UC2825B

UC1823A,B/1825A,B UC2823A,B/2825A,B UC3823A,B/3825A,B High Speed PWM Controller FEATURES Improved versions of the UC3823/UC3825 PWMs Compatible with Voltage or Current-Mode Topologies Practical Operation at Switching Frequencies to 1MHz 50ns Propagation Delay to Output High Current Dual Totem Pole Outputs (2A Peak) Trimmed Oscillator Discharge Current Low 100µA Startup Current Pulse-by-Pulse Current Limiting Comparator Latched Overcurrent Comparator With Full Cycle Restart DESCRIPTION The UC3823A & B and the UC3825A & B family of PWM control ICs are improved versions of the standard UC3823 & UC3825 family. Performance enhancements have been made to several of the circuit blocks. Error amplifier gain bandwidth product is 12MHz while input offset voltage is 2mV. Current limit threshold is guaranteed to a tolerance of 5%. Oscillator discharge current is specified at 10mA for accurate dead time control. Frequency accuracy is improved to 6%. Startup supply current, typically 100µA, is ideal for off-line applications. The output drivers are redesigned to actively sink current during UVLO at no expense to the startup current specification. In addition each output is capable of 2A peak currents during transitions. Functional improvements have also been implemented in this family. The UC3825 shutdown comparator is now a high-speed overcurrent comparator with a threshold of 1.2V. The overcurrent comparator sets a latch that ensures full discharge of the soft start c...