STMicroelectronics STM6822SWY6F

Overview

STM6822SWY6F from STMicroelectronics is a 5-pin precision voltage supervisor IC with integrated watchdog timer and manual reset input, designed for microprocessor reset management in industrial embedded systems. It monitors VCC at 3.3 V (±2.5%), asserts active-low open-drain RST for ≥1.4 ms upon fault, features 1.6 s watchdog timeout, and guarantees reset assertion down to VCC = 1.0 V. Used in power-sensitive MCU-based controllers requiring reliable brownout and software-fault recovery.

For engineers reviewing the STM6822SWY6F datasheet, STM6822SWY6F pinout, STM6822SWY6F application, or STM6822SWY6F equivalent, key selection criteria include its open-drain RST output configuration, 3 µA typical supply current, -40 to +85 °C operating range, and compatibility with 3.3 V logic domains in space-constrained SOT23-5 layouts.

Technical Context

The STM6822 implements a precision bandgap reference and comparator to monitor VCC against a fixed 3.3 V threshold (±2.5% over temperature), triggering reset when undervoltage occurs. Its internal watchdog timer resets on WDI inactivity exceeding 1.6 s (typ.), and clears on any WDI edge - enabling robust firmware health monitoring without external timing components.

Reset assertion is controlled by three independent sources: VCC dropout, MR pin low, or watchdog timeout. The open-drain RST output requires an external pull-up resistor (e.g., 10 kΩ) and supports level-shifting across supply domains up to 6 V, while the internal 52 kΩ MR pull-up eliminates need for external biasing in push-button applications.

Key Specifications

Pinout & Package

STM6822SWY6F is housed in a standard 5-pin SOT23-5 package (JEDEC TO-236AB), with 1.3 mm height, 2.9 mm × 1.6 mm body, and 0.95 mm lead pitch. Pin 1 is marked with a dot; device orientation follows JEDEC standard pin 1 indicator.

Key Features

Applications

Equivalent & Alternatives

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

Compared with STM6822SWY6F, MAX6322UR33+T offers higher drive strength but sacrifices MR integration and watchdog flexibility, while TPS3808G33DBVR reduces complexity and cost where software supervision is managed elsewhere - making STM6822SWY6F optimal for compact, self-contained MCU reset and watchdog systems.

Availability

STM6822SWY6F is available at Aetrix Electronics and suitable for industrial PLC controllers, smart energy meters, medical infusion pumps, and automotive body control modules requiring stable component supply across extended product lifecycles.

Supply support for STM6822SWY6F 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 applications with emphasis on reliability and longevity.

STM6xxx is ST's dedicated microprocessor supervisor product line, engineered for deterministic reset generation, low-power operation, and robust fault detection in mission-critical embedded control systems.

FAQ

What is the function of the WDI pin on STM6822SWY6F?

The WDI (Watchdog Input) pin monitors firmware health by requiring a logic edge every 1.6 seconds (typ.). If no transition occurs, the device asserts RST. The internal timer clears on any rising or falling edge, and the watchdog is disabled when WDI is left floating or driven by a tristate buffer - enabling flexible integration with diverse MCU architectures.

Can STM6822SWY6F be used with a 5 V supply?

Yes - STM6822SWY6F operates from 1.0 V to 5.5 V and monitors VCC relative to its fixed 3.3 V threshold. When powered from 5 V, it correctly detects brownout conditions below 3.22 V (3.3 V −2.5%) and maintains full functionality, including RST assertion, MR response, and watchdog timing, across the entire industrial temperature range.

Why does STM6822SWY6F use an open-drain RST output?

The open-drain RST output enables wired-OR reset bus configurations, supports level shifting to higher-voltage domains (up to 6 V), and avoids contention when interfacing with microprocessors having bidirectional reset pins. A 10 kΩ external pull-up resistor is recommended to ensure fast rise time and noise immunity while minimizing current draw during reset assertion.

How is manual reset implemented on STM6822SWY6F?

Manual reset is implemented via the MR pin, which is active-low and internally pulled up to VCC with 52 kΩ. Connecting MR to ground through a momentary switch asserts RST for the full reset timeout period (1.4 ms) plus trec delay. No external debounce components are required, and the pin tolerates TTL/CMOS logic levels or open-collector drivers.