Texas Instruments LP3873ESX-1.8/NOPB

Overview

LP3873ESX-1.8/NOPB from Texas Instruments is a 3A ultra-low-dropout linear regulator optimized for microprocessor core and I/O power delivery, featuring 800 mV dropout at 3 A, ±1.5% output voltage accuracy at room temperature, and 1 µA shutdown quiescent current. It operates from 2.5 V to 7.0 V input and delivers a fixed 1.8 V output for low-voltage logic rails in embedded computing and DSP systems.

For engineers reviewing the LP3873ESX-1.8/NOPB datasheet, LP3873ESX-1.8/NOPB pinout, LP3873ESX-1.8/NOPB application, or LP3873ESX-1.8/NOPB equivalent, key selection criteria include dropout performance under full 3 A load, remote-sense capability (not supported on LP3873 variant), error flag behavior, thermal derating in TO-263 package, and minimum 10 µF output capacitance with ESR stability requirements.

Technical Context

The LP3873ESX-1.8/NOPB uses a CMOS-based PMOS pass transistor architecture enabling ultra-low dropout and load-independent quiescent current. Its control loop provides fast transient response-critical for microprocessor supply rails experiencing rapid load steps-and integrates overtemperature and overcurrent protection with automatic thermal foldback.

Unlike the LP3876 variant, the LP3873ESX-1.8/NOPB lacks a dedicated SENSE pin and regulates voltage at the VOUT pin only; it features an ERROR flag (open-drain) that asserts low when output drops >10% below nominal, with built-in hysteresis and 1 µs reset delay.

Key Specifications

Pinout & Package

LP3873ESX-1.8/NOPB is housed in a thermally enhanced 5-pin DDPAK/TO-263 surface-mount package (KTT0005B), with exposed thermal pad for PCB heat sinking. Pin 1 is SD (Shutdown), Pin 2 is VIN, Pin 3 is GND, Pin 4 is VOUT, and Pin 5 is ERROR (open-drain flag output). No SENSE pin is present-voltage regulation is referenced solely to the VOUT pin.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar LDO regulator applications.

Compared with TPS75718KC and TPS76718QPWPRQ1, the LP3873ESX-1.8/NOPB offers the lowest dropout (800 mV) and lowest ground current (6 mA at 3 A), making it optimal for thermally constrained industrial designs where input voltage margin is minimal and efficiency is prioritized over automotive qualification or ultra-high-frequency PSRR.

Availability

LP3873ESX-1.8/NOPB is available at Aetrix Electronics and suitable for microprocessor core supplies, GTL+ bus terminators, and DSP power management requiring stable component supply, long-term lifecycle support, and traceable sourcing for production programs.

Supply support for LP3873ESX-1.8/NOPB 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 ICs, with decades of expertise in high-reliability linear regulators and power delivery solutions.

The LP3873 series was designed specifically for high-current, low-voltage microprocessor and DSP applications demanding ultra-low dropout, fast transient response, and robust thermal protection in compact surface-mount packages.

FAQ

What is the minimum input voltage required for LP3873ESX-1.8/NOPB to maintain regulation at full 3 A load?

The LP3873ESX-1.8/NOPB requires a minimum input voltage of 2.6 V to sustain 1.8 V output regulation at 3 A, based on its typical 800 mV dropout voltage. At lower loads, dropout decreases-for example, 80 mV at 300 mA-allowing operation down to 1.88 V input. The absolute minimum input is 2.5 V per datasheet operating ratings, but actual dropout depends on junction temperature and load current.

Does LP3873ESX-1.8/NOPB support remote sensing like the LP3876 variant?

No, LP3873ESX-1.8/NOPB does not support remote sensing. It regulates voltage at the VOUT pin only. The LP3876 variant includes a dedicated SENSE pin for remote load regulation, while the LP3873ESX-1.8/NOPB lacks this pin and corresponding internal circuitry. For applications requiring remote-sense accuracy, LP3876-1.8/NOPB or equivalent must be selected instead of LP3873ESX-1.8/NOPB.

What output capacitor is required for stable operation of LP3873ESX-1.8/NOPB?

LP3873ESX-1.8/NOPB requires a minimum 10 µF output capacitor with ESR between 10 mΩ and 1 Ω for stable full-load operation. Ceramic (X7R/X5R), tantalum, or polymer capacitors meeting this ESR range are acceptable. Aluminum electrolytics are discouraged unless ESR is validated across −40°C to +125°C. The capacitor must be placed within 1 cm of the device and connected via Kelvin traces to VOUT and GND pins.

How does the ERROR pin on LP3873ESX-1.8/NOPB behave during shutdown?

During shutdown (SD pin pulled low), the ERROR pin on LP3873ESX-1.8/NOPB is forced invalid and ceases to reflect output status-this is intentional to minimize leakage current. The ERROR flag resumes normal operation only after SD is returned high and the regulator has fully powered up. External pull-up to VIN (via 10 kΩ–1 MΩ resistor) is mandatory for valid flag operation in active mode.

Can LP3873ESX-1.8/NOPB be used in battery-powered applications with long standby life?

Yes, LP3873ESX-1.8/NOPB is well-suited for battery-powered applications requiring long standby life: its shutdown quiescent current is just 1 µA typical, and ground pin current remains low (6 mA at 3 A) due to CMOS design. Combined with its ability to operate from as low as 2.5 V input, it extends runtime in single-cell Li-ion or multi-cell alkaline systems powering portable instrumentation or IoT edge nodes.