiated default startup. It may also be accomplished by setting all three supply enables simultaneously in the Enable Register, and leaving the Sequence Control bit low to permit sequencing. 2. When starting from an all-off condition and a subset of the supplies is to be turned on, sequencing is permitted. 3. When one or more supplies are on, and a supply is to be turned off or on, sequencing must be disabled by setting SEQ CNT high. 4. When a subset of the supplies has been turned on via the Enable Register, an active transition on the EN pin must not be used to turn on the remaining supplies.
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Micrel, Inc. Sequencing rules do not apply to the last supply in the sequencing chain (the supply labeled "3rd" in the sequence table). The 3rd supply may be turned on and off at any time, since there are no downstream supplies from the 3rd. Available Default Startup Sequences The following table shows available default startup sequences for the MIC2827. Please contact Micrel factory to request customized default startup voltages and sequences.
Sequence Number Sequence 2 DC-DC 1st LDO1 2nd LDO2 3rd SequenceEnabled Part? Yes
MIC2827
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MIC2827
Functional Description - Fast-mode IC Interface
IC Address The seven-bit IC address of the MIC2827 is set at the factory to 1011010 binary, which would be identified as B4h using standard IC nomenclature, in which the read/write bit takes the least significant position of the eight-bit address. Other IC base addresses are available; please contact Micrel for details.
Electrical Characteristics - Serial Interface Timing
3.0V VDVIN 3.6V unless otherwise noted. Bold values indicate -40C TA +125C. Symbol t1 t2 t3 t4 t5 Parameter SCL (clock) period Data In Setup Time to SCL High Data Out Stable After SCL Low SDA Low Setup Time to SCL Low SDA High Hold Time after SCL High Start Stop Conditions Min 2.5 100 0 100 100 Typ Max Units s ns ns ns ns
Serial Interface Timing
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Micrel, Inc. Serial Port Operation The MIC2827 uses standard Write_Byte, Read_Byte, and Read_Word operations for communication with its host. The Write_Byte operation involves sending the device's address (with the R/W bit low to signal a write operation), followed by the register address and the command byte. The Read_Byte operation is a composite write and read operation; the host first sends the device's address followed by the register address, as in a write operation. A new start bit must then be sent to
MIC2827 the MIC2827, followed by a repeat of the device address with the R/W bit (LSB) set to the high (read) state. The data to be read from the part may then be clocked out. These protocols are shown in Figure 1 and Figure 2. The Register Address is eight bits (one byte) wide. This byte carries the address of the MIC2827 register to be operated upon. Only the lower three bits are used.
Figure 1: Write_Byte protocol
Figure 2: Read_Byte protocol
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MIC2827 Enable/Startup Control Register (00h): The Enable Register is used to allow control of the MIC2827's power supplies. It allows each supply to be turned on and off, and whether sequencing is used. When a default startup is executed as a result of the EN pin being taken from low to high, the Sequence Control, and Supply Enable bits are all set to their default values. The Sequence Control bit, only implemented in sequence-enabled parts, must be used carefully. See the section on "Ensuring Clean Switching in SequenceEnabled Parts".
Functional Description - IC Control Registers
Register Address 00h 01h 02h 03h 04h Register Name Enable Status DC-DC LDO1 LDO2 Read/ Write R/W R/W R/W R/W R/W Description Enable and startup control register Regulator output & fault condition status register DC-DC regulator voltage control register LDO1 voltage control register LDO2 voltage control register
D7 Name Access POR Value Data N/A 00 00
D6
D5 POAF R/W 1 0 = Remain off after fault 1 = Restore power after fault
D4 SEQ CNT R/W 0 0 = Sequencing enabled 1 = Sequencing disabled
D3 Reserved N/A 0
D2 LDO2-EN R/W 0
D1 LDO1-EN R/W 0
D0 DC-EN R/W 0
Reserved
0 = Disable 1 = Enable
Set by Default Startup? Set by a fault?
Yes No
Yes No
Yes Yes
Yes No
Yes Yes, if POAF=1
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Micrel, Inc. Status Register (01h): The Status Register allows the state of each supply to be interrogated, supports flags that are set when fault conditions occur, and controls the use of the MIC2827's interrupt pin.
