CM494

2000/12/29

Preliminary

Champion Microelectronic Corporation

Page 1

GENERAL DESCRIPTION

FEATURES

This of PWM modulator provides a complete pulse width

modulation system in a single monolithic integrated circuit.

This device includes a 5V reference accurate to

±1%, two

independent amplifiers usable for both voltage and current

sensing, an externally synchronizable oscillator with its

linear ramp generator, and two-uncommitted transistor

output switches. These two outputs may be operated

either in parallel for single-ended operation or alternating

for push-pull applications with an externally controlled

dead-band. This unit is internally protected against

double-pulsing of a single output or from extraneous

output signals when the input supply voltage is below

minimum.

The CM494 contains an on-chip 39V zener diode for

high-voltage applications where Vcc would be greater

than 40V, and a buffered output steering control that

overrides the internal control of the pulse steering flip-flop.

!

Dual uncommitted 40V, 200mA output transistors.

!

1% accurate 5V reference.

!

Dual error amplifiers.

!

Wide range, variable dead time.

!

Single-ended or push-pull operation.

!

Under-voltage lockout with hysteresis.

!

Double pulse protection.

!

Master or slave oscillator operation.

APPLICATIONS

PIN CONFIGURATION

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Linear Regulators

!

Adjustable Supplies

!

Switching Power Supplies

!

Battery Operated Computers

!

Instrumentation

!

Computer Disk Drives

16-PIN PDIP/SOP

(Top View)

1

2

3

4

5

6

7

8

16

15

14

13

12

11

10

9

1IN+

1IN-

FEEDBACK

DTC

CT

RT

GND

C1

2IN+

2IN-

REF

OUTPUT CTRL

VCC

C2

E2

E1