STMicroelectronics STM1816TWX7F

Overview

STM1816TWX7F from STMicroelectronics is an open-drain, active-low reset supervisor IC designed for 3.3 V/3.0 V power supply monitoring in microcontroller systems. It features a factory-trimmed 3.06 V reset threshold (±2.5% accuracy), 100 ms minimum reset pulse width, 4 µA typical supply current, and guaranteed operation down to VCC = 1.0 V over –40 °C to +105 °C. It is used in portable embedded systems to prevent code execution errors during brownout and power-up sequences.

For engineers reviewing the STM1816TWX7F datasheet, STM1816TWX7F pinout, STM1816TWX7F application, or STM1816TWX7F equivalent, key selection criteria include open-drain RST compatibility with bidirectional MCU reset pins, internal 5.5 kΩ pull-up resistor, transient immunity against sub-20 µs VCC glitches, and SOT23-3 footprint constraints.

Technical Context

The STM1816TWX7F implements a precision voltage comparator with a factory-trimmed 3.06 V reference to monitor VCC, asserting an active-low reset signal when supply drops below threshold. Its reset timer guarantees ≥100 ms assertion after VCC recovery, with no external components required.

As an open-drain device, it interfaces directly with bidirectional MCU reset pins without external pull-up resistors-its internal 5.5 kΩ pull-up to VCC enables shared reset bus configurations. It ignores negative-going VCC transients ≤20 µs at 100 mV overdrive, enhancing noise immunity in noisy power environments.

Key Specifications

Pinout & Package

STM1816TWX7F is housed in a 3-pin SOT23-3 (WX) package - a surface-mount, space-constrained outline measuring 2.9 mm × 1.3 mm × 1.0 mm, optimized for high-density PCB layouts in portable electronics.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX809TRD3T and TPS3808G30DBVR, STM1816TWX7F offers optimal balance of integrated pull-up (reducing component count), SOT23-3 footprint (saving board space), and 3.06 V threshold matched to standard 3.3 V/3.0 V rails - making it ideal for cost- and size-sensitive industrial and portable designs.

Availability

STM1816TWX7F is available at Aetrix Electronics and suitable for industrial PLC I/O modules, portable medical sensor nodes, automotive body control modules, and smart home hub power management requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for STM1816TWX7F 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, specializing in microcontrollers, power management, analog, and sensor solutions for industrial, automotive, and consumer markets.

STM181x is ST's low-power reset supervisor product line, engineered specifically for reliable power-on reset, brownout protection, and manual reset integration in space-constrained, battery-operated, and industrial embedded systems.

FAQ

What is the function of the internal 5.5 kΩ pull-up resistor on the RST pin?

The internal 5.5 kΩ pull-up resistor connects RST to VCC, enabling open-drain operation without external components. It ensures the RST line remains high-impedance when inactive and pulls up to VCC when not driven low - critical for interfacing with bidirectional MCU reset pins and supporting wired-OR reset bus topologies in multi-device systems.

Can STM1816TWX7F operate reliably during fast VCC transients?

Yes - STM1816TWX7F rejects negative-going VCC transients ≤20 µs in duration when the overdrive is 100 mV below the 3.06 V threshold. This immunity is achieved via internal comparator hysteresis and timing filtering, preventing spurious resets in electrically noisy environments such as motor drives or switching power supplies.

Does STM1816TWX7F support manual reset functionality?

No - STM1816TWX7F is an open-drain, active-low reset supervisor without manual reset detect capability. That feature is exclusive to STM1813/STM1818 variants. STM1816TWX7F asserts reset solely based on VCC monitoring and has no internal push-button debounce circuitry or MR pin detection logic.

What is the minimum VCC voltage at which STM1816TWX7F guarantees valid reset assertion?

STM1816TWX7F guarantees correct logic state on RST down to VCC = 1.0 V across the full operating temperature range (–40 °C to +105 °C). Below 1.0 V, the output becomes high-impedance; for applications requiring validity down to 0 V, a 100 kΩ external pull-down resistor on RST is recommended per ST's application guidance.