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Part: MAX1926
Category:
Power Management
-> Battery Management
Description: MAX1925, MAX1926 Switch-mode 1-Cell Li+ Chargers
Company: Maxim Integrated Products
Datasheet: Download MAX1926 datasheet File size : 649 kB
Request For quote: Find where to buy MAX1926
Datasheet text preview:
19-2556; Rev 1; 10/02
KIT ATION EVALU ABLE AVAIL
Switch-Mode 1-Cell Li+ Chargers
General Description Features
o Small (4mm 4mm) Package o 4.25V to 12V Input Range (MAX1926) o Overvoltage Lockout at 6.1V (MAX1925) o ±0.75% Battery Regulation Voltage o Set Charge Current with One Resistor o Automatic Input Power Sense o LED (or Logic-Out) Charge Status and Fault Indicator o Programmable Safety Timer o Autorestart at Cell = 4V o Thermistor Monitor Input
MAX1925/MAX1926
T h e MAX1925/MAX1926 single-cell lithium-ion (Li+) switch-mode battery chargers use an external PMOS pass element step-down configuration. Charge current is programmable, and an external capacitor sets the maximum charge time. A d d i t i o n a l features include automatic input power detection (ACON output), logic-controlled enable, and temperature monitoring with an external thermistor. The M A X 1 9 2 5 disables charging for inputs greater than 6.1V, while the MAX1926 charges for inputs between 4.25V and 12V. The MAX1925/MAX1926 feature two precondition levels to restore near-dead cells. The devices source 4mA to a cell that is below 2V while sourcing C/10 to a cell between 2V and 3V. Full charge current is then applied a b o v e 3V. A CHG o u t p u t drives an LED to indicate charging (LED on) and fault conditions (LED blinking). T h e MAX1925/MAX1926 are available in a 12-pin 4mm 4mm thin QFN package and are specified over the extended temperature range (-40°C to +85°C). An evaluation kit is available to speed design.
Ordering Information
PART TEMP RANGE -40°C to +85°C -40°C to +85°C PINPACKAGE 12 Thin QFN 4mm x 4mm 12 Thin QFN 4mm x 4mm INPUT CHARGING RANGE 4.5V to 6.1V 4.25V to 12V
Applications
Digital Cameras Self-Charging Battery Packs PDAs Cradle Chargers
MAX1925ETC MAX1926ETC
Typical Operating Circuit Pin Configuration
IN 12 INP 11 EXT 10
IN INP EXT PGND CS INPUT 4.5V TO 12V
CHG EN THRM
1 2 3
9
PGND GND BATT
LED CHG BATT CT
MAX1925 MAX1926
8 7
MAX1925 MAX1926
GND
THRM
4 ACON
5 CT
6 CS
ON OFF
EN
ACON
1-CELL Li+ BATTERY
THIN QFN
________________________________________________________________ Maxim Integrated Products
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For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at 1-888-629-4642, or visit Maxim's website at www.maxim-ic.com.
Switch-Mode 1-Cell Li+ Chargers MAX1925/MAX1926
ABSOLUTE MAXIMUM RATINGS
IN, INP, ACON to GND..........-0.3V to +14V CHG, EXT to PGND ..-0.3V to (VINP + 0.3V) CS, BATT, EN, THRM to GND ..........-0.3V to +6V CT to GND .......-0.3V to +4V EN, THRM, CT to IN......-14V to +0.3V INP to IN .......-0.3V to +0.3V PGND to GND .......-0.3V to +0.3V CS to BATT ...-0.3V to +0.3V EXT Continuous RMS Current........±100mA Continuous Power Dissipation (TA = +70°C) Exposed Paddle Soldered to Board (derate 16.9mW/°C above +70°C) .....1349mW Exposed Paddle Unsoldered (derate 9mW/°C above +70°C) ...721mW Operating Temperature Range ...-40°C to +85°C Junction Temperature ......+150°C Storage Temperature Range .....-65°C to +150°C Lead Temperature (soldering, 10s) .........+300°C
Stresses beyond those listed under "Absolute Maximum Ratings" may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.
