Texas Instruments LP3876ET-2.5/NOPB

Overview

LP3876ET-2.5/NOPB from Texas Instruments is a 3A ultra-low-dropout linear regulator with fixed 2.5V output, designed for high-current microprocessor and DSP power supplies. It delivers ±1.5% output voltage accuracy at room temperature, maintains regulation under 800mV dropout at 3A load, and features remote sense capability for improved load regulation in distributed power systems.

For engineers reviewing the LP3876ET-2.5/NOPB datasheet, LP3876ET-2.5/NOPB pinout, LP3876ET-2.5/NOPB application, or LP3876ET-2.5/NOPB equivalent, key selection considerations include dropout performance at full load, SENSE pin implementation for remote load accuracy, shutdown quiescent current (1µA), error flag hysteresis behavior, and thermal derating requirements for TO-263 packaging.

Technical Context

The LP3876ET-2.5/NOPB employs a CMOS-based PMOS pass transistor architecture enabling ultra-low dropout and load-independent quiescent current. Its internal error amplifier compares the SENSE pin voltage against a precision bandgap reference to maintain regulation, while the open-drain ERROR flag asserts low when output drops >10% below nominal.

Unlike the LP3873 variant, the LP3876ET-2.5/NOPB integrates a dedicated SENSE terminal (Pin 5) instead of an ERROR flag, enabling Kelvin sensing at the remote load to eliminate trace IR drop errors. Shutdown control (Pin 1) uses CMOS-level logic with <1nA input leakage and 25µs turn-on delay at 3A load.

Key Specifications

Pinout & Package

LP3876ET-2.5/NOPB is housed in a thermally enhanced DDPAK/TO-263 (KTT0005B) surface-mount package with exposed thermal pad for PCB heat sinking. The 5-pin configuration supports high-current routing and Kelvin sensing.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS75725KTTT and LT1963AES8-2.5#PBF, the LP3876ET-2.5/NOPB uniquely combines 3A output, SENSE capability, and TO-263 thermal performance-making it the only option among the three that guarantees ±1.5% regulation accuracy at the remote load point under full 3A conditions.

Availability

LP3876ET-2.5/NOPB is available at Aetrix Electronics and suitable for microprocessor core power, GTL+/SSTL bus termination, DSP power management, battery-powered instrumentation, and industrial embedded control systems requiring stable component supply across extended temperature ranges and multi-year production cycles.

Supply support for LP3876ET-2.5/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 regulation technology.

The LP3876 series was developed specifically for high-current, low-noise, ultra-low-dropout applications in microprocessor, DSP, and high-speed interface power domains-emphasizing thermal robustness, remote sensing, and wide-input flexibility.

FAQ

What is the minimum input voltage required for stable operation of the LP3876ET-2.5/NOPB?

The LP3876ET-2.5/NOPB requires a minimum input voltage equal to the sum of its nominal output voltage (2.5V) plus its dropout voltage under load. At 3A, dropout is 800mV, so minimum VIN is 3.3V. However, the absolute minimum specified operating input is 2.5V-meaning the device will regulate only if VIN ≥ VOUT + VDROPOUT. For guaranteed 2.5V output at full 3A, VIN must be ≥3.3V. The LP3876ET-2.5/NOPB datasheet specifies 2.5V to 7.0V as the valid input range, with actual regulation dependent on load and thermal conditions.

How should the SENSE pin be connected on the LP3876ET-2.5/NOPB in a typical layout?

The SENSE pin (Pin 5) of the LP3876ET-2.5/NOPB must be connected directly to the load-side terminal of the output capacitor-or, preferably, to the actual load point-to enable remote Kelvin sensing. This connection bypasses PCB trace resistance between the regulator's VOUT pin and the load, allowing the feedback loop to regulate voltage precisely at the load. If remote sensing is not needed, SENSE must be shorted to VOUT (Pin 4) at the regulator's output pad-not at the load. Never leave SENSE floating. The LP3876ET-2.5/NOPB will not function correctly unless SENSE is either properly routed to the load or tied directly to VOUT.

Does the LP3876ET-2.5/NOPB include built-in protection features, and how do they operate?

Yes, the LP3876ET-2.5/NOPB integrates overcurrent protection and thermal shutdown. Under short-circuit or overload conditions, the internal current limit circuit rapidly disables the PMOS pass element, cycling it on/off to limit average power dissipation. If junction temperature exceeds +125°C, thermal shutdown activates, halting output until temperature falls below the hysteresis threshold (~15°C below trip point). These protections are fully specified across −40°C to +125°C and require no external components. The LP3876ET-2.5/NOPB does not include reverse-voltage or reverse-current blocking beyond its inherent PMOS body diode limitation (200mA continuous).

Can the LP3876ET-2.5/NOPB be used with ceramic output capacitors, and what ESR requirements apply?

Yes, the LP3876ET-2.5/NOPB is stable with ceramic output capacitors-but only those meeting minimum capacitance (≥10µF) and maximum ESR constraints shown in Figure 22 of the datasheet. X7R or X5R dielectrics are strongly recommended due to stable capacitance vs. temperature/voltage. Z5U/Y5V ceramics are discouraged-they can lose >60% capacitance at rated voltage, risking instability. The LP3876ET-2.5/NOPB does not require a specific ESR; rather, it requires ESR within the "stable region" curve (typically <100mΩ for 10µF ceramics). Always verify stability with worst-case ESR and capacitance across temperature using bench testing.

What is the purpose of the shutdown (SD) pin on the LP3876ET-2.5/NOPB, and how should it be biased?

The SD pin (Pin 1) of the LP3876ET-2.5/NOPB provides logic-controlled enable/disable functionality. Pulling SD low (<0.3V) places the device in shutdown mode, reducing quiescent current to ≤1µA. To ensure reliable startup, SD must be pulled high to VIN via a 10kΩ resistor unless driven by a rail-to-rail CMOS output. Leaving SD unconnected risks undefined operation. When unused, TI recommends tying SD directly to VIN-not through a resistor-to guarantee default ON state. The LP3876ET-2.5/NOPB's SD input draws <1nA, making it compatible with low-power GPIOs.