Texas Instruments LP38690DT-2.5

Overview

LP38690DT-2.5 from Texas Instruments is a 1-A, low-dropout CMOS linear regulator delivering a fixed 2.5 V output with ±2.5% accuracy at 25°C, 450 mV dropout at 1 A (VOUT = 5 V), and stable operation with only 1 µF ceramic output capacitance. It employs a PMOS pass transistor to maintain ground pin current below 100 µA across load, temperature, and input voltage - ideal for battery-powered instrumentation requiring ultra-low quiescent current and high thermal reliability.

For engineers reviewing the LP38690DT-2.5 datasheet, LP38690DT-2.5 pinout, LP38690DT-2.5 application, or LP38690DT-2.5 equivalent, this page delivers verified package mapping (TO-252-3), confirmed electrical specs (VIN = 2.7–10 V, IQ = 55 µA typ, TSD = 160°C), thermal metrics (RθJA = 50.5°C/W), and real-world design constraints including SNS pin exclusivity to WSON variants and absence of enable functionality in LP38690 variants.

Technical Context

The LP38690DT-2.5 uses a precision trimmed bandgap reference and PMOS pass element to achieve tight output tolerance and near-zero DC ground current dependency on load. Its architecture eliminates base-drive losses and enables stable regulation with ultra-low-ESR ceramic capacitors - no tantalum or electrolytic required.

It operates across –40°C to +125°C junction temperature with guaranteed specifications, incorporates foldback current limiting (1500 mA at VIN–VOUT < 4 V), and features thermal shutdown activation at 160°C with 10°C hysteresis - all without an enable pin, distinguishing it from the LP38692 family.

Key Specifications

Pinout & Package

LP38690DT-2.5 is supplied in a 3-pin TO-252 (DPAK) package with exposed thermal pad (DAP). The package measures 6.58 mm × 6.10 mm and provides low RθJA = 50.5°C/W when soldered to ≥1 in² copper pour - enabling full 1 A operation up to +85°C ambient.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar low-dropout linear regulator applications.

Compared with TSS721AIDR and TPS7A2025PDQNR, LP38690DT-2.5 uniquely combines 1 A output, –40°C to 125°C operation, integrated thermal shutdown, and TO-252 thermal robustness - making it the only viable choice for high-reliability, high-current, wide-temperature embedded power rails.

Availability

LP38690DT-2.5 is available at Aetrix Electronics and suitable for hard disk drives, notebook computers, battery-powered devices, portable instrumentation, and industrial control systems requiring stable component supply, long-lifecycle assurance, and traceable sourcing.

Supply support for LP38690DT-2.5 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 designing analog ICs, embedded processors, and connectivity solutions for industrial, automotive, and consumer markets - with over 50 years of power management innovation.

The LP38690 series belongs to TI's precision low-dropout linear regulator product line, engineered specifically for battery-powered and thermally constrained applications demanding high accuracy, ceramic-capacitor compatibility, and guaranteed operation across extreme temperatures.

FAQ

Does LP38690DT-2.5 include an enable (EN) pin?

No, LP38690DT-2.5 does not feature an enable pin. Unlike the LP38692 variant, the LP38690 family - including LP38690DT-2.5 - is always-on when input voltage is applied within specification (2.7–10 V). To implement ON/OFF control, external MOSFET switching on the input rail is required. This simplifies layout but removes dynamic power gating capability inherent in LP38692 designs.

What is the minimum input voltage required for LP38690DT-2.5 to regulate 2.5 V output?

LP38690DT-2.5 requires VIN ≥ (VOUT + VDO), where VDO is the dropout voltage. At 1 A load and 25°C, VDO is 800 mV (typical); thus, minimum VIN is 3.3 V. At higher temperatures or lower loads, VDO decreases - e.g., 145 mV at 0.1 A and 25°C - allowing regulation down to 2.645 V input. However, guaranteed operation begins at VIN = 2.7 V per recommended conditions.

Can LP38690DT-2.5 be used with a 1 µF ceramic output capacitor?

Yes, LP38690DT-2.5 is explicitly designed and tested for stability with a single 1 µF X7R or X5R ceramic capacitor on the output. This eliminates ESR requirements and allows smaller, more reliable, and longer-life decoupling vs. tantalum or aluminum electrolytic alternatives - a key differentiator confirmed in TI's SNVS322M datasheet Section 8.2.1.

Is the SNS (sense) pin available on LP38690DT-2.5?

No, the SNS pin is exclusive to WSON-package variants of LP38690 and LP38692. LP38690DT-2.5 uses the TO-252-3 package, which has only IN, OUT, and GND pins. Remote sensing is not supported; output voltage regulation is referenced internally to the OUT pin, so PCB trace resistance between regulator and load introduces direct error proportional to load current × trace resistance.

What thermal performance can be expected from LP38690DT-2.5 in a standard 2-layer PCB layout?

In a standard 2-layer PCB with 1 in² (6.45 cm²) 2-oz copper pour connected to the TO-252 exposed pad, LP38690DT-2.5 achieves RθJA = 50.5°C/W. At 1 A load with VIN = 5 V and VOUT = 2.5 V (PD = 2.5 W), junction temperature rise is ~126°C above ambient - meaning maximum ambient must be ≤ –1°C to stay within 125°C TJ limit. For reliable 1 A operation at +70°C ambient, ≥2 in² copper and/or airflow is recommended.