Semiconductor
S3843
Current Mode PWM Controller
Descriptions
The S3843 is fixed Current PWM controller for Off-line and DC-DC converter applications.
The internal circuits feature 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 for driving a power MOSFET. Protection circuitly
includes built in under voltage lockout and current limiting. S3843 have UVLO threshold of
8.4V(on) and 7.6V(off) , S3843 can operate within 100% duty cycle.
Features
•
Optimized for off-line and DC to DC converters
•
Low start up current < 1 mA
•
Operating range up to 500 KHz
•
Pulse-by-pulse current limiting
•
Under Voltage Lock Out with hysteresis
•
High current totempole output
•
Short shutdown delay time ; typical 100nsec
Ordering Information
Type NO.
S3843
Marking
S3843
Package Code
SOP-8
Outline Dimensions
unit :
mm
PIN Connections
1. Output / Compensation
2. Voltage feedback. Input
3. Current sense Input
4. Rt/Ct
5. GND
6. Output
7. Vcc
8. Vref
KSI-8007-001
1