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 components. Internally implemented circuits include 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 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