D7 Name Access POR Value Data Reserved RO 0 0 D6 INT-EN R/W 0 0: Interrupt is disabled 1: Interrupt is enabled
Note:
MIC2827
D5 UVLO Echo reset 0 0: Normal 1: DVIN undervoltage occurred
D4 TSD Echo reset 0 0: Normal 1: Thermal shutdown occurred
D3 Reserved RO 0 0
D2 L2-Status RO 0 0 = LDO2 Not Valid 1 = LDO2 Valid
D1 L1-Status RO 0 0 = LDO1 Not Valid 1 = LDO1 Valid
D0 DC-Status RO 0 0 = DC-DC Not Valid 1 = DC-DC Valid
"Echo reset" bits remain set until cleared. Clearing these bits is accomplished by writing a one to that bit location ("echo the one to reset"). If the fault condition (UVLO or thermal shutdown) persists after the echo reset, the corresponding Status Register bit will be set high again immediately.
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Micrel, Inc. DC-DC Regulator Voltage Control Register (02h) This register controls the output voltage of the DC-DC PWM/PFM Regulator. The DC-DC Regulator employs a dual scale voltage step size to cover a wide range of output voltages from 0.8V to 1.8V. From 0.8V to 1.2V a step size of 25mV allows maximum power saving when the Processor Core is placed into a light load state. From 1.2V to 1.8V, a step size of 50mV provides a wide range of output voltages for power system flexibility.
MIC2827 DC-DC Regulator Voltage Control Register Table DC-DC Regulator Voltage Control Register Address: 02h
Step Size 25mV Register Value 00h 01h 02h 03h 04h 05h 06h 07h 08h 09h 0Ah 0Bh 0Ch 0Dh 0Eh 0Fh 50mV 10h 11h 12h 13h 14h 15h 16h 17h 18h 19h 1Ah 1Bh 1Ch Output Voltage 0.800 0.825 0.850 0.875 0.900 0.925 0.950 0.975 1.000 1.025 1.050 1.075 1.100 1.125 1.150 1.175 1.200 1.250 1.300 1.350 1.400 1.450 1.500 1.550 1.600 1.650 1.700 1.750 1.800
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Micrel, Inc. LDO1, LDO2 Voltage Control Registers Table LDO1 Regulator Voltage Control Register Address: 03h LDO2 Regulator Voltage Control Register Address: 04h
Step Size 50mV Register Value 00h 0Bh 14h 1Dh 25h 2Eh 37h 3Eh 45h 4Ch 52h 57h 5Ch 61h 65h 69h 6Dh 72h 79h 7Fh 85h 8Bh 91h 96h 9Ah 9Fh A4h A8h ACh B0h B4h B7h Output Voltage 0.800 0.850 0.900 0.950 1.000 1.050 1.100 1.150 1.200 1.250 1.300 1.350 1.400 1.450 1.500 1.550 1.600 1.650 1.700 1.750 1.800 1.850 1.900 1.950 2.000 2.050 2.100 2.150 2.200 2.250 2.300 2.350 Step Size 50mV Register Value BAh BDh C1h C4h C7h C9h CCh CEh D1h D3h D6h D8h DAh DCh DEh E1h E3h E6h E8h
MIC2827
Output Voltage 2.400 2.450 2.500 2.550 2.600 2.650 2.700 2.750 2.800 2.850 2.900 2.950 3.000 3.050 3.100 3.150 3.200 3.250 3.300
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MIC2827 LDO1OUT The LDO1OUT pin provides the regulated output voltage of LDO1. Power is provided by LDO1IN. LDO1OUT voltage can be dynamically scaled through I2C control. The recommended output capacitance is 1F, decoupled to AGND. LDO2OUT The LDO2OUT pin provides the regulated output voltage of LDO2. Power is provided by LDO2IN. LDO2OUT voltage can be dynamically scaled through I2C control. The recommended output capacitance is 1F, decoupled to AGND. SCL The I2C clock input pin provides a reference clock for clocking in the data signal. This is a fast-mode 400kHz input pin, and requires a 4.7k pull-up resistor. Please refer to "Serial Port Operation" for more details. SDA The I2C data bidirectional pin allows for data to be written to and read from the MIC2827. This is a fastmode 400kHz I2C pin, and requires a 4.7k pull-up resistor. Please refer to "Serial Port Operation" for more details. IRQb The IRQb (open drain) pin provides an interrupt for when either the UVLO or TSD faults are asserted. When enabled through I2C, the IRQb pin will assert together with the corresponding fault condition. Please refer to the "Interrupt Operation" for more details. DGND Power ground (DGND) is the ground path for the DC-DC MOSFET drive current. The current loop for the Power ground should be as small as possible and separate from the Analog ground (AGND) loop. Refer to the layout consideration for more details. AGND Analog ground (AGND) is the ground path for the biasing and control circuitry. The current loop for the Analog ground should be separate from the Power ground (AGND) loop. Refer to the layout consideration for more details.
