Microchip Technology RE46C109S16TF

Overview

RE46C109S16TF from R&E International (a Microchip Technology subsidiary) is a monolithic CMOS integrated circuit combining a 3V low-dropout voltage regulator, a 12V switched-capacitor boost converter, and dual-output piezoelectric horn driver. It features low-quiescent current (6.5µA), analog low-battery detection (LBAT), power-good monitoring (PG), and bi-directional interconnect logic (IO1/IO2/IODIR) for multi-unit alarm systems. It is used in battery-powered smoke and CO detectors requiring regulated microprocessor supply and audible alert generation.

For engineers reviewing the RE46C109S16TF datasheet, RE46C109S16TF pinout, RE46C109S16TF application, or RE46C109S16TF equivalent, key selection considerations include its 12V VPOS output capability, 3V VREG regulation with ±5% tolerance, LBST-strobed low-battery sensing, HRNEN-controlled horn activation, and SOIC-16 package compatibility with DIP-16 footprints.

Technical Context

The RE46C109S16TF integrates three core functional blocks: a bandgap-referenced LDO regulator delivering 3V at up to 50mA; a charge-pump-based boost converter generating 10.7–12.7V RMS at VPOS with 85% power efficiency under 16mA load; and complementary high-side horn drivers (HORNB/HORNS) supporting full VPOS-to-VSS swing. All blocks share a common VDD input (6–12V) and are controlled via TTL-compatible digital inputs (HRNEN, LBST, IODIR).

Its interconnect logic enables peer-to-peer communication between multiple units using IO1/IO2 pins under IODIR direction control, while PG provides open-drain status signaling tied to VREG regulation window (72–94% of VREG), and LBAT delivers a proportional analog voltage for external ADC sampling. Brownout protection disables VREG when VDD falls below 4.5–5.5V.

Key Specifications

Pinout & Package

RE46C109S16TF is housed in a 16-pin SOIC package (body width 3.9mm, lead pitch 1.27mm), pin-compatible with the DIP-16 variant (RE46C109P16TF). The package supports RoHS-compliant Pb-free soldering and operates from -40°C to +85°C.

Key Features

Applications

Equivalent & Alternatives

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

Compared with RE46C109S16TF, RE46C110S16TF adds temperature compensation for battery sensing but retains identical horn drive capability, whereas MAX6326–30D2T+T omits all audio functions and requires external circuitry for audible alerts-making it suitable only for supervisory-only roles.

Availability

RE46C109S16TF is available at Aetrix Electronics and suitable for smoke detector systems, CO gas detectors, and personal security alarms requiring stable component supply, long-term lifecycle support, and RoHS-compliant manufacturing.

Supply support for RE46C109S16TF 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 highly integrated analog and mixed-signal ICs for safety-critical and battery-operated consumer and industrial applications.

The RE46C109S16TF belongs to R&E's alarm and audible notification product line, designed specifically to consolidate power regulation, battery monitoring, and piezoelectric drive into a single SOIC package for UL-listed life-safety devices.

FAQ

What is the maximum continuous output current capability of the RE46C109S16TF's VPOS pin?

The RE46C109S16TF's VPOS pin supports a continuous operating current of 50mA, as specified in the Absolute Maximum Ratings table. This rating applies to both horn driver outputs (HORNB and HORNS) when driving piezoelectric loads. Exceeding this limit risks thermal overstress and permanent damage, especially under sustained 12V output conditions.

Can the RE46C109S16TF operate from a 6V supply, and what is its minimum VDD requirement?

Yes, the RE46C109S16TF operates from a minimum VDD of 6V, as confirmed in the Electrical Characteristics table (Vdd MIN = 6V). At 6V input, the charge pump maintains VPOS output within specification (10.7–12.7V RMS at -16mA), and VREG remains regulated at 3.0V ±5%. Operation below 6V violates the absolute minimum and may cause brownout or regulator dropout.

How does the LBST pin function in the RE46C109S16TF, and why is it not continuously asserted?

The LBST pin on the RE46C109S16TF is a strobe input that enables the low-battery detection circuit only during active sampling-reducing average current consumption. When pulsed high, it activates the internal resistor-divider measurement path feeding LBAT. Keeping LBST low between readings ensures quiescent current stays at ≤6.5µA, preserving battery life in multi-year deployments like smoke detectors.

What external components are mandatory for stable operation of the RE46C109S16TF?

Four external components are mandatory: (1) a ≥10µF capacitor between VREG and VSS for LDO stability; (2) a 1µF ceramic capacitor (C1) between VCAP+ and VCAP−; (3) a 10µF capacitor (C2) between VCAP+ and VSS; and (4) a low-ESR 10µF capacitor (C4) between VPOS and VSS. Omitting any compromises regulation, boost efficiency, or horn performance.

Is the RE46C109S16TF pin-compatible with the RE46C109P16TF DIP variant?

Yes, the RE46C109S16TF (SOIC-16) and RE46C109P16TF (DIP-16) share identical pin numbering, signal mapping, and electrical specifications. They differ only in package type and thermal characteristics-SOIC offers smaller footprint and surface-mount assembly, while DIP supports through-hole prototyping and legacy board designs.