Current-mode PWM controller

Philips Semiconductors Linear Products
Current-mode PWM controller
Product specification
UC3842
DC AND AC ELECTRICAL CHARACTERISTICS
0≤T J ≤70°C for UC3842; V CC =15 4 ; R T =10kΩ; C T =3.3nF, unless otherwise specified
SYMBOL PARAMETER TEST CONDITIONS
Output section
V OL
V OH
Output Low-Level
Output High-Level
UC3842
Min Typ Max
I SINK =20mA 0.1 0.4
I SINK =200mA 1.5 2.2
I SOURCE =20mA 13 13.5
I SOURCE =200mA 12 13.5
t R Rise time C L =1nF 50 150 ns
t F Fall time C L =1nF 50 150 ns
Undervoltage lockout section
PWM section
Start threshold 14.5 16 17.5 V
Min. operating voltage after turn on 8.5 10 11.5 V
Maximum duty cycle 93 97 100
Minimum duty cycle 0
Total standby current
Start-up current 0.5 1 mA
I CC Operating supply current V PIN 2 =V PIN 3 =0V 11 17 mA
V CC zener voltage I CC =25mA 34 V
Maximum operating frequency section
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 V PIN 2 =0.
3. Gain defined as:
A V PIN 1
; 0 V
V PIN 3 0.8V
PIN 3
UNIT
V
V
%
400 kHz
UNDERVOLTAGE LOCKOUT
ERROR AMP CONFIGURATION
V CC
7
ON/OFF COMMAND
TO REST OF IC
2.5V
+
0.5mA
I CC
V ON
V OFF
UC3842
16V
10V
Z I
NOTE:
Error AMP can source or sink up to 0.5mA.
2
V FB
1
COMP
–