General Description

The MAX5068 is a high-frequency, current-mode,

pulse-width modulation (PWM) controller that integrates

all the building blocks necessary for implementing AC-

DC or DC-DC fixed-frequency power supplies. Isolated

or nonisolated power supplies are easily constructed

using either primary- or secondary-side regulation.

Current-mode control with leading-edge blanking sim-

plifies control-loop design, and a programmable inter-

nal slope-compensation circuit stabilizes the current

loop when operating at duty cycles above 50%. The

MAX5068A/B limit the maximum duty cycle to 50% for

use in single-ended forward converters. The

MAX5068C/D/E/F allow duty cycles up to 75%. The

MAX5068 features an accurate externally programma-

ble oscillator that simplifies system design.

An input undervoltage lockout (UVLO) programs the

input-supply startup voltage and ensures proper opera-

tion during brownout conditions.

A single external resistor programs the output switching

frequency from 12.5kHz to 1.25MHz. The MAX5068A/

B/C/E provide a SYNC input for synchronization to an

external clock. The maximum FET-driver duty cycle is

50% for the MAX5068A/B and 75% for the MAX5068C/

D/E/F. Programmable hiccup current limit provides

additional protection under severe faults.

The MAX5068 is specified over the -40°C to +125°C

automotive temperature range and is available in a

16-pin thermally enhanced TSSOP-EP package. Refer to

the MAX5069 data sheet for dual FET-driver applications.

Warning: The MAX5068 is designed to work with high

voltages. Exercise caution.

Applications

Universal-Input AC Power Supplies

Isolated Telecom Power Supplies

Networking System Power Supplies

Server Power Supplies

Industrial Power Conversion

Features

♦ Current-Mode Control with 47µA (typ) Startup

Current

♦ Resistor-Programmable ±4.5% Accurate

Switching Frequency:

25kHz to 1.25MHz (MAX5068A/B)

12.5kHz to 625kHz (MAX5068C/D/E/F)

Input (MAX5068A/C/D)

♦ Input Directly Driven from 10.8V to 24V

(MAX5068B/E/F)

♦ Frequency Synchronization Input

(MAX5068A/B/C/E)

♦ Programmable Dead Time and Slope

Compensation

♦ Programmable Startup Voltage (UVLO)

♦ Programmable UVLO Hysteresis

(MAX5068A/B/D/F)

♦ Integrating Fault Protection (Hiccup)

♦ -40°C to +125°C Automotive Temperature Range

♦ 16-Pin Thermally Enhanced TSSOP-EP Package

High-Frequency, Current-Mode PWM Controller

with Accurate Programmable Oscillator

________________________________________________________________ Maxim Integrated Products

1

16

15

14

13

12

11

10

9

1

2

3

4

5

6

7

8

RT

REG5

IN

NDRV

AGND

PGND

AGND

CS

TOP VIEW

MAX5068A/B

TSSOP-EP

SYNC

HYST

FB

DT

UVLO/EN

COMP

FLTINT

Pin Configurations

Ordering Information

19-3176; Rev 1; 7/04

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.

*EP = Exposed pad.

PART

TEMP RANGE

PIN-PACKAGE

MAX5068AAUE

-40°C to +125°C

16 TSSOP-EP*

MAX5068BAUE

-40°C to +125°C

16 TSSOP-EP*

MAX5068CAUE

-40°C to +125°C

16 TSSOP-EP*

MAX5068DAUE

-40°C to +125°C

16 TSSOP-EP*

MAX5068EAUE

-40°C to +125°C

16 TSSOP-EP*

MAX5068FAUE

-40°C to +125°C

16 TSSOP-EP*

Pin Configurations continued at end of data sheet.

Selector Guide appears at end of data sheet.