@vic AV3842A / 3843A LINEAR INTEGRATED CIRCUIT
QW-R103-002,B

CURRENT MODE PWM CONTROL
CIRCUITS

DESCRIPTION
The @vic AV3842A/3843A provide the necessary functions
to implement off-line or DC to DC fixed frequency current
mode , controlled switching circuits with a minimal external
part count

FEATURES
*Low external part count.
*Low start up current ( Typical 0.12mA )
*Automatic feed forward compensation
*Pulse-by-Pulse current limiting
*Under-voltage lockout with hysteresis
*Double pulse Suppression
*High current totem pole output to drive MOSFET directly
*Internally trimmed band gap reference
*500kHz operation


DIP-8
SOP-8




BLOCK DIAGRAM

7
5
7
6
5
4
3
1
2
8
Internal
Bias
5V REF S/R
U.V.L.O
R
S
PWM
LATCH
Vref
Good
Logic
ERROR
AMPLIFIER
1/2Vref
1/3Vref
1V
OSCILLATOR
Vref
VFB
COMP
CURRENT SENSE
RT/CT
Vcc
GND
OUTPUT
Vcc
GND
CURRENT
SENSE
COMPARATOR


ABSOLUTE MAXIMUM RATINGS(Ta=25°C)
PARAMETER SYMBOL VALUE UNIT
Supply Voltage(Low Impedance Source) VCC 30 V
Supply Voltage(Icc<30mA) Vcc Self Limiting V
Output Current ( Peak ) Io +-1 A
Output Energy(capacity Load) 5 µJ
Analog Inputs(pin 2,3) VI(ANA) -0.3 ~ +6.3 V
Error Amplifier Output Sink Current ISINK(EA) 10 mA
Power Dissipation PD DIP-8 at Tamb<=25°C 1.0 W
SOP-8 at Tamb<=25°C 0.5 W
Lead Temperature( Soldering 10 Sec ) Tlead 300 °C