STMicroelectronics STM812RW16F

Overview

STM812RW16F from STMicroelectronics is an industrial-grade active-high reset supervisor IC with manual reset input, designed for reliable power-on and brownout detection in microcontroller-based systems. It monitors 2.55–2.70 V supply rails, asserts a push-pull RST signal for ≥140 ms after power-up or voltage drop, guarantees valid reset down to VCC = 1.0 V, and features 20 kΩ internal MR pull-up - used in embedded control modules, industrial PLCs, and battery-powered IoT edge nodes.

For engineers reviewing the STM812RW16F datasheet, STM812RW16F pinout, STM812RW16F application, or STM812RW16F equivalent, key selection criteria include reset threshold accuracy (±2.5% over –40 °C to +85 °C), MR debounce-free manual reset capability, guaranteed RST assertion at low VCC, and SOT143-4 package compatibility with space-constrained PCB layouts.

Technical Context

The STM812RW16F implements a precision voltage comparator with hysteresis and an internal reset timer to generate a minimum 140 ms active-high RST pulse upon power-up or VCC dropout below its 2.63 V nominal threshold. Its MR input accepts TTL/CMOS logic levels and triggers reset independently of VCC level, with 0.5 µs propagation delay and 100 ns glitch immunity.

It operates across 1.0–5.5 V supply range and maintains valid RST output down to VCC = 1.0 V (industrial temperature range); below that, a 100 kΩ pull-up resistor ensures RST remains high. The device draws only 7 µA typical supply current and exhibits <45 ppm/°C reset threshold drift.

Key Specifications

Pinout & Package

SOT143-4 (W1) package: 4-pin, small-outline transistor outline with gull-wing leads, 1.92 mm pitch, 2.80 × 2.10 mm body size, lead-free ECOPACK® compliant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with STM812RW16F, MAX809TRD3-T saves board area but removes MR flexibility, while TPS3808G12QDBVRQ1 adds automotive reliability and adjustability at the cost of larger package and non-drop-in pinout - making STM812RW16F optimal for industrial 2.7 V systems needing compact, self-contained manual+power reset.

Availability

STM812RW16F is available at Aetrix Electronics and suitable for industrial motor control, smart energy metering, and programmable logic controller applications requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant packaging.

Supply support for STM812RW16F 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, microcontroller, power, and sensor solutions for industrial, automotive, and consumer markets.

The STM8xx series is ST's dedicated family of low-power, precision reset supervisors targeting industrial and embedded applications where deterministic power-on sequencing and brownout immunity are critical.

FAQ

What is the exact reset threshold voltage tolerance for STM812RW16F over temperature?

The STM812RW16F has a nominal reset threshold of 2.63 V, with a guaranteed range of 2.55 V to 2.70 V across –40 °C to +85 °C. This ±2.5% tolerance is specified in Table 5 of the datasheet (Doc ID 9873 Rev 5), and includes both initial accuracy and temperature drift up to 45 ppm/°C.

Can STM812RW16F drive a reset pin that requires 10 mA sink current?

No - the STM812RW16F RST output is rated for 500 µA source and 1.2 mA sink (per Table 5, VOH/ VOL test conditions). Driving 10 mA would exceed absolute maximum ratings and cause output voltage collapse. An external buffer or MOSFET is required for loads >1.2 mA.

Is the MR input compatible with 1.8 V logic levels?

Yes - the MR input accepts logic-low signals down to 0.25 × VCC (min) and logic-high up to 0.7 × VCC (max) for R/S/T versions (Table 5). With VCC = 2.7 V, this translates to VIH ≥ 1.89 V and VIL ≤ 0.675 V, making it compatible with 1.8 V CMOS outputs when VCC ≥ 2.7 V.

Does STM812RW16F require an external capacitor on the MR pin for noise immunity?

No - the MR input includes built-in 100 ns glitch immunity (Table 5), and its 20 kΩ internal pull-up provides sufficient noise rejection for most industrial environments. A 0.1 µF capacitor to ground is optional only in exceptionally noisy settings, per Section 2.2 of the datasheet.