The RE46C194 is a low power, low voltage CMOS photoelectric type smoke detector ASIC. With minimal external components, this circuit will provide all the required functions and features for a photoelectric smoke detector. Programmable setup, calibration and feature selection are the key to reduced component count and reduced manufacturing costs. The low average operating current of the RE46C194 allows smoke detectors to achieve 10-year operation with lithium ion batteries. The boost regulator insures proper operation of the infrared diode and the piezoelectric horn under low battery conditions. The design incorporates a programmable gain integrating photo amplifier for use with an infrared emitter diode. The infrared emitter drive current is programmable along with smoke alarm limits which provides the designer with exceptional flexibility when designing a smoke detector. Smart IO with CO temporal horn pattern allows the RE46C194 to be used in combined CO and photoelectric smoke detectors.