Texas Instruments LP3964ESX-3.3/NOPB

Overview

LP3964ESX-3.3/NOPB from Texas Instruments is a fixed-output 3.3 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 precision regulation at distributed loads - used in microprocessor core supplies and GTL bus terminators.

For engineers reviewing the LP3964ESX-3.3/NOPB datasheet, LP3964ESX-3.3/NOPB pinout, LP3964ESX-3.3/NOPB application, or LP3964ESX-3.3/NOPB equivalent, key selection criteria include dropout performance under 800-mA load, SENSE pin implementation for remote load regulation, thermal derating in SOT-223, and compatibility with low-ESR tantalum output capacitors (0.2–5 Ω).

Technical Context

The LP3964ESX-3.3/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 internal CMOS architecture delivers load-independent quiescent current (15 µA in shutdown) and supports fast transient response critical for digital load steps.

Unlike the LP3961, this variant replaces the ERROR flag with a SENSE pin that enables closed-loop regulation at the remote load point - requiring direct connection of SENSE to the load return path to achieve ±0.02% load regulation. Shutdown control is active-low via the SD pin, with internal pullup not provided.

Key Specifications

Pinout & Package

SOT-223 (5-pin) package: 6.50 mm × 3.56 mm body, exposed thermal pad on bottom (pin 3), rated R_θJA = 65.2°C/W, requires PCB copper pour for thermal management.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TSS721AIPW and TPS7A4701RGWR, the LP3964ESX-3.3/NOPB uniquely combines SENSE-based remote regulation, sub-250 mV dropout at 800 mA, and 150 µV_RMS noise - making it optimal for high-current digital loads with distributed placement.

Availability

LP3964ESX-3.3/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 guaranteed traceability.

Supply support for LP3964ESX-3.3/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 technologies, with decades of LDO design heritage and automotive-grade reliability validation.

The LP396x series was engineered specifically for low-voltage, high-current digital systems - emphasizing ultra-low dropout, fast transient response, and remote-sense precision in cost-sensitive industrial and computing applications.

FAQ

What is the minimum input voltage required for LP3964ESX-3.3/NOPB to regulate 3.3 V at 800 mA?

The LP3964ESX-3.3/NOPB requires a minimum input voltage of 3.54 V (3.3 V + 240 mV dropout) to maintain regulation at 800 mA load. At lighter loads, the dropout drops to 24 mV, allowing operation from as low as 3.324 V. Input must remain ≥2.5 V per absolute ratings, but functional regulation begins at VOUT + VDROPOUT.

How should the SENSE pin be connected in LP3964ESX-3.3/NOPB for optimal remote load regulation?

For optimal remote load regulation, the SENSE pin of the LP3964ESX-3.3/NOPB must be connected directly to the load's ground return point - not to the regulator's GND pin. This closes the feedback loop at the load, compensating for voltage drop across PCB traces. If unused, SENSE must be tied to the OUT pin.

Does LP3964ESX-3.3/NOPB include reverse-current protection?

Yes, the LP3964ESX-3.3/NOPB contains an inherent parasitic body diode in its PMOS pass transistor. It blocks reverse current under normal operation but allows up to 200 mA continuous or 1 A peak if the output is forced above the input - a design consideration for hot-swap or backup-supply scenarios.

What output capacitor specifications are mandatory for stable operation of LP3964ESX-3.3/NOPB?

The LP3964ESX-3.3/NOPB requires a minimum 33 µF output capacitor with ESR between 0.2 Ω and 5 Ω. Tantalum capacitors are recommended due to stable ESR over temperature; ceramic capacitors alone are unstable unless paralleled with sufficient ESR. Total capacitance may exceed 33 µF without limit.

Can LP3964ESX-3.3/NOPB be used in automotive applications?

The LP3964ESX-3.3/NOPB is qualified for −40°C to 125°C junction temperature operation and includes overtemperature shutdown at 165°C - meeting extended temperature requirements for under-hood and infotainment modules. However, it is not AEC-Q200 qualified; automotive designs require additional system-level validation.