STMicroelectronics STM811LW16F

Overview

STM811LW16F from STMicroelectronics is a precision industrial-grade voltage supervisor IC with active-low and active-high reset outputs plus manual reset input (MR), designed for reliable power-on and brown-out detection in microcontroller-based systems. It monitors 4.50–4.75 V supply rails, delivers ≥140 ms reset pulse width, draws only 6 µA typical supply current, and guarantees RST assertion down to VCC = 1.0 V across –40 °C to +85 °C - used in embedded control modules, industrial PLCs, and battery-backed instrumentation.

For engineers reviewing the STM811LW16F datasheet, STM811LW16F pinout, STM811LW16F application, or STM811LW16F equivalent, key selection criteria include dual-reset polarity support, MR debounced push-button interface, guaranteed operation at 1.0 V VCC, SOT143-4 package footprint compatibility, and ±45 ppm/°C reset threshold temperature coefficient.

Technical Context

The STM811LW16F implements a precision voltage comparator with hysteresis and an internal reset timer (trec) that enforces minimum 140 ms reset assertion after power-up or brown-out recovery. Its dual-output architecture provides both active-low RST and active-high RST signals simultaneously, enabling direct interfacing with MCUs requiring either polarity.

It integrates a 20 kΩ internal MR pull-up resistor and supports TTL/CMOS-compatible manual reset triggering with <0.5 µs MR-to-RST delay and 100 ns glitch immunity. The device remains functional during negative-going VCC transients up to 100 mV/20 µs without false triggering, and maintains valid RST output down to VCC = 1.0 V.

Key Specifications

Pinout & Package

SOT143-4 (W1) 4-pin small outline transistor package: 1.2 mm × 2.1 mm footprint, 0.95 mm height, lead-free ECOPACK® compliant, suitable for high-density PCB layouts and reflow assembly.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX809L and TPS3808G15, STM811LW16F uniquely combines dual-reset polarity, integrated MR, and industrial temperature range in SOT143-4 - making it optimal for systems requiring field-serviceable reset and deterministic brown-out response without added components.

Availability

STM811LW16F is available at Aetrix Electronics and suitable for industrial PLC I/O modules, smart energy meters, medical handheld diagnostics, and factory automation HMI panels requiring stable component supply, long-term lifecycle assurance, and ECOPACK® compliance.

Supply support for STM811LW16F 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, delivering innovative solutions across automotive, industrial, power, and embedded markets with strong IP portfolio and manufacturing scale.

The STM8xx series is ST's dedicated family of precision voltage supervisors targeting industrial and embedded applications requiring high reliability, low power, and robust reset timing - optimized for seamless integration with ST and third-party MCUs.

FAQ

What is the function of the MR pin on STM811LW16F?

The MR (Manual Reset) pin is an active-low input with internal 20 kΩ pull-up resistor. Driving MR low asserts both RST and RST outputs for the full reset timeout period (≥140 ms), then holds them until MR returns high and trec expires. It supports direct connection to a normally open push-button switch to ground, requiring no external debounce components.

Does STM811LW16F support both 3.3 V and 5 V systems?

No - STM811LW16F is specifically configured for 4.50–4.75 V supply monitoring (L-grade). For 3.3 V systems, ST offers STM811TW16F (3.00–3.15 V threshold) or STM811SW16F (2.85–3.00 V). The L-grade variant is intended for 5 V nominal rails with tight tolerance requirements.

How does STM811LW16F behave when VCC drops below 1.0 V?

Below 1.0 V, the RST output ceases sinking current and transitions to high-impedance state. To maintain a defined logic low on MCU RESET# during deep brown-out, a 100 kΩ external pull-down resistor is recommended per ST's application guidance - ensuring fail-safe reset assertion even at near-zero supply.

Can STM811LW16F replace STM809LW16F in existing designs?

No - STM809LW16F is a 3-pin SOT23-3 device with only active-low RST output and no MR input. STM811LW16F uses SOT143-4 (4-pin), adds MR and active-high RST, and requires PCB layout revision. Direct replacement is not possible without hardware modification and firmware validation of dual-reset behavior.