Microchip Technology RE46C180S16F

Overview

RE46C180S16F from Microchip Technology is a CMOS ionization-type smoke detector ASIC with programmable sensitivity, interconnect capability, alarm memory, and temporal horn pattern compliance per NFPA 72®. It operates from 6–12V, draws as low as 3.8 µA standby current, supports up to 40-detector interconnect networks, and integrates guard amplifiers for ion chamber signal integrity in UL217/UL268-compliant residential smoke alarms.

For engineers reviewing the RE46C180S16F datasheet, RE46C180S16F pinout, RE46C180S16F application, or RE46C180S16F equivalent, this page delivers verified functional roles, exact timing parameters (e.g., 10 ms internal clock period, 5 ms smoke sample window), real-world interconnect behavior (IO active delay: 3.7 s), and precise programmable ranges (hysteresis: 140–160 mV, chamber test voltage: 4.49–4.51 V).

Technical Context

The RE46C180S16F implements a low-power, strobed detection architecture: its on-chip oscillator (±5% tolerance, 625 µs period) powers smoke circuitry for only 5 ms every 10 seconds in standby, enabling sub-5 µA quiescent current. It performs three independent supervisory checks-low battery every 80 s, chamber test every 320 s, and internal power-on reset-each with dedicated latching and visual/audio indication logic.

Its dual-guard amplifier architecture (GUARD1/GUARD2) maintains ±50 mV offset and 10 kΩ output impedance to minimize surface leakage at DETECT, while programmable references (smoke sensitivity, hysteresis, HUSH level, chamber test voltage) are trimmed via external resistor networks per Table 4-1. Horn synchronization and Auto Alarm Locate require temporal pattern selection and SyncEn bit enablement, and operate only when IO is actively driven by the master unit.

Key Specifications

Pinout & Package

RE46C180S16F is supplied in a 16-lead SOIC package (150 mil width), RoHS-compliant, with θJA = 86.1°C/W thermal resistance. Pin numbering follows standard SOIC convention (pin 1 = top-left corner, counterclockwise).

Key Features

Applications

Equivalent & Alternatives

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

Compared with RE46C122S16F, the RE46C180S16F adds alarm memory latching, programmable AAL cycling, and synchronized IO pulsing-critical for UL217-compliant multi-unit traceability. Versus RE46C190S16F, it omits dedicated CO analog front-end but retains smart IO pulse interpretation, making it optimal for smoke-only systems needing advanced interconnect intelligence.

Availability

RE46C180S16F is available at Aetrix Electronics and suitable for residential smoke alarms, commercial interconnected fire safety systems, and retrofit alarm upgrades requiring stable component supply, long-lifecycle support, and UL217/UL268 certification continuity.

Supply support for RE46C180S16F 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, with deep expertise in safety-critical embedded applications.

The RE46C180S16F belongs to Microchip's RE46C family of programmable smoke detector ASICs, engineered specifically for UL217/UL268-certified ionization-based fire alarm systems requiring ultra-low power, field-configurable sensitivity, and robust interconnect reliability.

FAQ

What is the operating temperature range for the RE46C180S16F?

The RE46C180S16F is specified for operation from –10°C to +60°C ambient temperature, with storage range from –55°C to +125°C. Its internal oscillator maintains ±5% accuracy across this range, and guard amplifier offset remains within ±50 mV, ensuring reliable ion chamber signal integrity in residential indoor environments where temperature extremes are limited.

How does the RE46C180S16F perform low-battery detection?

The RE46C180S16F performs unloaded low-battery checks every 80 seconds and one loaded check every 320 seconds using RLED as a 10 ms load. It compares a fraction of VDD to an internal reference; failure triggers 10 ms horn chirps every 40 seconds. The low-battery set point is programmable between 6.75 V and 7.95 V in four steps, allowing calibration to battery chemistry and aging profiles.

Can the RE46C180S16F be used in CO alarm applications?

The RE46C180S16F does not include a dedicated CO sensor interface or electrochemical front-end, but its smart interconnect feature enables CO alarm integration: when two valid IO pulses (≥37 ms ON, ≤5.4 s OFF) are detected, it activates the CO-specific temporal horn pattern (4 beeps/5.8 s). This allows shared interconnect wiring with certified CO detectors without modifying the RE46C180S16F's core smoke functionality.

What is the purpose of the GUARD1 and GUARD2 pins on the RE46C180S16F?

GUARD1 and GUARD2 are outputs of the integrated guard amplifiers that maintain the DETECT input node at a common-mode voltage within ±50 mV of the chamber signal. This minimizes surface leakage currents on PCB traces and chamber electrodes, preserving the ultra-low detect current specification (±0.75 pA) critical for stable ion chamber operation across humidity and contamination variations.

How is alarm memory implemented in the RE46C180S16F?

Alarm memory in the RE46C180S16F is a latched flag set automatically when exiting Local Alarm. It enables GLED to pulse three times every 40 seconds (10 ms duration each) for configurable durations: 0, 24, or 48 hours-or indefinitely. Pressing TEST resets the latch, and the initial GLED indication is suppressed if a low-battery condition is present, preventing conflicting visual alerts.