Datasheet

MAX1925/MAX1926
Switch-Mode 1-Cell Li+ Chargers
4 _______________________________________________________________________________________
ELECTRICAL CHARACTERISTICS
(V
PGND
= V
GND
= 0, V
INP
= V
IN
= V
CHG
= 5V, V
BATT
= V
CS
= V
EN
= 4V, THRM = 10kΩ to GND, C
CT
= 100nF, T
A
= -40°C to +85°C,
unless otherwise noted. Typical values are at T
A
= +25°C.) (Note 4)
PARAMETER CONDITIONS MIN TYP MAX UNITS
Supply Voltage Range V
INP
, V
IN
(MAX1925 does not charge above 6.1V) 4.5 12.0 V
MAX1925 4.30 4.78
V
INP
, V
IN
rising
MAX1926 4.0 4.5
MAX1925 4.17 4.43
ACON Trip point
V
INP
, V
IN
falling
MAX1926 3.9 4.4
V
Rising 5.8 6.4
INP, IN Shutdown Threshold MAX1925
Falling 5.3 5.9
V
EN Input Resistance MAX1926 internally pulled up to 3V 125 550 kΩ
EN Leakage Current MAX1925 -1 +1 µA
EN Logic Input High Threshold 2 V
EN Logic Input Low Threshold 0.8 V
DONE State, V
BATT
= 4.1V 50
EN = GND (Note 2) 10
BATT + CS Input Current
(Total Current into BATT and CS)
V
BATT
= V
INP
= V
IN
= 4V, shutdown (Note 1) 10
µA
EN = GND 8 mA
V
BATT
= V
INP
= V
IN
= 4V, shutdown 10 µA
V
BATT
= 4.1V, charging 10
IN + INP Total Input Current
V
BATT
= 4.3V, done 8
mA
VOLTAGE LOOP
Voltage Loop Set Point 4.158 4.242 V
BATT Prequal1 Voltage Threshold 1.9 2.1 V
BATT Prequal2 Voltage Threshold 2.85 3.15 V
Restart Threshold Charging restarts when BATT falls to this point 3.92 4.08 V
BATT Voltage Fault Threshold
If BATT exceeds this threshold, EXT is high (external
MOSFET is off) and CHG blinks
4.275 4.425 V
CURRENT LOOP
CS - BATT Sense Threshold V
CS
- V
BATT
, average value 127 157 mV
Prequal1 Charge Current V
BATT
< 2V 3 6 mA
Current Threshold for Full-Battery
Indication
I
LOAD
falling, as percentage of fast charge current 4 20 %
DRIVER FUNCTIONS
EXT On-Resistance EXT high or low 12 Ω
TIMER FUNCTIONS
Timer Accuracy C
CT
= 100nF for 3 hours -16 +16 %
CHG Output Low Current V
CHG
= 1V 7 14 mA