STMicroelectronics STM812SW16F

Overview

STM812SW16F from STMicroelectronics is an industrial-grade active-high reset supervisor IC with manual reset input (MR), precision 2.93 V supply monitoring, 140 ms minimum reset pulse width, and SOT143-4 package. It asserts a valid RST signal down to VCC = 1.0 V and delivers 6 µA typical supply current, enabling reliable power-on reset in microcontroller-based embedded systems.

For engineers reviewing the STM812SW16F datasheet, STM812SW16F pinout, STM812SW16F application, or STM812SW16F equivalent, key selection criteria include reset threshold accuracy (2.85–3.00 V over temperature), MR input debounce capability, guaranteed RST validity at low VCC, and compatibility with 3.3 V system rails.

Technical Context

The STM812SW16F implements a voltage comparator with hysteresis to monitor VCC against a trimmed internal reference, triggering reset assertion when VCC falls below 2.85–3.00 V. Its internal timer ensures RST remains asserted for ≥140 ms after VCC recovers above threshold.

It features a dedicated MR input with 20 kΩ internal pull-up, supporting TTL/CMOS-compatible manual reset initiation. The push-pull RST output sources/sinks up to 20 mA and remains functional across –40 °C to +85 °C.

Key Specifications

Pinout & Package

SOT143-4 (W1) package: 4-pin, surface-mount, lead-free, 2.8 mm × 2.1 mm footprint with 1.92 mm pin pitch.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar reset supervisor applications.

Compared with MAX809TRD2T and TPS3808G125DBVR, the STM812SW16F uniquely combines SOT143-4 compactness, integrated MR, and guaranteed RST validity down to 1.0 V-making it optimal for space-constrained industrial controllers requiring field-serviceable reset.

Availability

STM812SW16F is available at Aetrix Electronics and suitable for industrial PLC controllers, smart energy meters, IoT edge sensor nodes, and medical diagnostic handhelds requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for STM812SW16F 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

STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, designing and manufacturing analog, digital, and mixed-signal ICs for industrial, automotive, and consumer markets.

The STM8xx series is ST's dedicated family of low-power voltage supervisors targeting robust, cost-effective power-on reset and brown-out protection in resource-constrained embedded systems.

FAQ

What is the exact reset threshold voltage range for STM812SW16F?

The STM812SW16F has a guaranteed reset threshold of 2.85 V to 3.00 V over the full –40 °C to +85 °C temperature range, corresponding to the 'S' grade designation per ST's ordering scheme. At 25 °C, the typical value is 2.93 V, with ±15 mV tolerance.

Does STM812SW16F require external components to function as a reset supervisor?

No external components are required for basic operation: VCC, VSS, RST, and MR form a complete 4-pin interface. A 0.1 µF bypass capacitor on VCC is recommended for transient immunity, and a 100 kΩ pull-up resistor on RST is optional if validity below 1.0 V is needed-but neither is mandatory for standard use.

How does the MR input behave when left unconnected?

The MR input has a factory-trimmed 20 kΩ internal pull-up resistor to VCC, so it defaults to logic high when floating. This disables manual reset by default; connecting MR to ground (e.g., via push-button) actively asserts reset. No external pull-up is needed.

Can STM812SW16F be used with a 1.8 V microcontroller supply?

Yes-the device operates down to VCC = 1.0 V and guarantees RST assertion validity at that level. However, its 2.85–3.00 V threshold is optimized for 3.3 V rails. For 1.8 V systems, consider STM812RW16F (2.55–2.70 V threshold) instead to ensure appropriate undervoltage detection margin.