STMicroelectronics STM6322MWY6F

Overview

STM6322MWY6F 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 3.3 V power supplies, provides active-low open-drain RST output, delivers 1.4 ms reset pulse width (typ.), guarantees RST assertion down to VCC = 1.0 V, and draws only 3 µA supply current (typ.) at VCC < 3.6 V.

For engineers reviewing the STM6322MWY6F datasheet, STM6322MWY6F pinout, STM6322MWY6F application, or STM6322MWY6F equivalent, this device supports critical power-on sequencing, brown-out detection, and system recovery in resource-constrained MCU platforms where low quiescent current and guaranteed reset validity at ultra-low VCC are mandatory.

Technical Context

The STM6322MWY6F implements a precision bandgap reference and comparator to monitor VCC against a fixed 3.3 V threshold (±2.5% accuracy), asserting RST when out-of-tolerance. Its watchdog timer triggers reset if WDI remains static for ≥1.6 s (typ.), and clears on any WDI edge (≥50 ns pulse width).

Reset assertion is sustained for trec (1.4 ms typ.) after VCC recovery, MR release, or watchdog timeout. The MR input features an internal 52 kΩ pull-up, enabling direct connection to a momentary switch to ground without external components.

Key Specifications

Pinout & Package

STM6322MWY6F is housed in a standard 5-pin SOT23 package (JEDEC MO-178AA), with 1.3 mm height, 2.9 mm × 1.6 mm footprint, and lead-free RoHS-compliant construction.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6322US33D3+ and TPS3808G33DBVR, STM6322MWY6F uniquely combines 1.4 ms reset timing, open-drain RST, sub-µA quiescent current, and guaranteed 1.0 V operation-making it optimal for compact, battery-aware industrial controllers needing both precise power sequencing and runtime watchdog coverage.

Availability

STM6322MWY6F is available at Aetrix Electronics and suitable for industrial PLCs, smart energy meters, medical infusion pumps, and building automation gateways requiring stable component supply, long-term lifecycle support, and RoHS-compliant sourcing.

Supply support for STM6322MWY6F 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 STM6xxx series is engineered specifically for robust microprocessor supervision in harsh industrial environments, emphasizing low-power operation, wide temperature range, and guaranteed reset validity under marginal supply conditions.

FAQ

What is the exact reset threshold voltage and tolerance for STM6322MWY6F?

The STM6322MWY6F has a nominal VCC reset threshold of 3.3 V with a tolerance of ±2.5% over the full operating temperature range (–40 to +85 °C). This value is factory-trimmed and specified in Table 6 of the datasheet (DocID11110 Rev 14), ensuring consistent brown-out detection across production lots and environmental conditions.

Can the watchdog function be disabled, and how?

Yes, the watchdog function is disabled when the WDI pin is left unconnected (floating) or driven by a tristated buffer. In this state, the internal watchdog counter is held inactive, and no reset will occur due to watchdog timeout. No configuration register or external signal is required-disconnection alone suffices.

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

A 10 kΩ pull-up resistor to the target logic supply (e.g., 3.3 V or 5 V) is recommended for the RST output. This value ensures reliable logic-high levels while limiting sink current to ≤330 µA during reset assertion, staying well within the 20 mA absolute maximum rating and accommodating typical MCU input leakage.

Does STM6322MWY6F support interfacing with bidirectional MCU reset pins?

Yes, it supports bidirectional reset pins via a 4.7 kΩ series resistor placed between RST and the MCU's reset I/O. This resistor prevents signal contention when both devices attempt to drive the line simultaneously, as documented in Figure 14 of the datasheet and validated for STM32, PIC, and MSP430 families.