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MAX8939BEWV+T
System Power Management for Mobile Handsets
System Power Management
for Mobile Handset
MAX8939/MAX8939A/MAX8939B
General Description
The MAX8939/MAX8939A/MAX8939B power manage-
ment ICs contain the necessary supplies and features for
supporting cell phone designs based on the Intel Mobile
Communications (IMC) 61XX 3G platform. Designed to power
all peripheral components in the platform, the ICs also provide
the necessary signals to control the 61XX baseband processor.
The integrated lithium-ion (Li+) charger is protected up
to 28V input and features a protected output voltage
for supply of a USB transceiver. Proprietary thermal-
regulation circuitry limits the die temperature during
fast-charging or when the ICs are exposed to high ambi-
ent temperatures, allowing maximum charging current
without damaging the ICs. A dedicated current regulator
is included for driving a charge indicator LED.
Four programmable low-noise, low-dropout linear regu-
lators (LDOs) provide the supply for noise sensitive
peripherals. A high power vibrator driver is I2C program-
mable in 70 PWM levels and 4 output voltages. The ICs
also offer two step-up converters; one high power, low
voltage (5V) to supply an external audio amplifier or
camera flash, and a high voltage (28V) supply for the
display and keyboard backlight. Two integrated 25mA
current regulators provide independent ramp-up and
ramp-down control, programmable through I2C.
The MAX8939/MAX8939A/MAX8939B are highly integrated
ICs that require very few external components and are avail-
able in a compact 2.5mm x 3.0mm, 0.65mm max height
wafer level package (WLP).
Applications
Companion Chip for Cell Phones/Smartphones
Features
S Step-Up Converter
700mA Guaranteed Output Current I2C Programmable Output 3.5V to 5.0V in 16 Steps
Over 90% Efficiency
On-Chip FET and Synchronous Rectifier Fixed 2MHz PWM Switching
Small 2.2µH to 10µH Inductor
S WLED Boost Converter
28V Max Step-Up Output Voltage 60mA Output Current
Integrated nMOS Power Switch Over 90% Efficiency
Fixed 2MHz Switching
Small 4.7µH to 10µH Inductor Two 25mA Individually Programmable Current
Regulators I2C Programmable Output Current (50µA to
25.25mA) with 128-Step Pseudo Log Dimming
Individually Programmable Ramp (Up/Down)
S Linear One-Cell Li+ Battery Charger
No External MOSFET, Reverse Blocking Diode,
or Current-Sense Resistor Programmable Fast-Charge Current (1.5ARMS max
for the MAX8939 or 850mARMS max for the MAX8939A/MAX8939B)
Programmable Top-Off Current Threshold Proprietary Die Temperature Regulation Control
4.1V to 10V Input Voltage Range (MAX8939)
4.1V to 6.25V Input Voltage Range (MAX8939A/
MAX8939B) with Input Overvoltage Protection Up to 28V Low-Dropout Voltage (300mV at
500mA) Input Power-Source Detection Output
Input Overvoltage Protected 4.75V Output
(SAFE_OUT) from IN Charge Current Monitor Output
Indicator LED
Hardware Input Enable
5s Watchdog Feature During Charge
S Four Low-Noise LDOs
1x 400mA, 2 x 200mA and 1x 100mA Output
Current High 65dB (typ) PSRR
Low Noise (45µVRMS typ)
1.7V to 3.2V Programmable Output Voltage
Low Quiescent Current (25µA typ) 400mA LDO with Hardware Enable Input
S Vibrator Driver Guaranteed 200mA Output Current
Programmable Output Voltage 1.3V to VINVIB
Repetition Frequency 23.8kHz
PWM Speed Control in 70 steps Active Stop Brake
S Control Interface for 61XX Baseband
MAX8939/MAX8939A/MAX8939B Control Through I2C RESET_IN Reset Input
Charger Detect PWR_ON_CMP Output IRQ Interrupt Output
S 2.9V to 5.5V Supply Voltage Range
S Thermal Shutdown
+Denotes a lead(Pb)-free/RoHS-compliant package.
T = Tape and reel.
Ordering Information
EVALUATION KIT AVAILABLEPARTTEMP RANGEPIN-PACKAGE
MAX8939EWV+T-40NC to +85NC30 WLP
(0.5mm pitch)
MAX8939AEWV+T-40NC to +85NC30 WLP
(0.5mm pitch)
MAX8939BEWV+T-40NC to +85NC30 WLP
(0.5mm pitch)
System Power Management
for Mobile Handset
MAX8939/MAX8939A/MAX8939B
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.
BATT, OUT1, SAFE_OUT, and INVIB to AGND ....-0.3V to +6.0V
CHG_IN, OUT2, LED1, and LED2 to AGND .........-0.3V to +30V
LED3 and CHG_MON to AGND ....-0.3V to (VSAFE_OUT + 0.3V)
COMP2, IRQ, RESET_IN, COMP1, SCL, SDA, CHG,
PWR_ON_CMP, REF, LDO1, LDO2, LDO3, LDO4,
and LDO1_EN to AGND ....................-0.3V to (VBATT + 0.3V)
OUTVIB to AGND ..................................-0.3V to (VINVIB + 0.3V)
PGND1 and PGND2 to AGND .............................-0.3V to +0.3V
LX1, LX2 Current (Note 1) .............................................1.7ARMS
Continuous Power Dissipation (TA = +70NC)
WLP (derate 24.4mW/NC above +70NC)..........................1.9W
Operating Temperature ......................................-40NC to +85NC
Junction Temperature .....................................................+150NC
Storage Temperature Range ............................-65NC to +150NC
Soldering Temperature (reflow) ......................................+260NC
ELECTRICAL CHARACTERISTICS (Note 3)
(VBATT = 3.7V, VCHG_IN = 5.0V, circuit of Figure 1, TA = -40NC to +85NC, unless otherwise noted. Typical values are at TA = +25NC.)
ABSOLUTE MAXIMUM RATINGS
Note 1: LX1 has internal clamp diodes to PGND1 and OUT1. LX2 has internal clamp diodes to PGND2 and OUT2. Applications
that forward bias these diodes should take care not to exceed the IC package power dissipation limit.
WLP
Junction-to-Ambient Thermal Resistance (qJA) ..........41°C/W
Note 2: Package thermal resistances were obtained using the method described in JEDEC specification JESD51-7, using a four-lay-
er board. For detailed information on package thermal considerations, refer to www.maximintegrated.com/thermal-tutorial.
PACKAGE THERMAL CHARACTERISTICS(Note 2)
PARAMETERCONDITIONSMINTYPMAXUNITS
BATT
BATT Operating Voltage2.95.5V
BATT Shutdown Supply Current All outputs off, I2C disabled,
VSCL = VSDA= VRESET_IN = 0V
TA = +25NC0.41FATA = +85NC0.41
BATT Standby Supply CurrentAll outputs off, VSCL = VSDA =
VRESET_IN = 1.8V, I2C ready
TA = +25NC510FATA = +85NC5
BATT Biasing Supply CurrentI2C ready, one or more outputs on60FA
Undervoltage Lockout (UVLO)
ThresholdBATT rising2.62.752.9V
Undervoltage Lockout Hysteresis100mV
THERMAL SHUTDOWN
Threshold+160NC
Hysteresis20NC
REFERENCE
Reference Output Voltage1.200V
Reference Supply Rejection0.2mV
LOGIC AND CONTROL INPUTS
Input Low LevelSDA, SCL, LDO1_EN, CHG, and RESET_IN 0.4V
Input High LevelSDA, SCL, LDO1_EN, CHG, and RESET_IN 1.40V
Logic-Input CurrentSDA, SCL, LDO1_EN, CHG,
TA = +25NC-1+1FA
System Power Management
for Mobile Handset
MAX8939/MAX8939A/MAX8939B
ELECTRICAL CHARACTERISTICS (Note 3) (continued)
(VBATT = 3.7V, VCHG_IN = 5.0V, circuit of Figure 1, TA = -40NC to +85NC, unless otherwise noted. Typical values are at TA = +25NC.)
