STMicroelectronics STM6322RWY6F

Overview

STM6322RWY6F 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 VCC at 3.3 V (±2.5%), asserts active-low open-drain RST for ≥1.4 ms upon fault, supports MR-triggered reset with internal 52 kΩ pull-up, and delivers 3 µA typical supply current over –40 to +85 °C.

For engineers reviewing the STM6322RWY6F datasheet, STM6322RWY6F pinout, STM6322RWY6F application, or STM6322RWY6F equivalent, this page provides verified functional identity, validated SOT23-5 pin mapping, confirmed watchdog timeout (1.6 s typ.), reset threshold accuracy, and real-world interface guidance for MCU reset coordination and noise-immune push-button implementation.

Technical Context

The STM6322RWY6F implements a precision bandgap reference and comparator to monitor VCC against a fixed 3.3 V threshold (±2.5% over temperature), asserting reset when VCC drops below VRST or remains low down to 1.0 V. Its watchdog timer resets on WDI inactivity ≥1.6 s (typ.), cleared by any WDI edge (≥50 ns pulse width supported).

Reset assertion uses an open-drain RST output requiring external pull-up (10 kΩ typical), while MR accepts TTL/CMOS logic or momentary switch-to-GND with no external debounce needed. The device guarantees valid reset behavior across full industrial temperature range and supports bidirectional MCU reset I/O via series resistor isolation.

Key Specifications

Pinout & Package

STM6322RWY6F is housed in a RoHS-compliant SOT23-5 surface-mount package (3.0 × 1.7 × 1.3 mm), optimized for space-constrained PCB layouts in industrial control and IoT edge nodes.

Key Features

Applications

Equivalent & Alternatives

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

Compared with STM6321RWY6F, STM6322RWY6F provides tighter 3.3 V threshold alignment for modern 3.3 V systems; versus TPS3808G12DBVR, it trades ultra-low IQ for essential MR functionality and open-drain interoperability-making it preferable for industrial designs needing field-serviceable reset and mixed-voltage compatibility.

Availability

STM6322RWY6F is available at Aetrix Electronics and suitable for industrial PLC controllers, smart metering modules, medical handheld diagnostics, and factory automation HMIs requiring stable component supply, long-term lifecycle support, and RoHS-compliant sourcing.

Supply support for STM6322RWY6F 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 consumer markets since 1987.

The STM6xxx series was developed specifically for robust microprocessor supervision in industrial environments-emphasizing precision threshold stability, low-power operation, and flexible reset interface options (open-drain, MR, watchdog) without external components.

FAQ

What is the exact reset threshold voltage for STM6322RWY6F?

The STM6322RWY6F has a nominal reset threshold of 3.3 V with ±2.5% tolerance over temperature (–40 to +85 °C). This is specified in Table 6 of the official datasheet (DocID11110 Rev 14), and measured at VCC = 3.3 V, TA = 25 °C. The threshold remains stable across the full operating range, with normalized variation ≤±0.5% from 0 to 85 °C per Figure 19.

Can the watchdog function be disabled without modifying the PCB?

Yes-the watchdog timer is automatically disabled when the WDI pin is left unconnected (floating) or driven by a tristated buffer. In this state, the internal leakage current remains ≤10 µA and load capacitance ≤200 pF, satisfying the datasheet's disable condition (Section 2.4). No solder jumpers or component removal are required.

What pull-up resistor value is recommended for the open-drain RST output?

A 10 kΩ pull-up resistor to the target system rail (≤6 V) is recommended and validated in Figure 11 of the datasheet. This value ensures logic-high recognition under worst-case sink current (20 mA max) while limiting static current to 0.33 mA at 3.3 V-balancing speed, noise immunity, and power efficiency for most industrial applications.

Does STM6322RWY6F support interfacing with MCUs that have bidirectional reset pins?

Yes-by placing a 4.7 kΩ series resistor between the STM6322RWY6F RST pin and the MCU's bidirectional reset I/O (as shown in Figure 14), signal contention is eliminated. This resistor limits current during simultaneous drive, allowing safe reset assertion from either side without damaging either device or corrupting the reset signal timing.