Functional Description
DVIN The DVIN pin provides power to the source of the internal switch P-channel MOSFET, I2C control and voltage references for the MIC2827. The DVIN operating voltage range is from 2.7V to 5.5V. In order for any MIC2827 outputs to regulate, the appropriate input voltage must be applied to the DVIN pin. Due to the high switching speeds, a 4.7F capacitor is recommended as close as possible to the DVIN and power ground (DGND) pin for bypassing. Please refer to layout recommendations. LDO1IN LDO1IN provides power to the source of the LDO1 Pchannel MOSFET. The LDO1IN operating voltage range is from 1.8V to VDVIN. The recommended bypass capacitor is 1F. LDO2IN LDO2IN provides power to the source of the LDO2 Pchannel MOSFET. The LDO2IN operating voltage range is from 1.8V to VDVIN. The recommended bypass capacitor is 1F. EN The enable pin controls the ON and OFF state of all the outputs of the MIC2827. The EN pin is transition sensitive and not level sensitive. By toggling the enable pin low-to-high, this activates the default startup sequence of the part. SW The switching pin connects directly to one end of the inductor and provides the switching current during switching cycles. The other end of the inductor is connected to the load, output capacitor, and the FB pin. Due to the high speed switching on this pin, the switch node should be routed away from sensitive nodes. FB The feedback pin provides the control path to control the output. A recommended 4.7F bypass capacitor should be connected in shunt with the DC-DC output. It is good practice to connect the output bypass capacitor to the DGND and FB should be routed to the top of COUT.
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MIC2827 The MIC2827 was designed for use with an inductance range from 0.47H to 4.7H. Typically, a 1H inductor is recommended for a balance of transient response, efficiency and output ripple. For faster transient response a 0.47H inductor may be used. For lower output ripple, a 4.7H is recommended. Proper selection should ensure the inductor can handle the maximum average and peak currents required by the load. Maximum current ratings of the inductor are generally given in two methods; permissible DC current and saturation current. Permissible DC current can be rated either for a 40C temperature rise or a 10% to 20% loss in inductance. Ensure the inductor selected can handle the maximum operating current. When saturation current is specified, make sure that there is enough margin that the peak current will not saturate the inductor. Peak current can be calculated as follows:
1 - VOUT /VIN IPEAK = IOUT + VOUT 2 x f x L
Application Information
The Micrel MIC2827 is a three output, programmable Power Management IC, optimized for high efficiency power support. The device integrates a single 500mA PWM/PFM synchronous buck (step-down) regulator with two Low Dropout Regulators and an IC interface that provides programmable Dynamic Voltage Scaling (DVS), Power Sequencing, and individual output Enable/Disable controls allowing the user to optimally control all three outputs. Input Capacitors A 4.7F ceramic capacitor is recommended on the DVIN pin for bypassing. X5R or X7R dielectrics are recommended for the input capacitor. Y5V dielectrics lose most of their capacitance over temperature and are therefore not recommended. Also, tantalum and electrolytic capacitors alone are not recommended because of their reduced RMS current handling, reliability, and ESR increases. An additional 0.1F is recommended close to the DVIN and DGND pins for high frequency filtering. Smaller case size capacitors are recommended due to their lower ESR and ESL. Minimum 1.0F ceramic capacitors are recommended on the LDO1IN and LDO2IN pins for bypassing. Please refer to layout recommendations for proper layout of the input capacitors. Output Capacitors The MIC2827 is designed for a 2.2F or greater ceramic output capacitor for the DC-DC converter and 1.0F for the LDO regulators. Increasing the output capacitance will lower output ripple and improve load transient response but could increase solution size or cost. A low equivalent series resistance (ESR) ceramic output capacitor such as the TDK C1608X5R0J475K, size 0603, 4.7F ceramic capacitor is recommended based upon performance, size and cost. X5R or X7R dielectrics are recommended for the output capacitor. Y5V dielectrics lose most of their capacitance over temperature and are therefore not recommended. In addition to a 4.7F, a small 0.1F is recommended close to the load for high frequency filtering. Smaller case size capacitors are recommended due to their lower equivalent series ESR and ESL. Inductor Inductor selection will be determined by the following (not necessarily in the order of importance); * * * * Inductance Rated current value Size requirements DC resistance (DCR) 23
As shown by the previous calculation, the peak inductor current is inversely proportional to the switching frequency and the inductance; the lower the switching frequency or the inductance the higher the peak current. As input voltage increases, the peak current also increases. The size of the inductor depends on the requirements of the application. Refer to the Application Circuit and Bill of Material for details. DC resistance (DCR) is also important. While DCR is inversely proportional to size, DCR can represent a significant efficiency loss. Refer to the Efficiency Considerations. Efficiency Considerations Efficiency is defined as the amount of useful output power, divided by the amount of power supplied.
