19-0100; Rev 5; 4/02
NiCd/NiMH Battery
Fast-Charge Controllers
General Description
Features
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 convert-
er, 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.
ꢀ Fast-Charge NiMH or NiCd Batteries
ꢀ Voltage Slope, Temperature, and Timer
Fast-Charge Cutoff
ꢀ Charge 1 to 16 Series Cells
ꢀ Supply Battery’s Load While Charging
(Linear Mode)
ꢀ Fast Charge from C/4 to 4C Rate
ꢀ C/16 Trickle-Charge Rate
ꢀ Automatically Switch from Fast to Trickle Charge
ꢀ Linear or Switch-Mode Power Control
ꢀ 5µA (max) Drain on Battery when Not Charging
ꢀ 5V Shunt Regulator Powers External Logic
The MAX712 terminates fast charge by detecting zero
voltage slope, while the MAX713 uses a negative
voltage-slope detection scheme. Both parts come in 16-
pin DIP and SO packages. An external power PNP tran-
sistor, blocking diode, three resistors, and three
capacitors are the only required external components.
Ordering Information
PART
TEMP RANGE
0°C to +70°C
PIN-PACKAGE
16 Plastic DIP
16 Narrow SO
Dice*
MAX712CPE
MAX712CSE
MAX712C/D
MAX712EPE
MAX712ESE
MAX712MJE
For high-power charging requirements, the MAX712/
MAX713 can be configured as a switch-mode battery
charger that minimizes power dissipation. Two evaluation
kits are available: Order the MAX712EVKIT-DIP for quick
evaluation of the linear charger, and the MAX713EVKIT-
SO to evaluate the switch-mode charger.
0°C to +70°C
0°C to +70°C
-40°C to +85°C
-40°C to +85°C
-55°C to +125°C
16 Plastic DIP
16 Narrow SO
16 CERDIP**
________________________Applications
Ordering Information continued at end of data sheet.
*Contact factory for dice specifications.
**Contact factory for availability and processing to MIL-STD-883.
Battery-Powered Equipment
Laptop, Notebook, and Palmtop Computers
Handy-Terminals
Cellular Phones
Typical Operating Circuit
Portable Consumer Products
Portable Stereos
Q1
2N6109
DC IN
Cordless Phones
R2
150Ω
C4
0.01µF
R1
Pin Configuration
DRV
THI
V+
D1
WALL
CUBE
1N4001
TOP VIEW
REF
V+
VLIMIT
BATT+
PGM0
PGM1
THI
1
2
3
4
5
6
7
8
16
15
14
VLIMIT
REF
C1
BATT+
1µF
C3
DRV
R3
68kΩ
10µF
MAX712
MAX713
BATTERY
13 GND
12 BATT-
11 CC
MAX712
MAX713
TEMP
LOAD
R4
22kΩ
10µF
CC BATT- TLO GND
TLO
10
9
PGM3
PGM2
TEMP
C2
0.01µF
FASTCHG
R
SENSE
SEE FIGURE 19 FOR SWITCH-MODE CHARGER CIRCUIT.
DIP/SO
________________________________________________________________ Maxim Integrated Products
1
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.