IP1844

• Guaranteed ±1% reference voltage tolerance
• Guaranteed ±10% frequency tolerance
• Low startup current (<500 mA)
• Under voltage lockout with hysteresis
• Output state completely defined for all supply and input conditions
• Interchangeable with UC1844 and UC1845 series for improved operation
• 500kHz Oscillator operation 250kHz Output operation

The IP1844 and IP1845 series of switching regulator control circuits contain all the functions necessary to implement off-line, current mode switching regulators, using a minimum number of external parts.

Functions included are voltage reference, error amplifier, current sense comparator, oscillator, totem-pole output driver and under-voltage lockout circuitry. In addition there is a toggle flip-flop which blanks the output on every second clock pulse, thereby ensuring that the duty cycle never exceeds 50%.

Although pin compatible with the IP1844 series, SEMELAB has incorporated several improvements in the IP1844 and IP1845 series allowing tighter and more complete specification of electrical performance .