Texas Instruments TPS3820-33DBVRG4

Overview

TPS3820-33DBVRG4 from Texas Instruments is a 3.3V supply voltage supervisor IC with integrated watchdog timer, active-low push-pull reset output, manual reset input, and 25ms reset delay. It monitors VDD ≥ 1.1V power-up, asserts RESET low when VDD falls below 2.86–3.00V (V_IT−), and supports microcontroller reset sequencing in battery-powered systems.

For engineers reviewing the TPS3820-33DBVRG4 datasheet, TPS3820-33DBVRG4 pinout, TPS3820-33DBVRG4 application, or TPS3820-33DBVRG4 equivalent, key selection criteria include its 25ms delay (vs. 200ms in other TPS382x variants), 15μA typical supply current, 3.3V fixed threshold, SOT-23-5 package, and watchdog timeout of 200ms - all critical for low-power embedded reset integrity.

Technical Context

The TPS3820-33DBVRG4 implements a fixed-threshold supervision architecture using an internal resistor divider to set V_IT− = 2.93V (nominal) with 50mV hysteresis. Its watchdog timer triggers reset if WDI sees no falling edge within 112–300ms, and its MR pin forces reset independently of VDD level.

Reset assertion occurs at VDD ≥ 1.1V during power-up; thereafter, RESET remains low until VDD exceeds V_IT− + V_HYS, then holds low for 15–37ms (td) before releasing. The device requires no external components and operates across −40°C to 85°C.

Key Specifications

Pinout & Package

TPS3820-33DBVRG4 uses a 5-pin SOT-23 (DBV) package with nominal body size 2.90mm × 1.60mm and thermal resistance R_θJA = 185°C/W.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS3823-33DBVR, TPS3820-33DBVRG4 offers 8× faster reset release (25ms vs. 200ms), improving system responsiveness; compared with TPS3808G33DBVR, it adds watchdog supervision at the cost of higher quiescent current - making it optimal for firmware-critical embedded controllers.

Availability

TPS3820-33DBVRG4 is available at Aetrix Electronics and suitable for microcontroller power sequencing, battery-powered IoT node design, and industrial programmable logic controller development requiring stable component supply and long-term production continuity.

Supply support for TPS3820-33DBVRG4 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 company delivering analog and embedded processing solutions for industrial, automotive, and personal electronics markets.

The TPS382x product line delivers compact, low-power voltage supervisors with integrated watchdog timers and manual reset inputs, designed specifically for reliable power-on initialization and runtime fault detection in DSP and microcontroller-based systems.

FAQ

What is the exact reset threshold voltage range for TPS3820-33DBVRG4?

The TPS3820-33DBVRG4 has a negative-going input threshold voltage (V_IT−) of 2.86V (min), 2.93V (typ), and 3.00V (max) across −40°C to 85°C. This 3.3V-specific threshold ensures precise supervision of standard 3.3V logic rails with guaranteed 70mV margin above common LDO dropout voltages. The device uses an internal resistor divider, requiring no external calibration.

Does TPS3820-33DBVRG4 support watchdog functionality, and what is its timeout window?

Yes, TPS3820-33DBVRG4 includes a watchdog timer triggered by falling edges on the WDI pin. Its timeout window is 112ms (min), 200ms (typ), and 300ms (max). If WDI remains static beyond this interval, RESET asserts for the full 15–37ms delay period. The timer clears on each valid WDI transition, making it suitable for periodic firmware heartbeat monitoring.

How does the 25ms reset delay of TPS3820-33DBVRG4 differ from other TPS382x family members?

TPS3820-33DBVRG4 is the only member of the TPS382x family with a 25ms nominal reset delay; all others (TPS3823/4/5/8) use 200ms. This shorter delay enables faster system recovery in applications like portable instrumentation or real-time control loops where prolonged reset hold times degrade responsiveness or throughput.

Can TPS3820-33DBVRG4 operate with supply voltages below 3.3V?

Yes, TPS3820-33DBVRG4 operates from 1.1V to 5.5V and begins asserting RESET during power-up once VDD exceeds 1.1V. However, its 3.3V threshold (V_IT−) remains fixed - meaning it will not assert RESET due to undervoltage until VDD drops below ~2.86V. This allows robust operation across brown-out conditions while maintaining accurate 3.3V rail supervision.

What is the function of the MR pin on TPS3820-33DBVRG4, and does it require an external pull-up?

The MR (manual reset) pin on TPS3820-33DBVRG4 is an active-low asynchronous input that forces RESET low regardless of VDD level or watchdog state. It features an internal 90kΩ pull-up resistor, so no external component is needed when unused. Driving MR low (e.g., via pushbutton or GPIO) initiates immediate reset, and RESET remains low for the full 25ms delay after MR returns high.