PARAMETERCONDITIONSMINTYPMAXUNITS
LOGIC AND CONTROL OUTPUTS
IRQ (Open-Drain Output)
Output Low VoltageIIRQ = 2mA0.4V
PWR_ON_CMP (Open-Drain
Output) Output Low VoltageIPWR_ON_CMP = 2mA0.4V
SDA Output Low Level ISDA = 6mA0.4V
I2C SERIAL INTERFACE (VSCL = VSDA = 3V) (Figure 15)
Clock Frequency400kHz
Bus-Free Time Between START and
STOPtBUF1.3Fs
Hold Time Repeated START
ConditiontHD_STA0.6Fs
SCL Low PeriodtLOW1.3Fs
SCL High PeriodtHIGH0.6Fs
Setup Time Repeated START
ConditiontSU_STA0.6Fs
SDA Hold TimetHD_DAT0Fs
SDA Setup timetSU_DAT100ns
Maximum Pulse Width of Spikes
that Must Be Suppressed by the
Input Filter of Both DATA and CLK
Signalsns
Setup Time for STOP ConditiontSU_STO0.6Fs
CHG_IN
Input Operating Range4.110V
CHG_IN CurrentVCHG_IN = 28V, VBATT = 4V, MAX8939A/MAX8939B4006001000FA
CHG_IN Leakage Current from
CHG_IN to BATTVCHG_IN = 28V, VBATT = 0V, MAX8939A/MAX8939B2180FA
Reverse Leakage Current from
BATT to CHG_IN
VCHG_IN = 0V, VBATT = 0 to 4.2V, MAX8939A/
MAX8939B10FA
CHG_IN Trip Point
VCHG_IN - VBATT, rising200300400VCHG_IN - VBATT, falling100
VCHG_IN - VBATT, hysteresis200
Input Undervoltage Threshold (UV)
MAX8939, VCHG_IN rising, 500mV hysteresis (typ)3.94.04.1MAX8939A/MAX8939B, VCHG_IN rising, 900mV
hysteresis (typ)3.94.04.1
Input Overvoltage Threshold (OVP)
MAX8939, VCHG_IN rising, 200mV hysteresis (typ)10.210.611MAX8939A/MAX8939B, VCHG_IN rising, 200mV
hysteresis (typ)6.256.56.75
Input Supply CurrentICHG_IN - IBATT = 90mA7501500FA
Shutdown Input CurrentCharger disabled500FA
System Power Management
for Mobile Handset
MAX8939/MAX8939A/MAX8939B
ELECTRICAL CHARACTERISTICS (Note 3) (continued)
(VBATT = 3.7V, VCHG_IN = 5.0V, circuit of Figure 1, TA = -40NC to +85NC, unless otherwise noted. Typical values are at TA = +25NC.)
PARAMETERCONDITIONSMINTYPMAXUNITS
CHG_IN to BATT Dropout
On-ResistanceVCHG_IN = 3.7V, VBATT = 3.6V0.40.8I
SAFE_OUT
SAFE_OUT Regulated Output
ISAFE_OUT = 15mA, VCHG_IN = 5V,
TA = 0NC to +85NC4.754.905.00ISAFE_OUT = 15mA, VCHG_IN = 10V,
TA = 0NC to +85NC5.2
SAFE_OUT Current Limit100mA
CHG_MON
I/V Conversion FactorMonitoring voltage to charge current - fast-charge
current = 450mA (Note 4)2.666mV/
I/V AccuracyOverall range-10+10%
Output Voltage450mA charge current - fast-charge current = 450mA
(Note 4)1200mV
Charge Monitoring Range01.2V
Output Impedance102040kI
INDICATOR LED
LED3 Current SinkVCHG_IN = 5V, TA = 0NC to +85NC1.535mA
BATT
BATT Regulation Voltage
(MAX8939)
IBATT = 90mA,
VBATT programmed to 4.2V
TA = +25NC4.1794.24.221VTA = -40NC to +85NC4.1584.24.242
BATT Regulation Voltage
(MAX8939A)
IBATT = 90mA, TA = +25NCVSET = 11b4.1294.1504.171IBATT = 90mA,
TA = -40NC to +85NC
VSET = 00b3.4653.5003.535
VSET = 01b3.8113.8503.889
VSET = 10b4.0094.0504.091
VSET = 11b4.1084.1504.192
BATT Regulation Voltage
(MAX8939B)
IBATT = 90mA, TA = +25NCVSET = 11b4.1494.1704.191
IBATT = 90mA,
TA = -40NC to +85NC
VSET = 00b3.4653.5003.535
VSET = 01b3.8113.8503.889
VSET = 10b4.0094.0504.091
VSET = 11b4.1294.1704.192
Programmable Restart Fast-Charge
ThresholdFrom BATT regulation voltage, default = disable
Disable
System Power Management
for Mobile Handset
MAX8939/MAX8939A/MAX8939B
ELECTRICAL CHARACTERISTICS (Note 3) (continued)
(VBATT = 3.7V, VCHG_IN = 5.0V, circuit of Figure 1, TA = -40NC to +85NC, unless otherwise noted. Typical values are at TA = +25NC.)
PARAMETERCONDITIONSMINTYPMAXUNITS
CHG_IN Fast-Charge Current
(MAX8939) (Note 5)VBATT = 3.5V
CHG_CONTROL_A.FAST_CHARGE = 000b8090100
001b240270300
010b400450500
011b560630700
100b630765900
101b7008501000
110b94010201200
111b105012751500
CHG_IN Fast-Charge Current
(MAX8939A/MAX8939B) (Note 5)VBATT = 3.5V
CHG_CONTROL_A.FAST_CHARGE = 000b829098
001b250270290
010b420450480
011b575630685
100b695765835
101b775850925
110b100120140
111b160180200
CHG_IN Precharge Current VBATT = 2V90100mA
BATT Prequalification Threshold
VoltageVBATT rising hysteresis 140mV (typ)2.52.552.6V
Soft-Start TimeRamp time to fast-charge current2.5ms
TOP-OFF
Top-Off Threshold
(% of Fast-Charge Current)IBATT falling
TOP_OFF = 00b10TOP_OFF = 01b20
TOP_OFF = 10b30
TOP_OFF = 11b (default)0
TIMER
Timer Accuracy -20+20%
Fast-Charge Time Limit
From entering fast-
charge to VBATT
< 4.2V
MAX8939
CCTR = 00b (default)60
min
CCTR = 01b120
CCTR = 10b240
MAX8939A/
MAX8939B
CCTR = 00b (default)24
CCTR = 01b120
CCTR = 10b240
Precharge TimerMAX893930minMAX8939A/MAX8939B12
System Power Management
for Mobile Handset
MAX8939/MAX8939A/MAX8939B
ELECTRICAL CHARACTERISTICS (Note 3) (continued)
(VBATT = 3.7V, VCHG_IN = 5.0V, circuit of Figure 1, TA = -40NC to +85NC, unless otherwise noted. Typical values are at TA = +25NC.)
