The RE46C112 is an ionization type smoke detector IC. It is intended for applications using ionization type chambers to detect smoke. When enabled, VOUT is ? of either the DETECT input or VDD depending on the status of the SELECT input. When the Select input is allowed to float the circuit is in the low current mode with only the guard amplifier enabled. Utilizing low power CMOS technology the RE46C112 was designed for use in smoke detectors that comply with Underwriters Laboratory Specification UL217.