Texas Instruments LP3966ESX-1.8/NOPB

Overview

LP3966ESX-1.8/NOPB from Texas Instruments is a 3A ultra-low-dropout linear regulator with fixed 1.8V output, designed for high-current microprocessor core supplies and post-regulation in noise-sensitive analog systems. It delivers ±1.5% output accuracy at room temperature, 800mV dropout at 3A load, and operates from 2.5V to 7.0V input. Its CMOS architecture enables 15µA shutdown current and supports remote sensing via SENSE pin for improved load regulation.

For engineers reviewing the LP3966ESX-1.8/NOPB datasheet, LP3966ESX-1.8/NOPB pinout, LP3966ESX-1.8/NOPB application, or LP3966ESX-1.8/NOPB equivalent, key selection criteria include dropout performance under 3A load, thermal behavior in DDPAK/TO-263 package, remote-sense capability for point-of-load accuracy, and compatibility with low-ESR tantalum output capacitors (0.2–5Ω).

Technical Context

The LP3966ESX-1.8/NOPB uses a PMOS pass element with 240mΩ typical R_DS(on), enabling ultra-low dropout operation independent of load current. Its internal CMOS biasing maintains stable quiescent current across output load conditions, unlike bipolar LDOs.

Unlike the LP3963, this variant features a SENSE/ADJ pin instead of ERROR, allowing remote voltage sensing at the load to compensate for PCB trace IR drop. It lacks error flag functionality but retains overtemperature and overcurrent protection with thermal shutdown at 165°C and hysteresis of 10°C.

Key Specifications

Pinout & Package

LP3966ESX-1.8/NOPB is packaged in DDPAK/TO-263-5 (surface-mount), thermally enhanced with exposed metal tab for heatsinking. The package supports >3A continuous current with appropriate PCB copper area (0.5in², 1oz).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 3A ultra-low-dropout linear regulator applications.

Compared with TPS75718 and LP3878MR-1.8, LP3966ESX-1.8/NOPB uniquely combines 3A capability, 800mV dropout, and remote sense functionality - making it the only option among the three qualified for high-current, point-of-load regulated 1.8V rails in dense embedded systems.

Availability

LP3966ESX-1.8/NOPB is available at Aetrix Electronics and suitable for microprocessor core supplies, GTL bus terminators, and battery-powered DSP systems requiring stable component supply, consistent parametric performance, and long-term industrial availability.

Supply support for LP3966ESX-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 regulation and thermal design.

The LP3966 series belongs to TI's ultra-low-dropout linear regulator product line, engineered specifically for high-current, low-voltage microprocessor and memory subsystems demanding precision, speed, and robust protection.

FAQ

What is the minimum input voltage required for LP3966ESX-1.8/NOPB to regulate 1.8V output?

The minimum input voltage is determined by dropout: at 3A load, LP3966ESX-1.8/NOPB requires VIN ≥ 2.6V (1.8V + 0.8V dropout). At lighter loads, dropout drops to 80mV (e.g., 1.88V min at 300mA). The absolute minimum operating VIN is 2.5V per datasheet, but actual regulation requires VIN ≥ VOUT + VDROPOUT under load.

Can LP3966ESX-1.8/NOPB be used without connecting the SENSE pin?

Yes - LP3966ESX-1.8/NOPB functions as a standard fixed-output LDO when the SENSE pin is tied directly to VOUT. This configuration disables remote sensing but preserves all other specifications including 1.8V output accuracy, 3A rating, and protection features.

What output capacitor types are compatible with LP3966ESX-1.8/NOPB?

LP3966ESX-1.8/NOPB requires an output capacitor with 0.2Ω–5Ω ESR and ≥33µF capacitance. Solid tantalum capacitors are recommended; aluminum electrolytics may be used if ESR stays within range across −40°C to +125°C. Standard ceramic capacitors alone are incompatible due to sub-0.2Ω ESR.

Does LP3966ESX-1.8/NOPB include thermal shutdown protection?

Yes - LP3966ESX-1.8/NOPB incorporates internal thermal shutdown that activates at 165°C junction temperature, with 10°C hysteresis. Once triggered, the device cycles on/off until temperature falls below 155°C, preventing permanent damage during sustained overload or inadequate heatsinking.

How does the shutdown pin (SD) behave in LP3966ESX-1.8/NOPB?

The SD pin is active-low and CMOS-compatible. Pulling SD ≤0.2V disables the regulator, reducing quiescent current to 15µA. A 10kΩ pull-up resistor to VIN is required unless driven by a rail-to-rail CMOS source. During shutdown, the ERROR function is inactive (not applicable to LP3966), and SENSE/VOUT remain unregulated.