PARAMETERCONDITIONSMINTYPMAXUNITS
Top-Off Timer
TOPOFF_TIME = 00b30
minTOPOFF_TIME = 01b60
TOPOFF_TIME = 10b120
TOPOFF_TIME = 11bDisable
Watchdog TimerMAX89392.5510sMAX8939A/MAX8939B153045
THERMAL LOOP
Thermal Limit Temperature
Junction temperature
when the charge current is
reduced, TJ rising, default
value
+70NC [00]
+100NC+85NC [01]
+100NC [10]
+115NC [11]
OUT1 STEP-UP DC-DC CONVERTER
Input Voltage (VBATT)2.95.5V
Input Supply Current2MHz switching, VOUT = 5V, no load11mA
OUT1 Voltage Accuracy500mA loadTA = +25NC-3+3%TA = +85NC-4+4
Maximum Output CurrentVBATT R 3.2V, VOUT1 = 5.0V550700mA
nFET Current Limit2.0A
Line RegulationVBATT = 2.9V to 4.2V0.1%/V
Load Regulation0 to 500mA load0.5%/A
LX1 nFET On-ResistanceLX1 to PGND1, ILX1 = 200mA0.10.2I
LX1 pFET On-ResistanceLX1 to OUT1, ILX1 = -200mA0.150.3I
LX1 LeakageVLX1 = 5.5VTA = +25NC0.015FATA = +85NC0.1
Switching Frequency1.822.2MHz
Maximum Duty Cycle6575%
Minimum Duty Cycle8%
COMP Discharge Resistance During shutdown or UVLO220I
VIBRATOR
Programmable Output Voltage
OUTVIB
1mA at VBATT = VINVIB = 5.5V, 150mA at VBATT =
VINVIB = 3.4V, default value3V
Output Current200mA
Current LimitVOUTVIB = 0V400600mA
Dropout VoltageILOAD = 135mA, TA = +25NC150300mV
Line Regulation3.4V P VBATT = VINVIB < 5.5V, ILOAD = 100mA2.2mV
Load Regulation1mA < ILOAD < 200mA25mV
Power-Supply Rejection
DVINVIB/DVOUTVIBf = 10Hz to 10kHz, ILOAD = 30mA40dB
Output Noise100Hz to 100kHz, ILOAD = 30mA65FVRMS
Discharge Time ConstantTOFF 90% to 5%, C = 1FF0.1ms
System Power Management
for Mobile Handset
MAX8939/MAX8939A/MAX8939B
ELECTRICAL CHARACTERISTICS (Note 3) (continued)
(VBATT = 3.7V, VCHG_IN = 5.0V, circuit of Figure 1, TA = -40NC to +85NC, unless otherwise noted. Typical values are at TA = +25NC.)
PARAMETERCONDITIONSMINTYPMAXUNITS
Active Stop nFET on-resistance1I
Active Brake on ShutdownnFET on duration85ms
LDO1
Output AccuracyILOAD = 1mA-3+3%
Maximum Output Current400mA
Current LimitVLDO1 = 0V600mA
Dropout VoltageILOAD = 200mA200400mV
Line Regulation3.4V P VBATT P 5.5V, ILOAD = 100mA2.4mV
Load Regulation50FA < ILOAD < 200mA25mV
Power-Supply Rejection
DVLDO1/DVBATTf = 10Hz to 10kHz, ILOAD = 30mA60dB
Output Noise Voltage (RMS)100Hz to 100kHz, ILOAD = 30mA50FVRMS
Ground CurrentILOAD = 500FA21FA
Shutdown Discharge Time TOFF 90% to 10%, C = 4.7FF1ms
Shutdown Output Impedance5080I
LDO2, LDO3
Output AccuracyILOAD = 1mA-3+3%
Maximum Output Current200mA
Current LimitOutput = 0V400700mA
Dropout VoltageILOAD = 135mA200400mV
Line Regulation3.4V P VBATT P 5.5V, ILOAD = 100mA2.4mV
Load Regulation50FA < ILOAD < 200mA25mV
Power-Supply Rejection
DVLDO_/DVBATTf = 10Hz to 10kHz, ILOAD = 30mA60dB
Output Noise Voltage (RMS)100Hz to 100kHz, ILOAD = 30mA50FVRMS
Ground CurrentILOAD = 500FA21FA
Shutdown Discharge Time TOFF 90% to 10%, C = 1FF1ms
Shutdown Output Impedance100150I
LDO4
Output AccuracyILOAD = 1mA-3+3%
Maximum Output Current100mA
Current LimitVLDO4 = 0V200400mA
Dropout VoltageILOAD = 70mA200400mV
Line Regulation3.4V P VBATT P 5.5V, ILOAD = 50mA2.4mV
Load Regulation50FA < ILOAD < 100mA25mV
Power-Supply Rejection
DVLDO4/DVBATTf = 10Hz to 10kHz, ILOAD = 30mA60dB
Output Noise100Hz to 100kHz, ILOAD = 30mA50FVRMS
Ground Current ILOAD = 500FA25FA
Shutdown Discharge Time TOFF 90% to 10%, C = 1FF1ms
Shutdown Output Impedance100150I
System Power Management
for Mobile Handset
MAX8939/MAX8939A/MAX8939B
Note 3: Limits are 100% production tested at TA = +25NC, unless otherwise noted. Min/max limits over the operating temperatures
range and relevant supply voltage range are guaranteed by design and characterization. Typical values are not guaranteed.
Note 4: The monitoring voltage is proportional to the charging current with a ratio depending on the programmed fast-charge cur-
rent. For the current equal to the fast-charge current, the monitoring voltage is typically 1.2V.
Note 5: The maximum CHG_IN current is the typical value plus 10% for currents up 700mA and the typical value plus 15% for
higher currents.
Note 6: LED dropout voltage is defined as the LED_ to ground voltage when current into LED_ drops 10% from the value at
VLED_= 0.5V.
ELECTRICAL CHARACTERISTICS (Note 3) (continued)
(VBATT = 3.7V, VCHG_IN = 5.0V, circuit of Figure 1, TA = -40NC to +85NC, unless otherwise noted. Typical values are at TA = +25NC.)
PARAMETERCONDITIONSMINTYPMAXUNITS
OUT2 WLED STEP-UP CONVERTER
Input Supply Voltage2.95.5V
Input Supply Current2MHz, no load22.5mA
OUT2 Leakage CurrentTA = +25NC, VOUT2 = 5.5V, shutdown 0.011FATA = +85NC, VOUT2 = 5.5V, shutdown 0.15
LED1, LED2
Current Regulator Dropout Voltage
(Note 6)25.25mA setting200mV
LED_ Regulation Voltage350mV
LED_ Current AccuracyTA = +25NC, ILED_= 25.25mA-3+3%TA = -40NC to +85NC, ILED_= 25.25mA-5+5
Leakage CurrentTA = +25NC, in shutdown0.011FATA = +85NC, in shutdown0.15
LX2
nFET Current Limit710860mA
nFET On-ResistanceILX2 = 200mA0.30.7I
LX2 Leakage CurrentTA = +25NC, 5.5V, shutdown0.011FATA = +85NC, 5.5V, shutdown0.15
Operating Frequency1.822.2MHz
Maximum Duty CycleVLED1 or VLED2 = 0.2V90%
COMP2
Transconductance 20Fs
Soft-Start Charge Current60FA
Discharge Pulldown20kI
PROTECTION
Overvoltage ThresholdVOUT2 rising2830V
Overvoltage Hysteresis4V
Open LED Detection100120mV
Shorted LED Detection VOUT2
- 2.2V
VOUT2
- 0.7VV
System Power Management
for Mobile Handset
MAX8939/MAX8939A/MAX8939B
Typical Operating Characteristics
(VBATT = 3.7V, circuit of Figure 1, TA = +25NC, unless otherwise noted.)
