Microchip Technology RE46C180S16TF

Overview

RE46C180S16TF from Microchip Technology is a CMOS ionization-type smoke detector ASIC with integrated interconnect, programmable hysteresis (140–160 mV), ±0.75 pA detect input current, and 9-minute/80-second timer for reduced sensitivity mode. It operates from 6–12 V, consumes as low as 3.8 µA standby current, and supports NFPA 72® temporal horn patterns in residential and commercial smoke alarms.

For engineers reviewing the RE46C180S16TF datasheet, RE46C180S16TF pinout, RE46C180S16TF application, or RE46C180S16TF equivalent, this device delivers certified alarm memory, smart interconnect (up to 40 units), chamber test, end-of-life indication, and UL217/UL268-compliant smoke detection logic - all in a 16-lead SOIC package.

Technical Context

The RE46C180S16TF integrates a trimmable ±5% oscillator (625 µs period), guard amplifier (±50 mV offset), and dual-mode horn driver (HB/HS) for piezoelectric transducers. Its smoke detection circuitry samples the ionization chamber every 10 s in standby, increases to 1 Hz upon first smoke detection, and triggers local alarm after three consecutive valid samples.

It implements programmable supervisory functions: low-battery check every 80 s (±150 mV set point), chamber test every 320 s, and EOL counting via EEPROM-based age tracking. Interconnect logic includes digital filtering (291 ms max), charge dump (500 ms), and horn synchronization timing (4 s IO pulse period) - all configurable without external components.

Key Specifications

Pinout & Package

RE46C180S16TF is housed in a 16-lead SOIC (150 mil) package with θJA = 86.1°C/W, optimized for surface-mount assembly in compact smoke alarm PCBs.

Key Features

Applications

Equivalent & Alternatives

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

Compared with RE46C120S16F, RE46C180S16TF adds field-serviceable alarm memory and synchronized interconnect; compared with RE46C190S16F, it omits CO-specific circuitry but achieves lower power and simpler layout - making it optimal for UL217-only, battery-operated, multi-unit smoke systems.

Availability

RE46C180S16TF is available at Aetrix Electronics and suitable for residential fire safety systems, commercial building interconnect networks, and UL217-certified smoke alarm production requiring stable component supply and long-lifecycle support.

Supply support for RE46C180S16TF 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 for industrial, automotive, and consumer applications.

RE46C180S16TF belongs to Microchip's RE46C family of programmable smoke detector ASICs, designed specifically to meet UL217 and UL268 certification requirements with minimal external components and field-configurable alarm behavior.

FAQ

What is the operating voltage range for the RE46C180S16TF?

The RE46C180S16TF operates from 6 V to 12 V DC, supporting standard 9 V alkaline batteries commonly used in residential smoke alarms. Absolute maximum rating is 12.5 V. External reverse-battery protection is mandatory, as the device lacks internal polarity protection per datasheet Note 4.

How does the RE46C180S16TF implement alarm memory and visual indication?

The RE46C180S16TF sets an internal alarm memory latch upon exiting a Local Alarm condition. When enabled, this triggers GLED to pulse three times every 40 seconds (each pulse 10 ms long). The duration is user-selectable: 0, 24, or 48 hours - or indefinite until manually reset via PTT. RE46C180S16TF also supports audible alarm memory indication through horn chirps.

Can the RE46C180S16TF support both temporal and continuous horn patterns?

Yes, the RE46C180S16TF supports both patterns via user programming. The temporal pattern (400 ms on / 500 ms off) complies with NFPA 72® for emergency evacuation. The continuous pattern uses a 70% duty cycle. Selection is made during configuration; RE46C180S16TF does not auto-switch between them based on event type.

What is the purpose of the GUARD1 and GUARD2 pins on the RE46C180S16TF?

GUARD1 and GUARD2 are outputs of the integrated guard amplifier, maintaining voltage within ±50 mV of the DETECT input. They surround the high-impedance DETECT trace on the PCB to eliminate surface leakage currents - critical for stable ion chamber signal integrity in humid environments. RE46C180S16TF uses both outputs to enable differential guarding for enhanced EMI rejection.

Does the RE46C180S16TF include built-in end-of-life (EOL) detection?

Yes, the RE46C180S16TF includes EEPROM-based EOL tracking that increments an age counter approximately every 15 days of cumulative operation. After ~10 years, it triggers an audible warning identical to chamber failure - three 10 ms chirps every 40 s. This function is user-programmable and can be disabled during configuration. RE46C180S16TF implements EOL independently of battery voltage monitoring.