Microchip Technology RE46C141SW16F

Overview

RE46C141SW16F from R&E International (a Microchip Technology subsidiary) is a CMOS photoelectric smoke detector ASIC with integrated interconnect functionality, low-power strobed detection (4 µA standby current at 9 V), temporal horn pattern compliance with NFPA 72, and UL 217/UL 268 recognition. It integrates gain-selectable photoamplifier, internal oscillator, IRED driver, dual-tone horn control (HB/HS), and bidirectional interconnect logic for up to 40-unit networks - deployed in residential and commercial hardwired smoke alarms.

For engineers reviewing the RE46C141SW16F datasheet, RE46C141SW16F pinout, RE46C141SW16F application, or RE46C141SW16F equivalent, this page delivers verified electrical specs (e.g., VDD = 6–12 V, STROBE = VDD−5 V, TPER1 = 8.1 s), functional timing (TON2 = 104 µs IRED pulse), UL-certified alarm behavior, interconnect signaling protocol, and chamber integrity test methodology - all critical for safety-critical PCB layout and certification validation.

Technical Context

The RE46C141SW16F implements a pulsed photoelectric detection architecture: analog circuitry is powered only 100 µs every 8.1 s in standby, reducing IDD to 4 µA; smoke presence triggers accelerated sampling (down to 1 s intervals) and three consecutive detections initiate local alarm. Its internal oscillator uses external ROSC/COSC network (R9=100 kΩ, C5=1.5 nF) to set timing with ±10% production-tested tolerance.

Interconnect operation relies on bidirectional IO pin with 500 ms digital filtering, constant-current high-drive during local alarm, and NMOS discharge dump (1.1 s duration) to clear line capacitance. Horn output uses complementary HB/HS pins driving piezoelectric transducers with defined temporal pattern: 500 ms ON / 1.5 s OFF in local alarm, chirping every 32 s for low-battery or chamber failure.

Key Specifications

Pinout & Package

RE46C141SW16F is supplied in 16-lead SOIC-Wide (W SOIC) package, 7.5 mm body width, 1.27 mm pitch, RoHS-compliant Pb-free finish.

Key Features

Applications

Equivalent & Alternatives

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

Compared with RE46C141SW16F, RE46C142SW16F extends thermal operating range but forfeits out-of-box UL 217/268 compliance, while MC145012P omits interconnect and temporal horn support - making RE46C141SW16F the sole option for certified, networked photoelectric alarms with 4 µA standby power.

Availability

RE46C141SW16F is available at Aetrix Electronics and suitable for residential fire alarm systems, commercial building life-safety networks, and manufactured housing smoke detection requiring stable component supply, long-term lifecycle assurance, and UL-certified design reuse.

Supply support for RE46C141SW16F 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

R&E International is a wholly owned subsidiary of Microchip Technology Inc., specializing in safety-critical analog/mixed-signal ICs for fire and life-safety applications.

The RE46C141SW16F belongs to R&E's photoelectric smoke detector ASIC product line, engineered specifically to integrate detection, interconnect, and NFPA 72-compliant alarm generation into a single UL-recognized device for battery- and line-powered alarms.

FAQ

What is the standby current consumption of the RE46C141SW16F and how is it achieved?

The RE46C141SW16F draws only 4 µA typical standby current at 9 V. This ultra-low power is achieved through its strobed architecture: the internal oscillator activates the photoamplifier and IRED for just 100 µs every 8.1 seconds, keeping analog circuitry powered down >99.99% of the time. The RE46C141SW16F also disables battery monitoring and chamber testing during alarm states to maintain minimal quiescent draw - enabling over 10 years of operation on a single 9 V alkaline cell.

How does the RE46C141SW16F implement interconnect functionality across multiple smoke detectors?

The RE46C141SW16F uses its bidirectional IO pin to support wired-OR interconnection of up to 40 units. During local alarm, the IO pin drives high via a constant-current source; any unit detecting this signal enters remote alarm and activates its horn. Input filtering rejects noise and pulsed signals (e.g., from CO alarms). An NMOS discharge dump active for 1.1 s after local alarm clears line capacitance. The RE46C141SW16F's IO logic is UL 217-recognized, ensuring interoperability without external level-shifting or timing adjustments.

What is the purpose of the C1 and C2 pins on the RE46C141SW16F, and how do they differ in operation?

C1 and C2 are external capacitor inputs that set photoamplifier gain for distinct operational modes. C1 configures high gain (A = 1 + C1/10 pF) used exclusively during push-to-test and chamber integrity verification every 32 seconds. C2 sets normal gain (A = 1 + C2/10 pF) for standby smoke detection. This dual-capacitor architecture prevents false alarms during self-test while maintaining optimal sensitivity for real smoke events. The RE46C141SW16F automatically switches between C1 and C2 based on detection state - no external control required.

Does the RE46C141SW16F support NFPA 72 temporal horn patterns, and how is it implemented?

Yes, the RE46C141SW16F natively generates the NFPA 72 temporal-three pattern: 500 ms horn ON followed by 1.5 s OFF during local alarm. This is implemented via dedicated HB (metal electrode) and HS (ceramic electrode) complementary outputs that drive piezoelectric transducers with precise phase inversion. In fault conditions (low battery or chamber failure), it emits a 7.9 ms chirp every 32 seconds - timed to avoid overlap with LED pulses. The RE46C141SW16F's timing is production-tested and UL 217/268-recognized, eliminating need for external timing components or firmware.

What UL certifications apply to the RE46C141SW16F and what do they cover?

The RE46C141SW16F is UL Recognized under File S24036 for compliance with UL 217 (Standard for Single and Multiple Station Smoke Alarms) and UL 268 (Standard for Smoke Detectors). This certification covers its photoelectric smoke sensing architecture, temporal horn pattern generation, interconnect signaling protocol, low-battery and chamber integrity test functions, and operating temperature range (−25°C to +75°C). The RE46C141SW16F's UL recognition allows OEMs to leverage its qualification in end-product listings - significantly reducing time-to-market for new alarm designs.