EVALUATION KIT AVAILABLE
MAX712/MAX713
NiCd/NiMH Battery
Fast-Charge Controllers
General Description
The MAX712/MAX713 fast-charge Nickel Metal Hydride
(NiMH) and Nickel Cadmium (NiCd) batteries from a DC
source at least 1.5V higher than the maximum battery
voltage. 1 to 16 series cells can be charged at rates up
to 4C. A voltage-slope detecting analog-to-digital converter, timer, and temperature window comparator determine
charge completion. The MAX712/MAX713 are powered
by the DC source via an on-board +5V shunt regulator.
They draw a maximum of 5µA from the battery when not
charging. A low-side current-sense resistor allows the
battery charge current to be regulated while still
supplying power to the battery’s load.
The MAX712 terminates fast charge by detecting zero
voltage slope, while the MAX713 uses a negative
voltage-slope detection scheme. Both parts come in 16pin DIP and SO packages. An external power PNP transistor, blocking diode, three resistors, and three
capacitors are the only required external components.
The evaluation kit is available: Order the MAX712EVKITDIP for quick evaluation of the linear charger.
________________________Applications
Battery-Powered Equipment
Laptop, Notebook, and Palmtop Computers
Handy-Terminals
Cellular Phones
Portable Consumer Products
Portable Stereos
Cordless Phones
Features
o Fast-Charge NiMH or NiCd Batteries
o Voltage Slope, Temperature, and Timer
Fast-Charge Cutoff
o Charge 1 to 16 Series Cells
o Supply Battery’s Load While Charging
(Linear Mode)
o Fast Charge from C/4 to 4C Rate
o C/16 Trickle-Charge Rate
o Automatically Switch from Fast to Trickle Charge
o Linear Mode Power Control
o 5µA (max) Drain on Battery when Not Charging
o 5V Shunt Regulator Powers External Logic
Ordering Information
PART
TEMP RANGE
PIN-PACKAGE
MAX712CPE
0°C to +70°C
16 Plastic DIP
MAX712CSE
MAX712C/D
MAX712EPE
0°C to +70°C
0°C to +70°C
-40°C to +85°C
16 Narrow SO
Dice*
16 Plastic DIP
MAX712ESE
MAX712MJE
-40°C to +85°C
-55°C to +125°C
16 Narrow SO
16 CERDIP**
Ordering Information continued at end of data sheet.
*Contact factory for dice specifications.
**Contact factory for availability and processing to MIL-STD-883.
Typical Operating Circuit
Q1
2N6109
DC IN
Pin Configuration
VLIMIT 1
15 V+
D1
1N4001
V+
16 REF
BATT+ 2
DRV
THI
WALL
CUBE
TOP VIEW
R2
150Ω
C4
0.01μF
R1
14 DRV
PGM0 3
PGM1 4
C1
1μF
MAX712
MAX713
11 CC
TLO 6
BATT+
REF
R3
68kΩ
13 GND
MAX712
MAX713
BATTERY
C3
10μF
TEMP
12 BATT-
THI 5
VLIMIT
10μF
R4
22kΩ
LOAD
CC BATT- TLO GND
10 PGM3
TEMP 7
FASTCHG 8
9
PGM2
C2
0.01μF
RSENSE
DIP/SO
For pricing, delivery, and ordering information, please contact Maxim Direct
at 1-888-629-4642, or visit Maxim’s website at www.maximintegrated.com.
19-0100; Rev 7; 7/13