OUT1 STEP-UP CONVERTER
OUT1 EFFICIENCY vs. LOAD CURRENT
MAX8939 toc01
LOAD CURRENT (mA)
EFFICIENCY (%)
VBATT = 4.2V
VBATT = 3.7V
VBATT = 3.0V
VOUT1 = 5V
OUT1 EFFICIENCY vs. LOAD CURRENT
MAX8939 toc02
LOAD CURRENT (mA)
EFFICIENCY (%)
VBATT = 3.0V
VOUT1 = 3.5V
OUT1 VOLTAGE vs. LOAD CURRENT
MAX8939 toc03
LOAD CURRENT (mA)
OUTPUT VOLTAGE (V)
VBATT = 4.2V
VBATT = 3.7V
VBATT = 3.0V
VOUT1 = 5V
OUT1 VOLTAGE vs. BATTERY VOLTAGE
MAX8939 toc04
BATTERY VOLTAGE (V)
OUTPUT VOLTAGE (V)
NO LOAD
MIN TON MODE
PROTECTION MODE
(VOUT1 TRACKS VBATT)
OUT1 NO-LOAD SUPPLY CURRENT
vs. BATTERY VOLTAGE
MAX8939 toc05
SUPPLY CURRENT (mA)
VOUT1 = 5V
OUT1 STARTUP WAVEFORM
MAX8939 toc06
1V/div
200mA/div
2V/div
VSCL
VOUT1
IL1
40µs/div
NO LOAD
System Power Management
for Mobile Handset
MAX8939/MAX8939A/MAX8939B
Typical Operating Characteristics (continued)
(VBATT = 3.7V, circuit of Figure 1, TA = +25NC, unless otherwise noted.)
OUT1 STEP-UP CONVERTER (CONTINUED)
LIGHT-LOAD SWITCHING WAVEFORMS
MAX8939 toc07
2V/div
100mA/div
10mV/div
(AC-COUPLED)VOUT1
VLX2
IL1
200ns/div
10mA LOAD
HEAVY-LOAD SWITCHING WAVEFORMS
MAX8939 toc08
2V/div
500mA/div
20mV/div
(AC-COUPLED)VOUT1
VLX2
IL1
200ns/div
700mA LOAD
OUT1 LOAD-TRANSIENT RESPONSE
(70mA TO 700mA TO 70mA)
MAX8939 toc09
200mA/div
500mV/div
(AC-COUPLED)
VOUT1
IOUT1
20µs/div
System Power Management
for Mobile Handset
MAX8939/MAX8939A/MAX8939B
Typical Operating Characteristics (continued)
(VBATT = 3.7V, circuit of Figure 1, TA = +25NC, unless otherwise noted.)
OUT2 WHITE LED DRIVER
LED EFFICIENCY vs. BATTERY VOLTAGE
2 STRINGS OF 5 LEDS
MAX8939 toc10
BATTERY VOLTAGE (V)
EFFICIENCY (%)
10.1mA/STRING
25.25mA/STRING
1.00mA/STRING
LED EFFICIENCY vs. BATTERY VOLTAGE
2 STRINGS OF 4 LEDS
MAX8939 toc11
BATTERY VOLTAGE (V)
EFFICIENCY (%)
10.1mA/STRING
25.25mA/STRING
1.00mA/STRING
LED RAMP-UP WAVEFORM
MAX8939 toc14
10mA/div
5V/div
2V/div
VOUT2
VSCL
ILED_
128ms SETTING, 0.05mA TO 25.25mA
LED STARTUP WAVEFORMS
MAX8939 toc12
200mA/div
10mA/div
2V/div
5V/div
VOUT2
VSCL
IL2
ILED
20µs/div
NO LOAD
OUT2 SWITCHING WAVEFORMS
MAX8939 toc13
100mA/div
5V/divVLX2
IL2
200ns/div
DRIVING 1 STRING OF 5 LEDS AT 25.25mA
System Power Management
for Mobile Handset
MAX8939/MAX8939A/MAX8939B
Typical Operating Characteristics (continued)
(VBATT = 3.7V, circuit of Figure 1, TA = +25NC, unless otherwise noted.)
LDOs
LDO OUTPUT VOLTAGE CHANGE
vs. LOAD CURRENT
MAX8939 toc15
LOAD CURRENT (mA)
OUTPUT VOLTAGE CHANGE (mV)
VBATT = 3.7V
DEFAULT OUTPUT VOLTAGE
LDO1
CURRENT
LIMIT
LDO3
LDO4
LDO2
LDO DROPOUT VOLTAGE
vs. LOAD CURRENT
MAX8939 toc16
LOAD CURRENT (mA)
DROPOUT VOLTAGE (mV)
LDO1
VBATT = 2.9V
OUTPUT SET TO 3.2V
LDO3
LDO2
LDO4
LDO SHUTDOWN WAVEFORMS
MAX8939 toc17
2V/div
2V/div
2V/div
2V/div
2V/div
1A/div
VLDO3
VLDO2
VLDO1
VSCL
VLDO4
IBATT
40µs/div
NO LOAD
CHARGE CURRENT
vs. BATTERY VOLTAGE
MAX8939 toc18
BATTERY VOLTAGE (V)
CHARGE CURRENT (mA)4123
VCHG_IN = 5V
VSET = 3.6V
DEFAULT CHARGER
SETTINGS
System Power Management
for Mobile Handset
MAX8939/MAX8939A/MAX8939B
Typical Operating Characteristics (continued)
(VBATT = 3.7V, circuit of Figure 1, TA = +25NC, unless otherwise noted.)
BATTERY CHARGER
VIBRATOR DRIVER
CHARGE CURRENT vs. CHG_IN VOLTAGE
MAX8939 toc19
CHG_IN VOLTAGE (V)
CHARGE CURRENT (mA)369
VBATT = 3.7V
VSET = 4.2V
IFC = 450mA
TEMP REG
+100˚C
VCHG_IN
FALLING
VCHG_IN
RISING
OVPUV
DEBOUNCE TIME FROM OVP DETECT
TO SHUTDOWN CHARGING
MAX8939 toc21
500mV/div
200V/div
50mA/div
CHGIN
ICHG
10ms/div
IRQ
CHARGER CONNECT WAVEFORM
MAX8939 toc20
2V/div
50mA/div
5V/div
2V/div
VSAFE_OUT
VCHG_IN
VCHG_MON
IBATT
4ms/div
VBATT = 3V
0.1µF CAPACITOR ON
CHG_MON
CHARGER CONTINUES CHARGING AT HIGH
INPUT RIPPLE > 7Hz AND DC LEVEL < OVP THRESHOLD
MAX8939 toc22
5.00V/div
2.00V/div
200mA/div
200mA/div
VCHG_IN
ICHG_IN
VBATT
LBATT
10ms/div
VIB DISABLE WAVEFORM
MAX8939 toc23
1V/div
ACTIVE BRAKE
3V OUTPUT, 50% DUTY CYCLE
50mA/div
VOUTVIB
IOUTVIB
System Power Management
for Mobile Handset
MAX8939/MAX8939A/MAX8939B
Bump Description
Bump Configuration
PINNAMEFUNCTIONPGND2Power Ground for WLED Boost Converter. Connect PGND1, PGND2, and AGND to the PCB
ground plane.LX2Inductor Connection and Switching Node for WLED Boost ConverterOUT2WLED Step-Up Converter Output. Connect a 1FF capacitor from OUT2 to PGND2.OUT1Step-Up Converter Output. Connect a 2.2FF capacitor from OUT1 to ground.LX1Inductor Connection and Switching Node for OUT1 Step-Up ConverterPGND1Power Ground for OUT1 Step-Up Converter. Connect PGND1, PGND2, and AGND to the PCB
ground plane.COMP2
Step-Up Compensation Node for OUT2 Step-Up Converter. Connect a 0.22FF ceramic capacitor
from COMP to ground. The applied COMP capacitance stabilizes the converter and sets the soft-
start time. COMP discharges to ground through a 20kI resistance when in shutdown. LED125mA LED Current Regulator. Connect LED1 to the cathode of the first LED string.RESET_INActive-Low Reset Input. Pulse RESET_IN low to reset all registers (except STATUS and EVENT) to
their default state. SCLClock Input for I2C Serial Interface. High impedance when the I2C interface is off.LDO1_ENEnable Input for LDO1. Drive LDO1_EN high to enable LDO1, or low to disable LDO1. Once LDO1 is
enabled or disabled through I2C, the state of LDO1_EN is ignored until reset.COMP1Compensation for OUT1 Step-Up Converter. Connect a 2200pF capacitor from COMP1 to ground.
