Texas Instruments TPS3813K33DBVTG4

Overview

TPS3813K33DBVTG4 from Texas Instruments is a window-watchdog supervisory IC for microcontroller and DSP systems, featuring a fixed 2.93V supply voltage threshold (VIT), 25ms power-on reset delay, 9µA typical supply current, open-drain RESET output, and programmable watchdog window ratio via WDR/WDT pins. It operates across –40°C to +85°C and targets safety-critical embedded control in industrial and medical equipment.

For engineers reviewing the TPS3813K33DBVTG4 datasheet, TPS3813K33DBVTG4 pinout, TPS3813K33DBVTG4 application, or TPS3813K33DBVTG4 equivalent, key selection criteria include VIT tolerance (±70mV), watchdog window configurability (1:25.8 to 1:127.7), glitch immunity (3µs), low quiescent current, and SOT-23-6 compatibility with board space-constrained designs.

Technical Context

The TPS3813K33DBVTG4 integrates a precision voltage supervisor and a dual-boundary window-watchdog timer. Its internal bandgap reference sets a fixed 2.93V threshold with 40mV hysteresis, and power-on reset asserts when VDD exceeds 1.1V before releasing after 25ms once VDD rises above VIT.

Watchdog timing is configured by hard-wiring WDT (to GND/VDD) or connecting an external capacitor (155pF–63nF), while WDR selects lower-bound ratio (GND = narrow window, VDD = wide window). The device requires no external components for basic operation and supports independent RESET pull-up up to 6V.

Key Specifications

Pinout & Package

TPS3813K33DBVTG4 is housed in a 6-pin SOT-23 package (2.90mm × 1.60mm body size), optimized for high-density PCB layouts and automated assembly.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS3813K33DBVTG4, TPS3813K33DBVR offers identical supervision functionality in volume-optimized packaging, while MAX6326LT33D3+T provides simpler, lower-cost reset-only supervision without window-watchdog capability-making it unsuitable for applications requiring software execution validation.

Availability

TPS3813K33DBVTG4 is available at Aetrix Electronics and suitable for active antenna systems, electricity meters, infusion pumps, and HVAC safety controllers requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for TPS3813K33DBVTG4 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

Texas Instruments is a global semiconductor leader specializing in analog, embedded processing, and power management technologies, with decades of experience in high-reliability industrial and automotive ICs.

The TPS3813xxx family was designed specifically for safety-critical embedded systems requiring both precise voltage monitoring and intelligent software-execution supervision via window-watchdog architecture.

FAQ

What is the exact supply voltage threshold (VIT) of the TPS3813K33DBVTG4?

The TPS3813K33DBVTG4 has a nominal supply voltage threshold of 2.93V, with a guaranteed range of 2.87V to 3.00V over –40°C to +85°C. This value is factory-trimmed and fixed for the K33 variant, making it suitable for accurate supervision of 3.3V rails without external adjustment. The 40mV hysteresis prevents chatter during slow-rising or noisy supply conditions.

How does the window-watchdog function differ from a standard watchdog in the TPS3813K33DBVTG4?

Unlike standard watchdogs that trigger reset only on missing pulses, the TPS3813K33DBVTG4 implements a true window-watchdog: the supervised processor must assert WDI within a defined time window-not too early and not too late. This detects both software hangs and timing anomalies like ISR overrun or scheduler jitter, significantly enhancing fault coverage in safety-critical firmware.

Can the TPS3813K33DBVTG4 operate with a 2.5V supply rail?

Yes, the TPS3813K33DBVTG4 supports VDD from 2V to 6V per its Recommended Operating Conditions. However, its 2.93V VIT threshold means it will not assert reset on undervoltage for a 2.5V rail-it is intended for 3.3V systems. For 2.5V supervision, TI recommends the TPS3813J25DBVTG4 (2.25V threshold) instead.

What is the purpose of the WDR pin on the TPS3813K33DBVTG4?

The WDR pin on the TPS3813K33DBVTG4 selects the watchdog window ratio: tying WDR to GND configures a narrower lower boundary (e.g., 1:31.8), while tying it to VDD enables a wider lower boundary (e.g., 1:127.7). This determines how tightly the WDI pulse must fall within the programmed window, allowing designers to balance fault sensitivity against timing margin.

Is an external pull-up resistor required for the RESET output of the TPS3813K33DBVTG4?

Yes, the RESET pin is open-drain and requires an external pull-up resistor to define the high state. A 1MΩ resistor to the target logic rail (up to 6V) is typical. The value must be chosen considering VOL (0.4V max at 2mA), capacitive load, and required rise time-TI recommends 10kΩ–1MΩ depending on system speed and noise immunity needs.