Texas Instruments LP3873ES-5.0/NOPB

Overview

LP3873ES-5.0/NOPB from Texas Instruments is a 3A ultra-low-dropout linear regulator with fixed 5.0V output, 800mV dropout at 3A, ±1.5% output voltage accuracy, and 1µA shutdown quiescent current - designed for microprocessor core and I/O power supplies where tight regulation and fast transient response are critical.

For engineers reviewing the LP3873ES-5.0/NOPB datasheet, LP3873ES-5.0/NOPB pinout, LP3873ES-5.0/NOPB application, or LP3873ES-5.0/NOPB equivalent, this page delivers verified pin functions, real load-regulation behavior (0.08%), error flag timing, thermal protection limits, and validated alternatives for high-current low-noise LDO selection.

Technical Context

The LP3873ES-5.0/NOPB uses a CMOS-based PMOS pass element enabling ultra-low dropout and load-independent quiescent current. Its internal error amplifier drives the pass transistor with high gain and bandwidth to achieve <25µs turn-on delay and stable operation with ≥10µF output capacitance.

It integrates overtemperature and overcurrent protection, an open-drain ERROR flag that asserts low when VOUT drops >10% below nominal, and a dedicated SD pin requiring active pull-up. Unlike the LP3876 variant, it lacks a SENSE pin and regulates at the VOUT pin only.

Key Specifications

Pinout & Package

LP3873ES-5.0/NOPB is packaged in a 5-pin DDPAK/TO-263 surface-mount package with exposed thermal pad (KTT0005B), optimized for high-power dissipation on PCB copper planes.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 3A fixed-output LDO applications.

Compared with TPS75733KTTT and LT1963AES-5.0, LP3873ES-5.0/NOPB uniquely delivers 5.0V/3A with ultra-low dropout (800mV) in a thermally robust DDPAK package - making it the only option among the three capable of sustaining full 3A load in compact industrial enclosures without forced airflow.

Availability

LP3873ES-5.0/NOPB is available at Aetrix Electronics and suitable for microprocessor power supplies, GTL+ bus terminators, DSP power rails, SCSI-2 termination, and high-efficiency linear regulator designs requiring stable component supply across extended temperature ranges.

Supply support for LP3873ES-5.0/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 LDO design heritage and broad automotive/industrial qualification.

The LP3873 series belongs to TI's ultra-low-dropout linear regulator product line, engineered specifically for high-current, low-noise, and fast-transient applications in microprocessor, DSP, and bus-termination systems.

FAQ

What is the minimum input voltage required for LP3873ES-5.0/NOPB to regulate 5.0V output?

The minimum input voltage is the greater of [5.0V + dropout voltage] or 2.5V. At 3A load, dropout is 800mV, so minimum VIN = 5.8V. At light loads (<300mA), dropout drops to 80mV, allowing regulation from 5.08V. The absolute minimum specified VIN is 2.5V, but that only applies for outputs ≤2.5V - LP3873ES-5.0/NOPB requires ≥5.08V to maintain regulation. This value is confirmed in the Operating Ratings table of the SNVS220E datasheet.

Does LP3873ES-5.0/NOPB support remote sensing of the output voltage?

No. LP3873ES-5.0/NOPB does not include a SENSE pin; it regulates voltage solely at the VOUT pin. Remote load regulation requires the LP3876 variant (e.g., LP3876ES-5.0), which has a dedicated SENSE terminal. Attempting to route feedback from a remote point to LP3873ES-5.0/NOPB's VOUT pin will degrade load regulation due to trace IR drop - the device cannot compensate for it. This functional distinction is explicitly stated in the PIN DESCRIPTIONS and Block Diagram sections of the datasheet.

What is the maximum allowable junction temperature for LP3873ES-5.0/NOPB, and how is thermal protection implemented?

The maximum junction temperature is +125°C, with thermal shutdown engaging to cycle the output ON/OFF when this limit is exceeded. The device integrates a thermal sensor and protection loop that reduces average power dissipation by modulating duty cycle - not a hard latch-off. Recovery occurs automatically once junction temperature falls below the hysteresis threshold (~15°C below trip point). This behavior is documented in the SHORT-CIRCUIT PROTECTION and POWER DISSIPATION/HEATSINKING sections of SNVS220E.

Can LP3873ES-5.0/NOPB be used with aluminum electrolytic output capacitors?

Yes, but with strict qualification. Aluminum electrolytics must meet ESR requirements shown in Figure 22 (stable region), and their ESR must be verified at the lowest operating temperature (e.g., −40°C), where ESR can increase up to 50×. Only aluminum types specifying impedance at ≥20kHz should be used. TI recommends tantalum or ceramic capacitors for guaranteed stability. This guidance is detailed in the APPLICATION HINTS section under "CAPACITOR CHARACTERISTICS".

What happens to the ERROR pin during shutdown mode of LP3873ES-5.0/NOPB?

When the SD pin is pulled low to activate shutdown, the ERROR pin is forced invalid - its state becomes undefined and it does not reflect output voltage status. This is implemented to reduce leakage current during shutdown. The ERROR function resumes only after SD returns high and the regulator completes turn-on. This behavior is explicitly noted in the ERROR FLAG OPERATION section and Figure 23 timing diagram of the SNVS220E datasheet.