Texas Instruments TPS3825-33DBVT

Overview

TPS3825-33DBVT from Texas Instruments is a 3.3V fixed-threshold voltage supervisor IC with active-low and active-high reset outputs, manual reset input (MR), watchdog timer input (WDI), 200ms reset delay, and 15μA typical supply current in a 5-pin SOT-23 package. It monitors microcontroller supply rails and ensures reliable power-on initialization and fault recovery in embedded systems.

For engineers reviewing the TPS3825-33DBVT datasheet, TPS3825-33DBVT pinout, TPS3825-33DBVT application, or TPS3825-33DBVT equivalent, key selection criteria include its dual-reset output logic, 2.93V nominal threshold with ±70mV hysteresis, −40°C to 85°C operation, push-pull drive capability, and watchdog timeout compatibility with 3.3V DSP/microcontroller reset sequencing.

Technical Context

The TPS3825-33DBVT integrates a precision voltage reference, comparator with hysteresis, 200ms internal reset delay timer, and independent watchdog timer logic that triggers on WDI edge transitions. Its dual-output architecture provides both active-low RESET and active-high RESET signals for flexible interface with host processors requiring either polarity.

It operates across 1.1V–5.5V supply range but is factory-trimmed for 3.3V supervision (V_IT− = 2.93V typ), with MR input enabling external system-initiated resets and WDI input supporting watchdog timeout of 1.6s (shared with TPS3823/TPS3824/TPS3828 variants). No external components are required for basic supervision.

Key Specifications

Pinout & Package

TPS3825-33DBVT uses a 5-pin SOT-23 (DBV) package with nominal body size 2.90 mm × 1.60 mm and standard lead pitch. Pin functions are validated per TI SLVS165O Rev. MARCH 2025.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS3825-33DBVT, TPS3823-33DBVT reduces feature set (single output, no MR) for lower cost, while TPS3824-33DBVT matches dual-output capability but removes MR-making TPS3825-33DBVT the only variant offering full feature integration (dual reset + MR + WDI) in SOT-23.

Availability

TPS3825-33DBVT is available at Aetrix Electronics and suitable for industrial automation, portable medical instrumentation, and notebook platform design requiring stable component supply, guaranteed long-term availability, and TI-qualified automotive-grade traceability.

Supply support for TPS3825-33DBVT 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 delivering analog and embedded processing solutions, with over 50 years of innovation in power management, signal chain, and real-time control ICs.

The TPS382x family was designed specifically for robust, low-power supply monitoring and watchdog supervision in DSP, microcontroller, and microprocessor-based systems-emphasizing accuracy, small footprint, and zero-external-component operation.

FAQ

What is the exact reset threshold voltage of the TPS3825-33DBVT?

The TPS3825-33DBVT has a nominal negative-going input threshold voltage (V_IT−) of 2.93 V, with a guaranteed range of 2.86 V to 3.00 V across −40°C to 85°C ambient temperature. This fixed threshold is factory-trimmed for 3.3V rail supervision and includes 50 mV hysteresis to prevent oscillation during slow or noisy supply transitions. The value is specified in Section 6.5 of the TI SLVS165O datasheet.

Does the TPS3825-33DBVT support both active-high and active-low reset outputs simultaneously?

Yes, the TPS3825-33DBVT provides two independent reset outputs: pin 1 (RESET) is active-low, and pin 4 (RESET) is active-high-both driven by push-pull stages. They toggle synchronously during power-on, brown-out, or watchdog timeout events. This dual-output capability eliminates the need for external inverters when interfacing with mixed-logic systems such as Intel PCH (active-high) and legacy MCUs (active-low).

What is the watchdog timeout period for the TPS3825-33DBVT, and how is it triggered?

The TPS3825-33DBVT features a watchdog timeout (t_tout) of 0.9 s to 2.5 s (typical 1.6 s), triggered by absence of qualifying edges on the WDI pin. A falling edge on WDI clears the timer; if no edge occurs within t_tout, RESET asserts for the full reset delay period (t_d). WDI must be actively driven-floating WDI causes internal pulsing to inhibit false timeouts, per Section 7.3.4 of the datasheet.

Can the TPS3825-33DBVT be used without connecting the MR pin?

Yes, the MR pin of the TPS3825-33DBVT has an internal 90 kΩ pull-up resistor to VDD, so it may be left unconnected for normal operation. When MR is pulled low (≤0.3×V_DD), it forces RESET assertion regardless of VDD level or watchdog status. Leaving MR open ensures automatic supervision only; connecting it enables external hardware reset buttons or system-level fault signaling.

What package type and thermal characteristics does the TPS3825-33DBVT have?

The TPS3825-33DBVT is packaged in a 5-pin SOT-23 (DBV) with nominal dimensions 2.90 mm × 1.60 mm. Its junction-to-ambient thermal resistance (R_θJA) is 185°C/W, junction-to-board (R_θJB) is 52.4°C/W, and it is rated for operation from −40°C to 85°C. These values are specified in Section 6.4 of the TI SLVS165O datasheet and support standard reflow assembly and compact PCB layouts.