STMicroelectronics STM6822LWY6F

Overview

STM6822LWY6F from STMicroelectronics is a 5-pin precision voltage supervisor IC with integrated watchdog timer and manual reset input, designed for microprocessor power monitoring in industrial embedded systems. It monitors 3.3 V supply rails, provides active-low open-drain RST output, delivers 1.4 ms reset pulse width (typ.), guarantees reset assertion down to VCC = 1.0 V, and draws only 3 µA typical supply current.

For engineers reviewing the STM6822LWY6F datasheet, STM6822LWY6F pinout, STM6822LWY6F application, or STM6822LWY6F equivalent, key selection criteria include its open-drain RST output compatibility with multi-rail systems, guaranteed low-VCC reset validity, watchdog timeout of 1.6 s (typ.), and SOT23-5 footprint suitability for space-constrained PCB 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), asserting RST when undervoltage occurs. Its watchdog timer resets on WDI inactivity ≥1.6 s (typ.) and clears on any WDI edge - enabling MCU health supervision without external timing components.

Reset assertion persists for trec (1.4 ms typ.) after VCC recovery, MR release, or watchdog timeout. The MR input features an internal 52 kΩ pull-up, supporting direct push-button grounding without external biasing, while the open-drain RST requires an external pull-up resistor (e.g., 10 kΩ) for level translation across voltage domains.

Key Specifications

Pinout & Package

SOT23-5 package: compact 2.9 mm × 1.6 mm surface-mount outline with 0.95 mm pitch, optimized for high-density PCBs and automated assembly.

Key Features

Applications

Equivalent & Alternatives

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

Compared with STM6822LWY6F, STM6823LWY6F eliminates external component count but loses multi-rail flexibility, while TPS3808G33DBVR reduces quiescent current by 60% but removes two key system-level controls (MR and watchdog) essential for field-recoverable designs.

Availability

STM6822LWY6F is available at Aetrix Electronics and suitable for industrial PLC controllers, smart metering units, medical diagnostic sensor hubs, and automotive body control modules requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for STM6822LWY6F 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 industrial, automotive, and embedded markets since 1987.

STM6xxx is ST's dedicated family of micropower supervisors targeting robust, low-cost, and footprint-efficient power monitoring in resource-constrained embedded systems - emphasizing guaranteed low-VCC operation and integrated system recovery features.

FAQ

What is the exact reset threshold voltage for STM6822LWY6F?

The STM6822LWY6F has a nominal VCC reset threshold of 3.3 V with ±2.5% tolerance over –40 to +85 °C, as specified in Table 6 of the official datasheet (DocID11110 Rev 14). This value is factory-trimmed and does not require external calibration.

Can the watchdog function be disabled, and how?

Yes - the watchdog is automatically disabled when the WDI pin is left unconnected (floating) or driven by a tristate buffer in high-impedance state. No configuration register or external signal is needed; the internal timer remains inactive until WDI receives a valid logic transition.

Is an external pull-up resistor required for the RST output?

Yes. The STM6822LWY6F features an active-low open-drain RST output, which must be pulled up externally (e.g., 10 kΩ to 3.3 V or another compatible rail) to generate a valid logic-high level when deasserted. Without it, RST remains undefined during non-reset states.

Does STM6822LWY6F support operation below 3.3 V supply?

Yes - it operates across 1.0 V to 5.5 V VCC. While its 3.3 V threshold is fixed, the device continues asserting RST down to VCC = 1.0 V (guaranteed), enabling reliable reset behavior during deep brown-out conditions common in battery-powered or unregulated systems.