MAX1870AETJ Datasheet, PDF (1/32 Pages) Maxim Integrated Products – Step-Up/Step-Down Li+ Battery Charger

19-3243; Rev 0; 4/04
EVAALVUAAILTAIOBNLEKIT
Step-Up/Step-Down
Li+ Battery Charger
General Description
The MAX1870A step-up/step-down multichemistry bat-
tery charger charges with battery voltages above and
below the adapter voltage. This highly integrated
charger requires a minimum number of external compo-
nents. The MAX1870A uses a proprietary step-up/step-
down control scheme that provides efficient charging.
Analog inputs control charge current and voltage, and
can be programmed by the host or hardwired.
The MAX1870A accurately charges two to four lithium-
ion (Li+) series cells at greater than 4A. A programma-
ble input current limit is included, which avoids
overloading the AC adapter when supplying the load
and the battery charger simultaneously. This reduces
the maximum adapter current, which reduces cost. The
MAX1870A provides analog outputs to monitor the cur-
rent drawn from the AC adapter and charge current. A
digital output indicates the presence of an AC adapter.
When the adapter is removed, the MAX1870A con-
sumes less than 1µA from the battery.
The MAX1870A is available in a 32-pin thin QFN (5mm
x 5mm) package and is specified over the -40°C to
+85°C extended temperature range. The MAX1870A
evaluation kit (MAX1870AEVKIT) is available to help
reduce design time.
Applications
Notebook and Subnotebook Computers
Hand-Held Terminals
*Protected by U.S. Patent No. 6,087,816.
Features
♦ Patented Step-Up/Step-Down Control Scheme*
♦ ±0.5% Charge-Voltage Accuracy
♦ ±9% Charge-Current Accuracy
♦ ±8% Input Current-Limit Accuracy
♦ Programmable Maximum Battery Charge Current
♦ Analog Inputs Control Charge Current, Charge
Voltage, and Input Current Limit
♦ Analog Output Indicates Adapter Current
♦ Input Voltage from 8V to 28V
♦ Battery Voltage from 0 to 17.6V
♦ Charges Li+ or NiCd/NiMH Batteries
♦ Tiny 32-Pin Thin QFN (5mm x 5mm) Package
PART
MAX1870AETJ
Ordering Information
TEMP RANGE
-40°C to +85°C
PIN-PACKAGE
32 Thin QFN
Typical Operating Circuit
FROM WALL ADAPTER
CSSS
DCIN
VHP
CSSP
CSSN
VHN ^MAX1870A DHI
P
REF
CLS
CELLS
ASNS
IINP
DBST
CSIP
CSIN
REFIN
SHDN
ICTL
VCTL
LDO
DLOV
BATT
BLKP
PGND
GND
SYSTEM
LOAD
N
Pin Configuration appears at end of data sheet.
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