UC1843 Application Note

●Description

●The UC1842A/3A/4A/5A family of control ICs is a pin for pin compatible improved version of the UC3842/3/4/5 family. Providing the necessary features to control current mode switched mode power supplies, this family has the following improved features. Start up current is guaranteed to be less than 0.5mA. Oscillator discharge is trimmed to 8.3mA. During under voltage lockout, the output stage can sink at least 10mA at less than 1.2V for VCC over 5V.

●Features

● Optimized for Off-line and DC to DC Converters

● Low Start Up Current (<0.5mA)

● Trimmed Oscillator Discharge Current

● Automatic Feed Forward Compensation

● Pulse-by-Pulse Current Limiting

● Enhanced Load Response Characteristics

● Under-Voltage Lockout With Hysteresis

● Double Pulse Suppression

● High Current Totem Pole Output

● Internally Trimmed Bandgap Reference

● 500kHz Operation

● Low RO Error Amp