Texas Instruments LP3964EMPX-2.5/NOPB

Overview

LP3964EMPX-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 and 240 mV at 800 mA, ±1.5% output voltage accuracy, and remote sense (SENSE) capability for improved load regulation in distributed power systems.

For engineers reviewing the LP3964EMPX-2.5/NOPB datasheet, LP3964EMPX-2.5/NOPB pinout, LP3964EMPX-2.5/NOPB application, or LP3964EMPX-2.5/NOPB equivalent, key selection criteria include dropout performance under 800-mA load, thermal behavior in SOT-223, SENSE pin implementation for PCB layout, and compatibility with low-ESR output capacitors (0.2–5 Ω).

Technical Context

The LP3964EMPX-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. Its CMOS-based control architecture delivers 15 µA shutdown quiescent current independent of load, and supports fast transient response via internal compensation optimized for 33 µF minimum output capacitance.

Unlike the LP3961, this variant integrates a SENSE pin-not an ERROR flag-enabling remote voltage sensing at the load to compensate for IR drop across PCB traces. It operates within −40°C to 125°C junction temperature range and includes overtemperature shutdown (165°C threshold) and short-circuit protection (2.8 A peak limit).

Key Specifications

Pinout & Package

SOT-223 (5-pin) package: 6.50 mm × 3.56 mm body size, thermally enhanced with exposed pad (connected to GND), suitable for high-power-density layouts on 2-layer PCBs without heatsink.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPL7407LPGQ1 and TPS7A2025PDQNR, the LP3964EMPX-2.5/NOPB uniquely combines 800-mA capability, SENSE-based remote regulation, and ultra-low dropout in SOT-223 - making it the only viable option for high-current, precision point-of-load applications demanding ±1.5% accuracy at the load node.

Availability

LP3964EMPX-2.5/NOPB is available at Aetrix Electronics and suitable for microprocessor core supplies, GTL+/SSTL bus terminators, and DSP power rails requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.

Supply support for LP3964EMPX-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 specializing in analog and embedded processing technologies, with leadership in power management ICs for industrial, automotive, and communications markets.

The LP396x series was designed specifically for high-current, ultra-low-dropout applications in space-constrained systems - targeting microprocessor, DSP, and high-speed bus power delivery where traditional LDOs fail to meet dropout or regulation requirements.

FAQ

What is the minimum input voltage required for LP3964EMPX-2.5/NOPB to regulate 2.5 V output?

The LP3964EMPX-2.5/NOPB requires a minimum input voltage of 2.5 V + dropout voltage. At 800 mA load, dropout is 240 mV (typical), so VIN must be ≥2.74 V to maintain regulation. The datasheet specifies 2.5 V as absolute minimum survival voltage, but functional operation begins at VOUT + VDROPOUT - confirmed in Section 6.3 Recommended Operating Conditions.

Can LP3964EMPX-2.5/NOPB be used without connecting the SENSE pin?

Yes - the SENSE pin must be connected directly to the OUT pin if remote sensing is not required. This configuration configures the LP3964EMPX-2.5/NOPB for local regulation identical to standard LDO operation. Leaving SENSE floating is prohibited and may cause regulation instability or damage, per Section 8.1 Application Information.

What output capacitor ESR range is required for stable operation of LP3964EMPX-2.5/NOPB?

The LP3964EMPX-2.5/NOPB requires an output capacitor with ESR between 0.2 Ω and 5 Ω for loop stability, as specified in Section 8.2.2.1.2. Ceramic capacitors alone are unsuitable due to sub-10 mΩ ESR; solid tantalum (e.g., 33 µF, 1–2 Ω ESR) is recommended. Using a 100 µF tantalum with ~3 µF ceramic in parallel is acceptable if total ESR remains within range.

Does LP3964EMPX-2.5/NOPB include reverse current protection?

The LP3964EMPX-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 supply scenarios), reverse current flows - limited to 200 mA continuous or 1 A peak, per Absolute Maximum Ratings Table 6.1. External reverse-blocking circuitry is required for strict unidirectional operation.

How does the shutdown (SD) pin function on LP3964EMPX-2.5/NOPB?

The SD pin is an active-low CMOS input that disables the LP3964EMPX-2.5/NOPB when pulled below 0.2 V (max). It draws only 1 nA leakage current and must be pulled up to IN via 10-kΩ resistor for reliable operation. When SD is low, the device enters 15 µA shutdown mode, and the ERROR flag (not present on this variant) is disabled - verified in Sections 6.5 and 7.4.2.