Texas Instruments LP2985AIM5-3.8

Overview

LP2985AIM5-3.8 from Texas Instruments is a micropower, ultra-low-dropout linear regulator delivering 150 mA output current with 3.8 V fixed output voltage, 1% accuracy (A-grade), 350 mV max dropout at 150 mA, and 75 µA quiescent current at 1 mA load - designed for battery-powered portable electronics requiring low noise and high efficiency.

For engineers reviewing the LP2985AIM5-3.8 datasheet, LP2985AIM5-3.8 pinout, LP2985AIM5-3.8 application, or LP2985AIM5-3.8 equivalent, key selection criteria include guaranteed 150-mA output under ultra-low dropout (≤350 mV), <2 µA shutdown current, BYPASS-pin-enabled 30 µV_RMS noise performance, and SOT-23-5 stability with 2.2 µF ceramic output capacitor.

Technical Context

The LP2985AIM5-3.8 employs a vertically integrated PNP (VIP) pass transistor architecture enabling ultra-low dropout (350 mV max at 150 mA) and minimal ground current (850 µA typ. at full load). Its internal reference and error amplifier deliver 1% output voltage tolerance across –40°C to 125°C junction temperature.

It integrates logic-controlled ON/OFF functionality (enable threshold: 1.6 V min, disable threshold: 0.15 V max), foldback current limiting (400 mA short-circuit limit), and thermal shutdown protection. The dedicated BYPASS pin supports external 10 nF capacitor to reduce output noise to 30 µV_RMS (300 Hz–50 kHz).

Key Specifications

Pinout & Package

SOT-23-5 package (2.90 mm × 1.60 mm body size), surface-mount, thermally enhanced for PCB heat dissipation in space-constrained designs.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar low-noise, ultra-low-dropout regulator applications.

Compared with LP2985AIM5-3.8, TLC7603-38 offers higher current but sacrifices noise performance and dropout; MCP1703T-3802E/MB provides greater current and lower quiescent current but trades off 2× higher dropout and no noise-bypass capability - making LP2985AIM5-3.8 optimal where battery life, low noise, and tight voltage tolerance are critical.

Availability

LP2985AIM5-3.8 is available at Aetrix Electronics and suitable for cellular phones, wearable sensors, industrial handheld terminals, and medical point-of-care monitors requiring stable component supply with long-term manufacturability.

Supply support for LP2985AIM5-3.8 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 company specializing in analog and embedded processing technologies, with leadership in power management ICs for portable and industrial applications.

The LP2985-N product line delivers micropower, ultra-low-dropout regulators optimized for battery-powered portable electronics - emphasizing low noise, high accuracy, and ceramic-capacitor compatibility in minimal SOT-23-5 footprint.

FAQ

What is the minimum input voltage required for LP2985AIM5-3.8 to regulate 3.8 V output?

The LP2985AIM5-3.8 requires a minimum input voltage of 3.1 V per datasheet specifications. This accounts for its maximum dropout voltage of 350 mV at 150 mA load and ensures regulation remains within ±1% accuracy. At lighter loads (e.g., 1 mA), dropout drops to 7 mV, allowing operation as low as 3.807 V input - but design margin mandates 3.1 V minimum for full-load reliability across temperature.

Can LP2985AIM5-3.8 operate without the BYPASS capacitor?

Yes, LP2985AIM5-3.8 functions without the BYPASS capacitor, delivering 3.8 V output with standard LDO performance. However, omitting the 10 nF capacitor on the BYPASS pin increases output noise from 30 µV_RMS to approximately 75 µV_RMS. Applications requiring low-noise analog supplies - such as precision ADCs or RF receivers - must retain the BYPASS capacitor to meet specification.

What output capacitor value and type does LP2985AIM5-3.8 require for stability?

LP2985AIM5-3.8 requires a minimum 2.2 µF ceramic output capacitor with ESR ≤50 mΩ for guaranteed stability across 0–150 mA load and –40°C to 125°C. X5R or X7R dielectrics are recommended. Tantalum or film capacitors may be used but are not optimized; ceramic is preferred for size, cost, and ESR consistency. Capacitor tolerance and temperature drift must ensure ≥2.2 µF minimum capacitance over full operating range.

How does the ON/OFF pin behave during startup and shutdown of LP2985AIM5-3.8?

The ON/OFF pin of LP2985AIM5-3.8 is active-high: pulling it ≥1.6 V initiates soft-start and enables regulation; pulling it ≤0.15 V disables output and reduces quiescent current to ≤2 µA. During startup, output voltage rises with ~100 µs typical delay after ON/OFF exceeds threshold. No external pull-up is required - internal bias ensures defined state when floating, but TI recommends active termination to VIN or GND for robustness.

Is LP2985AIM5-3.8 RoHS compliant and halogen-free?

Yes, LP2985AIM5-3.8 is RoHS compliant and halogen-free per Texas Instruments' official product change notices and packaging data. It meets JEDEC J-STD-609 Category 1 for bromine/chlorine content (<900 ppm) and adheres to EU Directive 2011/65/EU. Full compliance documentation, including material declarations and test reports, is available via TI's Quality & Environmental Information portal.