Philips Semiconductors Linear Products
Product specification
Current-mode PWM controller
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
UC3842
Min
Typ
Max
UNIT
Output section
V
OL
V
OH
t
R
t
F
Output Low-Level
Output High-Level
Rise time
Fall time
I
SINK
=20mA
I
SINK
=200mA
I
SOURCE
=20mA
I
SOURCE
=200mA
C
L
=1nF
C
L
=1nF
14.5
8.5
13
12
0.1
1.5
13.5
13.5
50
50
150
150
0.4
2.2
V
V
ns
ns
Undervoltage lockout section
Start threshold
Min. operating voltage after turn on
16
10
17.5
11.5
V
V
PWM section
Maximum duty cycle
Minimum duty cycle
93
97
100
0
%
Total standby current
Start-up current
I
CC
Operating supply current
V
CC
zener voltage
V
PIN 2
=V
PIN 3
=0V
I
CC
=25mA
0.5
11
34
1
17
mA
mA
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.
DV
PIN 1
3. Gain defined as:
; 0
v
V
PIN 3
v
0.8V
A
+
DV
PIN 3
400
kHz
UNDERVOLTAGE LOCKOUT
7
V
CC
ON/OFF COMMAND
TO REST OF IC
ERROR AMP CONFIGURATION
2.5V
0.5mA
+
Z
I
2
V
FB
1
–
V
ON
V
OFF
I
CC
UC3842
16V
10V
COMP
NOTE:
Error AMP can source or sink up to 0.5mA.
<15mA
<1mA
V
OFF
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.
V
ON
V
CC
August 31, 1994
1103
PHILIPS [ NXP SEMICONDUCTORS ]
