Rainbow Electronics MAX1870A - Manual (Page 13)

MAX1870A
Step-Up/Step-Down
Li+ Battery Charger
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Pin Description (continued)
PIN NAME FUNCTION
12 ICTL
Charge-Current Control Input. Drive ICTL from V REFIN / 32 to V REFIN to adjust the charge current. See the
Setting the Charge Current section. Drive ICTL to GND to disable charging.
13 CELLS
Cell-Count Selection Input. Connect CELLS to GND for two Li+ cells. Float CELLS for three Li+ cells, or
connect CELLS to REFIN for four Li+ cells.
14 IINP
Input-Current Monitor Output. IINP is a replica of the input current sensed by the MAX1870. It represents
the sum of the current consumed by the charger and the current consumed by the system. IINP has a
transconductance of 2.8µA/mV.
15 SHDN
Shutdown Comparator Input. Pull SHDN low to stop charging. Optionally connect a thermistor to stop
charging when the battery temperature is too hot.
16 BATT Battery-Voltage Feedback Input
17 CSIN Charge Current-Sense Negative Input
18 CSIP
Charge Current-Sense Positive Input. Connect a current-sense resistor from CSIP to CSIN. Connect a
2.2µF capacitor from CSIP to GND.
19 BLKP Power Connection for Current-Sense Amplifier. Connect BLKP to BATT.
20, 21 I.C. Internally Connected. Do not connect this pin.
22 DBST Step-Up Power MOSFET (NMOS) Gate-Driver Output
23 PGND Power Ground
24 I.C. Internally Connected. Do not connect this pin.
25 DLOV Low-Side Driver Supply. Bypass DLOV with a 1µF capacitor to GND.
26 VHN
Power Connection for the High-Side MOSFET Driver. Bypass VHP to VHN with a 1µF or greater ceramic
capacitor.
27 DHI
High-Side Power MOSFET (PMOS) Driver Output. Connect to the gate of the high-side step-down
MOSFET.
28 VHP
Power Connection for the High-Side MOSFET Driver. Bypass VHP to VHN with a 1µF or greater ceramic
capacitor.
29 CSSN
Negative Terminal for Current-Sense Resistor for Charger Current. Connect a 2.2µF capacitor from CSSN
to GND.
30 CSSS Negative Terminal for Current-Sense Resistor for System Load Current
31 CSSP
Positive Terminal for Input Current-Sense Resistors. Connect a current-sense resistor from CSSP to
CSSN. Connect an equivalent sense resistor from CSSP to CSSS.
32 DCIN DC Supply Voltage Input. Bypass DCIN with a 1µF or greater ceramic capacitor to power ground.
Paddle Paddle. Connect to GND.