19-1776; Rev 4; 8/09
KIT
ATION
EVALU
BLE
AVAILA
High-Voltage, Step-Down DC-DC
Controllers in µMAX
The MAX1744/MAX1745 are step-down DC-DC controllers 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 external components for space-critical applications.
Operation to 100% duty cycle permits the lowest possible 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-saving 10-pin μMAX® package.
________________________Applications
Automotive Electronics
____________________________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
Telecom Systems
Ordering Information
Wall-Cube-Powered Devices
TEMP RANGE
PIN-PACKAGE
Industrial Control Systems
MAX1744EUB+
PART
-40°C to +85°C
10 μMAX
Firewire®/IEEE® 1394
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
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.
+Denotes a lead(Pb)-free/RoHS-compliant package.
/V Denotes an automotive qualified part.
Typical Operating Circuit
IN
4.5V TO 36V
Pin Configuration
TOP VIEW
+
IN
VH
ON
GND 1
P
SHDN
3.3V
5V
OFF
EXT
3/5
VL
10 IN
VL
CS
REF
GND
OUT
OUT
3.3V
OR 5V
3
3/5 (FB)
MAX1744
2
REF
4
7
SHDN
OUT
5
6
CS
9
MAX1744
MAX1745
EXT
8
VH
μMAX
( ) ARE FOR MAX1745 ONLY.
________________________________________________________________ Maxim Integrated Products
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.
1
MAX1744/MAX1745
General Description
