Texas Instruments LP3964EMP-2.5/NOPB

Overview

LP3964EMP-2.5/NOPB from Texas Instruments is a fixed-output 2.5 V, 800-mA ultra-low-dropout linear regulator in SOT-223 package, featuring 24 mV dropout at 80 mA, ±1.5% output voltage accuracy at 25°C, and remote-sense capability via SENSE pin for improved load regulation in distributed power systems.

For engineers reviewing the LP3964EMP-2.5/NOPB datasheet, LP3964EMP-2.5/NOPB pinout, LP3964EMP-2.5/NOPB application, or LP3964EMP-2.5/NOPB equivalent, key selection criteria include dropout performance under 800-mA load, thermal behavior in SOT-223 (R_θJA = 65.2°C/W), remote-sense implementation, shutdown control timing (25 µs turnon delay), and compatibility with low-ESR tantalum output capacitors (0.2–5 Ω).

Technical Context

The LP3964EMP-2.5/NOPB uses a PMOS pass element with 240 mΩ typical R_ds(on), enabling ultra-low dropout operation down to 24 mV at light load and 240 mV at full 800-mA load. Its internal error amplifier compares feedback from either the OUT pin (standard) or SENSE pin (remote sensing), allowing precise regulation at point-of-load.

It integrates overtemperature shutdown (165°C threshold, 10°C hysteresis), short-circuit protection (2.8-A peak limit), and CMOS-compatible shutdown control with 1-nA input leakage. The device operates across −40°C to 125°C junction temperature and supports input voltages from 2.5 V to 7 V - minimum VIN = V_OUT + 0.35 V for stable regulation.

Key Specifications

Pinout & Package

SOT-223 (5-pin, 6.50 mm × 3.56 mm) package with exposed thermal pad on bottom side for enhanced heat dissipation; requires PCB copper pour connected to GND for optimal thermal performance (R_θJB = 9.9°C/W).

Key Features

Applications

Equivalent & Alternatives

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

Compared with TSS721AIDR, LP3964EMP-2.5/NOPB delivers 60% more output current and enables remote sensing for precision loads; versus TPS7A4701RGWR, it offers smaller SOT-223 footprint and lower unit cost at the expense of adjustable features and power-good signaling.

Availability

LP3964EMP-2.5/NOPB is available at Aetrix Electronics and suitable for microprocessor core supplies, GTL/SSTL bus terminators, DSP I/O rails, and battery-powered sensor nodes requiring stable component supply with long-term manufacturability.

Supply support for LP3964EMP-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 company headquartered in Dallas, Texas, designing and manufacturing analog and embedded processing chips for industrial, automotive, and consumer applications.

The LP396x series was developed specifically for low-voltage, high-current linear regulation in space-constrained systems where ultra-low dropout, fast transient response, and remote sensing are required - targeting microprocessor, DSP, and high-speed digital interface power domains.

FAQ

What is the minimum input voltage required for LP3964EMP-2.5/NOPB to regulate 2.5 V output?

The LP3964EMP-2.5/NOPB requires a minimum input voltage of V_OUT + 0.35 V = 2.85 V under nominal conditions, per Section 7.4.1. At 800 mA load, the dropout voltage is 240 mV, so 2.74 V input would still maintain regulation within 2% tolerance. However, design margin dictates using ≥2.85 V to ensure stability across temperature and process variation.

Can LP3964EMP-2.5/NOPB operate without the SENSE pin connected?

Yes - the LP3964EMP-2.5/NOPB functions as a standard LDO when the SENSE pin is tied directly to the OUT pin, as specified in Section 8.1. This configuration provides local regulation only. Leaving SENSE floating is not allowed; it must be connected to OUT or to a remote load node to avoid instability or undefined regulation behavior.

What output capacitor types are compatible with LP3964EMP-2.5/NOPB?

The LP3964EMP-2.5/NOPB requires an output capacitor with 33 µF minimum capacitance and ESR between 0.2 Ω and 5 Ω, as defined in Section 8.2.2.1.2. Solid tantalum capacitors meet this requirement reliably; aluminum electrolytics may be used if ESR remains within bounds across −40°C to 125°C. Standard ceramic capacitors are incompatible due to sub-10 mΩ ESR causing instability.

Does LP3964EMP-2.5/NOPB include reverse current protection?

No - the LP3964EMP-2.5/NOPB contains an inherent parasitic body diode in its PMOS pass transistor. If the output voltage exceeds the input (e.g., during hot-swap or backup battery scenarios), reverse current flows through this diode. It is rated for 200 mA continuous and 1 A peak, per Section 7.3.5. External reverse-blocking circuitry is required for strict unidirectional operation.

How does the ERROR pin behave when the shutdown (SD) pin is asserted?

When the SD pin is pulled low, the ERROR pin is forced invalid (high-impedance state) to conserve power, as stated in Section 7.3.2. The ERROR flag only reports output undervoltage during active regulation. During shutdown, no flag assertion occurs - designers must monitor SD status separately to infer regulator state.