Send an Inquiry

To receive a quote for your project, please fill in the following information, and we’ll get back to you promptly.

Submit Inventory List

Please fill in the following information, and we’ll get back to you promptly.

Home > Products > Integrated Circuits (ICs) > Power Management (PMIC) > Supervisors

STMicroelectronics STWD100NPWY3F

Name: STWD100NPWY3F
Brand: STMicroelectronics
SKU: STWD100NPWY3F
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

Compare

Part No.:: STWD100NPWY3F

Manufacturer:: STMicroelectronics

Category:: Supervisors

Package:: SC-74A, SOT-753

Datasheet:: STWD100NPWY3F.pdf

Description:: IC SUPERVISOR 1 CHANNEL SOT23-5

Quantity:: RFQ Add To RFQ list

Payment:

Shipping:

Inventory:18,080

Please send an inquiry. Send us your inquiry, and we will respond immediately.

Product details

Overview

STWD100NPWY3F from STMicroelectronics is a single-supply, automotive-qualified watchdog timer IC with fixed timeout options (3.4 ms, 6.3 ms, 102 ms, or 1.6 s), 13 µA typical supply current, and –40 to 125 °C operating range. It features WDI input for periodic reset, EN pin for chip enable/disable, and configurable open-drain or push-pull WDO output - used in telecom power supervision and industrial control systems to recover locked microcontrollers.

For engineers reviewing the STWD100NPWY3F datasheet, STWD100NPWY3F pinout, STWD100NPWY3F application, or STWD100NPWY3F equivalent, key selection criteria include timeout period selection, EN pin behavior under transient conditions, WDO output drive configuration, and compatibility with bidirectional MCU reset I/O interfaces.

Technical Context

The STWD100NPWY3F implements a self-contained watchdog timer with internal oscillator-based timing, no external components required. Its timeout periods are factory-set per variant: STWD100NPWY3F uses the 1.6 s (typ.) setting (t_WD = 1.12–2.24 s). The EN pin has an internal 32–100 kΩ pull-down and enables the device when floating.

WDI accepts ≥1 µs pulses with 100 ns glitch rejection; toggling resets the timer. WDO asserts low after timeout - minimum 10 µs pulse width on STWD100xP variants like this one - and supports either open-drain (with external pull-up) or push-pull output modes per configuration.

Key Specifications

Parameter	Value and Actual Design Meaning
Watchdog timeout	1.6 s typical (1.12–2.24 s min/max); determines maximum allowable MCU hang time before system reset
Supply current	13 µA typical at V_CC = 5 V; enables ultra-low-power always-on monitoring in battery-backed systems
Operating voltage	2.7–5.5 V; compatible with 3.3 V and 5 V logic domains without level-shifting
Temperature range	–40 to 125 °C; qualified for under-hood automotive and industrial environments
ESD rating	HBM: 2000 V, CDM: 1000 V; ensures robustness during board handling and system integration
EN input behavior	Pull-down resistor 32–100 kΩ; device enabled by floating EN - simplifies default-enable designs
WDO output type	Configurable open-drain or push-pull; open-drain allows wired-OR reset bus sharing with other devices

Pinout & Package

SOT23-5 package (3.0 × 2.8 × 1.3 mm, 5-pin surface-mount), RoHS-compliant and ECOPACK® certified.

Pin/Terminal	Circuit Role	Design Meaning
1 (WDO)	Watchdog output	Active-low reset signal; open-drain or push-pull configurable; drives MCU reset line or system supervisor
2 (GND)	Ground reference	Primary return path for V_CC, WDI, EN, and WDO; must be low-impedance for noise immunity
3 (EN)	Chip enable input	Internal 32–100 kΩ pull-down; floating = enabled; driven high >1 µs triggers immediate WDO assertion
4 (WDI)	Watchdog input	Edge-sensitive reset trigger; ≥1 µs pulse clears timer; 100 ns glitch rejection prevents false clearing
5 (V_CC)	Supply voltage	2.7–5.5 V input; powers internal oscillator and logic; startup threshold V_START = 1.9–2.7 V

