Texas Instruments TPS3125J18DBVTG4

Overview

TPS3125J18DBVTG4 from Texas Instruments is a precision ultra-low-voltage supervisor IC with 1.62 V nominal reset threshold (V_IT−), 180 ms fixed power-on reset delay, active-high push-pull RESET output, manual reset (MR) input, and operation down to 0.9 V supply. It monitors 1.8 V rails in battery-powered DSP and microcontroller systems where reliable power sequencing and fault recovery are critical.

For engineers reviewing the TPS3125J18DBVTG4 datasheet, TPS3125J18DBVTG4 pinout, TPS3125J18DBVTG4 application, or TPS3125J18DBVTG4 equivalent, key selection criteria include its guaranteed 1.56–1.68 V threshold tolerance over –40°C to +85°C, 14 µA typical supply current at 0.9 V, MR-triggered reset assertion, and SOT-23-5 package compatibility with space-constrained embedded designs.

Technical Context

The TPS3125J18DBVTG4 implements a fixed-threshold voltage supervision architecture with internal hysteresis (20 mV) to prevent false resets during supply transients. Its active-high RESET output remains asserted low until V_DD exceeds V_IT− + V_{HYS, then holds high for 180 ms before deassertion.}

This device integrates manual reset control via the MR pin-asserting RESET on logic-low input-and supports stable operation across 0.9 V to 3.3 V supply range. It lacks watchdog timer functionality (exclusive to TPS3123/3124/3128 variants) and uses a dedicated 5-pin SOT-23 package with GND, V_DD, MR, RESET, and NC terminals.

Key Specifications

Pinout & Package

TPS3125J18DBVTG4 is housed in a 5-pin SOT-23 (DBV) package measuring 2.90 mm × 1.60 mm, optimized for high-density PCB layouts and reflow-compatible assembly.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS3125J18DBVTG4, the TPS3125L30DBVR offers identical supervision architecture but targets higher-voltage rails, while the TPS3808G18DBVR trades fixed-threshold simplicity for adjustable thresholds and lower power at the cost of added components and package size.

Availability

TPS3125J18DBVTG4 is available at Aetrix Electronics and suitable for portable medical sensors, industrial PLC I/O modules, smart meter communication modules, and automotive body control units requiring stable component supply with guaranteed long-term availability.

Supply support for TPS3125J18DBVTG4 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, embedded processing, and connectivity solutions for industrial, automotive, and consumer applications.

The TPS312x family was designed specifically for ultra-low-voltage power-rail supervision in DSP and microcontroller-based systems, emphasizing minimal external components, wide supply range, and robust reset timing.

FAQ

What is the exact reset threshold voltage of the TPS3125J18DBVTG4?

The TPS3125J18DBVTG4 has a nominal reset threshold (V_IT−) of 1.62 V, with a guaranteed range of 1.56 V to 1.68 V across –40°C to +85°C. This value is factory-trimmed and does not require external calibration. The "J18" suffix explicitly denotes the 1.8 V nominal rail supervision variant, and the TPS3125J18DBVTG4 maintains this specification under all recommended operating conditions.

Does the TPS3125J18DBVTG4 include a watchdog timer function?

No, the TPS3125J18DBVTG4 does not include a watchdog timer. Watchdog functionality is exclusive to TPS3123, TPS3124, and TPS3128 variants per the official TI datasheet. The TPS3125J18DBVTG4 provides only voltage supervision and manual reset capability, making it suitable for applications where software hang detection is handled externally or not required.

What is the function of Pin 4 (NC) on the TPS3125J18DBVTG4?

Pin 4 on the TPS3125J18DBVTG4 is designated NC (No Connect) and has no internal connection. It must remain unconnected on the PCB - neither tied to ground, V_DD, nor any signal net. This is confirmed in TI's Pin Functions table (Table 5-1) and functional block diagram, where only Pins 1 (RESET), 2 (GND), 3 (MR), and 5 (V_DD) are electrically active in the TPS3125 variant.

Can the TPS3125J18DBVTG4 operate from a 0.9 V supply?

Yes, the TPS3125J18DBVTG4 is fully specified to operate with supply voltages as low as 0.9 V, with 14 µA typical supply current at that level. However, RESET output validity requires V_DD ≥ 0.9 V, and the device will not assert or deassert RESET reliably below this voltage. Its minimum operating voltage is a key differentiator for ultra-low-power applications where other supervisors fail to function.

Is the TPS3125J18DBVTG4 pin-compatible with other TPS312x devices in SOT-23-5?

The TPS3125J18DBVTG4 shares the same 5-pin SOT-23 (DBV) package and pinout as TPS3123/3124/3125/3126/3128 variants, including identical assignments for GND (Pin 2), MR (Pin 3), RESET (Pin 1), and V_DD (Pin 5). However, Pin 4 is NC for TPS3125/3126 but WDI for TPS3123/3124/3128 - so direct substitution requires verification that the WDI signal is unused or disconnected in the target design.