[ASTEC]

Description

The AS3842 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.

Features

• 2.5 V bandgap reference trimmed to 1.0 and temperature-compensated

• Standard temperature range extended to 105°C

• AS3842/3 oscillations trimmed for precision duty cycle clamp

• AS3844/5 have 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