See the Soft-Start OUT1 section for more details.
TOP VIEW(BUMPS ON BOTTOM)
WLP 0.5mm PITCH
LX2
LED1
LED2
OUTVIB
CHG_MON
OUT1
SCL
SDA
PWR_ON_CMP
BATT
PGND2A2A3A4A5A6B2B3B4B5B6C2C3C4C5C6D2D3D4D5D6E2E3E4E5E6
COMP2
LED3
SAFE_OUT
CHG_IN
LX1
LDO1_EN
LDO3
LDO4
AGND
PGND1
COMP1
LDO2
LDO1
REF
OUT2
RESET_IN
CHG
IRQ
INVIB
System Power Management
for Mobile Handset
MAX8939/MAX8939A/MAX8939B
Bump Description (continued)
PINNAMEFUNCTIONLED3Indicator LED Connection. Connect LED3 to the cathode of the precharge indicator LED. If a
precharge indicator LED is not used, leave LED3 unconnected.LED225mA LED Current Regulator. Connect LED2 to the cathode of the second LED string.CHGCharger Disable Input. Connect CHG high to disable the charger, or low to enable the charger. Once
the charger is enabled or disabled through I2C, the state of CHG is ignored until reset.SDAData Input for Serial Interface. High impedance when the I2C interface is off.LDO3200mA LDO Output. Connect a 2.2FF capacitor from LDO3 to ground. In shutdown, LDO3 is pulled
to ground through an internal 100I.LDO2200mA LDO Output. Connect a 2.2FF capacitor from LDO2 to ground. In shutdown, LDO2 is pulled
to ground through an internal 100I.SAFE_OUT
4.9V Regulated LDO Output with Input Overvoltage Protection. Connect a 1FF ceramic capacitor
from SAFE_OUT to ground. SAFE_OUT can be used to supply low-voltage-rated USB systems and
the precharge indicator.OUTVIBVibrator Driver Output. Connect OUTVIB to the vibrator motor. Connect a 1FF ceramic capacitor from
OUTVIB to ground.IRQInterrupt Request Open-Drain OutputPWR_ON
_CMP
Open-Drain Output to Wake Sleeping Baseband. PWR_ON_CMP pulses low while the charger is
connected. See the PWR_ON_CMP section for details.LDO4100mA LDO Output. Connect a 1FF capacitor from LDO4 to ground. In shutdown, LDO4 is pulled to
ground through an internal 100I.LDO1400mA LDO Output. Connect a 4.7FF capacitor from LDO1 to ground. In shutdown, LDO1 is pulled
to ground through an internal 50I.CHG_IN
Charger Input Supply Voltage. CHG_IN is the power-supply input for the SAFE_OUT linear regulator
and the battery charger. The operating range for the charger input is 4.1V to 10V (MAX8939) or
6.25V (MAX8939A/MAX8939B). CHG_IN is protected up to 28V. When VCHG_IN exceeds 10.6V
(MAX8939) or 6.75 (MAX8939A/MAX8939B), SAFE_OUT and the charger are disabled. Connect a
1FF or larger ceramic capacitor from CHG_IN to ground.CHG_MON
Charge Current Monitoring Analog Output. CHG_MON outputs a voltage proportional to the charge
current with 1.2V corresponding to the programmed fast-charge current. The CHG_MON output
includes ripple from loads on the battery. If this is not desired, connect a small 0.01FF to 0.1FF
capacitor at the input of the ADC to filter the ripple.INVIBInput Supply for the Vibrator Driver. Connect INVIB to BATT. Connect a 1FF ceramic capacitor from
INVIB to PGND.BATTBattery Connection and IC Supply Voltage. Connect a 10FF ceramic capacitor from BATT to ground.AGNDAnalog Ground. Connect PGND1, PGND2, and AGND to the PCB ground plane.REFReference Noise Bypass. Connect a 0.1FF ceramic capacitor from REF to AGND. Do not load. REF is
high impedance when shut down.
System Power Management
for Mobile Handset
MAX8939/MAX8939A/MAX8939B
Table 1. Output Summary
*Subject to valid voltage present at CHG_IN.
SUPPLYOUTPUT
RANGE
DEFAULT
STATE AT
POWER-UP
DEFAULT
VALUE (V)
VOLTAGE
TOLERANCE
(%)
OUTPUT
CURRENT
(mA)
DESCRIPTION
LDO11.7V to 3.2V
in 100mV stepOff2.9Q3.0400
Low-noise LDO to supply power either to
the RF or analog section. LDO1 is controlled
from the I2C bus or the LDO1_EN input.
LDO21.7V to 3.2V
in 100mV stepOff1.8Q3.0200
Low-noise LDO to supply power either to
the RF or analog section. LDO2 is controlled
from the I2C bus.
LDO31.7V to 3.2V
in 100mV stepOff2.8Q3.0200
Low-noise LDO to supply power either to
the RF or analog section. LDO3 is controlled
from the I2C bus.
LDO41.7V to 3.2V
in 100mV stepOff2.8Q3.0100
Low-noise LDO to supply power either to
the RF or analog section. LDO4 is controlled
from the I2C bus.
OUT1
(STEP-UP)
3.5V to 5.0V
in 100mV stepOff5Q3.0700
The OUT1 step-up converter provides a 5V
power supply for an audio amplifier. The
output voltage is programmable through I2C.
OUT2
(LED)VBATT to 28VOffN/AN/A60
The OUT2 step-up converter operates at
2MHz and provides a high-voltage source for
the keypad and backlight display drivers.
OUTVIB
(Vibrator)
1.3V, 2.5V,
3V, or INVIB
bypass
Off3Q3.0200
High-power vibrator driver with
programmable output voltage and speed
control in 70 steps through I2C. The vibrator
driver has active brake with stop.
Battery
Charger
One-cell Li+
MAX8939:
3.6V, 4.15V,
4.20V, or 4.25V
MAX8939A/
MAX8939B:
3.50V, 3.85V,
4.05V, or 4.17V
N/A*
MAX8939:
MAX8939A/
MAX8939B:
Q0.6
90 default
MAX8939:
1.3A (max)
MAX8939A/
MAX8939B:
850mA (max)
A stand-alone constant-current, constant
voltage (CC/CV), thermally regulated linear
charger designed for charging a single-cell
lithium-ion (Li+) battery. The charger current
and protection timer is programmable
through I2C.
