UC3842AM Microsemi Analog Mixed Signal Group, UC3842AM Datasheet - Page 8

• Manufacturer Part Number: UC3842AM
• Description: IC CTRLR PWM CURRENT MODE 8DIP
• Manufacturer: Microsemi Analog Mixed Signal Group

Specifications of UC3842AM

• Pwm Type: Current Mode
• Number Of Outputs: 1
• Frequency - Max: 500kHz
• Duty Cycle: 100%
• Voltage - Supply: 11.5 V ~ 25 V
• Buck: Yes
• Boost: Yes
• Flyback: Yes
• Inverting: No
• Doubler: No
• Divider: No
• Cuk: No
• Isolated: Yes
• Operating Temperature: 0°C ~ 70°C
• Package / Case: 8-DIP
• Frequency-max: 500kHz
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

UC184xA/284xA/384xA
8
SPECIFICATIONS
Input line voltage:
Input frequency:
Switching frequency:
Output power:
Output voltage:
Output current:
Line regulation:
Load regulation:
Efficiency @ 25 Watts,
Output short-circuit current:
INPUT
AC
V
V
IN
IN
3.6k
= 90VAC:
= 130VAC:
1N4004
1N4004
0.01µF
20k
100pF
150k
1N4004
1N4004
10k
.0022µF
4.7k
T Y P I C A L A P P L I C A T I O N C I R C U I T S
P R O D U C T D A T A B O O K 1 9 9 6 / 1 9 9 7
1W
2
1
8
4
UC3844A
V
COMP
V
R
90VAC to 130VAC
50 or 60Hz
40KHz ±10%
25W maximum
5V +5%
2 to 5A
0.01%/V
8%/A*
70%
65%
2.5Amp average
T
FB
REF
/C
C
220µF
250V
16V
T
U R R E N T
P
R O D U C T I O N
GND
V
7
5
CC
FIGURE 8. — OFF-LINE FLYBACK REGULATOR
OUT
CUR
SEN
140k
1/2W
6
3
M
0.01µF
O D E
4.7k
27k
2W
470pF
P W M C
1k
* This circuit uses a low-cost feedback scheme in which the DC
1N4935
D
voltage developed from the primary-side control winding is
sensed by the UC3844A error amplifier. Load regulation is
therefore dependent on the coupling between secondary and
control windings, and on transformer leakage inductance.
10µF
20V
A T A
O N T R O L L E R
0.85k
3600pF
400V
1N4935
S
H E E T
820pF
(continued)
2.5k
BOUNDARY
ISOLATION
TI
MBR735
4700µF
10V
2-5A
5V
Copyright © 1995
Rev. 1.2a 10/25