Texas Instruments TPS3125J18DBVR

Overview

TPS3125J18DBVR from Texas Instruments is a 1.8V-supply-voltage supervisory IC with active-high push-pull RESET output, manual reset (MR) input, and 180ms fixed power-on reset delay. It monitors VDD down to 0.9V, asserts RESET when VDD falls below 1.62V (typical threshold), and operates across –40°C to +85°C - used in low-voltage DSP and microcontroller systems requiring reliable power sequencing and fault recovery.

For engineers reviewing the TPS3125J18DBVR datasheet, TPS3125J18DBVR pinout, TPS3125J18DBVR application, or TPS3125J18DBVR equivalent, this page delivers verified electrical parameters, SOT-23-5 terminal mapping, functional mode behavior, and validated alternative options for industrial and portable embedded designs.

Technical Context

The TPS3125J18DBVR implements a fixed-threshold voltage supervisor with internal hysteresis (20mV typical) and a dedicated MR input that forces RESET assertion independent of VDD level or watchdog state. Its active-high RESET output remains high during under-voltage conditions and deasserts after VDD exceeds VIT+ = VIT− + VHYS, with propagation delay tPLH ≤ 0.1µs from MR to RESET.

This device belongs to the TPS312x family optimized for ultra-low-voltage operation (0.9V minimum VDD), featuring no external components required for threshold setting and guaranteed RESET validity only above 0.9V. Unlike TPS3123/3124 variants, it excludes watchdog timer (WDI) functionality but retains manual reset capability and push-pull output drive.

Key Specifications

Pinout & Package

SOT-23-5 package (2.90mm × 1.60mm body size), surface-mount, RoHS-compliant, MSL Level-1.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS3125J18DBVR, TPS3125G15DBVR offers identical functionality at a different threshold voltage, while TPS3808G18DBVR trades MR and push-pull simplicity for adjustable delay and open-drain flexibility - making the former a drop-in replacement and the latter a design-alternative for timing-critical applications.

Availability

TPS3125J18DBVR is available at Aetrix Electronics and suitable for industrial PLC I/O modules, portable medical sensor hubs, factory automation gateways, smart building HVAC controllers, and battery-backed edge devices requiring stable component supply across extended production lifecycles.

Supply support for TPS3125J18DBVR 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 over 90 years of innovation in industrial, automotive, and communications markets.

The TPS312x product line delivers ultra-low-voltage supervisory circuits for DSP and microcontroller-based systems, emphasizing minimal external components, wide temperature operation, and robust reset timing control in space-constrained applications.

FAQ

What is the exact reset threshold voltage of the TPS3125J18DBVR?

The TPS3125J18DBVR has a negative-going input threshold voltage (VIT−) of 1.56V (min), 1.62V (typ), and 1.68V (max) over –40°C to +85°C. This 1.8V-nominal threshold is factory-trimmed and does not require external calibration - the TPS3125J18DBVR guarantees detection of supply droops below 1.56V while ignoring noise within the 20mV hysteresis band.

Does the TPS3125J18DBVR include a watchdog timer function?

No, the TPS3125J18DBVR does not include a watchdog timer. Per TI's device comparison table and functional block diagram, watchdog input (WDI) is present only on TPS3123/3124/3128 variants. The TPS3125J18DBVR retains manual reset (MR) and active-high push-pull RESET but omits WDI - confirmed by pin function table showing Pin 4 as NC and absence of WDI timing specifications in its datasheet section.

What is the purpose of Pin 4 on the TPS3125J18DBVR SOT-23-5 package?

Pin 4 on the TPS3125J18DBVR is a no-connect (NC) terminal. The device's functional pinout uses only Pins 1 (RESET), 2 (GND), 3 (MR), and 5 (VDD); Pin 4 has no internal connection. TI's pin configuration diagrams and package drawings explicitly label it as NC - it may be left floating or tied to GND for mechanical stability, but it carries no electrical function in the TPS3125J18DBVR.

Can the TPS3125J18DBVR operate from a 0.9V supply?

Yes, the TPS3125J18DBVR is specified to operate with VDD as low as 0.9V, and its supply current remains at 14µA (typ) at this voltage. However, RESET output is only valid above 0.9V - below this level, the internal circuitry cannot guarantee correct logic states. The TPS3125J18DBVR is designed for ultra-low-voltage supervision, enabling use in energy-harvesting and single-cell battery systems where rail collapse must be detected early.

Is the RESET output of the TPS3125J18DBVR push-pull or open-drain?

The TPS3125J18DBVR features an active-high push-pull RESET output, as confirmed by Table 4-1 (Reset Output Topologies) and Section 7.3.3 in the datasheet. Unlike TPS3126/3128 variants, it does not use open-drain architecture - meaning it actively drives both high and low states without requiring an external pull-up resistor. This simplifies interface design and improves rise/fall time performance in the TPS3125J18DBVR.