STMicroelectronics STM1816SWX7F

Overview

STM1816SWX7F from STMicroelectronics is an open-drain, active-low reset supervisor IC designed for 3.3 V/3.0 V power supply monitoring in microcontroller-based 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 requiring reliable brownout detection and MCU reset assertion.

For engineers reviewing the STM1816SWX7F datasheet, STM1816SWX7F pinout, STM1816SWX7F application, or STM1816SWX7F equivalent, this page delivers verified technical context, SOT23-3 package mapping, open-drain RST interface behavior, manual reset compatibility with bidirectional MCUs, and validated alternative options for 3.3 V supervisor replacement.

Technical Context

The STM1816SWX7F implements a precision voltage comparator with internal 5.5 kΩ pull-up resistor on its open-drain RST output, enabling direct connection to bidirectional MCU reset pins without external components. Its reset assertion is triggered when VCC falls below 3.06 V (typ.), with hysteresis minimized for tight threshold control.

It guarantees valid reset output down to VCC = 1.0 V across full temperature range and rejects transients ≤20 µs at 100 mV overdrive. Unlike push-pull variants, it does not include manual reset detect - that function is exclusive to STM1813/1818.

Key Specifications

Pinout & Package

STM1816SWX7F is housed in a 3-pin SOT23-3 (WX) package - compact, surface-mount, and RoHS-compliant per ECOPACK® standards. Pin 1 is RST (active-low open-drain), Pin 2 is VCC (supply input and threshold reference), and Pin 3 is VSS (ground reference).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 3.3 V open-drain reset supervisor applications.

Compared with TPS3808G33DBVR and MAX809SEUR+T, STM1816SWX7F uniquely combines SOT23-3 footprint, integrated pull-up, lowest IQ (4 µA), and precise 3.06 V threshold - making it optimal for space- and power-constrained 3.3 V embedded systems requiring zero-external-component reset interface.

Availability

STM1816SWX7F is available at Aetrix Electronics and suitable for industrial PLC I/O modules, portable medical sensor hubs, automotive body control modules, and smart home gateway controllers requiring stable component supply and long-term lifecycle support.

Supply support for STM1816SWX7F 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 power management, microcontrollers, analog ICs, and automotive-grade components.

STM181x is ST's low-power reset supervisor product line, engineered specifically for reliable brownout detection and deterministic MCU reset in portable, industrial, and automotive embedded systems operating at 3.0 V, 3.3 V, and 5.0 V rails.

FAQ

Does STM1816SWX7F support manual reset via external push-button?

No. STM1816SWX7F does not include manual reset detect functionality - that feature is exclusive to STM1813 and STM1818 variants. Its RST pin is strictly an open-drain output with internal pull-up; externally pulling it low will not trigger a reset timeout. For push-button reset capability, STM1818T/S/R is the direct family alternative.

Can STM1816SWX7F interface directly with a bidirectional MCU reset pin?

Yes. Its open-drain RST output with integrated 5.5 kΩ pull-up resistor allows direct connection to bidirectional MCU reset pins (e.g., many STM32, NXP Kinetis, and Silicon Labs EFM32 devices) without external components. The MCU can drive RST low to initiate system reset, and STM1816SWX7F will assert RST low during brownout - enabling shared reset bus architecture.

What is the maximum sink current capability of the RST output?

The RST output is rated for 20 mA maximum sink current (per Absolute Maximum Ratings, Table 7). Typical V_OL is ≤0.3 V at 1.2 mA sink (Figure 16), confirming robust low-state drive strength for driving standard CMOS inputs and small capacitive loads (<50 pF) without signal degradation.

Is STM1816SWX7F compatible with DS1816 or MXD1816 devices?

Yes. Per ST's official documentation (Doc ID11464 Rev 8, p.1), STM1816SWX7F is "fully compatible with DS181x and MXD181x products" in pinout, electrical behavior, and functional role. It serves as a direct drop-in replacement for Maxim DS1816 and Microchip MXD1816 in 3.3 V open-drain reset applications, including identical SOT23-3 footprint and 3.06 V threshold.