Texas Instruments LP38692MPX-ADJ

Overview

LP38692MPX-ADJ from Texas Instruments is a 1-A adjustable-output low-dropout CMOS linear regulator with PMOS pass element, stable with 1-µF ceramic output capacitors, 450-mV dropout at 1 A (5-V output), ±2.5% ADJ pin voltage accuracy at 25°C, and integrated enable (EN) control - used in notebook computers and battery-powered instrumentation for clean, efficient local regulation.

For engineers reviewing the LP38692MPX-ADJ datasheet, LP38692MPX-ADJ pinout, LP38692MPX-ADJ application, or LP38692MPX-ADJ equivalent, key selection factors include EN pin logic thresholds (0.4 V OFF / 1.8–4 V ON), thermal shutdown at 160°C with 10°C hysteresis, foldback current limiting (450 mA at VIN–VOUT > 5 V), and SOT-223 package compatibility with high-ambient-temperature PCB layouts.

Technical Context

The LP38692MPX-ADJ uses a PMOS pass transistor to eliminate DC base drive current, keeping ground pin current below 100 µA across load, input voltage, and temperature. Its precision trimmed 1.25-V bandgap reference enables 2.5% ADJ pin voltage accuracy over –40°C to +125°C, supporting output voltages from 1.25 V to 9 V via external R1/R2 divider.

It integrates thermal overload protection, foldback current limiting (threshold dependent on VIN–VOUT differential), and an active-low enable input with no internal pull-up/pull-down - requiring explicit termination. The device achieves 55 dB PSRR at 120 Hz and 0.7 µV/√Hz output noise (10 Hz–10 kHz) with 10-µF ceramic output capacitor.

Key Specifications

Pinout & Package

LP38692MPX-ADJ is housed in a 5-pin SOT-223 package (6.50 mm × 3.56 mm) with exposed thermal pad (DAP) soldered to PCB copper for enhanced heat dissipation. Pin 1 = IN, Pin 2 = ADJ, Pin 3 = EN, Pin 4 = IN (dual-input configuration), Pin 5 = OUT, Pin 6 = GND (tab). GND tab provides both electrical grounding and primary thermal path.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TLS850F0TLE and MCP1826T-ADJ/DC, LP38692MPX-ADJ uniquely balances 1-A capability, adjustable output, integrated enable, and ultra-low noise - making it optimal for portable, battery-sensitive systems requiring flexible voltage scaling and precise power sequencing.

Availability

LP38692MPX-ADJ is available at Aetrix Electronics and suitable for notebook computers, portable instrumentation, and industrial sensor nodes requiring stable component supply with long-term lifecycle assurance and consistent parametric performance.

Supply support for LP38692MPX-ADJ 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 connectivity technologies, with decades of expertise in power management IC design and manufacturing.

LP38692MPX-ADJ belongs to TI's LP3869x family of low-noise, ceramic-capacitor-stable LDOs engineered for portable, battery-powered digital systems demanding fast start-up, low quiescent current, and robust thermal performance in compact SOT-223 packages.

FAQ

What is the minimum load current requirement for stable operation of the LP38692MPX-ADJ?

The LP38692MPX-ADJ requires a minimum load current of 100 µA to ensure proper regulation and stability. This is satisfied by the ADJ pin's internal reference current and external R1/R2 divider network. TI recommends R2 ≤12 kΩ to guarantee adequate loading across all operating conditions, preventing output drift or oscillation due to insufficient bias current at the ADJ node.

How does the foldback current limiting behave in the LP38692MPX-ADJ during a short-circuit event?

In the LP38692MPX-ADJ, foldback current limiting reduces output current as output voltage collapses. When VIN–VOUT exceeds 5 V, the limit is ~450 mA; when VIN–VOUT falls below 4 V, the limit rises to ~1500 mA. During a hard short, initial current is clamped to ~450 mA, minimizing power dissipation and junction temperature rise - protecting the device while allowing safe recovery once fault clears.

Can the LP38692MPX-ADJ be used with a 1-µF ceramic output capacitor, and what ESR range is supported?

Yes, the LP38692MPX-ADJ is explicitly designed and tested for stability with 1-µF ceramic output capacitors. It supports output capacitor ESR from 0 Ω to 100 mΩ - accommodating X7R/X5R ceramics with near-zero ESR and eliminating need for ESR-stabilizing resistors. This enables smaller, more reliable, and lower-cost power solutions versus traditional LDOs requiring higher-ESR tantalum capacitors.

What is the thermal resistance (RθJA) of the LP38692MPX-ADJ in its SOT-223 package, and how does it impact maximum output current?

The LP38692MPX-ADJ in the SOT-223 package has a junction-to-ambient thermal resistance (RθJA) of 68.5°C/W under JEDEC High-K board conditions. At 25°C ambient, this allows ~1 A continuous output before reaching the 125°C max junction temperature - assuming proper PCB layout with GND tab soldered to ≥1 cm² copper and ≥4 thermal vias. Derating is required above 85°C ambient.

Is the EN pin of the LP38692MPX-ADJ internally pulled up or down, and how should it be terminated if not used?

The EN pin of the LP38692MPX-ADJ has no internal pull-up or pull-down resistor and must be actively terminated. If enable functionality is not required, TI specifies connecting EN directly to IN to ensure permanent ON operation. Leaving EN floating risks undefined behavior, potential oscillation, or unintended shutdown due to noise coupling - especially in high-density or noisy PCB environments.