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LM3842A Datasheet, PDF (1/7 Pages) HTC Korea TAEJIN Technology Co. – CURRENT MODE PWM CONTROLLER | |||
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CURRENT MODE PWM CONTROLLER
LM3842A/3A/4A/5A
FEATURES
8 SOP/ 8 DIP PIN Configulation
â Automatic feed forward compensation
â Optimized for offline converter
â Double pulse suppression
Compen
sation
1
Voltage
Feedback 2
8 VREF
7 Vcc
â Current mode operation to 500 KHz
â High gain totem pole output
â Internally trimmed bandgap reference
Current
Sense
3
RT/CT 4
6 OUTPUT
5 GND
â Undervoltage lockout with hysteresis
â Low start up current :ï¼ 0.3 mA
ORDERING INFORMATION
Device
Package
DESCRIPTION
LM3842A/3A/4A/5A D
8 SOP
LM3842A/3A/4A/5A N
8 DIP
The LM3842A is fixed frequency current-mode PWM controller. It is specially designed for Off-Line and
DC-to-DC converter applications with minimal external components.
This integrated circuit features a trimmed oscillator for precise duty cycle control, a temperature
compensated reference, high gain error amplifier, current sensing comparator, and a high current
totempole output ideally suited for driving a power MOSFET.
Protection circuitry includes built in under-voltage lockout and current limiting.
SIMPLIFIED BLOCK DIAGRAM
VREF â§
RT/CT â£
VFB â¡
COMP â
5V
Reference
R
VREF
R
Undervoltage
Lockout
Vcc
Undervoltage
Lockout
Oscillator
+
-
Error
Amplifie
r
Latching
PWM
ABSOLUTE MAXIMUM RATINGS (TA= 25â)
Characteristic
Power Supply Voltage
Output Current
Analog Inputes Voltage
Error Amp Output Sink Current
Power Dissipation
Storage Temperature Range
Lead Temperature (soldering 5 sec)
Symbol
Vcc
I
VIN
ISINK
PD
Tstg
T
Value
30
±1
-0.3 to 5.5V
10
1
-65 to 150
260
⦠Vcc
⥠Output
⤠Ground
⢠Current
Sense
Input
Unit
V
A
V
mA
W
â
â
1
HTC
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