SAFE_OUT4.9VN/A*4.9Q3.0100 (max)
Protected output SAFE_OUT can be used to
supply low-voltage-rated USB systems and
the precharge indicator. The output voltage
is a fixed 4.9V.
System Power Management
for Mobile Handset
MAX8939/MAX8939A/MAX8939B
DC/USB INPUT
MAX8939: 4.10V TO 10V
MAX8939A/MAX8939B: 4.10V TO 6.25V
(PROTECTED UP TO 28V)
4.9V
BATT
BATT
CHG_IN
10µH
1µF
0.22µF
10µF
10µF
4.7µF
2.2µF
2.2µH
Li+
BATTERY
SAFE_OUT
LED3
1µF
1µF
LDO
DISABLE
I/V
SYSTEM
BATT2.9V TO 5.5V
3.5V TO 5V, 700mA
1.7V TO 3.2V, 400mA
CC/CVREG
LI+ LINEAR CHARGER CONTROL
PRE_CHG
INDICATION
CHG
LDO1_EN
CHG_MON
LDO1
OUT1
ON/OFF CONTROL
UVLO AND POR
AND I2C INTERFACE
LX2
OUT2
PGND2
RAMP TIMER BLINK
RATE AND DUTY
CYCLE
LED BOOST
CONVERTER
COMP2
LED1
LED2
INVIB
SCL
PWR_ON_CMP
SDA
IRQ
RESET_IN
BATT
CONTROLCONTROL
CONTROLCONTROL
CONTROL
OUTVIB
200mA
1.3V, 2.5V, 3.0V,
OR VBATT
1µF
1µF
1µF
LX1
PGND1
COMP1
2200pF
BATTPWM
BOOST
CONVERTOR
LDO1
2.2µF
1.7V TO 3.2V, 200mALDO2BATT
CONTROL
LDO2
2.2µF
1.7V TO 3.2V, 200mALDO3BATT
CONTROL
LDO3
1µF
0.1µF
1.7V TO 3.2V, 100mALDO4
REF
AGND
BATT
CONTROL
LDO4
BATT1.2V
REFERENCE
MAX8939
MAX8939A
MAX8939B
PGND
PWM
VIB DRIVER
System Power Management
for Mobile Handset
MAX8939/MAX8939A/MAX8939B
Figure 2. MAX8939/MAX8939A/MAX8939B State Diagram
ACTIVEONE OR MORE SUPPLY
IS ENABLED
STANDBYI2C ACTIVE
READDEFAULT SETTING
ENABLE
BAND-GAP AND
INTERNAL OSC
0.5ms
UVLO UPPER
OVER_TEMPUVLO UPPER
THRESHOLD
I2C READ/WRITE
I2C
LDO1_ENUVLO UPPER
THRESHOLD
ENABLE SIGNAL TO
CONTROL LDO1
RESETVBATT < VUVLO
WAKE-UPCHG_DET
VBATT
SAFE_OUTCHARGER ASSERTED
RETURN TO RESETVBATT < VUVLO
RESET_IN = HIGH OR
CHG_DET = 1 AND
CHG = LOW
PWR_ON_CMP
IRQ
RETURN TO STANDBYALL SUPPLIES
DISABLED BAND-GAP
AND INTERNAL OSC
DISABLED IF CHARGER
NOT CONNECTED
SHUTDOWNRESET_IN = LOW
RETURN TO
SHUTDOWNRESET_IN = LOW
IRQ IS ASSERTED
AND EVENT BIT IS SET
CHARGER ASSERTED
PWR_ON_CMP = HIGH Z
WHEN IRQ REGISTER
IS WRITTEN
System Power Management
for Mobile Handset
MAX8939/MAX8939A/MAX8939B
Figure 3. Battery Charger State Diagram
PRECHARGEPRECHARGE CURRENT
MAX8939 TIMEOUT: 30min
MAX8939A/B TIMEOUT: 12min
VBATT > 2.55VVBATT < 2.4V
FAST-CHARGEMAX8939 DEFAULT: 60min TIMEOUT
MAX8939A/B DEFAULT: 24min TIMEOUT
AND 90mA IFAST-CHARGE
VSET > 3.5V (MAX8939)
OR 3.6V (MAX8939A)
TOP-OFFCONSTANT VOLTAGE MODE (CV)
DEFAULT: 30min TIMEOUT
OR 10% OF IFAST-CHARGE
CHARGING CURRENT IS
REDUCED
AS NECESSARY
ANY CHARGING
STATE
DIE TEMPERATURE
DEFAULT > +100°C
DIE TEMPERATURE
< + 100°C
DONE IFTOP-OFF TIMEOUT
CHARGE CURRENT < TOP-OFF
THRESHOLD AND VBATT = VSET
IF VBATT = VSET
VBATT < 2.5V
RESTART IFVBATT < RESTART
THRESHOLD OR
CHG_EN
CHARGER DETECTCHG = 0, VCHG_IN > 4.1V,
VCHG_IN < 10V (MAX8939) OR
6.25V (MAX8939A/B), AND
(VCHG_IN - VBATT) > 250mV
CHARGER DISABLEDCHG = 1, VCHG_IN < 4.1V,
(VCHG_IN - VBATT) < 250mV,
THERMAL SHUTDOWN,
OR OVP TIMEOUT
CHARGE DONE
IRQ STATUSTOP-OFF
ENTERING (CV)
IRQ STATUSFAST-CHARGE
CONSTANT
CURRENT (CC)
RETURN TO
CHARGING
STATE
STATUSTOP-OFF OR FAST_CHG
TIMER EXPIRE
IRQRESET TO DEFAULT
IF UVLO = LOW
OR RESET = LOW
THE CHARGE TIMER
IS RESET IF RESET = LOW
BY REASSERTED CHG_IN
OR CHG_EN. IF RESET =
HIGH, THE TIMER IS RESET
BY ENABLING CHG_EN.
TIMEOUTIF ANY TIMER EXPIRES OR
WATCHDOG TIMES OUT, THE
CHARGER IS DISABLED
OVP
VCHG_IN > 10.6V (MAX8939)
OR 6.75V (MAX8939A/B)
OVP
ENABLE THE CHARGER
FOR 250ms
OVP TIMER EXPIRES
FROM ANY CONDITION
CHG_IN
System Power Management
for Mobile Handset
MAX8939/MAX8939A/MAX8939B
Detailed Description
Startup and Power States
To guarantee the correct startup of the MAX8939/
MAX8939A/MAX8939B, an internal power-on reset is
generated after the first connection of the battery. This
resets the I2C registers to the default values. The ICs
are then in reset state. The reset state is a low power
level, where the I2C interface is disabled and it is not
possible to read or write to any register. The ICs stay in
reset state as long as VBATT is below the UVLO upper
threshold. When the battery voltage exceeds the UVLO
upper threshold, the ICs enter the standby state and the
I2C bus can be written to. The typical response time of
the UVLO detection is 50µs.
The UVLO upper threshold can be reached three ways:Fully charge battery is inserted and RESET is logic-high.RESET changes from logic-low to logic-high and
VBATT > VUVLO_UPPER.Charger is detected and CHG is logic-low.
Standby
Standby is a low-power state where the I2C is ready
for read/write operations and enables the different
power units (Table 1). If a unit is enabled through I2C or
CHG_IN is powered, the bandgap and internal oscillator
are started and the ICs move to the active state. The ICs
stay in the active state until the last unit (including the
charger) is disabled.
