The UC3844B, UC3845B series are high performance fixed frequency current mode controllers. They are specifically designed for Off?Line and dc?dc converter applications offering the designer a cost?effective solution with minimal external components. These integrated circuits feature an oscillator, a temperature compensated reference, high gain error amplifier, current sensing comparator, and a high current totem pole output ideally suited for driving a power MOSFET.

特性 Features

? Trimmed Oscillator for Precise Frequency Control

? Oscillator Frequency Guaranteed at 250 kHz

? Current Mode Operation to 500 kHz Output Switching Frequency

? Output Deadtime Adjustable from 50 to 70

? Automatic Feed Forward Compensation

? Latching PWM for Cycle?By?Cycle Current Limiting

? Internally Trimmed Reference with Undervoltage Lockout

? High Current Totem Pole Output

? Undervoltage Lockout with Hysteresis

? Low Startup and Operating Current

? Pb?Free Packages are Available