UC3842 Просмотр технического описания (PDF) - Philips Electronics

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UC3842

Current-mode PWM controller

Philips Electronics 

Philips Semiconductors Linear Products

Current-mode PWM controller

Product specification

UC3842

DC AND AC ELECTRICAL CHARACTERISTICS

0≤TJ≤70°C for UC3842; VCC=154; RT=10kΩ; CT=3.3nF, unless otherwise specified

SYMBOL

PARAMETER

TEST CONDITIONS

Output section

VOL

Output Low-Level

VOH

Output High-Level

tR

Rise time

tF

Fall time

Undervoltage lockout section

ISINK=20mA

ISINK=200mA

ISOURCE=20mA

ISOURCE=200mA

CL=1nF

CL=1nF

Start threshold

Min. operating voltage after turn on

PWM section

Maximum duty cycle

Minimum duty cycle

Total standby current

Start-up current

ICC

Operating supply current

VCC zener voltage

Maximum operating frequency section

VPIN 2=VPIN 3=0V

ICC=25mA

Maximum operating frequency for all

functions operating cycle-by-cycle

NOTES:

1. These parameters, although guaranteed, are not 100% tested in production.

2. Parameter measured at trip point of latch with VPIN 2=0.

3.

Gain defined as:

A

+

DVPIN 1

DVPIN 3

;

0 v VPIN 3

v 0.8V

UC3842

Min Typ Max

UNIT

0.1 0.4

V

1.5 2.2

13 13.5

V

12 13.5

50 150

ns

50 150

ns

14.5 16 17.5

V

8.5 10 11.5

V

93 97 100

%

0

0.5 1

mA

11 17

mA

34

V

400

kHz

UNDERVOLTAGE LOCKOUT

ERROR AMP CONFIGURATION

7

VCC

ON/OFF COMMAND

TO REST OF IC

VON

VOFF

ICC

UC3842

16V

10V

2.5V

+

ZI

2

–

VFB

1

COMP

NOTE:

Error AMP can source or sink up to 0.5mA.

0.5mA

<15mA

<1mA

VOFF VON

VCC

NOTE:

During Undervoltage Lock-Out, the output driver is biased to a high

impedance state. Pin 6 should be shunted to ground with a bleeder

resistor to prevent activating the power switch with output leakage current.

August 31, 1994

1103

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