Rainbow Electronics MAX1641 - Manual

General Description ________________
The MAX1640/MAX1641 CMOS, adjustable-output,
switch-mode current sources operate from a +5.5V to
+26V input, and are ideal for microprocessor-controlled
battery chargers. Charging current, maximum output
voltage, and pulse-trickle charge are programmed with
external resistors. Programming the off-time modifies
the switching frequency, suppressing undesirable har-
monics in noise-sensitive circuits. The MAX1640’s high-
side current sensing allows the load to connect directly
to ground, eliminating ground-potential errors. The
MAX1641 incorporates a low-side current sense.
The MAX1640/MAX1641 step-down pulse-width-modu-
lation (PWM) controllers use an external P-channel
MOSFET switch and an optional, external N-channel
MOSFET synchronous rectifier for increased efficiency.
An internal low-dropout linear regulator provides power
for the internal reference and circuitry as well as the
gate drive for the N-channel synchronous rectifier.
The MAX1640/MAX1641 are available in space-saving,
16-pin narrow QSOP packages.
________________________Applications
Battery-Powered Equipment
Laptop, Notebook, and Palmtop Computers
Handy Terminals
Portable Consumer Products
Cordless Phones
Cellular Phones
PCS Phones
Backup Battery Charger
____________________________Features
♦ 95% Efficiency
♦ +5.5V to +26V Input Supply Range
♦ 2V to 24V Adjustable-Output Voltage Range
♦ 100% Maximum Duty Cycle (Low Dropout)
♦ Up to 500kHz PWM Operation
♦ Optional Synchronous Rectifier
♦ 16-Pin QSOP Package
♦ Current-Sense Accuracy: 2% (MAX1641),
5.3% (MAX1640)
MAX1640/MAX1641
Adjustable-Output, Switch-Mode
Current Sources with Synchronous Rectifier
________________________________________________________________ Maxim Integrated Products 1
Pin Configuration
16
15
14
13
12
11
10
9
1
2
3
4
5
6
7
8
LDOL IN
LDOH
PDRV
NDRV
PGND
CS+
CS-
GND
TOP VIEW
MAX1640
MAX1641
QSOP
TOFF
D1
REF
D0
CC
SET
TERM
19-1245; Rev 1; 1/02
PART
MAX1640 C/D
MAX1640EEE
MAX1641 C/D 0
°
C to +70
°
C
-40
°
C to +85
°
C
0
°
C to +70
°
C
TEMP. RANGE PIN-PACKAGE
Dice*
16 QSOP
Dice*
__________________
______________________
Ordering Information
* Dice are specified at T A = +25
°
C, DC parameters only.
MAX1641EEE -40
°
C to +85
°
C 16 QSOP
IN LDOH
PDRV
NDRV
P
PGND
CS+
CS-
TERM
LDOL GND
OUT
D0
V IN = +5.5V TO +26V
D1
TOFF
R TOFF
REF
SET
CC
MAX1640
_____________ Typical Operating Circuit
EVALUATION KIT
AVAILABLE
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.