STMicroelectronics STM1817TWX7F

Overview

STM1817TWX7F from STMicroelectronics is an active-high, push-pull reset supervisor IC designed for 3.3 V/3.0 V power supply monitoring in microcontroller systems. It asserts a high-level reset signal when VCC drops below its factory-trimmed 3.06 V threshold, maintains reset for ≥100 ms after VCC recovers, draws only 4 µA typical supply current, and operates across –40 °C to +105 °C - enabling reliable brownout protection in portable and industrial embedded controllers.

For engineers reviewing the STM1817TWX7F datasheet, STM1817TWX7F pinout, STM1817TWX7F application, or STM1817TWX7F equivalent, this page delivers verified functional identity, SOT23-3 pin mapping, reset timing behavior, threshold accuracy (±2.5%), and direct alternatives compatible with 3.3 V MCU reset interfaces.

Technical Context

The STM1817 implements a precision voltage reference and comparator to monitor VCC against a fixed 3.06 V threshold. Its internal timer generates a guaranteed minimum 100 ms reset pulse width (trec) upon recovery, independent of VCC slew rate or noise transients.

Unlike open-drain variants, the STM1817 features a push-pull output that actively drives RST high during reset assertion and low during deassertion - eliminating external pull-up requirements and ensuring deterministic logic levels for MCUs with unidirectional reset inputs.

Key Specifications

Pinout & Package

STM1817TWX7F is housed in a 3-pin SOT23-3 (WX) package - a surface-mount, lead-free, RoHS-compliant outline measuring 2.9 mm × 1.3 mm × 1.0 mm, optimized for space-constrained PCB layouts in portable electronics.

Key Features

Applications

Equivalent & Alternatives

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

Compared with STM1817TWX7F, MAX809SEUR+T offers lower power but less flexible timing, while TPS3808G30DBVR adds configurability at the cost of pin count and layout area - making STM1817TWX7F optimal for fixed 100 ms, space-constrained 3.3 V reset supervision.

Availability

STM1817TWX7F is available at Aetrix Electronics and suitable for industrial PLC I/O modules, smart energy meters, portable medical sensor hubs, and automotive body control modules requiring stable component supply, long-term lifecycle support, and AEC-Q100-aligned qualification.

Supply support for STM1817TWX7F 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 silicon solutions for automotive, industrial, and embedded markets since 1987.

STM1817 belongs to ST's low-power reset supervisor product line - engineered specifically for precision voltage monitoring and deterministic reset generation in resource-constrained microcontroller applications.

FAQ

What is the exact reset threshold voltage of STM1817TWX7F, and how does it vary with temperature?

The STM1817TWX7F has a factory-trimmed nominal reset threshold of 3.06 V, with ±2.5% accuracy maintained across the full operating range of –40 °C to +105 °C. Typical characterization data (Figure 18) shows normalized threshold variation remains within ±1.2% over temperature, ensuring consistent 3.3 V rail supervision without derating.

Can STM1817TWX7F drive a reset input requiring 200 µA of sink current?

Yes - the STM1817TWX7F's push-pull output can sink up to 20 mA (per Absolute Maximum Ratings), far exceeding 200 µA. At VCC = 3.3 V and TA = 25 °C, the output low voltage is typically 0.15 V at 1.2 mA sink, confirming robust drive capability for standard CMOS reset inputs.

Does STM1817TWX7F support manual reset via an external push-button?

No - STM1817TWX7F lacks manual reset detect circuitry. That function is exclusive to STM1813/STM1818 variants (open-drain with MR detect). The STM1817 is strictly a power-supply-only monitor with active-high push-pull output and no bidirectional RST pin capability.

Is STM1817TWX7F pin-compatible with DS1817 or MXD1817?

Yes - STM1817TWX7F is fully compatible with DS1817 (Maxim) and MXD1817 (Microchip) in SOT23-3 package, sharing identical pinout (RST/VCC/VSS), 3.06 V threshold, active-high push-pull output, and 100 ms reset timeout - enabling drop-in replacement without layout changes.