Watchdog Timer: Supply Voltage 1.8V to 5.5V

Component Specifications

Definition

A watchdog timer (WDT) is an electronic or software-based timing device used in microprocessor and logic solver systems to detect and recover from malfunctions. It operates by requiring the system to periodically reset the timer before it expires. If the system fails to do so (indicating a software hang, hardware fault, or abnormal operation), the watchdog timer triggers a system reset or generates an interrupt to restore normal operation, ensuring reliability in industrial applications.

Working Principle

The watchdog timer counts down from a preset value. The system software must regularly 'pet' or reset the timer before it reaches zero. If the timer expires due to lack of reset signals (caused by software errors, infinite loops, or hardware failures), it generates a reset signal to restart the microprocessor or trigger a fail-safe response, preventing prolonged system failure.

Materials

Typically consists of semiconductor materials (silicon for integrated circuits), ceramic or plastic packaging, and metal contacts. Common IC packages include DIP, SOIC, or QFN with operating temperature ranges of -40°C to +85°C or industrial-grade -40°C to +125°C.

Technical Parameters

Parameter	Typical range	Notes & selection driver
Package	SOT-23, SOIC-8, DFN
Output Type	Active-low or active-high reset
Reset Timeout	1ms to 10s (configurable)
Supply Voltage	1.8V to 5.5V
Current Consumption	1µA to 10µA (typical)
Operating Temperature	-40°C to +125°C

Ranges are indicative industry figures for RFQ preparation, not a supplier commitment. Confirm every value and standard with the legal manufacturer before ordering.

Standards

ISO 13849-1, IEC 61508, IEC 61131-2

Parent Products

This component is used in the following industrial products

Microprocessor/Logic Solver

The core processing unit within a safety controller that executes safety-critical logic functions and monitors safety inputs.

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Protection Logic IC / Microcontroller

Integrated circuit or microcontroller designed to implement safety protection logic and monitoring functions in electronic systems.

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Engineering Analysis

Risks & Mitigation

Single point of failure if not redundant
Incorrect timeout setting causing unnecessary resets
Software bugs preventing proper timer reset

FMEA Triads

Trigger: Software hang or infinite loop
Failure: Watchdog timer expires, system resets
Mitigation: Implement robust software with periodic timer resets and error handling

Trigger: Hardware fault in timer circuit
Failure: Timer fails to reset or triggers falsely
Mitigation: Use redundant timers, select high-reliability components, and follow derating guidelines

Trigger: Power supply fluctuation
Failure: Unstable timer operation
Mitigation: Implement power monitoring and brown-out detection circuits

Industrial Ecosystem

Compatible With

Typical Suppliers & Equivalents

Compliance & Inspection

Tolerance

±1% to ±10% timing accuracy depending on application criticality

Test Method

Functional testing via software simulation of failures, environmental stress testing (temperature, voltage), and compliance with IEC 61508 SIL levels

Procurement Evaluation Criteria

A practical evidence checklist for RFQ preparation and supplier evaluation.

Technical documentation

Request current drawings, revision history, and a signed specification sheet.

Manufacturing capability

Verify equipment lists, process limits, capacity, and representative production evidence.

Inspection readiness

Confirm test methods, calibrated equipment, sampling plans, and traceable reports.

Supplier transparency

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Manufacturers of Watchdog Timer

Manufacturer profiles associated with Watchdog Timer.

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Compiled and source-reviewed by the CNFX editorial team. Each manufacturer above links to the page on that company's own website where the product is listed, with the date we checked it. How we source and review

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Frequently Asked Questions

What is the main purpose of a watchdog timer?

To detect and recover from system malfunctions by resetting the microprocessor if it fails to operate correctly within a specified time frame.

Can a watchdog timer be implemented in software?

Yes, software watchdogs exist but are less reliable than hardware timers as they depend on the same faulty system; hardware watchdogs are preferred for critical applications.

What happens when a watchdog timer expires?

It triggers a system reset, interrupt, or fail-safe action to restore normal operation and prevent unsafe conditions.

Data Basis

Editorial classification, named public sources where available, and source-reviewed manufacturer records. See the editorial policy.

Preliminary Technical Classification

This page supports structured research, RFQ preparation, and supplier evaluation. It does not replace buyer-led supplier qualification, standards review, or technical approval.

Watchdog Timer