Texas Instruments LP3875ES-ADJ/NOPB

Overview

LP3875ES-ADJ/NOPB from Texas Instruments is an adjustable ultra-low-dropout linear regulator (LDO) delivering up to 1.5 A DC output current with dropout as low as 38 mV at 150 mA and 380 mV at full load. It operates from 2.5 V to 7 V input, features 10 nA shutdown quiescent current, and supports precise output voltage programming via external resistors R1/R2 - ideal for microprocessor core supplies and post-regulation in space-constrained battery-powered systems.

For engineers reviewing the LP3875ES-ADJ/NOPB datasheet, LP3875ES-ADJ/NOPB pinout, LP3875ES-ADJ/NOPB application, or LP3875ES-ADJ/NOPB equivalent, key selection criteria include verified dropout performance at 1.5-A load, thermal resistance of 40.3°C/W (TO-263), adjustable output voltage range (≥1.216 V), shutdown threshold compatibility (0.3 V low, 2 V high), and confirmed stability with 10-µF tantalum or ceramic output capacitors.

Technical Context

The LP3875ES-ADJ/NOPB uses a CMOS-based PMOS pass element enabling ultra-low dropout and load-independent quiescent current. Its internal reference voltage is 1.216 V (±1.5% over temperature), and regulation relies on feedback through the ADJ pin with typical bias current of 10 nA.

It integrates short-circuit protection with 3.2-A peak current limit and thermal shutdown. Shutdown mode is controlled by a CMOS-compatible SD pin requiring active pull-up (10 kΩ recommended); turnon/turnoff delays are 25 µs and 20 µs respectively at 1.5-A load.

Key Specifications

Pinout & Package

LP3875ES-ADJ/NOPB is available in TO-263 (KTT) 5-pin package with exposed thermal tab electrically connected to GND. Package dimensions: 10.16 mm × 8.42 mm. Thermal resistance: R_θJA = 40.3°C/W (JEDEC High-K board).

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS7A8300RGRT and MCP1826T-ADJ/DC, LP3875ES-ADJ/NOPB offers the broadest input range (2.5 V), lowest shutdown current (10 nA), and proven stability with minimal 10-µF output capacitance - making it optimal for portable, battery-first, and thermally constrained applications where design simplicity and long shelf life are priorities.

Availability

LP3875ES-ADJ/NOPB is available at Aetrix Electronics and suitable for microprocessor core supplies, GTL+ bus terminators, and battery-powered medical sensors requiring stable component supply across extended production lifecycles.

Supply support for LP3875ES-ADJ/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 since the 1980s.

The LP3875ES-ADJ/NOPB belongs to TI's ultra-low-dropout LDO family designed specifically for high-current, low-voltage digital systems where efficiency, transient response, and shutdown leakage are critical - targeting portable computing, communications infrastructure, and precision instrumentation.

FAQ

What is the minimum input voltage required for LP3875ES-ADJ/NOPB to regulate a 1.8-V output?

The minimum input voltage is determined by dropout: VIN(MIN) = VOUT + VDROPOUT. At 1.5-A load, VDROPOUT = 380 mV, so VIN(MIN) = 1.8 V + 0.38 V = 2.18 V. However, the absolute minimum specified VIN is 2.5 V per datasheet - thus LP3875ES-ADJ/NOPB requires ≥2.5 V input regardless of output setting. This ensures guaranteed operation across temperature and process variation.

Can LP3875ES-ADJ/NOPB be used with ceramic output capacitors, and what ESR range is acceptable?

Yes, LP3875ES-ADJ/NOPB is stable with ceramic output capacitors. The datasheet specifies stable operation with ESR from 100 mΩ to 4 Ω. For X7R/X5R ceramics, typical ESR is <10 mΩ - well within the lower bound. Stability is maintained because the device's compensation is optimized for low-ESR types; no series resistor is needed. Use ≥10 µF, rated ≥6.3 V, with X7R dielectric for best temperature/voltage stability.

How does the ADJ pin function in LP3875ES-ADJ/NOPB, and what tolerance impact do external resistors have on output accuracy?

The ADJ pin senses the internal 1.216-V reference and forms a feedback divider with R1 and R2 to set VOUT = 1.216 × (1 + R1/R2). ADJ pin bias current is ≤100 nA over temperature, introducing negligible error if R1 ≤ 100 kΩ. Resistor tolerance dominates accuracy: using 1% R1 and R2 yields ~1.4% total output error (RSS sum), independent of LP3875ES-ADJ/NOPB's own reference tolerance (±1.5%).

Does LP3875ES-ADJ/NOPB require a feed-forward capacitor (CFF), and how is its value calculated?

Yes, CFF is required for optimal transient response and phase margin. Its value depends on R1: CFF = 1 / (2π × R1 × 45 kHz). For example, if R1 = 100 kΩ, CFF ≈ 35 pF. Use X5R/X7R ceramic with tight tolerance (±10%) and place it close to the ADJ and OUT pins. Omitting CFF may cause overshoot during load steps or instability with certain capacitor ESR values.

What thermal considerations apply when using LP3875ES-ADJ/NOPB in TO-263 package at 1.5-A load?

In TO-263 (KTT) package, R_θJA = 40.3°C/W on JEDEC High-K board. At 1.5-A load with 3.3-V output and 5-V input, power dissipation is (5 − 3.3) × 1.5 = 2.55 W. Junction rise = 2.55 × 40.3 ≈ 103°C. With 25°C ambient, TJ ≈ 128°C - exceeding 125°C max. Solution: increase copper area on GND pad, add thermal vias to inner layers, or reduce input voltage. Derate output current if ambient exceeds 40°C.