KA3844
DESCRIPTION
KA3842/43/44/45 are fixed frequency current mode PWM controller. They are specially designed for OFF- Line and DC to DC converter applications with a minimal external ponents. Internally implemented circuits include a trimmed oscillator for precise duty cycle control, a temperature pensated reference, high gain error amplifier, current sensing parator, and a high current totempole output ideally suited for driving a power MOSFET. Protection circuitry includes built undervoltage lockout and current limiting.
The UC3842A(AM) and UC3844A(AM) have UVLO thresholds of 16 V (on) and 10 V (off).
The corresponding thresholds for the UC3843A(AM)/45A(AM) are 8.4V (on) and
7.6V
(off). The UC3842A(AM) and UC3843A(AM) can operate within 100% duty cycle. The
UC3844A(AM) and UC3845A(AM) can operate within 50% duty cycle.
The UC384XA(AM) has Start-Up Current 0.17m A (typ).
FEATURES
- Low Start-Up and Operating Current
- High Current Totem Pole Output
- Undervoltage Lockout With...