V xI Efficiency % = OUT OUT V xI IN IN x 100
Maintaining high efficiency serves two purposes. It reduces power dissipation in the power supply, reducing the need for heat sinks and thermal design considerations and it reduces consumption of current for battery powered applications. Reduced current draw from a battery increases the devices operating time and is critical in hand held devices. There are two types of losses in switching converters; DC losses and switching losses. DC losses are simply the power dissipation of I2R. Power is dissipated in the high side switch during the on cycle. Power loss is equal to the high side MOSFET RDSON multiplied by the Switch Current squared. During the off cycle, the low side Nchannel MOSFET conducts, also dissipating power. Device operating current also reduces efficiency. The
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Micrel, Inc. product of the quiescent (operating) current and the supply voltage is another DC loss. The current required driving the gates on and off at a constant 4MHz frequency and the switching transitions make up the switching losses.
Efficiency VOUT=1.8V
100 90 80 EFFICIENCY (%) 70 60 50 40 30 20 10 0 1 10 100 LOAD CURRENT (mA) 1000
MIC2827 PMOS on and keeps it on for the duration of the minimum-on-time. This increases the output voltage. If the output voltage is over the regulation threshold, then the error comparator turns the PMOS off for a minimumoff-time until the output drops below the threshold. The NMOS acts as an ideal rectifier that conducts when the PMOS is off. Using a NMOS switch instead of a diode allows for lower voltage drop across the switching device when it is on. The asynchronous switching combination between the PMOS and the NMOS allows the control loop to work in discontinuous mode for light load operations. In discontinuous mode, the MIC2827 works in pulse frequency modulation (PFM) to regulate the output. As the output current increases, the off-time decreases, thus providing more energy to the output. This switching scheme improves the efficiency of MIC2827 during light load currents by only switching when it is needed. As the load current increases, the MIC2827 goes into continuous conduction mode (CCM) and switches at a frequency centered at 4MHz. The equation to calculate the load when the MIC2827 goes into continuous conduction mode may be approximated by the following formula:
VIN=3.6V
VIN=2.7V VIN=4.2V
The Figure above shows an efficiency curve. From no load to 100mA, efficiency losses are dominated by quiescent current losses, gate drive and transition losses. By using the HyperLight LoadTM mode the MIC2827 is able to maintain high efficiency at low output currents. Over 100mA, efficiency loss is dominated by MOSFET RDSON and inductor losses. Higher input supply voltages will increase the Gate-to-Source threshold on the internal MOSFETs, thereby reducing the internal RDSON. This improves efficiency by reducing DC losses in the device. All but the inductor losses are inherent to the device. In which case, inductor selection becomes increasingly critical in efficiency calculations. As the inductors are reduced in size, the DC resistance (DCR) can become quite significant. The DCR losses can be calculated as follows: DCR Loss = IOUT2 x DCR From that, the loss in efficiency due to inductor resistance can be calculated as follows:
VOUT x IOUT x 100 Efficiency Loss = 1 - V OUT x IOUT + L_PD
(V - VOUT ) x D ILOAD > IN 2L x f As shown in the previous equation, the load at which MIC2827 transitions from HyperLight LoadTM mode to PWM mode is a function of the input voltage (VIN), output voltage (VOUT), duty cycle (D), inductance (L) and frequency (f). This is illustrated in the graph below. Since the inductance range of MIC2827 is from 0.47H to 4.7H, the device may then be tailored to enter HyperLight LoadTM mode or PWM mode at a specific load current by selecting the appropriate inductance. For example, in the graph below, when the inductance is 4.7H the MIC2827 will transition into PWM mode at a load of approximately 5mA. Under the same condition, when the inductance is 1H, the MIC2827 will transition into PWM mode at approximately 70mA.