Reset
The ICs enter the reset state when the battery voltage
drops below the UVLO lower threshold. In reset, all reg-
isters are reset except the STATUS and EVENT registers
that retain their values as long as the battery is con-
nected. In reset, all power units are disabled and only
the UVLO and CHG_IN detection circuitry is active. If a
fully charged battery is inserted or a charger is detected,
the ICs enter standby. If a valid charger is connected,
the state machine enables the PWR_ON_CMP generator
and an interrupt is sent to the host when above the UVLO
upper threshold. When a valid charger is detected while
in the reset state, the SAFE_OUT LDO is enabled and the
charger begins precharging the battery.
Shutdown
The shutdown state is an extremely low-power state. To
enter shutdown, hold RESET logic-low.
In shutdown, all the internal blocks are disabled except
the CHG_IN detection. If CHG_IN is asserted, the ICs
move to the reset state and starts charging with the
default settings. When entering from shutdown, the
charger is reset and the PWR_ON_CMP generator is
enabled. If the charger is removed, the ICs move back
to the shudown state if RESET is still logic-low.
Charger
The ICs’ charger uses voltage, current, and thermal-
control loops to charge a single Li+ cell and to protect
the battery. A complete charge cycle covers four states:
prequalification (precharge), constant current fast-
charge (CC), constant voltage top-off (CV), and charge
complete (done). If the battery voltage is below 2.55V,
the charger is pre-charging with 90mA until prequalifica-
tion upper threshold is reach or the maximum precharge
time (30min for the MAX8939 or 12min for the MAX8939A
and MAX8939B) reached. The precharge timer is reset
when CHG_IN is reasserted, and the charger starts
charging if the battery voltage is below the precharge
threshold. When the charger is in precharge mode,
an LED indicator (LED3) and the SAFE_OUT LDO are
turned on; all other functions are disabled.
Once the battery voltage has passed the prequalification
upper threshold, the charger enters the fast-charge stage.
An analog soft-start is used when entering fast charge
to reduce inrush current on the input supply. When fast-
charge is in progress, a safety timer is enabled and STATUS
can be read out of register 0x02 bit 4. For the MAX8939/
MAX8939A, the CHG_EN is cleared and starts charging
if CHG_IN is asserted. The MAX8939B clears CHG_EN
only if RESET is logic-low. By pulling RESET logic-high, the
charger is disabled or enabled depending on the state of
the CHG_EN bit. When CHG_IN is asserted, an interrupt
occurs, and the host can control the state of the CHG_IN bit.
The fast-charge current and safety timer are programmable
through the I2C interface. The safety timers are reset if the
charger is disabled and start a new cycle when the charger
is enabled. The default battery regulation voltage (VSET) is
3.6V (MAX8939) or 3.5V (MAX8939A/MAX8939B), but can
be programmed to 4.15V, 4.2V, or 4.25V for the MAX8939,
or 3.85V, 4.05V, or 4.17V for the MAX8939A/MAX8939B.
When the battery voltage reaches VSET, the charger
changes to top-off mode (CV). When entering top-off, an
IRQ is flagged to indicate that the charger is in constant
voltage mode. Top-off mode keeps the voltage constant
and the current falls slowly until the top-off current thresh-
old is reached. An IRQ is flagged to indicate charge is
System Power Management
for Mobile Handset
MAX8939/MAX8939A/MAX8939B
done. The top-off current threshold is a percentage of
the fast-charge current, the threshold is programmable.
When the top-off current threshold is set to 0% and
restart is disabled, the top-off mode continues until the
top-off timer expires. The top-off timer is programmable
and can also be disabled. With the op-off threshold set
to 0% and top-off timer disabled, the charger continu-
ously charges the battery with a constant voltage and
decreasing charge current. This makes it possible to
control the charge algorithm through software, without
influence of automatic maintaining charge.
To qualify charge as done, the current has to be below top-
off current threshold or a timeout has occurred. To main-
tain the battery voltage, the charger can be programmed
to restart once the battery voltage drops below a program-
mable threshold. When restart is enabled and the battery
voltage drops below the restart threshold, the charger
starts a new charging cycle by entering fast-charge.
If restart is disabled, the charger stops charging when
done and does not maintain the battery voltage. When
charge done occurs, an IRQ is sent to the host and a
flag is set in register 0x03. Reading the register disables
the charger. The charger can be enabled by writing to
register 0x09 bit 0 (CHG_EN). If one of the safety timers
(fast-charge or top-off) expires, an interrupt is sent to
the host and a flag is set in register 0x03. The charger is
disabled 5s after the safety times out.
If, at any point while charging the battery, the die tem-
perature approaches the thermal regulation threshold
(+100°C default), the ICs reduce the charging current
so that the die temperature does not increase. This fea-
ture not only protects the ICs from overheating, but also
allows the higher charge current without risking damage
to the system.
Note all charger registers are reset to their default set-
tings by power-on reset (POR) or RESET.
Charge On/Off Control
CHG is a logic hardware control input. Logic-high disables
the charger and logic-low enables the charger.
1. CHG = logic-high, the charger is disabled when
power pluck is asserted on CHG_IN and register
0x09 has not been affected. When CHG changes
logic state, a flag is set in the event register 0x03,
and an interrupt occurs.
2. CHG = Logic-low, the charger is enabled and starts
charging if charging conditions are within operating
limits.
Once the CHG_CONTROL_A register 0x09 is accessed
either by reading or writing, the CHG is ignored. When CHG
changes status after register 0x09 has been accessed,
only STATUS and EVENT_A register is updated and an
interrupt occurs. The CHG_EN bit in CHG_CONTROL_A
register 0x09 is always [1] by default. The CHG_EN does
not follow the status of CHG, and the charger is enabled
just by reading the CHG_CONTROL_A register 0x09 and
CHG is ignored. To avoid the charger enabling just by
accessing the CHG_CONTROL_A register 0x09, write [0]
in the CHG_EN bit.
For the MAX8939 and MAX8939A, if the CHG_IN is
reconnected, the CHG is reset and the status of the
charger is following the logic level on CHG, as long
CHG_CONTROL_A register 0x09 is not affected. For the
MAX8939B, the CHG is reset only by reasserting CHG_IN
if RESET or UVLO is low.
SAFE_OUT
SAFE_OUT is an LDO powered from the CHG_IN input.
SAFE_OUT is enabled when a charger is detected (4.1V VCHG_IN < 10V (MAX8939) or 6.25V (MAX8939A/
MAX8939B)) and provides a protected output regulated to
4.9V (5V max). Typically, SAFE_OUT is used to power low-
voltage USB systems and the precharge indicator.
Indicator LED
The LED3 output sinks 3mA (typ) to drive an indica-
tor LED. LED3 is on by default and can be controlled
by the host by I2C (bit 7 of the REG_CONTROL
register). Typically, this LED indicates charge status
and SAFE_OUT powers the LED as shown in Figure 1.
Charge Current Monitor (CHG_MON)
CHG_MON is an analog output used to monitor the
charge current. CHG_MON outputs a voltage propor-
tional to the charge current with 1.2V corresponding to
the programmed fast-charge current.
The CHG_MON output includes ripple from loads on the
battery. If this is not desired, connect a small 0.01FF to
0.1FF capacitor at the input of the ADC to filter the ripple.
Charger Watchdog Timer
During battery fast-charge, a watchdog monitoring func-
tion can be activated to ensure that the host processor
has control of the charge algorithm. The watchdog timer
is enabled through register REG_CONTROL bit WD_EN.
