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.

General Description

The MAX1709 sets a new standard of space savings for

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

to 20W 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 pushbut-

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

The MAX1709 also features programmable soft-start

and current limit for design flexibility and optimum per-

formance with batteries.

The MAX1709 is supplied in both a high-power TSSOP

4A output, and a narrow SO package, which supplies a

narrow SO device has a lower RMS switch rating, it has

the same peak switch current rating as the TSSOP

device, and so can supply 4A loads intermittently. If

loads of 2A or less are required, refer to the MAX1708.

________________________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

♦ On-Chip 10A Power MOSFET

♦ 5V, 4A Output from a 3.3V Input

♦ Fixed 3.3V or 5V Output Voltage or

Adjustable (2.5V to 5.5V)

♦ Input Voltage Range Down to 0.7V

♦ Low Power Consumption

1mW Quiescent Power

1µA Current in Shutdown Mode

♦ Low-Noise, Constant Frequency Operation

(600kHz)

♦ Synchronizable Switching Frequency

(350kHz to 1000kHz)

4A, Low-Noise, High-Frequency,

Step-Up DC-DC Converter

________________________________________________________________

Maxim Integrated Products

1

28

27

26

25

24

23

22

1

2

3

4

5

6

7

ONB

CLK

NC

LX

LX

LX

ONA

TOP VIEW

MAX1709

NC

PGND

PGND

LX

LX

21

8

PGND

LX

20

9

PGND

NC

19

10

PGND

NC

18

11

PGND

GND

17

12

NC

SS/ILM

16

13

FB

REF

15

14

OUT

GND

LX

TSSOP-EP*

3.3/5

Pin Configurations

ONA

REF

SS/LIM

CLK

OUTPUT

3.3V, 5V,

OR ADJ

UP TO 4A

OUT

GND

LX

1

μH

OFF ON

INPUT

1V TO 5V

SYNC

OR

INTERNAL

MAX1709

Typical Operating Circuit

19-1724; Rev 2; 4/07

EVALUATION

KIT

AVAILABLE

Ordering Informations

PART

TEMP RANGE

PIN-PACKAGE

MAX1709ESE

-40°C to +85°C

16 Narrow SO

MAX1709EUI+

-40°C to +85°C

28 TSSOP-EP*

+

Indicates lead(Pb)-free/RoHS-compliant package.

*

Exposed pad.

Pin Configurations continued at end of data sheet.