19-0100; Rev 3; 1/97
NiCd /NiMH Ba t t e ry
Fa s t -Ch a rg e Co n t ro lle rs
2/MAX713
_______________Ge n e ra l De s c rip t io n
____________________________Fe a t u re s
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
b a tte ry c ha rg e c urre nt to b e re g ula te d while s till
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
volta g e s lop e , while the MAX713 us e s a ne g a tive
voltage-slope detection scheme. Both parts come in 16-
pin DIP and SO packages. An external power PNP tran-
s is tor, b loc king d iod e , thre e re s is tors , a nd thre e
capacitors are the only required external components.
______________Ord e rin g In fo rm a t io n
PART
TEMP. RANGE
0°C to +70°C
PIN-PACKAGE
16 Plastic DIP
16 Narrow SO
Dice*
MAX712CPE
MAX712CSE
MAX712C/D
MAX712EPE
MAX712ESE
MAX712MJE
0°C to +70°C
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
-40°C to +85°C
-40°C to +85°C
-55°C to +125°C
16 Plastic DIP
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.
________________________Ap p lic a t io n s
Battery-Powered Equipment
Laptop, Notebook, and Palmtop Computers
Handy-Terminals
__________Typ ic a l Op e ra t in g Circ u it
Q1
2N6109
DC IN
Cellular Phones
Portable Consumer Products
Portable Stereos
R2
150Ω
C4
0.01µF
R1
Cordless Phones
DRV
THI
V+
__________________P in Co n fig u ra t io n
D1
1N4001
WALL
CUBE
TOP VIEW
VLIMIT
REF
C1
1µF
BATT+
REF
V+
VLIMIT
BATT+
PGM0
PGM1
THI
1
2
3
4
5
6
7
8
16
15
14
C3
R3
68kΩ
10µF
MAX712
MAX713
BATTERY
DRV
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
R
SENSE
FASTCHG
SEE FIGURE 19 FOR SWITCH-MODE CHARGER CIRCUIT.
DIP/SO
________________________________________________________________ Maxim Integrated Products
1
For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800