MAX1775_09 Datasheet, PDF (1/16 Pages) Maxim Integrated Products – Dual-Output Step-Down DC-DC Converter for PDA/Palmtop Computers

19-1811; Rev 2; 4/09
EVAALVUAAILTAIOBNLEKIT
Dual-Output Step-Down
DC-DC Converter for PDA/Palmtop Computers
General Description
The MAX1775 dual, step-down DC-DC converter gen-
erates both the main (+3.3V at over 2A) and core
(+1.8V at up to 1.5A) supplies for a complete power
solution for PDAs, subnotebooks, and other hand-held
devices. The main output is adjustable from +1.25V to
+5.5V. The core output is adjustable from 1V to 5V.
Both switching converters operate at up to 1.25MHz for
small external components and use synchronous recti-
fiers to achieve efficiencies up to 95%. Operation with
up to 100% duty cycle provides the lowest possible
dropout voltage to extend useful battery life.
The MAX1775 accepts inputs from +2.7V up to +28V,
allowing use with many popular battery configurations as
well as AC-DC wall adapters. Digital soft-start reduces
battery current surges at power-up. Both the main and
core converters have separate shutdown inputs. The
MAX1775 comes in a small 16-pin QSOP package.
The MAX1775 evaluation kit is available to help reduce
design time.
________________________Applications
Hand-Held Computers
PDAs
Internet Access Tablets
POS Terminals
Subnotebooks
Features
♦ Dual, High-Efficiency, Synchronous Rectified
Step-Down Converter
♦ Main Power
Adjustable from +1.25V to +5.5V
Over 2A Load Current
Up to 95% Efficiency
♦ Core Power
Adjustable from 1V to 5V
Internal Switches
Up to 1.5A Load Current
Up to 92% Efficiency
♦ 100% (max) Duty Cycle
♦ Up to 1.25MHz Switching Frequency
♦ Input Voltage Range from +2.7V to +28V
♦ 170μA Quiescent Current
♦ 5μA Shutdown Current
♦ Digital Soft-Start
♦ Independent Shutdown Inputs
PART
MAX1775EEE
Ordering Information
TEMP RANGE
-40°C to +85°C
PIN-PACKAGE
16 QSOP
Typical Operating Circuit
IN 2.7V TO 5.5V (28V IN CASCADE)
Pin Configuration
TOP VIEW
SHDNM 1
SHDNC 2
PGND 3
NDRV 4
CVL 5
IN 6
PDRV 7
CVH 8
MAX1775
16 LXC
15 INC
14 GND
13 FBC
12 CS-
11 CS+
10 FBM
9 REF
16 QSOP
IN CVH
ON
INC
OFF SHDNM
ON
OFF SHDNC
PDRV
NDRV
CVL
MAX1775 _CS+
REF
CS-
FBM
PGND
LXC
GND
FBC
MAIN
3.3V
OVER 2A
CORE
1.8V
1.5A
________________________________________________________________ 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.