UC3842 Datasheet Text
UMW R
UMW UC3842/43/44/45
Description
The 3842/43/44/45 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 3842 and 3844 have UVLO thresholds of 16 V (on) and 10 V (off). The corresponding thresholds for the 3843/ 45 are 8.4V (on) and 7.6V (off). The 3842) and 3843 can operate within 100% duty cycle. The 3844 and 3845 can operate within 50% duty cycle. The 384X has Start-Up Current 0.5mA (typ).
Features
- Low Start-Up and Operating Current
- High Current Totem Pole Output
- Undervoltage Lockout With Hysteresis
- Operating Frequency Up To 500KHz
Pin Connection
Block diagram
(toggle flip flop used only in 3844, 3845)
Top...