ELECTRICAL CHARACTERISTICS
(VPGND = VGND = 0, VINP = VIN = V CHG = 5V, VBATT = VCS = VEN = 4V, THRM = 10k to GND, CCT = 100nF, TA = 0°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C.)
PARAMETER Supply Voltage Range CONDITIONS VINP, VIN (MAX1925 does not charge above 6.1V) VINP, VIN rising ACON Trip Point VINP, VIN falling INP, IN Shutdown Threshold EN Input Resistance EN Leakage Current EN Logic Input High Threshold EN Logic Input Low Threshold BATT + CS Input Current (Total Current into BATT and CS) CS Input Current DONE state, VBATT = 4.1V EN = GND (Note 1) VBATT = VINP = VIN = 4V, shutdown (Note 1) Charging EN = GND IN + INP Total Input Current VBATT = VINP = VIN = 4V, shutdown VBATT = 4.1V; charging VBATT = 4.3V; done VOLTAGE LOOP Voltage Loop Set Point Voltage Loop Hysteresis BATT Prequal1 Voltage Threshold BATT Prequal2 Voltage Threshold 1.9 2.85 4.1685 4.2000 15 2 3 2.1 3.15 4.2315 V mV V V 5 25 2 2 39 5 2 8 10 10 8 MAX1925 MAX1925 MAX1926 MAX1925 MAX1926 Rising Falling MIN 4.5 4.30 4.00 4.17 3.90 5.8 5.3 125 -1 2 0.8 50 10 10 µA mA µA mA µA 300 4.50 4.25 4.30 4.15 TYP MAX 12.0 4.78 4.50 4.43 4.40 6.4 5.9 550 +1 V k µA V V V UNITS V
MAX1926 internally pulled up to 3V MAX1925
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Switch-Mode 1-Cell Li+ Chargers
ELECTRICAL CHARACTERISTICS (continued)
(VPGND = VGND = 0, VINP = VIN = V CHG = 5V, VBATT = VCS = VEN = 4V, THRM = 10k to GND, CCT = 100nF, TA = 0°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C.)
PARAMETER Restart Threshold BATT Voltage Fault Threshold CURRENT LOOP CS - BATT Sense Threshold Prequal1 Charge Current Prequal2 CS - BATT Sense Threshold Current Threshold for Full-Battery Indication DRIVER FUNCTIONS EXT Sink/Source Current EXT On-Resistance Nominal Switching Frequency TIMER FUNCTIONS Full-Time Timeout - tFULL Prequal1 Timeout Prequal2 Timeout Timer Accuracy CHG Output Low Current CHG Output High Leakage Current CHG Blink Rate - Fault ACON High Leakage ACON Sink Current THERMISTOR MONITOR (Note 2) THRM Sense Current for Hot Qualification THRM Sense Current for Cold Qualification THRM Sense-Voltage Trip Point (Note 3) 344.1 47.58 1.386 352.9 48.80 1.400 361.7 50.02 1.414 µA µA V CCT = 100nF CCT = 100nF CCT = 100nF CCT = 100nF for 3 hours VCHG = 1V VCHG = 12V Fault state (50% duty cycle), CCT = 100nF VACON = 12V VACON = 0.4V 2 0.5 0.01 1.00 -15 7 10 3.02 tFULL/1088 (10s) tFULL/17 (10.67 min) +15 14 1 hours s min % mA µA Hz µA mA EXT high or low VBATT = 3.6V, L =10µH 1 5 235 12 A kHz VCS - VBATT, average value Rise/fall hysteresis VBATT < 2V Average value, 2V < VBATT < 3V (charge current is C/10) Rise/fall hysteresis, 2V < VBATT < 3V ILOAD falling, as percentage of fast charge current 6 3 132 142 30 4 14 12 12 20 6 152 mV mA mV % CONDITIONS Charging restarts when BATT falls to this point If BATT exceeds this threshold, EXT is high (external MOSFET is off) and CHG blinks MIN 3.92 4.275 TYP 4.00 4.350 MAX 4.08 4.425 UNITS V V
MAX1925/MAX1926
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