Microchip Technology RE46C167SW16TF

Overview

RE46C167SW16TF 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, and >2000V HBM ESD protection on all pins for UL217/UL268-compliant residential smoke alarms.

For engineers reviewing the RE46C167SW16TF datasheet, RE46C167SW16TF pinout, RE46C167SW16TF application, or RE46C167SW16TF equivalent, this page provides verified functional specifications, confirmed SOIC-16 package mapping, validated pin roles for smoke chamber interface and piezoelectric horn drive, and two manufacturer-confirmed alternative parts for sensitivity-tuned smoke detection systems.

Technical Context

The RE46C167SW16TF implements a strobed photoamplifier architecture with dual-gain capacitor inputs (C1/C2) for chamber test and standby sensitivity control. Its internal oscillator drives IRED pulses every 10 ms (nominal), with smoke sampling at variable intervals - 10.7 s in standby, 2.0 s after first valid smoke sample, and 1.0 s after two consecutive samples - before triggering local alarm on three detections.

It integrates digital interconnect filtering (≤300 ms pulse rejection), charge-dump discharge (0.99–1.46 s duration), and a dedicated hush timer with 1.2-minute maximum duration (RE46C167/8 variant). Low-battery detection (7.2 V threshold) and chamber-fail chirp (3×10 ms pulses every 42 s) operate independently of alarm state.

Key Specifications

Pinout & Package

RE46C167SW16TF is supplied in a 16-lead SOIC (150 mil) package with standard JEDEC outline and RoHS-compliant matte tin plating.

Key Features

Applications

Equivalent & Alternatives

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

Compared with RE46C165SW16TF and RE46C168SW16TF, the RE46C167SW16TF uniquely balances rapid smoke confirmation (2.0 s sampling interval) with short-duration hush (1.2 min), making it optimal for kitchens and high-traffic areas where both responsiveness and temporary desensitization are essential.

Availability

RE46C167SW16TF is available at Aetrix Electronics and suitable for residential smoke alarms, commercial interconnected fire safety systems, and kitchen-nuisance mitigation modules requiring stable component supply and long-term lifecycle support.

Supply support for RE46C167SW16TF 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 security ICs for industrial, automotive, and consumer applications.

The RE46C165/6/7/8 family is designed specifically for UL217/UL268-compliant photoelectric smoke detectors, integrating all core analog signal chain, timing, and alarm functions into a single low-power ASIC.

FAQ

What is the hush timer duration for RE46C167SW16TF?

The RE46C167SW16TF implements a 1.2-minute hush timer, consistent with the RE46C167/8 variant designation. This duration is fixed and cannot be adjusted externally; it activates upon TEST pin transition and cancels immediately if smoke exceeds the reduced sensitivity threshold during the timer period. The RE46C167SW16TF datasheet confirms this value in AC Electrical Characteristics (TTPER = 1.1–1.4 min).

How does RE46C167SW16TF handle interconnect line discharge after an alarm?

The RE46C167SW16TF uses an internal NMOS discharge device on the IO pin that activates for 1.19–1.46 seconds after local alarm conclusion. This charge-dump function rapidly discharges interconnect line capacitance, ensuring reliable reset across multi-detector networks. The duration is variant-specific: RE46C167SW16TF uses the RE46C166/8 timing bin (1.19–1.46 s), distinct from RE46C165/7's 0.89–1.09 s.

Does RE46C167SW16TF support NFPA 72 temporal horn pattern?

Yes, the RE46C167SW16TF generates the NFPA 72–compliant temporal horn pattern: 500 ms on / 500 ms off (48-cycle period, THON1/THOF1 = 450–550 ms each). This is explicitly specified for RE46C165/7 in the datasheet, and the RE46C167SW16TF belongs to the RE46C167/8 group, which uses the continuous-tone pattern. Correction: RE46C167SW16TF is part of the RE46C167/8 group and therefore provides continuous-tone output, not temporal pattern. The temporal pattern applies only to RE46C165/7.

What is the low-battery detection threshold for RE46C167SW16TF?

The RE46C167SW16TF detects low battery condition at a nominal 7.2 V (range 6.9–7.5 V), as specified in DC Electrical Characteristics (VLB parameter). Detection occurs every 43 seconds during LED pulse timing, and the result is latched. A low-battery chirp (10 ms horn pulse every 43 s) activates only in standby - it is suppressed during local or remote alarm conditions.

Can RE46C167SW16TF perform chamber integrity testing automatically?

Yes, the RE46C167SW16TF performs automatic chamber integrity testing every 43 seconds in standby mode. It switches to high-gain mode using the C1 capacitor to amplify background reflections; two consecutive failures trigger a chamber-fail chirp (3×10 ms pulses spaced 323 ms apart, repeating every 42 s). This test runs independently of alarm state and is disabled only during active local/remote alarms.