Key Features

Feature	Design Value
Four factory-selectable timeout periods	Enables precise match to system boot time, firmware loop duration, or safety-critical response window
Chip enable (EN) with internal pull-down	Eliminates need for external pull-down resistor; simplifies PCB layout and reduces BOM count
Configurable WDO output (open-drain/push-pull)	Supports both shared reset buses (open-drain) and direct MCU reset pins (push-pull) without redesign
100 ns glitch rejection on WDI/EN	Prevents spurious timeout due to EMI or digital noise on control lines in electrically noisy environments
Automotive qualification (AEC-Q100)	Validated for use in engine control units, ADAS modules, and other automotive electronics requiring reliability

Applications

Telecom Power Supervision

Industrial PLC Control

Use Scenario: Monitors FPGA or DSP firmware execution in base station power management units during brownout recovery.

IC Role / Device Role / Timing Role: Standalone watchdog timer asserting WDO to force hardware reset if communication stack hangs longer than 1.6 s.

Use Value: Prevents silent failure of remote radio units by enforcing deterministic recovery without host CPU intervention.

Use Scenario: Embedded in programmable logic controller backplane to supervise main CPU operation during cyclic scan execution.

IC Role / Device Role / Timing Role: Hardware-level fault detector that triggers system-wide reset upon missed WDI toggle within 102 ms or 1.6 s window.

Use Value: Maintains functional safety integrity by isolating software faults before they propagate to I/O modules or field actuators.

Medical Infusion Pump

Automotive Body Control Module

Use Scenario: Integrated into battery-powered infusion pump MCU subsystem to detect motor driver lockup or sensor read failure.

IC Role / Device Role / Timing Role: Independent safety monitor asserting active-low WDO to halt pump actuation and illuminate fault LED.

Use Value: Meets IEC 62304 Class C software safety requirements via hardware-enforced timeout independent of application code.

Use Scenario: Used in BCM to supervise gateway MCU during CAN message processing and sleep/wake transitions.

IC Role / Device Role / Timing Role: Automotive-grade watchdog ensuring MCU responsiveness during LIN/CAN protocol stack execution.

Use Value: Supports ISO 26262 ASIL-B compliance by providing fail-safe reset capability under extended temperature stress.

Equivalent & Alternatives

The following parts are listed as comparable options for similar watchdog timer applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
MAX6375US29D3+	Fixed 2.9 s timeout; 1.8–5.5 V supply; no EN pin; only open-drain WDO	Lacks chip enable and shorter timeout granularity; not AEC-Q100 qualified	Select when longer timeout and simplified enable logic suffice, and automotive qualification is unnecessary
TPL92012DSER	Adjustable timeout (10 ms–10 s via external capacitor); 1.6–5.5 V; integrated reset delay; no EN pin	Requires external RC network; lacks EN functionality and automotive qualification	Choose when programmable timeout and built-in reset delay are prioritized over pin-count minimization and automotive compliance

Compared with MAX6375US29D3+ and TPL92012DSER, STWD100NPWY3F offers factory-set precision timing, integrated EN control, and AEC-Q100 qualification - making it optimal for space-constrained, safety-critical automotive and industrial systems where deterministic behavior and qualification evidence are mandatory.

Availability

STWD100NPWY3F is available at Aetrix Electronics and suitable for telecom power supervision, industrial PLC control, and automotive body control modules requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for STWD100NPWY3F 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, designing and manufacturing analog, MCU, power, and sensing solutions for industrial, automotive, and consumer markets.

The STWD100 series belongs to ST's dedicated safety and supervision IC product line, engineered specifically for reliable, low-power system-level fault detection in harsh environments where software-only monitoring is insufficient.

FAQ

What is the exact watchdog timeout period for STWD100NPWY3F?

The STWD100NPWY3F is the 'Y' variant in the STWD100 family and provides a nominal watchdog timeout of 1.6 seconds, with a guaranteed range of 1.12 to 2.24 seconds across temperature and voltage. This value is factory-trimmed and does not require external components or configuration.

