Microchip Technology RE46C317E8F

Overview

RE46C317E8F from Microchip Technology is a CMOS piezoelectric horn driver IC with integrated 10V boost converter, designed for 3V battery-powered smoke and CO detectors. It delivers 10V ±1V output at 10 mA load, features tri-state Horn Enable (HRNEN) logic, and achieves ≤0.5 µA standby supply current in float mode.

For engineers reviewing the RE46C317E8F datasheet, RE46C317E8F pinout, RE46C317E8F application, or RE46C317E8F equivalent, this device supports low-power alarm systems requiring fast horn turn-on delay (<1 ms), high-efficiency boost conversion (>80%), and robust ESD protection (1500V HBM).

Technical Context

The RE46C317E8F implements a current-mode boost regulator with dual control loops: an inner cycle-by-cycle current limit and outer voltage regulation to maintain 10V nominal VO. Its tri-state HRNEN input enables three operational modes-standby (disabled), boost-only (VO enabled, horn disabled), and normal operation (VO + horn enabled)-supporting battery health checks without sounding alarms.

It drives three-terminal piezoelectric horns via complementary HORNB/HORNS outputs with ≤0.5V low-state voltage and ≥9.5V high-state voltage at 16 mA, while FEED pin monitors horn feedback through an external resistor. The LX pin delivers up to 1 A peak current to drive external inductors with ≤0.3 Ω total series resistance for reliable 2V–5V input operation.

Key Specifications

Pinout & Package

RE46C317E8F is housed in an 8-lead PDIP (300 mil) package with matte tin (Pb-free) finish, JEDEC-standard footprint, and θ_JA = 89.3°C/W thermal resistance.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar piezoelectric horn driver applications.

Compared with RE46C317E8F, RE46C318E8F reduces standby current but removes diagnostic capability, while TC7660CPA increases component count and board area without delivering integrated horn control or feedback sensing.

Availability

RE46C317E8F is available at Aetrix Electronics and suitable for smoke detectors, CO detectors, and personal security alarms requiring stable component supply, long-term lifecycle support, and Pb-free compliance.

Supply support for RE46C317E8F 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 U.S.-based semiconductor manufacturer specializing in microcontrollers, analog, interface, and power management ICs for embedded control applications.

The RE46C317E8F belongs to Microchip's RE46C family of piezoelectric alarm drivers, engineered specifically for UL-listed life-safety equipment with stringent low-power, reliability, and regulatory compliance requirements.

FAQ

What is the function of the FEED pin on the RE46C317E8F?

The FEED pin on the RE46C317E8F connects to the feedback electrode of a three-terminal piezoelectric horn via a current-limiting resistor. It enables internal monitoring of horn integrity and response; if unused, it must be tied to VSS. This functionality supports open-circuit detection and improves system-level reliability in safety-critical applications like smoke detectors.

How does the tri-state HRNEN input affect operation of the RE46C317E8F?

The tri-state HRNEN input on the RE46C317E8F defines three distinct operating modes: float (standby, 0.5 µA IDD), low (boost-only, VO enabled but horn disabled), and high (normal operation, both VO and horn active). This allows battery voltage verification without sounding the alarm-critical for self-test routines in UL-certified smoke and CO detectors.

What external components are required for basic operation of the RE46C317E8F?

The RE46C317E8F requires five essential external components: a 10 µH inductor (LX to VDD), a Schottky diode (≤0.5 V FWD @ 1 A), two 10 µF low-ESR capacitors (input and VO), and a 1 nF capacitor on FEED. Optional resistors may be added for current limiting on FEED or horn electrodes depending on transducer specifications.

Can the RE46C317E8F drive two-terminal piezoelectric horns?

Yes, the RE46C317E8F can drive modified two-terminal piezoelectric horns by connecting HORNB and HORNS to opposite terminals and grounding the third terminal (or leaving it unconnected per transducer datasheet). The push-pull architecture delivers differential voltage swing, maintaining effective drive even without the dedicated feedback electrode.

What is the maximum allowable series resistance in the boost path for reliable RE46C317E8F operation at 2V input?

For reliable RE46C317E8F operation at VDD = 2 V, the total series resistance-including inductor DC resistance, battery internal resistance, and PCB trace resistance between LX/VDD and inductor-must not exceed 0.3 Ω. Battery internal resistance alone should be ≤0.5 Ω, and a 10 µF or larger low-ESR capacitor must be placed in parallel with the battery to average boost current pulses.