Texas Instruments TPS3820-33DBVR

Overview

TPS3820-33DBVR from Texas Instruments is a 3.3V fixed-threshold voltage supervisor IC with integrated watchdog timer, active-low push-pull reset output, manual reset input, and 25ms reset delay. It monitors VDD supply rails in microcontroller-based systems, asserts RESET below 2.86–3.00V threshold, and triggers system reset if WDI signal stalls beyond timeout. Used in portable equipment and industrial controllers requiring reliable power-on initialization and fault recovery.

For engineers reviewing the TPS3820-33DBVR datasheet, TPS3820-33DBVR pinout, TPS3820-33DBVR application, or TPS3820-33DBVR equivalent, key selection criteria include its 25ms delay (vs. 200ms in other TPS382x variants), 3.3V supervision accuracy, watchdog timeout behavior, SOT-23-5 package constraints, and compatibility with 1.1–5.5V operating range.

Technical Context

The TPS3820-33DBVR implements a fixed-threshold supervision architecture with internal voltage divider setting V_IT− = 2.93V (nominal) and 50mV hysteresis. Its watchdog timer requires periodic falling-edge transitions on WDI to prevent reset assertion, with timeout of 112–300ms. The device initiates power-on reset when VDD exceeds 1.1V and holds RESET low until VDD rises above V_IT− + V_HYS, then enforces 25ms delay before releasing RESET.

It features a dedicated manual reset (MR) input that forces active-low RESET regardless of VDD level or watchdog state, and uses push-pull output stage capable of sinking 3mA at 0.4V. No external components are required for basic operation, and internal pullup on MR simplifies interface design.

Key Specifications

Pinout & Package

TPS3820-33DBVR is housed in a 5-pin SOT-23 (DBV) package measuring 2.90mm × 1.60mm, optimized for space-constrained PCB layouts.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS3823-33DBVR, TPS3820-33DBVR reduces reset delay by 87.5%, accelerating system readiness; versus TPS3820-50DBVR, it shifts threshold to match 3.3V I/O domains, avoiding false resets during nominal operation.

Availability

TPS3820-33DBVR is available at Aetrix Electronics and suitable for industrial programmable controls, portable battery-powered equipment, and wireless communications systems requiring stable component supply and long-term production continuity.

Supply support for TPS3820-33DBVR 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 specializing in analog and embedded processing technologies, with leadership in power management, signal chain, and microcontroller solutions.

The TPS382x product line delivers compact, low-power voltage supervisors for processor-based systems, designed specifically to ensure robust power-on reset, supply rail monitoring, and watchdog-based fault recovery in space- and energy-constrained applications.

FAQ

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

The TPS3820-33DBVR has a negative-going input threshold voltage (V_IT−) ranging from 2.86V to 3.00V over −40°C to 85°C, with nominal value of 2.93V. This fixed threshold is set by an internal voltage divider and requires no external components. Hysteresis is 50mV, ensuring noise immunity during voltage transitions. The TPS3820-33DBVR does not support adjustable thresholds.

Does TPS3820-33DBVR support active-high reset output?

No, TPS3820-33DBVR provides only an active-low push-pull RESET output. Devices with dual active-high/active-low outputs (RESET and RESET) are TPS3824 and TPS3825 variants. The TPS3820-33DBVR pinout and functional block diagram confirm single RESET output on Pin 1, configured as active-low. External inversion would be required for active-high signaling.

How does the watchdog timer in TPS3820-33DBVR operate?

The TPS3820-33DBVR watchdog timer requires periodic falling-edge transitions on the WDI pin to prevent reset assertion. If WDI remains static (high or low) longer than the timeout window (112–300ms), RESET activates for the full 15–37ms delay period. Floating WDI generates internal pulses to avoid spurious timeouts. The timer resets upon any falling edge or when RESET is asserted.

Can TPS3820-33DBVR monitor supply voltages below 3.3V?

Yes, TPS3820-33DBVR operates from 1.1V to 5.5V supply range, but its supervision threshold is fixed at ~2.93V. It will assert RESET whenever VDD falls below this threshold, regardless of nominal rail voltage. For accurate monitoring of 2.5V or lower rails, use TPS3820-25DBVR (2.25V threshold) or TPS3820-30DBVR (2.63V threshold), which share identical timing and feature sets.

What is the function of the MR pin on TPS3820-33DBVR?

The MR (manual reset) pin on TPS3820-33DBVR is an active-low input that forces RESET assertion regardless of VDD level or watchdog status. Pulling MR low immediately triggers reset, and RESET remains low for the full 15–37ms delay after MR returns high. MR has an internal 90kΩ pullup resistor, so it may be left unconnected or tied to VDD when unused.