KA3842B Datasheet, PDF (1/12 Pages) Fairchild Semiconductor – SMPS Controller

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KA3842B/KA3843B/KA3844B/KA3845B
SMPS Controller
Features
• Low Start Up Current
• Maximum Duty Clamp
• UVLO With Hysteresis
• Operating Frequency Up To 500KHz
Description
The KA3842B/KA3843B/KA3844B/KA3845B are fixed
frequency current-mode PWM controller. They are spe-
cially designed for Off - Line and DC-to-DC converter
applications with minimum external components. These
integrated 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 Ideally suited for driving a
power MOSFET. Protection circuity Includes built in
under-voltage lockout and current limiting. The KA3842B
and KA3844B have UVLO thresholds of 16V (on) and
10V (off) The KA3843B and KA3845B are 8.5V (on) and
7.9V (off) The KA3842B and KA3843B can operate within
100% duty cycle. The KA3844B and KA3845B can operate
with 50% duty cycle.
8-DIP
1
14-SOP
1
©2000 Fairchild Semiconductor International
Rev. 5.0