General Description

The MAX1708 sets a new standard of space savings for

high-power, step-up DC-DC conversion. It delivers up

to 10W at a fixed (3.3V or 5V) or adjustable (2.5V to

5.5V) output, using an on-chip power MOSFET from a

+0.7V to +5V supply.

Fixed-frequency PWM operation ensures that the

switching noise spectrum is constrained to the 600kHz

fundamental and its harmonics, allowing easy postfilter-

ing for noise reduction. External clock synchronization

capability allows for even tighter noise spectrum con-

trol. Quiescent power consumption is less than 1mW to

extend operating time in battery-powered systems.

Two control inputs (ONA, ONB) allow simple push-on,

push-off control through a single momentary push-but-

ton switch, as well as conventional on/off logic control.

The MAX1708 also features programmable soft-start

and current limit for design flexibility and optimum per-

formance with batteries. The maximum RMS switch cur-

rent rating is 5A. For a device with a higher (10A)

switch current rating, refer to the MAX1709 data sheet.

________________________Applications

Routers, Servers, Workstations, Card Racks

Local 2.5V to 3.3V or 5V Conversion

Local 3.3V to 5V Conversion

3.6V or 5V RF PAs in Communications Handsets

Features

o On-Chip 5A Power MOSFET

o 5V, 2A Output from a 3.3V Input

o Fixed 3.3V or 5V Output Voltage or

Adjustable (2.5V to 5.5V)

o Input Voltage Range Down to 0.7V

o Low Power Consumption

1mW Quiescent Power

1µA Current in Shutdown Mode

o Low-Noise, Constant Frequency Operation

(600kHz)

o Synchronizable Switching Frequency

(350kHz to 1000kHz)

o Small QSOP Package

High-Frequency, High-Power, Low-Noise,

Step-Up DC-DC Converter

________________________________________________________________ Maxim Integrated Products

1

16

15

14

13

12

11

10

9

1

2

3

4

5

6

7

8

ONB

CLK

3.3/5

PGND

PGND

PGND

FB

OUT

GND

TOP VIEW

MAX1708

QSOP

ONA

LX

GND

LX

LX

SS/LIM

REF

Pin Configuration

ONA

REF

SS/LIM

CLK

OUTPUT

3.3V, 5V,

OR ADJ

UP TO 2A

OUT

GND

LX

2.2

µH

OFF ON

INPUT

1V TO 5V

SYNC

OR

INTERNAL

MAX1708

Typical Operating Circuit

19-2068; Rev 0; 7/01

Ordering Information

PART

TEMP. RANGE

PIN-PACKAGE

MAX1708EEE

-40

°C to +85°C

16 QSOP

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.