Can STWD100NPWY3F drive a standard microcontroller reset pin directly?

Yes - STWD100NPWY3F supports push-pull WDO output mode, enabling direct connection to most MCU reset inputs without external pull-up resistors. When configured as open-drain, a 10 kΩ external pull-up to V_CC or another logic rail up to 6 V is required.

How does the EN pin behave when left unconnected?

When the EN pin is left floating, the internal 32–100 kΩ pull-down resistor ensures it remains at logic low, enabling the watchdog function by default. Driving EN high for ≥1 µs forces immediate WDO assertion, regardless of WDI activity - useful for manual reset initiation.

Is STWD100NPWY3F qualified for automotive applications?

Yes - STWD100NPWY3F carries full AEC-Q100 Grade 0 qualification (–40 to +125 °C), with additional screening per AEC-Q001/Q002. Its SOT23-5 packaging, ESD robustness (HBM 2000 V), and specified DC/AC parameters across temperature confirm suitability for under-hood and body electronics.

STWD100NPWY3F Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: -

Package/Case:: SC-74A, SOT-753

Packaging:: Tape & Reel (TR)

Product Status:: Active

Programmable:: Not Verified

Type:: Watchdog Circuit

Number of Voltages Monitored:: 1

Voltage - Threshold:: -

Output:: Open Drain or Open Collector

Reset:: Active Low

Reset Timeout:: 2.3ms Minimum

Operating Temperature:: -40°C ~ 125°C (TA)

Grade:: Automotive

Qualification:: AEC-Q100

Mounting Type:: Surface Mount

Supplier Device Package:: SOT-23-5

STWD100NPWY3F FAQ

1.How can I place an order for STWD100NPWY3F through Aetrix?

Please submit a Request for Quotation (RFQ) for STWD100NPWY3F on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for STWD100NPWY3F reliable?

The price and inventory of STWD100NPWY3F are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for STWD100NPWY3F is usually 5 days.

3.What payment methods are accepted for STWD100NPWY3F?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for STWD100NPWY3F transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for STWD100NPWY3F?

STWD100NPWY3F orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your STWD100NPWY3F order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for STWD100NPWY3F?

For technical support, including STWD100NPWY3F datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your STWD100NPWY3F requirements.

6.How does Aetrix verify that STWD100NPWY3F is sourced from the original manufacturer or authorized distributors?

All STWD100NPWY3F products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that STWD100NPWY3F meets industry standards.

7.What is the process for return or replacement of STWD100NPWY3F?

All STWD100NPWY3F units undergo pre-shipment inspection (PSI). If there is an issue with STWD100NPWY3F, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The STWD100NPWY3F part is unused and in its original packaging.

Return procedure for STWD100NPWY3F:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

Tech Hub

2026-09-08 Obsolete Electronic Components: How to Source and Evaluate Replacements

A practical engineering and sourcing framework covering lifecycle verification, lifetime-buy calculations, replacement qualification, supplier checks and counterfeit-risk controls.

2026-09-07 TTL vs CMOS Logic Levels: 74HC and 74HCT Compatibility Explained

TTL and CMOS logic families differ in thresholds, loading, output drive, power and timing. This engineering guide compares 74HC and 74HCT, calculates noise margins and checks 3.3 V/5 V compatibility.

2026-09-04 Logic Level Shifter: How to Connect 3.3V and 5V Logic Safely

A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.

2026-09-03 74HC595 vs TPIC6B595: Output Drive, Pinout, Current, and Load Selection

The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…

2026-09-02 74HC595 Pinout, Timing, Output Current, and Applications

The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…

2026-09-01 Latch vs Flip-Flop: Timing, Differences and Design Choices

A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…

2026-08-30 D Latch Circuit: Truth Table, Timing, ICs and Applications

A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …

2026-08-28 SR Latch Explained: NOR and NAND Circuits, Truth Tables, and Applications

An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…

2026-08-27 Latch Circuit: SR and D Latches, Truth Tables, Timing, and Applications

Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…

2026-08-21 What Is an LED Driver? Types, Circuits, Dimming, and Selection

An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…