Microchip Technology RE46C144SW16F

Overview

RE46C144SW16F from Microchip Technology is a CMOS photoelectric smoke detector ASIC with integrated gain-selectable photo amplifier, 10-minute timer for sensitivity control, 75% duty cycle horn driver, interconnect capability for up to 40 detectors, and UL recognition per File S24036 for UL217/UL268 compliance. It operates from 6–12 V, draws only 4 µA typical standby current, and supports push-button chamber testing and low-battery detection.

For engineers reviewing the RE46C144SW16F datasheet, RE46C144SW16F pinout, RE46C144SW16F application, or RE46C144SW16F equivalent, this device serves as a complete, low-power smoke sensing solution requiring minimal external components - ideal for residential and commercial hardwired or battery-powered smoke alarms where regulatory certification, ultra-low quiescent current, and multi-unit interconnect are critical.

Technical Context

The RE46C144SW16F implements a strobed detection architecture: analog circuitry powers up for 10 ms every ~11 seconds (with 100 µs IRED pulse) to minimize standby current; smoke detection rate escalates upon valid samples, triggering alarm after three consecutive detections. Internal oscillation (9.4–11.5 ms period) sets timing for STROBE, IRED, LED, and horn cycles.

It integrates dual-gain photoamplifier selection (via C1/C2 capacitors), programmable sensitivity via VSEN in Timer mode, bidirectional interconnect logic with 670 ms digital filtering, and autonomous chamber integrity and low-battery checks every 43 seconds - all without external microcontroller intervention.

Key Specifications

Pinout & Package

RE46C144SW16F is housed in a 16-lead wide SOIC package (7.50 mm body width, 1.27 mm pitch), RoHS-compliant, with exposed pad not present and moisture sensitivity level (MSL) rated per JEDEC J-STD-020.

Key Features

Applications

Equivalent & Alternatives

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

Compared with RE46C144E16F and RE46C144S16F, the RE46C144SW16F offers optimal thermal resistance (80°C/W) and mechanical robustness for automated SMT assembly in high-volume smoke alarm production, while retaining full functional and timing equivalence across all three variants.

Availability

RE46C144SW16F is available at Aetrix Electronics and suitable for residential smoke alarms, commercial battery-powered detectors, and kitchen nuisance-alarm mitigation systems requiring stable component supply, long-lifecycle support, and UL-compliant design assurance.

Supply support for RE46C144SW16F 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 is a global semiconductor company specializing in microcontrollers, analog devices, and timing solutions, with ISO/TS 16949-certified manufacturing and broad safety-critical product validation.

The RE46C144SW16F belongs to Microchip's dedicated smoke detector ASIC family, engineered specifically for UL217/UL268-compliant photoelectric sensing - prioritizing ultra-low power, autonomous diagnostics, and interconnect interoperability in life-safety applications.

FAQ

What is the operating voltage range for the RE46C144SW16F?

The RE46C144SW16F operates from 6 V to 12 V DC. Its internal regulation supports stable STROBE (VDD−5 V) and IRED drive across this range, and the low-battery detection threshold is fixed at 6.9–7.5 V - ensuring reliable operation with both 9 V alkaline batteries and 12 V hardwired supplies. The RE46C144SW16F maintains full functionality including interconnect signaling and timer mode across the entire specified range.

How does the RE46C144SW16F perform chamber integrity testing?

The RE46C144SW16F performs autonomous chamber integrity testing every 43 seconds in standby mode by switching to high-gain configuration (C1 capacitor) and measuring background reflections in the smoke chamber. Two consecutive failures trigger a 10 ms horn chirp every 43 seconds. This test runs independently of alarm states and requires no external controller - a core function embedded directly in the RE46C144SW16F's analog timing and gain-switching logic.

Can the RE46C144SW16F be used in systems requiring UL268 compliance?

Yes - the RE46C144SW16F is UL Recognized per File S24036 for use in smoke detectors complying with both UL217 (residential) and UL268 (commercial fire alarm systems). Its integrated features - including interconnect signaling, self-test capability, and stable horn timing - meet the functional requirements of UL268 Annex B for initiating devices. The RE46C144SW16F itself is not a certified end product but enables UL268-compliant system design when implemented per Microchip's reference schematics and layout guidelines.

What is the purpose of the VSEN pin on the RE46C144SW16F?

The VSEN (pin 15) on the RE46C144SW16F serves as the external reference input for the 10-minute Timer mode. When enabled via TEST pin transition, the internal smoke comparator reference shifts from VDD−3.5 V to the voltage applied to VSEN - allowing adjustable sensitivity during temporary high-particulate conditions. If VSEN is left unconnected or tied to VSS, Timer mode is disabled. This function is exclusive to the RE46C144SW16F's analog control architecture and requires no firmware.

Does the RE46C144SW16F support interconnection with non-Microchip smoke detectors?

Yes - the RE46C144SW16F's IO pin includes a 670 ms digital filter and supports active-high remote alarm signaling compatible with industry-standard interconnect protocols. It can interface with CO detectors or other brands' alarms that output pulsed or latched interconnect signals, provided their output voltage stays within FEED pin limits (−10 V to +22 V) and meets the RE46C144SW16F's input threshold specifications. No protocol translation is needed - the RE46C144SW16F responds directly to valid logic-level transitions on IO.