Microchip Technology RE46C144SW16TF

Overview

RE46C144SW16TF 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 at 9 V, and supports push-button chamber testing and low-battery detection.

For engineers reviewing the RE46C144SW16TF datasheet, RE46C144SW16TF pinout, RE46C144SW16TF application, or RE46C144SW16TF equivalent, this device serves as a complete, low-power smoke sensing solution requiring minimal external components - ideal for residential and commercial photoelectric smoke alarms where regulatory certification, battery life, and multi-unit interconnect reliability are critical.

Technical Context

The RE46C144SW16TF integrates a strobed photo detection architecture: analog circuitry powers up for 10 ms every ~11 seconds (with 100 µs IRED pulse), reducing standby current to 4–6 µA. Smoke detection uses dual-gain photo amplification - normal gain via C2 capacitor during standby, high gain via C1 during chamber test or push-to-test - with internal reference comparison and three-consecutive-sample alarm latching.

It implements synchronized timing across multiple subsystems: 10.5 ms oscillator period (set by ROSC/COSC), 43-second battery/chamber test interval, 10-minute timer mode (enabled via TEST/VSEN), and programmable horn pattern (252 ms on / 84 ms off in alarm). Interconnect operation includes 670 ms digital filtering, constant-current IO drive, and 1-second NMOS discharge post-alarm.

Key Specifications

Pinout & Package

RE46C144SW16TF is supplied in a 16-lead wide SOIC package (7.50 mm body width), RoHS-compliant, tape-and-reel format (SW16TF suffix). Pin count, spacing, and thermal resistance (θJA = 80°C/W) match JEDEC MS-013AC standards.

Key Features

Applications

Equivalent & Alternatives

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

Compared with RE46C144E16F and RE46C144S16TF, the RE46C144SW16TF delivers the best balance of SMT manufacturability, thermal performance (θJA = 80°C/W), and UL-certified reliability - making it the preferred choice for high-volume, certified smoke alarm production.

Availability

RE46C144SW16TF is available at Aetrix Electronics and suitable for residential smoke alarms, commercial fire detection systems, multi-sensor interconnect networks, and UL-certified alarm modules requiring stable component supply and long-term lifecycle support.

Supply support for RE46C144SW16TF 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 security ICs, with a strong heritage in safety-critical and certified applications.

The RE46C144 product line was designed specifically for UL217/UL268-compliant photoelectric smoke detection - integrating precision analog sensing, ultra-low-power timing, and certified alarm signaling in a single ASIC.

FAQ

What is the primary function of the RE46C144SW16TF in a smoke alarm system?

The RE46C144SW16TF serves as the core photoelectric smoke sensing ASIC, performing strobed infrared detection, dual-gain photo amplification, low-battery monitoring, chamber integrity testing, and UL-compliant horn drive. It replaces discrete analog and timing circuits with a single IC, reducing BOM count and ensuring regulatory compliance for final alarm products.

How does the RE46C144SW16TF achieve ultra-low standby current?

The RE46C144SW16TF achieves 4 µA typical standby current by powering down analog circuitry between 10 ms detection windows, strobing the IRED for only 100 µs every ~11 seconds, and using CMOS design with internal power gating. This architecture enables multi-year battery life in 9 V-powered smoke alarms without compromising detection responsiveness.

Can the RE46C144SW16TF be used in interconnectable multi-unit smoke alarm systems?

Yes - the RE46C144SW16TF features a dedicated bidirectional IO pin with constant-current drive, 670 ms digital filtering, and NMOS discharge capability, enabling reliable interconnection of up to 40 units. When one unit alarms, it drives IO high to trigger synchronized alarms across the entire network, meeting UL217 interconnect requirements.

What is the purpose of the C1 and C2 pins on the RE46C144SW16TF?

C1 and C2 are capacitor inputs that set photo amplifier gain: C1 configures high gain for push-button chamber testing and background reflection analysis, while C2 sets normal gain for standby smoke detection. Gain equals 1 + (capacitance in pF)/10, allowing precise sensitivity tuning without external op-amps or resistors.

Is the RE46C144SW16TF certified for use in UL-listed smoke alarms?

Yes - the RE46C144SW16TF is UL Recognized per File S24036 and compliant with UL217 (single- and multiple-station smoke alarms) and UL268 (fire alarm systems). This pre-certification allows manufacturers to leverage the IC's qualification in their end-product submissions, significantly accelerating time-to-market.