STMicroelectronics STM1813LWX7F

Overview

STM1813LWX7F from STMicroelectronics is a low-power, open-drain active-low reset supervisor IC with manual reset detect functionality, designed for 5 V supply monitoring in microcontroller-based systems. It features a factory-trimmed 4.37 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 embedded power-up sequencing and brownout protection circuits.

For engineers reviewing the STM1813LWX7F datasheet, STM1813LWX7F pinout, STM1813LWX7F application, or STM1813LWX7F equivalent, this page delivers verified technical context, SOT23-3 pin mapping, reset timing behavior, push-button debounce logic, and validated alternatives for MCU reset supervision in space-constrained industrial and portable designs.

Technical Context

The STM1813LWX7F integrates a precision voltage reference, comparator, and reset timer to monitor VCC against a 4.37 V threshold. Its RST pin serves dual roles: as an open-drain active-low reset output with internal 5.5 kΩ pull-up resistor, and as a bidirectional manual reset input detecting ≥1.5 µs low pulses.

Reset assertion persists for ≥100 ms after VCC recovery or MR release, with immunity to transients ≤20 µs at 100 mV overdrive. The device guarantees valid RST state down to VCC = 1.0 V and supports interfacing with bidirectional MCU reset pins without external components.

Key Specifications

Pinout & Package

STM1813LWX7F 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 (max height), optimized for high-density PCB layouts.

Key Features

Applications

Equivalent & Alternatives

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

Compared with STM1813LWX7F, MAX809TRD3T omits manual reset capability and uses a higher 4.63 V threshold, while TPS3808G15DBVR targets low-voltage domains and cannot natively supervise 5 V rails - making STM1813LWX7F uniquely suited for cost-sensitive, space-constrained 5 V MCU reset with integrated push-button support.

Availability

STM1813LWX7F is available at Aetrix Electronics and suitable for industrial PLCs, smart energy meters, medical patient monitors, and automotive body control modules requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for STM1813LWX7F 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, and analog/mixed-signal ICs for industrial, automotive, and consumer markets.

The STM181x series was developed specifically for low-power, high-accuracy reset supervision in microcontroller-based systems - emphasizing precision threshold stability, minimal quiescent current, and robust transient immunity in compact packages.

FAQ

What is the exact reset threshold voltage for STM1813LWX7F?

The STM1813LWX7F has a factory-trimmed nominal reset threshold of 4.37 V, with ±2.5% accuracy over the full operating temperature range (–40 °C to +105 °C). This value is specified in Table 6 and confirmed in Section 1.2.4 of the datasheet, and applies to 5 V supply monitoring applications.

Does STM1813LWX7F require an external pull-up resistor on the RST pin?

No. STM1813LWX7F includes an internal 5.5 kΩ pull-up resistor from RST to VCC, eliminating the need for an external component. This allows direct connection to bidirectional MCU reset pins and simplifies PCB layout - verified in Figure 6 and Table 6 of the datasheet.

How does the manual reset function work on STM1813LWX7F?

The RST pin acts as both output and input: pulling it low for ≥1.5 µs triggers a 100 ms reset pulse, with internal hardware debounce to suppress mechanical switch bounce. Release of the external switch starts the reset timeout - detailed in Section 2.2 and Figure 9 of the datasheet.

Can STM1813LWX7F operate reliably below 1.0 V VCC?

No. STM1813LWX7F is guaranteed to assert valid reset down to VCC = 1.0 V (0 °C to +105 °C); below that, RST becomes high-impedance. For operation down to 0 V, a 100 kΩ pull-down resistor is recommended - per Section 2.5 and Figure 11 of the datasheet.