Rainbow Electronics MAX1745 - Manual

General Description
The MAX1744/MAX1745 are step-down DC-DC con-
trollers capable of handling up to 36V inputs. These
parts use a proprietary current-limited control scheme
for excellent light- and full-load efficiency, while their
330kHz (max) switching frequency permits small exter-
nal components for space-critical applications.
Operation to 100% duty cycle permits the lowest possi-
ble dropout voltage.
The MAX1744 contains an internal feedback network
that provides a pin-selectable output voltage of either
3.3V or 5V. The MAX1745 uses an external feedback
network to generate an adjustable output voltage
between 1.25V and 18V.
The MAX1744/MAX1745 are available in a space-sav-
ing 10-pin µMAX package.
________________________Applications
Automotive Electronics
Telecom Systems
Wall-Cube-Powered Devices
Industrial Control Systems
Firewire/IEEE1394
____________________________Features
♦ High-Voltage Operation (up to 36V IN)
♦ Efficiency >90%
♦ Output Power Capability Exceeds 50W
♦ 10-Pin µMax Package
♦ Low-Dropout Voltage
♦ 100% (max) Duty Cycle
♦ 90µA Quiescent Current
♦ 4µA Shutdown Current
♦ Up to 330kHz Switching Frequency
♦ Output Voltage
5V or 3.3V (MAX1744)
Adjustable 1.25V to 18V (MAX1745)
♦ Current-Limited Control Scheme
MAX1744/MAX1745
High-Voltage, Step-Down DC-DC
Controller in µMAX
________________________________________________________________ Maxim Integrated Products 1
19-1776; Rev 1; 10/01
Ordering Information
PART TEMP RANGE PIN-PACKAGE
MAX1744EUB -40 °C to +85°C 10 µMAX
MAX1744AUB -40 °C to +125°C 10 µMAX
MAX1745EUB -40 °C to +85°C 10 µMAX
MAX1745AUB -40 °C to +125°C 10 µMAX
GND OUT
REF
VL
CS
MAX1744
3/5
5V
3.3V
ON
OFF SHDN
IN VH EXT P
IN
4.5V TO 36V
OUT
3.3V
OR 5V
Typical Operating Circuit
1
2
3
4
5
10
9
8
7
6
IN
EXT
VH
3/5 (FB)
( ) ARE FOR MAX1745 ONLY.
REF
VL
GND
MAX1744
MAX1745
µMAX
TOP VIEW
CS OUT
SHDN
Pin Configuration
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.