Texas Instruments LP3874ESX-ADJ/NOPB

Overview

LP3874ESX-ADJ/NOPB from Texas Instruments is an adjustable ultra-low-dropout linear regulator IC designed for high-precision, low-noise power delivery in space-constrained applications. It delivers up to 0.8A DC output current with 24mV typical dropout at 80mA, 1.216V internal reference voltage, and 10nA shutdown quiescent current. It serves as a post-regulator or microprocessor core supply in systems requiring tight load regulation (0.04%) and stable operation from −40°C to +125°C.

For engineers reviewing the LP3874ESX-ADJ/NOPB datasheet, LP3874ESX-ADJ/NOPB pinout, LP3874ESX-ADJ/NOPB application, or LP3874ESX-ADJ/NOPB equivalent, key selection criteria include its DDPAK/TO-263-5 package thermal performance, adjustable output via external resistors, fast transient response, and compatibility with tantalum output capacitors for stability without feed-forward compensation in many designs.

Technical Context

The LP3874ESX-ADJ/NOPB uses a PMOS pass transistor architecture enabling ultra-low dropout operation independent of load current, supported by CMOS biasing that maintains low ground pin current (6mA typical at 0.8A). Its control loop is optimized for fast load-step response-under 50µs turn-on/turn-off delay-and integrates overtemperature and short-circuit protection with thermal foldback.

It operates from 2.5V to 7.0V input, supports adjustable output voltages ≥1.216V using two external resistors (VOUT = 1.216 × (1 + R1/R2)), and requires only 10µF minimum output capacitance with ESR ≤1Ω. The ADJ pin draws just 10nA, minimizing resistor-divider error, and the device achieves 73dB PSRR at 120Hz with 150µV_rms broadband output noise (10Hz–100kHz).

Key Specifications

Pinout & Package

LP3874ESX-ADJ/NOPB is packaged in DDPAK/TO-263-5 (Package Number NDH0005D), featuring an exposed thermal pad soldered to PCB copper for enhanced heat dissipation (θ_JA = 60°C/W with 0.5in² 1oz copper). The package supports surface-mount assembly and reflow per JEDEC Level-3 (245°C peak).

Key Features

Applications

Equivalent & Alternatives

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

Compared with TSS721AIDR and TPS7A4701RGWR, LP3874ESX-ADJ/NOPB uniquely balances 0.8A output, ultra-low dropout, and adjustable voltage in a thermally robust DDPAK package - making it the only option among the three capable of powering microprocessor cores or GTL+ bus terminators without external current boosting.

Availability

LP3874ESX-ADJ/NOPB is available at Aetrix Electronics and suitable for microprocessor core supplies, GTL+/SSTL bus terminators, and battery-powered instrumentation requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for LP3874ESX-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 technologies, with decades of expertise in high-reliability linear regulators and automotive-grade qualification.

The LP3874ESX-ADJ/NOPB belongs to TI's LP387x ultra-low-dropout LDO family, engineered specifically for high-current, low-headroom applications in computing, communications, and industrial control where fast transient response and thermal robustness are mandatory.

FAQ

What is the minimum input voltage required for LP3874ESX-ADJ/NOPB to regulate a 1.8V output?

The minimum input voltage is determined by the dropout specification: VIN(min) = VOUT + VDROPOUT. For LP3874ESX-ADJ/NOPB at 0.8A load, VDROPOUT = 240mV, so VIN(min) = 1.8V + 0.24V = 2.04V. However, the absolute minimum operating VIN is 2.5V per datasheet - thus 2.5V is the practical lower limit regardless of output voltage. LP3874ESX-ADJ/NOPB will not regulate below 2.5V input even if dropout margin is sufficient.

Can LP3874ESX-ADJ/NOPB be used with ceramic output capacitors instead of tantalum?

Yes, LP3874ESX-ADJ/NOPB supports ceramic output capacitors, but requires careful ESR selection: the stable region chart specifies COUT ≥10µF with ESR between 0.001Ω and 1Ω. X7R/X5R ceramics meeting this ESR range (e.g., 22µF/6.3V with ~5mΩ ESR) work reliably. Avoid Z5U/Y5V types due to severe capacitance loss with bias voltage. LP3874ESX-ADJ/NOPB does not require CFF with stable ceramics.

Does LP3874ESX-ADJ/NOPB require a feed-forward capacitor (CFF) in all designs?

No. CFF is optional and only recommended when using high-value R1 (>100kΩ) in the feedback divider to counteract ADJ pin bias current error, or when marginal phase margin is observed with specific capacitor types. Most standard designs using R2 = 10kΩ and R1 ≤100kΩ achieve stability with only CIN and COUT. The LP3874ESX-ADJ/NOPB datasheet confirms CFF is "required" only for certain high-R1 configurations - not universally.

How is thermal performance affected when LP3874ESX-ADJ/NOPB is mounted on a 2-layer PCB without an internal ground plane?

On a 2-layer board with 1oz copper and no internal plane, LP3874ESX-ADJ/NOPB's θ_JA rises to ~90°C/W (vs. 60°C/W with 0.5in² copper area), reducing max continuous power dissipation. At 0.8A and 3.3V output from 5V input (PD ≈ 1.36W), junction temperature rise would be ~122°C - exceeding 125°C max. To comply, reduce load current, increase copper area, or add thermal vias to inner layers. LP3874ESX-ADJ/NOPB's thermal shutdown activates if TJ exceeds 160°C.

Is LP3874ESX-ADJ/NOPB pin-compatible with LP3874ES-ADJ/NOPB?

Yes - LP3874ESX-ADJ/NOPB and LP3874ES-ADJ/NOPB share identical DDPAK/TO-263-5 package (NDH0005D), pinout, electrical specifications, and thermal characteristics. The only difference is packaging format: LP3874ESX-ADJ/NOPB ships in 500-unit large tape-and-reel, while LP3874ES-ADJ/NOPB uses 45-unit tube packaging. Both have identical part marking "LP3874ES ADJ" and RoHS-exempt lead finish.