UC3843 B ic control PWM

Description
The 3842A(AM)/43A(AM)/44A(AM)/45A(AM) 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 3842A(AM) and 3844A(AM) have UVLO thresholds of 16 V (on) and 10 V (off). The corresponding
thresholds for the 3843A(AM)/45A(AM) are 8.4V (on) and 7.6V (off). The MIK3842A(AM) and MIK3843A(AM) can operate within 100% duty
cycle. The 3844A(AM) and UC3845A(AM) can operate within 50% duty cycle.
The 384XA(AM) has Start-Up Current 0.17mA (typ).

Features
• Low Start-Up and Operating Current
• High Current Totem Pole Output
• Undervoltage Lockout With Hysteresis
•Operating Frequency Up To 300KHz (384XA)
500KHz (384XAM)