MAX1744_0908 Datasheet, PDF (1/15 Pages) Maxim Integrated Products – High-Voltage, Step-Down DC-DC Controllers in μMAX

19-1776; Rev 4; 8/09
EVAALVUAAILTAIOBNLEKIT
High-Voltage, Step-Down DC-DC
Controllers in µMAX
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^®/IEEE^® 1394
μMAX is a registered trademark of Maxim Integrated Products, Inc.
Firewire is a registered trademark of Apple, Inc.
IEEE is a registered service mark of the Institute of Electrical
and Electronics Engineers, Inc.
Typical Operating Circuit
____________________________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
Ordering Information
PART
TEMP RANGE
PIN-PACKAGE
MAX1744EUB+
-40°C to +85°C
10 μMAX
MAX1744AUB+
-40°C to +125°C 10 μMAX
MAX1744EUB/V+ -40°C to +85°C
10 μMAX
MAX1745EUB+
-40°C to +85°C
10 μMAX
MAX1745AUB+
-40°C to +125°C 10 μMAX
MAX1745EUB/V+ -40°C to +85°C
10 μMAX
+Denotes a lead(Pb)-free/RoHS-compliant package.
/V Denotes an automotive qualified part.
Pin Configuration
IN
4.5V TO 36V
TOP VIEW
ON
IN VH _EXT
P
OFF
SHDN
5V
3.3V
3/5
MAX1744
VL
REF
CS
GND ^OUT
OUT
3.3V
OR 5V
+
GND 1
VL 2
REF 3
3/5 (FB) 4
MAX1744
MAX1745
OUT 5
( ) ARE FOR MAX1745 ONLY.
μMAX
10 IN
9 EXT
8 VH
7 SHDN
6 CS
________________________________________________________________ Maxim Integrated Products 1
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim's website at www.maxim-ic.com.