Texas Instruments LP3965ESX-1.8/NOPB

Overview

LP3965ESX-1.8/NOPB from Texas Instruments is a 1.5A ultra-low-dropout linear regulator with fixed 1.8V output, CMOS-based architecture, 380mV dropout at 1.5A, ±1.5% output voltage accuracy, and SOT-223-5 package. It delivers stable microprocessor core power in space-constrained embedded systems where low quiescent current and fast load transient response are critical.

For engineers reviewing the LP3965ESX-1.8/NOPB datasheet, LP3965ESX-1.8/NOPB pinout, LP3965ESX-1.8/NOPB application, or LP3965ESX-1.8/NOPB equivalent, key selection criteria include dropout performance at full load, remote-sense capability (not present in this fixed-output variant), thermal shutdown behavior, and compatibility with low-ESR tantalum output capacitors per TI's stability guidelines.

Technical Context

The LP3965ESX-1.8/NOPB uses a PMOS pass element with 240mΩ typical R_DS(on), enabling ultra-low dropout operation down to 38mV at 150mA and 380mV at 1.5A. Its CMOS control circuitry maintains 15µA shutdown current and 5mA ground pin current at full load - independent of output current - ensuring predictable thermal behavior across operating conditions.

This fixed-output variant lacks the SENSE/ADJ pin functionality found on adjustable LP3965 versions; its feedback network is internal and trimmed for 1.8V ±1.5% over −40°C to +125°C. It includes overtemperature (165°C shutdown) and short-circuit protection but omits the ERROR flag output present on LP3962 and LP3965-ADJ variants.

Key Specifications

Pinout & Package

SOT-223-5 surface-mount package with exposed thermal pad (pin 3 is VOUT; pin 5 is GND; pin 4 is not used as SENSE/ADJ in this fixed-output version and must be left unconnected or tied to VOUT per TI design guidance).

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPL7407LDR and TPS7A0518PDBVR, LP3965ESX-1.8/NOPB uniquely delivers 1.5A continuous current with full protection, industrial temp rating, and proven stability using standard tantalum capacitors - making it the only viable option for high-reliability 1.8V power delivery in demanding embedded systems.

Availability

LP3965ESX-1.8/NOPB is available at Aetrix Electronics and suitable for microprocessor core supplies, GTL/SSTL bus terminators, and post-regulators requiring stable component supply, long-term lifecycle support, and guaranteed traceability.

Supply support for LP3965ESX-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 company headquartered in Dallas, Texas, designing analog ICs, embedded processors, and wireless connectivity solutions for industrial, automotive, and consumer markets.

The LP3965 series belongs to TI's precision linear regulator product line, engineered specifically for high-current, low-noise, ultra-low-dropout applications in microprocessor, DSP, and memory interface power systems.

FAQ

What is the minimum input voltage required for LP3965ESX-1.8/NOPB to regulate at full 1.5A load?

The minimum input voltage is determined by dropout: 1.8V + 380mV = 2.18V. However, the absolute minimum operating VIN is specified as 2.5V per TI's operating ratings - so LP3965ESX-1.8/NOPB requires ≥2.5V input even though dropout allows lower. This ensures guaranteed performance across temperature and process variation. Always verify with LP3965ESX-1.8/NOPB's Electrical Characteristics table under "Operating Ratings".

Does LP3965ESX-1.8/NOPB include an error flag or power-good output?

No. LP3965ESX-1.8/NOPB does not feature an ERROR pin - that function is exclusive to the LP3962 and LP3965-ADJ variants. The LP3965ESX-1.8/NOPB is a fixed-output version with pins SD, VIN, VOUT, NC, and GND only. If fault monitoring is required, external supervision circuitry must be added. Confirm pin configuration in the LP3965ESX-1.8/NOPB SOT-223-5 pinout diagram.

Can LP3965ESX-1.8/NOPB be used with ceramic output capacitors?

No - LP3965ESX-1.8/NOPB requires an output capacitor with 0.2Ω to 5Ω ESR for loop stability, and standard ceramic capacitors fall far below 0.2Ω. Using them risks oscillation. TI explicitly recommends tantalum (e.g., 33µF, 1–2Ω ESR) or aluminum electrolytic (with verified high-frequency impedance). Ceramic may be added in parallel only if total equivalent ESR remains within spec - never as sole output cap. See LP3965ESX-1.8/NOPB Application Information section on "OUTPUT CAPACITOR".

Is the SENSE pin functional on LP3965ESX-1.8/NOPB?

No. Pin 4 on LP3965ESX-1.8/NOPB is not connected internally (NC) - the SENSE/ADJ functionality is disabled in fixed-output variants. TI's datasheet states that for non-adjustable versions like LP3965ESX-1.8/NOPB, the SENSE/ADJ pin must be left unconnected or tied to VOUT. Remote sensing is only available on LP3965-ADJ versions. Verify against LP3965ESX-1.8/NOPB's Pin Descriptions table.

What thermal derating applies to LP3965ESX-1.8/NOPB in SOT-223 package?

In SOT-223-5, LP3965ESX-1.8/NOPB has θ_JA = 90°C/W (with 0.5in², 1oz copper). At 1.5A and 2.5V input (0.7V drop), power dissipation is ~1.05W - causing ~95°C junction rise above ambient. Thus, max ambient must be ≤30°C for safe 125°C junction limit. Use PCB copper area or small heatsink to reduce θ_JA. Derating curves are in LP3965ESX-1.8/NOPB's Thermal Characteristics section.