Microchip Technology RE46C167SW16F

Overview

RE46C167SW16F from Microchip Technology is a low-power CMOS photoelectric smoke detector ASIC with integrated interconnect, alarm memory, and 1.2-minute hush timer. It delivers temporal horn pattern output, <8 µA quiescent current, internal power-on reset, >2000V HBM ESD protection, and supports UL217/UL268 compliance in battery-powered residential smoke alarms.

For engineers reviewing the RE46C167SW16F datasheet, RE46C167SW16F pinout, RE46C167SW16F application, or RE46C167SW16F equivalent, key selection considerations include its 1.2-minute Timer mode sensitivity reduction, interconnect-driven multi-unit alarm synchronization, low-battery detection at 7.2 V, and dual-gain photoamplifier architecture for chamber testing and smoke discrimination.

Technical Context

The RE46C167SW16F implements a strobed detection architecture: analog circuitry powers down between 10-second intervals, activating for 10 ms per cycle with a 100 µs IRED pulse. Smoke verification uses three consecutive detections before entering local alarm, with gain increased ~10% during alarm for hysteresis.

Its bidirectional I/O pin features digital filtering (≤300 ms pulse rejection), 280 kΩ internal pull-down, and 1-second charge-dump discharge after local alarm. The Timer mode reconfigures the smoke comparator reference to VSEN voltage, enabling field-adjustable sensitivity for up to 1.2 minutes - distinct from the 9-minute RE46C165/6 variant.

Key Specifications

Pinout & Package

RE46C167SW16F is supplied in a 16-lead SOIC (150 mil) package with RoHS-compliant matte tin plating and thermal resistance θ_JA = 86.1°C/W.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar smoke detector ASIC applications.

Compared with RE46C165SW16F and RE46C168SW16F, the RE46C167SW16F uniquely balances rapid smoke verification (2.0 s detection interval) with precise 1.2-minute hush control and NFPA 72–compliant temporal output - making it optimal for kitchen-adjacent or high-traffic residential installations requiring both responsiveness and nuisance-alarm mitigation.

Availability

RE46C167SW16F is available at Aetrix Electronics and suitable for residential fire safety systems, interconnected alarm networks, and UL217-certified detector manufacturing requiring stable component supply, long-lifecycle support, and RoHS-compliant packaging.

Supply support for RE46C167SW16F includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Microchip Technology Inc. is a global semiconductor company specializing in microcontrollers, analog devices, and timing solutions for industrial, automotive, and consumer applications.

The RE46C165/6/7/8 family was designed specifically for UL217/UL268–compliant photoelectric smoke detectors, integrating all core signal conditioning, timing, alarm generation, and interconnect logic into a single low-power ASIC.

FAQ

What is the hush timer duration of the RE46C167SW16F?

The RE46C167SW16F provides a 1.2-minute hush timer, activated by a high-to-low transition on the TEST pin with appropriate external resistors (RADJ1/RADJ2) connected to VSEN. This differs from the 9-minute hush in the RE46C165/6 variants and is factory-trimmed to ±10% tolerance. The timer automatically resets upon local alarm entry or external alarm detection.

How does the RE46C167SW16F perform low-battery detection?

The RE46C167SW16F monitors VDD against an internal reference and latches low-battery status every 43 seconds at the conclusion of the LED pulse. It triggers a 10 ms horn chirp every 43 seconds when VDD falls below 7.2 V (6.9–7.5 V range). This notification is suppressed during local or remote alarm to avoid masking emergency signals.

What is the function of the C1 and C2 pins on the RE46C167SW16F?

C1 (Pin 1) sets high-gain photoamplifier response for push-to-test and chamber integrity checks (gain A = 1 + C1/10 pF), while C2 (Pin 2) sets normal-gain sensitivity for standby smoke detection (A = 1 + C2/10 pF). During local alarm, C2 gain increases ~10% internally to provide hysteresis and prevent oscillation near threshold.

Does the RE46C167SW16F support interconnection with other alarm types like CO detectors?

Yes - the RE46C167SW16F's I/O pin includes a 300 ms digital filter that rejects short pulses, allowing reliable interconnection with carbon monoxide (CO) alarms or other pulsed-signaling units. Its interconnect input accepts active-high signals up to 15 V and tolerates supply voltage mismatches between units without excessive current draw.

What horn pattern does the RE46C167SW16F generate during alarm?

The RE46C167SW16F generates the NFPA 72–compliant temporal horn pattern: 500 ms ON / 500 ms OFF, repeated every 4.0 seconds (48-clock period). This distinguishes it from the continuous pattern used in RE46C166/8 and ensures standardized emergency evacuation signaling in residential and commercial installations.