Switching Frequency v s. Load Current
10
L=4.7H
SW FREQUENCY (M Hz)
Efficiency loss due to DCR is minimal at light loads and gains significance as the load is increased. Inductor selection becomes a trade-off between efficiency and size in this case. HyperLight Load ModeTM The MIC2827 uses a minimum on and off time proprietary control loop (patented by Micrel). When the output voltage falls below the regulation threshold, the error comparator begins a switching cycle that turns the
1
L=2.2H
0.1
L=1H
DVIN =3.6V VOUT = 1.8V
0.01 1 10 100 LO AD CURRENT (mA) 1000
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MIC2827
Recommended Schematic
Bill of Materials
Item C1, C2, C3, C5 C6, C7 R1, R4 R2, R3 JP1 L1 Part Number GRM155R61A105KE15D C1005X5R0J105KT GRM188R60J475K C1608X5R0J475M CRCW040210K0FKEA CRCW04024K70FKEA 0022152046 LQM21PN1R0MC0 MLP2520S1R0L XPL2010-102ML CIG21W1R0MNE U1
Notes: 1. Murata Tel: www.murata.com. 2. TDK: www.tdk.com. 3. Vishay Tel: www.vishay.com. 4. Molex.: www.molex.com. 5. Coilcraft: www.coilcraft.com. 6. Samsung: www.sem.samsung.com. 7. Micrel, Inc.: www.micrel.com.
Manufacturer Murata(1) TDK(2) Murata(1) TDK
(2)
Description Capacitor, 1F, 10V, X5R, 0402 size Capacitor, 1F, 10V, X5R, 0402 size Capacitor, 4.7F, 6.3V, X5R, 0603 size Capacitor, 4.7F, 6.3V, X5R, 0603 size Resistor, 10k, 1%, 1/16W, 0402 size Resistor, 4.7k, 1%, 1/16W, 0402 size Connector, 2.54mm (0.1") Pitch PCB Connector, 4 circuits Inductor, 1.0H, 0.8A, 2.0 x 1.25 x 0.5mm Inductor, 1.0H, 1.5A, 2.5 x 2.0 x 1.0mm Inductor, 1.0H, 1.1A, 2.0 x 1.9 x 1.0mm Inductor, 1.0H, 1.05A, 2.0 x 1.25 x 1.0mm Triple Output PMIC with HyperLight LoadTM DC-DC, Two LDOs, and I2C Control
Qty. 4 2 2 2 1
Vishay(3) Vishay Molex
(3) (4)
Murata(1)) TDK(2) Coilcraft
(5 (6)
1
Samsung
MIC2827-xxYMT
Micrel, Inc.(7)
1
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MIC2827
Recommended Layout
Top Layout
Bottom Layout
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MIC2827
Package Information
14-Pin 2.5mm x 2.5mm Thin MLF(R) (MT)
MICREL, INC. 2180 FORTUNE DRIVE SAN JOSE, CA 95131 USA
TEL +1 (408) 944-0800 FAX +1 (408) 474-1000 WEB http://www.micrel.com
The information furnished by Micrel in this data sheet is believed to be accurate and reliable. However, no responsibility is assumed by Micrel for its use. Micrel reserves the right to change circuitry and specifications at any time without notification to the customer. Micrel Products are not designed or authorized for use as components in life support appliances, devices or systems where malfunction of a product can reasonably be expected to result in personal injury. Life support devices or systems are devices or systems that (a) are intended for surgical implant into the body or (b) support or sustain life, and whose failure to perform can be reasonably expected to result in a significant injury to the user. A Purchaser's use or sale of Micrel Products for use in life support appliances, devices or systems is a Purchaser's own risk and Purchaser agrees to fully indemnify Micrel for any damages resulting from such use or sale. (c) 2009 Micrel, Incorporated.
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