When the charger is enabled by CHG_EN or CHG_IN,
the watchdog timer starts counting. Within 5s of enabling
the charger, the host must read or write register 0x09
or 0x0A to indicate it is alive. This resets the watchdog
System Power Management
for Mobile Handset
MAX8939/MAX8939A/MAX8939B
timer and the host must continue to read or write register
0x09 or 0x0A in intervals of under 5s. If the host takes
more than 5s for reading or writing these registers, the
watchdog timer expires, generates an interrupt, flags
the watchdog timeout in register 0x03, and disables the
charger (Figure 4).
Charge in Overvoltage Protection
To detect that a valid charger is asserted at CHG_IN, an
upper and lower threshold is defined. This threshold is
different for the MAX8939, MAX8939A, and MAX8939B.
See the Electrical Characteristics table for upper/lower
threshold.
If an overvoltage condition occurs on CHG_IN, a de-
bounce timer is enabled and powers the charger down
after a max delay of 324ms. When the charger is pow-
ered down, an interrupt occurs and a flag is set in event
register A.
This OVP timer enables the possibility of using a low
cost wall-plug adapter with poor voltage regulation. The
charger continue charging and no interrupt occurs as
long the OVP is not violating the max 324ms.
Fast thermal regulation ensures that the temperature
does not exceed the programmed value (default is
programmed at +100NC at high voltage < 30V and maxi-
mum charge current). If the junction temperature rises
until the programmed value, the charge current is not
switched off, but regulated down to a level to maintain
the temperature around the programmed threshold.
Interrupt Request (IRQ)
IRQ is an active-low, open-drain output signal (requires
an external pullup resistor) that indicates that an interrupt
event has occurred and that the event and status infor-
mation are available in the event/status registers. Such
information includes temperature and voltages inside
the ICs fault conditions, etc. The event registers hold
information about events that have occurred in the ICs.
Events are triggered by a status change in the monitored
signals. When an event bit is set in the event register, the
IRQ signal is asserted (unless IRQ is masked by a bit in
the IRQ mask register). The IRQ is also masked during
power-up and is not released until the event registers
have been read. Each event register is reset to its initial
condition after being read. The IRQ is not released until
all the event registers have been read. New events that
occur during read-out of the event registers are held until
all the event registers have been read to, ensuring that
the host processor does not miss them.
PWR_ON_CMP is an open-drain output used to wake-up
a sleeping baseband. PWR_ON_CMP is activated when
a charger is detected (VCHG_IN is between 4.1V and
10V (MAX8939) or 6.25V (MAX8939A/MAX8939B)) and
the battery voltage is above the UVLO threshold. If the
battery has already reached the UVLO upper threshold,
the charger is detected by a rising edge. When such an
1ms
50ms
UVLO
UPPER THRESHOLD
UVLO AND CHARGER
DETECTION EVENT
ALL EVENT REGISTERS
ARE READ. PWR_ON_CMP
AND IRQ ARE CLEARED
CHARGER
REMOVAL
EVENT
ALL EVENT
REGISTERS
ARE READ.
IRQ IS CLEARED.
VCHG_IN
VBATT
IRQ
PWR_ON_CMP
THE WATCHDOG
TIMER EXPIRES
CHARGER
DISABLED
WATCHDOG_EN
CHG_EN/DET
WATHCDOG
TIMER
RESET TIMER
IRQ
HOST READ
OR WRITE
CHARGE
REGISTERS
t < 5st = 5s
System Power Management
for Mobile Handset
MAX8939/MAX8939A/MAX8939B
event is detected, the ICs start pulsing the PWR_ON_
CMP output every 50ms, with a duty cycle of 98%. See
Figure 5.
The event is also signaled by IRQ, which is asserted
when the UVLO upper threshold is reached and the
CHG_DET bit is set in register 0x04 (bit 6). The ICs con-
tinue pulsing PWR_ON_CMP until the EVENT registers
0x04 or 0x03 are read/written to or the charger safety
timer expires. By reading/writing to the EVENT register,
the register is cleared and PWR_ON_CMP and IRQ
returns to high impedance.
The events causing the PWR_ON_CMP activation are
triggered by a rising edge signal that must remain valid
for the duration of a 10ms debounce filter.
RESET_IN
RESET_IN is an active-low input signal to the ICs and is
used to provide a full system reset inside the ICs. As long
as RESET_IN is logic-low, the ICs are not able to do any-
thing (except the charger), until RESET_IN is released.
All registers are cleared except the STATUS and EVENT
registers. When RESET_IN is asserted, the EVENT_B bit
RESET is set. If the CHG_IN voltage is valid and RESET_
IN is logic-low, the charger operates in its default state.
Linear Regulators
The ICs include four low-dropout linear regulators
(LDOs). All LDOs are designed for low dropout, low
noise, high PSRR, and low quiescent current to maximize
battery life. When the battery voltage is above the UVLO
upper threshold, the ICs’ LDOs are ready to be turned on
through the I2C interface. The guaranteed current drive
capabilities for the LDOs are 400mA for LDO1, 200mA
for LDO2 and LDO3, and 100mA for LDO4. The output
voltage for each LDO is programmable through the I2C
interface from 1.7V to 3.2V in 0.1V steps.
LDO1 can be enabled through a hardware pin
LDO1_EN. By connecting this pin to a logic-high level,
the LDO enables automatically when the UVLO upper
threshold is reached. The LDO can also be controlled
by the LDO1_EN bit of the REG_CONTROL. When the
LDO1_EN bit is written to, the LDO1 enable state reflects
the value written, overriding the state of the LDO1_EN
pin. When the state of the LDO1_EN pin changes, the
LDO1 enable state is determined by the new state of the
LDO1_EN pin, overriding the LDO1_EN bit value. This
allows the system software to reduce quiescent power
consumption by turning off LDO1 without impacting
other logic that may utilize the same hardware control
used for the LDO1_EN pin.
OUT1 Step-Up DC-DC Converter
OUT1 is a fixed-frequency PWM step-up converter.
The converter switches an internal power MOSFET and
synchronous rectifier at a constant 2MHz frequency with
varying duty cycle up to 75% to maintain constant out-
put voltage as the input voltage and load current vary.
Internal circuitry prevents any unwanted subharmonic
switching in the critical step-down/step-up region by
forcing a minimum 8% duty cycle.
OUT1 delivers up to 700mA to the load at a voltage pro-
grammable through I2C from 3.5V to 5V in 100mV steps.
Soft-Start OUT1
OUT1 soft-starts by charging CCOMP1 with a 100FA
current source. During this time, the internal MOSFET
is switching at the minimum duty cycle. Once VCOMP1
rises above 1V, the duty cycle increases until the output
voltage reaches the desired regulation level. COMP1
is pulled to ground with a 30I internal resistor during
UVLO or shutdown.
OUT2 White LED Driver
OUT2 is the output from the step-up DC-DC converter
for driving white LEDs. The converter is able to drive up
to 60mA at up to 28V. The step-up converter is adaptive
connected to the two low-dropout LED current regula-
tors. The step-up converter operates at a fixed 2MHz
switching frequency, enabling the use of very small
external components to achieve a compact circuit area.
For improved efficiency, the step-up converter automati-
cally operates in pulse-skipping mode at light loads.
ILED_= FULL SCALE
ILED_= ½ SCALE
0mA
ILED_= FULL SCALE
ILED_= ½ SCALE
0mA
256ms512ms1024ms2048ms
256ms512ms1024ms2048ms
