© 2002 Microchip Technology Inc.

DS21395B-page 1

TC170

Features

• Low Supply Current With CMOS Technology:

3.8mA Max

• Internal Reference: 5.1V

• Dual Push-Pull Outputs

•Direct-Power MOSFET Drive

• High Totem-Pole Output Drive: 300mA

• Differential Current-Sense Amplifier

• Programmable Current Limit

• Soft-Start Operation

• Double-Pulse Suppression

• Undervoltage Lockout

• Wide Supply Voltage Operation: 8V to 16V

• High Frequency Operation: 200kHz

• Available with Low OFF State Outputs

• Low Power, Pin-Compatible Replacement for

UC3846

Applications

• Switching Power Supplies

• DC/DC Converters

• Motor Control

Device Selection Table

General Description

The TC170 offers maximum supply current of 3.8mA.

Bipolar current-mode control integrated circuits require

five times more operating current.

The dual totem-pole CMOS outputs drive power

MOSFETs or bipolar transistors. The 50nsec typical

output rise and fall times (1000pF capacitive loads)

minimize MOSFET power dissipation. Output peak

current is 300mA.

The TC170 contains a full array of system-protection

circuits (see Features Section).

Current-mode control lets users parallel power supply

modules. Two or more TC170 controllers can be slaved

together for parallel operation. Circuits can operate

from a master TC170 internal oscillator or an external

system oscillator.

The TC170 operates from an 8V to 16V power supply.

An internal 2%, 5.1V reference minimizes external

component count. The TC170 is pin compatible with

the

Unitrode

UC1846/UC2846/UC3846

bipolar

controller.

Other advantages inherent in current-mode control

include superior line and load regulation and automatic

symmetry correction in push-pull converters.

Package Type

Part Number

Package

Temp. Range

TC170COE

16-Pin SOIC (Wide)

0°C to +70°C

TC170CPE

16-Pin PDIP (Narrow)

0°C to +70°C

TC170CPE

SHDN

DD

SOFT START/

+ ERROR AMP IN

CMPTR

– ERROR AMP IN

NOTE: Outputs LOW in "OFF" state.

IN

1

2

3

4

16

15

5

6

7

9

8

1

2

3

4

15

16

14

13

5

6

7

12

11

10

9

8

TC170COE

SOFT START/

+ ERROR AMP IN

CMPTR

– ERROR AMP IN

SHDN

OUTPUT B

GND

OUTPUT A

SYNC

16-Pin SOIC (Wide)

16-Pin PDIP (Narrow)

CMOS Current Mode PWM Controller