Texas Instruments LP3875EMPX-ADJ/NOPB

Overview

LP3875EMPX-ADJ/NOPB from Texas Instruments is an adjustable ultra-low-dropout linear regulator (LDO) designed for high-current, low-voltage microprocessor and DSP power supplies. It delivers up to 1.5 A DC output current with dropout voltage as low as 38 mV at 150 mA and 380 mV at full load, operates from 2.5 V to 7 V input, and features 10 nA shutdown quiescent current - enabling battery-powered always-on systems.

For engineers reviewing the LP3875EMPX-ADJ/NOPB datasheet, LP3875EMPX-ADJ/NOPB pinout, LP3875EMPX-ADJ/NOPB application, or LP3875EMPX-ADJ/NOPB equivalent, key selection criteria include verified dropout performance at 1.5-A load, confirmed ADJ-pin-based output programming (1.216 V reference), thermal derating behavior in SOT-223-5 package, and validated short-circuit/overtemperature protection per TI SNVS247E.

Technical Context

The LP3875EMPX-ADJ/NOPB uses a CMOS-based PMOS pass element architecture, enabling load-independent quiescent current and ultra-low dropout operation. Its internal reference voltage is tightly regulated at 1.216 V (±1.5% over temperature), and output voltage is set externally via resistor divider (R1/R2) connected to the ADJ pin.

It integrates active shutdown control (SD pin), short-circuit protection with peak-current limiting (~3.2 A), and thermal shutdown. Ground pin current remains stable at ~6 mA under 1.5-A load, and PSRR reaches 73 dB at 120 Hz with 10 µF COUT - critical for noise-sensitive analog/digital mixed-signal rails.

Key Specifications

Pinout & Package

LP3875EMPX-ADJ/NOPB is packaged in a 5-pin SOT-223 (NDC) with exposed thermal pad electrically connected to GND. The package measures 6.50 mm × 3.56 mm and is optimized for surface-mount assembly and thermal conduction through PCB copper.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS7A4700RGWR and MCP1826T-ADJ/DC, LP3875EMPX-ADJ/NOPB uniquely balances 1.5-A capability, 380-mV dropout, and integrated protection in a thermally efficient SOT-223 - making it optimal for compact, high-reliability embedded power rails where both current and thermal headroom are constrained.

Availability

LP3875EMPX-ADJ/NOPB is available at Aetrix Electronics and suitable for microprocessor core supplies, GTL/SSTL bus terminators, DSP power management, battery-powered instrumentation, and other applications requiring stable component supply with guaranteed long-term manufacturability.

Supply support for LP3875EMPX-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 leader specializing in analog, embedded processing, and power management ICs, with decades of expertise in high-reliability power solutions.

The LP3875 series belongs to TI's ultra-low-dropout LDO portfolio, engineered specifically for high-current, low-voltage digital systems - including microprocessors, FPGAs, and memory interfaces - where minimal voltage overhead and fast transient response are essential.

FAQ

What is the minimum input voltage required for LP3875EMPX-ADJ/NOPB to regulate a 1.8-V output?

The minimum input voltage is determined by dropout: VIN(MIN) = VOUT + VDROPOUT. For 1.8 V output at 1.5 A, LP3875EMPX-ADJ/NOPB requires ≥2.18 V input (1.8 V + 380 mV). However, the absolute minimum specified VIN is 2.5 V per datasheet - so 2.5 V is the guaranteed operational floor regardless of load. This ensures margin for line regulation and thermal variation.

Can LP3875EMPX-ADJ/NOPB be used without the feed-forward capacitor (CFF)?

No - CFF is required for loop stability across the full 1.5-A load range. The datasheet mandates CFF placement between ADJ and OUT pins to add phase lead; omitting it risks oscillation, especially with low-ESR ceramic output capacitors. Typical CFF value is calculated from R1 to place a zero at ~45 kHz (e.g., 100 pF with 71.5 kΩ R1). LP3875EMPX-ADJ/NOPB will not meet stability specifications without CFF.

Does LP3875EMPX-ADJ/NOPB support reverse current protection?

LP3875EMPX-ADJ/NOPB contains an inherent body diode in its PMOS pass transistor. When VOUT exceeds VIN, this diode becomes forward-biased and allows reverse current up to 200 mA DC or 1 A peak. It does not block reverse current - external reverse-polarity protection (e.g., ideal diode controller or Schottky) is required if backfeeding must be prevented. This behavior is explicitly documented in the "Reverse Current Path" section of the LP3875EMPX-ADJ/NOPB datasheet.

What is the maximum allowable junction temperature for continuous operation of LP3875EMPX-ADJ/NOPB?

The absolute maximum junction temperature for LP3875EMPX-ADJ/NOPB is +125°C, and the device enters thermal shutdown if exceeded. For reliable continuous operation at 1.5 A, junction temperature must stay below this limit - requiring proper PCB copper area (≥250 mm² thermal pad), ambient temperature control, and derating per θJA = 65.2°C/W. At 85°C ambient, max power dissipation before thermal limit is ~0.54 W (40°C rise ÷ 65.2°C/W), constraining usable VIN–VOUT differential.

How does the ADJ pin bias current affect output voltage accuracy in LP3875EMPX-ADJ/NOPB designs?

LP3875EMPX-ADJ/NOPB ADJ pin bias current is typically 10 nA (max 100 nA over temperature), flowing into the feedback node. When R1 > 100 kΩ, this current introduces measurable error: e.g., with R1 = 200 kΩ and R2 = 100 kΩ, 10 nA creates ~2 mV offset at ADJ, causing ~0.6% VOUT error. To minimize impact, keep R2 ≤ 100 kΩ and use 1% metal-film resistors - LP3875EMPX-ADJ/NOPB output accuracy is dominated by resistor tolerance and reference drift, not ADJ current, when properly designed.