Texas Instruments TPS3813I50DBVR

Overview

TPS3813I50DBVR from Texas Instruments is a window-watchdog supervisory IC for microcontroller and DSP systems, featuring a fixed 4.55V 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 is used in safety-critical embedded systems requiring dual-voltage monitoring and time-bound software execution validation.

For engineers reviewing the TPS3813I50DBVR datasheet, TPS3813I50DBVR pinout, TPS3813I50DBVR application, or TPS3813I50DBVR equivalent, key selection criteria include its precise 4.55V VIT tolerance (±0.1V), configurable watchdog window (e.g., 1:64.5 ratio with external capacitor), SOT-23-6 package footprint, glitch-immune VDD sensing (3µs minimum pulse width), and compatibility with 2V–6V supply rails.

Technical Context

The TPS3813I50DBVR integrates a precision voltage supervisor and a user-programmable window-watchdog timer in a single 6-pin SOT-23 device. Its internal bandgap reference sets a fixed 4.55V threshold (VIT) with 60mV hysteresis, and it asserts RESET when VDD falls below VIT or when WDI pulses miss the programmed time window.

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

Key Specifications

Pinout & Package

TPS3813I50DBVR is housed in a 6-pin SOT-23 package (2.90mm × 1.60mm body size) with gull-wing leads, 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 TPS3813K33DBVR and MAX6326UT46D3+T, the TPS3813I50DBVR uniquely delivers 4.55V precision supervision *plus* configurable window-watchdog functionality in a drop-in 6-pin SOT-23 package-enabling both voltage integrity and deterministic software execution validation without layout changes.

Availability

TPS3813I50DBVR is available at Aetrix Electronics and suitable for industrial HVAC controllers, medical infusion pumps, revenue-grade electricity meters, and 5G mMIMO active antenna systems requiring stable component supply, long-lifecycle support, and guaranteed traceable sourcing.

Supply support for TPS3813I50DBVR 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 and embedded processing technologies, with decades of expertise in power management, signal chain, and real-time control ICs.

The TPS3813xxx family was designed specifically for safety-critical embedded systems needing simultaneous voltage supervision and programmable window-watchdog functionality-targeting medical, industrial, and communications infrastructure applications.

FAQ

What is the exact VIT threshold voltage for TPS3813I50DBVR, and how tightly is it specified?

The TPS3813I50DBVR has a nominal VIT threshold of 4.55V, with a guaranteed range of 4.45V to 4.65V over –40°C to +85°C. This 60mV hysteresis ensures clean, bounce-free reset assertion and release, and the value is laser-trimmed at wafer test-no external calibration is needed. The 4.55V point aligns precisely with 5V supply rails subject to ±5% tolerance, making TPS3813I50DBVR ideal for legacy and modern 5V systems.

How does the window-watchdog function in TPS3813I50DBVR differ from a standard watchdog timer?

Unlike a standard watchdog that triggers reset only on timeout (no pulse), the TPS3813I50DBVR implements a true window-watchdog: the supervised processor must assert WDI *within a defined time window*, not just before expiration. For example, with WDR = VDD and WDT = capacitor, the window is ~39ms–2.5s-pulses arriving too early or too late both cause RESET. This detects both software hangs *and* timing skew, significantly improving fault coverage in safety-critical TPS3813I50DBVR deployments.

Can TPS3813I50DBVR's RESET output interface directly with a 3.3V microcontroller?

Yes. The TPS3813I50DBVR features an open-drain RESET output rated for up to 6V, allowing use of a 3.3V pull-up resistor. When RESET is inactive (high-impedance), the microcontroller's 3.3V rail pulls the line high; when asserted, TPS3813I50DBVR sinks current to ground, pulling the line below 0.4V (guaranteed VOL at 500µA). No level shifter is required-this interoperability simplifies mixed-voltage designs while maintaining noise immunity.

What is the minimum external capacitor value usable with TPS3813I50DBVR's WDT pin, and why does it matter?

The minimum valid capacitor for the WDT pin is 155pF, per TI's electrical specifications. Using smaller values risks violating the internal oscillator's timing model, causing unpredictable watchdog window sizing or failure to initialize. Capacitors below 155pF may also exhibit excessive leakage (>5nA) or parasitic effects that degrade timing accuracy. Always select X7R or C0G dielectrics with tight tolerance (±5%) and low ESR to ensure repeatable TPS3813I50DBVR window behavior across temperature and life.

Does TPS3813I50DBVR require external components for basic operation, and what is mandatory?

TPS3813I50DBVR requires no external components for core voltage supervision and fixed-delay reset-only VDD, GND, and RESET pull-up are essential. However, a 0.1µF ceramic bypass capacitor at VDD is strongly recommended to stabilize the internal reference and suppress supply noise. For window-watchdog operation, WDR and WDT must be tied to defined logic levels (VDD or GND) or connected to a valid capacitor; leaving either floating will cause undefined or immediate RESET assertion. These connections are mandatory for functional TPS3813I50DBVR deployment.