The AS3844 family of control ICs provide pin-for-pin replacement of the industry standard UC3842 series of devices. The devices are redesigned to provide significantly improved tolerances in power supply manufacturing. The 2.5 V reference has been trimmed to 1.0% tolerance. The oscillator discharge current is trimmed to provide guaranteed duty cycle clamping rather than specified discharge current. The circuit is more completely specified to guarantee all parameters impacting power supply manufacturing tolerances.In addition,the oscillator and flip-flop sections have been enhanced to provide additional performance. The RT/CT pin now doubles as a synchronization input that can be easily driven from open collector/open drain logic outputs. This sync input is a high impedance input and can easily be used for externally clocked systems. The new flip-flop topology allows the duty cycle on the AS3844 to be guaranteed between 49 and 50%.
2.5 V bandgap reference trimmed to 1.0% and temperature-compensated
Standard temperature range extended to 105°C
Has exact 50% max duty cycle clamp
Advanced oscillator design simplifies synchronization
Improved specs on UVLO and hysteresis provide more predictable start-up and shutdown
Improved 5 V regulator provides better AC noise immunity
Guaranteed performance with current sense pulled below ground
8 pin DIP. Actual brand may vary from picture.