UC1823A, UC2823A, UC2823B,
UC3823A, UC3823B, UC1825A,
UC2825A, UC2825B, UC3825A, UC3825B
SLUS334E − AUGUST 1995 − REVISED SEPTEMBER 2010
HIGH-SPEED PWM CONTROLLER
D Improved Versions of the UC3823/UC3825
D Compatible with Voltage-Mode or
Current-Mode Control Methods
D Practical Operation at Switching Frequencies
to 1 MHz
D 50-ns Propagation Delay to Output
D High-Current Dual Totem Pole Outputs
D Trimmed Oscillator Discharge Current
D Low 100-μA Startup Current
D Pulse-by-Pulse Current Limiting Comparator
D Latched Overcurrent Comparator With Full
The UC3823A and UC3823B and the UC3825A and
UC3825B family of PWM controllers are improved
versions of the standard UC3823 and UC3825 family.
Performance enhancements have been made to several
of the circuit blocks. Error amplifier gain bandwidth product
is 12 MHz, while input offset voltage is 2 mV. Current limit
threshold is assured to a tolerance of 5%. Oscillator
discharge current is specified at 10 mA for accurate dead
time control. Frequency accuracy is improved to 6%.
Startup supply current, typically 100 μA, 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
2-A peak currents during transitions.
* On the UC1823A version, toggles Q and Q are always low.
16 5.1 VREF
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