STWD100

Active

Watchdog timer circuit

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Product overview

Description

The STWD100 watchdog timer circuits are self-contained devices which prevent system failures that are caused by certain types of hardware errors (such as, non-responding peripherals and bus contention) or software errors (such as a bad code jump and a code stuck in loop).

The STWD100 watchdog timer has an input, WDI, and an output, WDO. The input is used to clear the internal watchdog timer periodically within the specified timeout period, twd. While the system is operating correctly, it periodically toggles the watchdog input, WDI. If the system fails, the watchdog timer is not reset, a system alert is generated and the watchdog output, WDO, is asserted.

The STWD100 circuit also has an enable pin, EN, which can enable or disable the watchdog functionality. The EN pin is connected to the internal pull-down resistor. The device is enabled if the EN pin is left floating.

  • All features

    • Current consumption 13 µA typ.
    • Available watchdog timeout periods are 3.4 ms, 6.3 ms, 102 ms, and 1.6 s
    • Chip enable input
    • Open drain or push-pullWDO output
    • Operating temperature range: –40 to 125 °C
    • Packages: SOT23-5 and SC70-5 (SOT323-5)
    • ESD performance
      • HBM: 2000 V
      • RCDM: 1000 V
    • Automotive qualified

Circuit Diagram

The current status of a product:
Active: Product is in volume production
Evaluation: Product is under characterization. Limited Engineering samples available
Preview: Product is in design stage
Target: Product is in design feasibility stage.No commitment taken to produce
Proposal: Marketing proposal for customer feedback.No commitment taken to design or produce
NRND: Not Recommended for New Design.Product is in volume production only to support customers ongoing production.
Marketing description of the package type.Compliancy of the device with industry requirement domains (IRD)The RoHS status of a product:
ECOPACK 1: Initial grade to identify European RoHS compliant products.
ECOPACK 2: New grade to identify brominated chlorinated and antimony oxide flame retardant free products.
ECOPACK 3: Halogen free RoHS exemptions free products.
(*): ECOPACK 2 version available upon request.
(**): Some versions still existing in ECOPACK 1 or not compliant.
The current status of a product:
Active: Product is in volume production
Evaluation: Product is under characterization. Limited Engineering samples available
Preview: Product is in design stage
Target: Product is in design feasibility stage.No commitment taken to produce
Proposal: Marketing proposal for customer feedback.No commitment taken to design or produce
NRND: Not Recommended for New Design.Product is in volume production only to support customers ongoing production.
Budgetary PriceMarketing description of the package type.Storage method used to contain product.Main country of assembly or fabrication of the product.ECCNs are five character alpha-numeric designations used on the Commerce Control List to identify dual-use items for export control purposes. ECCNs are five character alpha-numeric designations used on the Commerce Control List to identify dual-use items for export control purposes.The value as specified by level (minTypMax) of the ambient temperature (in Cel) in which this item was designed to operate.The value as specified by level (minTypMax) of the ambient temperature (in Cel) in which this item was designed to operate.The value as specified by level (minTypMax) of the ambient temperature (in Cel) in which this item was designed to operate.