© Semiconductor Components Industries, LLC, 2000

August, 2000 – Rev. 6

1

Publication Order Number:

MC34063A/D

MC34063A, MC33063A

DC-to-DC Converter

Control Circuits

The MC34063A Series is a monolithic control circuit containing the

primary functions required for DC–to–DC converters. These devices

consist of an internal temperature compensated reference, comparator,

controlled duty cycle oscillator with an active current limit circuit,

driver and high current output switch. This series was specifically

designed to be incorporated in Step–Down and Step–Up and

Voltage–Inverting applications with a minimum number of external

components. Refer to Application Notes AN920A/D and AN954/D

for additional design information.

Representative Schematic Diagram

SQ

R

Q2

Q1

100

Comparator

+

-

1.25 V

Reference

Regulator

1

2

3

4

5

6

7

8

Drive

Collector

Sense

Comparator

Inverting

Input

Switch

Collector

Switch

Emitter

Timing

Capacitor

Gnd

(Bottom View)

This device contains 51 active transistors.

http://onsemi.com

SO–8

D SUFFIX

CASE 751

PDIP–8

P, P1 SUFFIX

CASE 626

1

8

1

8

1

8

SOEIAJ–8

M SUFFIX

CASE 968

See detailed ordering and shipping information in the package

dimensions section on page 11 of this data sheet.

ORDERING INFORMATION

See general marking information in the device marking

section on page 11 of this data sheet.

DEVICE MARKING INFORMATION

1

Switch

Collector

Switch

Emitter

Timing

Capacitor

Gnd

Driver

Collector

Comparator

Inverting

Input

(Top View)

2

3

45

6

7

8

PIN CONNECTIONS