TPS3813K33-EP Texas Instruments Integrated Circuit (SOT23 (6-Pin)) In Stock
TPS3813K33-EP is an enhanced-product supervisory circuit with a fixed 3.3 V undervoltage threshold, integrated watchdog timer, and manual RESET input in a 6-pin SOT-23 package. It monitors processor supply rails and asserts a reset signal during power-up or fault conditions, with a programmable watchdog timeout. Designed for DSP and microprocessor initialization in industrial and extended-temperature embedded systems.
- Manufacturer
- Texas Instruments
- Package
- SOT23 (6-Pin)
- Pin Count
- 6
- Lifecycle
- ACTIVE
- Datasheet
- TPS3813K33-EP Datasheet PDF
- Category
- Integrated Circuit
- RoHS
- Compliant
- Lead Time
- 3–7 business days
- Shipping
- DHL Express · Worldwide
Key Features
- Fixed 3.3 V supervisory threshold with ±1.5% detection accuracy
- Integrated watchdog timer with programmable timeout via external capacitor
- Manual RESET input (MR) for push-button or external reset assertion
- Enhanced product (EP) qualification for -55°C to 125°C operation
- 6-pin SOT-23 package integrating supervision and watchdog in minimal board area
- Active-low open-drain RESET output compatible with 3.3 V and 5 V logic
Applications
TPS3813K33-EP is used in DSP-based systems, embedded processor boards, and industrial motor controllers that require both power-on reset supervision at 3.3 V and watchdog timer protection to recover from software lock-up conditions. Its manual reset input enables push-button system restart in field-deployed equipment without additional glue logic. The enhanced-product temperature rating makes it suitable for avionics, military, and outdoor industrial installations where ambient temperatures exceed the standard -40°C to 85°C commercial range.
Compliance & Regulatory
| RoHS Status | Compliant |
| Lead-Free | Yes (Pb-Free) |
Alternate & Equivalent Parts
Compatible alternatives and drop-in replacements for TPS3813K33-EP:
Frequently Asked Questions
How is the watchdog timeout period set on TPS3813K33-EP?
The watchdog timeout period on TPS3813K33-EP is set by connecting an external capacitor between the CT pin and ground. The timeout is proportional to the capacitor value, with larger capacitance producing longer timeout windows. A 0.1 µF capacitor typically yields a timeout on the order of hundreds of milliseconds, while a 1 µF capacitor extends the window to several seconds, allowing designers to match the watchdog period to the worst-case processor service interval for the specific 3.3 V system under supervision.
What happens when the TPS3813K33-EP watchdog is not serviced before timeout?
If the processor fails to toggle the watchdog input (WDI pin) within the programmed timeout window, TPS3813K33-EP asserts the active-low RESET output for a minimum of 200 ms reset pulse width, forcing the microprocessor or DSP into reset. The watchdog counter is also cleared during this reset pulse. After the reset pulse completes, the RESET output releases and the processor restarts, recovering from the software hang without requiring manual power cycling. This self-recovery mechanism is critical for unattended industrial equipment running at 3.3 V.
Does TPS3813K33-EP include a manual reset input, and how is it used in a product design?
Yes, TPS3813K33-EP includes an active-low manual reset (MR) input that allows an external source such as a push-button switch or host supervisory controller to assert RESET independently of the undervoltage comparator or watchdog timer. Connecting a normally-open push-button between MR and ground, with a 100 kΩ pull-up resistor to the 3.3 V rail, creates a reliable operator-initiated reset function. The MR input is debounced internally, so mechanical switch bounce does not generate multiple reset pulses on the SOT-23 device.
Which temperature range does the EP qualification cover for TPS3813K33-EP in harsh environments?
The enhanced-product (EP) version of TPS3813K33-EP is tested and specified over the -55°C to 125°C junction temperature range, which exceeds the standard industrial -40°C to 85°C grade. This qualification is achieved through additional burn-in, high-temperature life testing, and tighter parametric screening compared to the commercial version. The extended range allows designers to use TPS3813K33-EP in avionics, downhole instrumentation, and outdoor telecom equipment where ambient temperatures can swing well beyond the typical industrial window.
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About Texas Instruments
Texas Instruments (TI) is a global semiconductor company headquartered in Dallas, Texas. TI designs and manufactures analog and embedded processing chips used in industrial, automotive, consumer, communications, and enterprise systems.
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