Rainbow Electronics MAX1870A - Manual

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
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
MAX1870A
Step-Up/Step-Down
Li+ Battery Charger
________________________________________________________________ Maxim Integrated Products 1
Ordering Information
MAX1870A
REFIN
DCIN
CSSP
CSSN
DHI
DBST
CSIP
CSIN
BATT
SHDN
ASNS
VCTL
IINP
PGND
SYSTEM
LOAD
N
P
GND
ICTL
CLS
CELLS
FROM WALL ADAPTER
CSSS
VHN
VHP
BLKP
REF
LDO
DLOV
Typical Operating Circuit
19-3243; Rev 0; 4/04
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.
EVALUATION KIT
AVAILABLE
Pin Configuration appears at end of data sheet.
PART TEMP RANGE PIN-PACKAGE
MAX1870AETJ -40°C to +85°C 32 Thin QFN
* Protected by U.S. Patent No. 6,087,816.