Texas Instruments LP3871ES-3.3/NOPB

Overview

LP3871ES-3.3/NOPB from Texas Instruments is a 0.8-A ultra-low-dropout linear regulator in SOT-223 package, delivering fixed 3.3 V output with ±1.5% accuracy at room temperature, 240 mV dropout at full load, and 10 nA shutdown quiescent current. It serves as a primary power supply for microprocessors and DSPs where tight regulation, fast transient response, and low-noise operation are critical.

For engineers reviewing the LP3871ES-3.3/NOPB datasheet, LP3871ES-3.3/NOPB pinout, LP3871ES-3.3/NOPB application, or LP3871ES-3.3/NOPB equivalent, key selection criteria include dropout voltage under 0.8-A load, ERROR flag behavior at 10% output deviation, ground current vs. load, thermal performance in SOT-223, and compatibility with 10-µF tantalum output capacitors.

Technical Context

The LP3871ES-3.3/NOPB uses a CMOS-based PMOS pass element enabling ultra-low dropout (24 mV typical at 80 mA) and load-independent quiescent current. Its internal error amplifier drives the pass transistor with high loop gain to achieve 0.04% load regulation and 0.02% line regulation.

It integrates an open-drain ERROR flag that asserts low when output falls ≥10% below nominal, with built-in hysteresis (5% typ), and a dedicated shutdown input requiring active pull-up. Unlike the LP3874 variant, it lacks a SENSE pin and regulates voltage only at the OUT pin.

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 moderate-power linear regulation without heatsink in ambient ≤60°C.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LP3871ES-3.3/NOPB, TSS721AIDR and TPS7A2033PDBVR offer smaller packages and lower cost but sacrifice output current headroom, integrated fault signaling, and ultra-low dropout performance-making them unsuitable for demanding microprocessor or DSP supply roles where LP3871ES-3.3/NOPB's 0.8-A capability and ERROR flag provide essential system-level reliability.

Availability

LP3871ES-3.3/NOPB is available at Aetrix Electronics and suitable for microprocessor power supplies, GTL bus terminators, and battery-powered instrumentation requiring stable component supply, long-term lifecycle assurance, and traceable sourcing.

Supply support for LP3871ES-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 designing analog ICs, embedded processors, and connectivity solutions for industrial, automotive, and communications markets.

The LP387x series was developed to address demand for high-current, ultra-low-dropout LDOs in battery-sensitive and thermally constrained applications-emphasizing fast transient response, precision output, and integrated protection features.

FAQ

What is the minimum input voltage required for LP3871ES-3.3/NOPB to regulate 3.3 V output?

The minimum input voltage is the greater of [3.3 V + dropout voltage] or 2.5 V. At 0.8 A load, dropout is 240 mV, so minimum VIN is 3.54 V. At light loads (80 mA), dropout drops to 24 mV, allowing regulation from 3.324 V. The absolute minimum specified input is 2.5 V, but operation below 3.324 V at full load will cause dropout and output collapse. LP3871ES-3.3/NOPB must be operated within these boundaries to maintain regulation.

Does LP3871ES-3.3/NOPB require an external SENSE connection like the LP3874?

No. LP3871ES-3.3/NOPB does not have a SENSE pin and regulates voltage solely at the OUT pin. Remote load regulation requires careful PCB layout to minimize trace resistance between OUT and the load. In contrast, the LP3874 variant includes a dedicated SENSE pin for feedback at the load point. LP3871ES-3.3/NOPB's pinout and functionality are fixed per its SOT-223 package configuration and do not support remote sensing.

How does the ERROR flag on LP3871ES-3.3/NOPB behave during shutdown?

The ERROR flag is disabled and invalid during shutdown mode. When the SD pin is pulled low, the internal ERROR comparator is powered down to conserve current, and the ERROR pin enters high-impedance state. It only becomes active when SD is high and the device is in normal operation. Therefore, LP3871ES-3.3/NOPB cannot report output faults while in shutdown - system-level monitoring must occur before entering low-power state. This behavior is explicitly documented in the device functional modes section of the datasheet.

What output capacitor types are recommended for stable operation of LP3871ES-3.3/NOPB?

Tantalum capacitors are recommended for the output due to their stable ESR (100 mΩ to 4 Ω) across temperature, which ensures loop stability. Ceramic capacitors may be used if X7R/X5R dielectric is selected and ESR remains within the stable region shown in Figure 13 of the datasheet; Z5U/Y5V ceramics are unsuitable due to severe capacitance loss with voltage and temperature. Aluminum electrolytics are discouraged unless impedance is specified at ≥20 kHz and ESR derating for cold temperatures is validated. LP3871ES-3.3/NOPB requires ≥10 µF at the OUT pin with proper ESR for guaranteed stability.

Can LP3871ES-3.3/NOPB be used in automotive applications?

LP3871ES-3.3/NOPB is rated for −40°C to +125°C junction temperature and includes overtemperature and overcurrent protection, making it suitable for under-hood and infotainment applications meeting AEC-Q100 stress test requirements - however, it is not officially AEC-Q100 qualified. For automotive-grade deployment, designers must perform full qualification per vehicle manufacturer specifications. LP3871ES-3.3/NOPB's thermal metrics (RθJA = 65.2°C/W in SOT-223) and robust protection features support reliable operation in harsh environments when properly heatsinked.