MAX1758
Stand-Alone, Switch-Mode
Li+ Battery Charger with Internal 28V Switch
8 _______________________________________________________________________________________
NAME FUNCTION
1 VL
Chip Power Supply. Output of the 5.4V linear regulator from DCIN. Bypass VL to GND with 2.2µF or larger
ceramic capacitor.
2 ISETIN
Input Current Limit Adjust. Use a voltage-divider to set the voltage between 0 and V
REF
. See Input Current
Regulator section.
PIN
3 ISETOUT
Battery Charging Current Adjust. Use a voltage-divider to set the voltage between 0 and V
REF
. See
Charging Current Regulator section.
4 THM
Thermistor Input. Connect a thermistor from THM to GND to set qualification temperature range. If unused,
connect a 10kΩ resistor from THM to GND. See Thermistor section.
8 BATT Battery Voltage-Sense Input and Current-Sense Negative Input
7 VADJ
Voltage Adjustment. Use a voltage-divider to set the voltage between 0 and V
REF
to adjust the battery reg-
ulation voltage by ±5%. See Battery Regulation Voltage section.
6 GND Analog Ground
5 REF 4.2V Reference Voltage Output. Bypass REF to GND with 1µF or larger ceramic capacitor.
13 TIMER2 Timer2 Adjustment. Connect a capacitor from TIMER2 to GND to set the fast-charge time. See Timers section.
12 TIMER1
Timer1 Adjustment. Connect a capacitor from TIMER1 to GND to set the prequalification, full-charge, and
top-off times. See Timers section.
11 CELL
Cell-Count Programming Input. Connect CELL to GND, REF, or VL to set 1, 3, or 4 cells, or leave uncon-
nected to set 2 cells.
9, 10 HSD High-Side Drain. This is the drain of the internal high-side FET. See Figure 3.
Pin Description
14
FAULT
Charge Fault Indicator. Open-drain output pulls low when charging terminates abnormally. See Table 1.
15
FASTCHG
Fast-Charge Indicator. Open-drain output pulls low when charging with constant current.
16
FULLCHG
Full-Charge Indicator. Open-drain output pulls low when charging with constant voltage in full-charge
state.
17
SHDN Shutdown Input. Drive SHDN low to disable charging. Connect SHDN to VL for normal operation.
18 PGND Power Ground. Current from the low-side power MOSFET switch source flows through PGND.
19, 20 LX Power Inductor Switching Node and High-Side Power MOSFET Source
21 CS Battery Current-Sense Positive Input. Connects to internal 0.1Ω resistor between BATT and CS.
22 BST High-Side MOSFET Gate Drive Bias. Connect a 0.1µF capacitor from BST to LX.
23 CCS Charger Source Current Regulation Loop Compensation Point. See Compensation section.
24 CCI Battery Charge Current Regulation Loop Compensation Point. See Compensation section.
25 CCV Voltage Regulation Loop Compensation Point. See Compensation section.
26 CSSN Source Current-Sense Negative Input. See Input Current Regulator section.
27 CSSP Source Current-Sense Positive Input. See Input Current Regulator section.
28 DCIN
Power-Supply Input. DCIN is the input supply for the VL regulator. Bypass DCIN to GND with a 0.1µF or
greater capacitor. See Detailed Description.
