Texas Instruments LP2985IM5X-2.9/NOPB

Overview

LP2985IM5X-2.9/NOPB from Texas Instruments is a micropower, ultra-low-dropout linear regulator delivering 150 mA output current with 2.9 V fixed output, 300 mV typical dropout at full load, 1% output voltage accuracy (A-grade), and 30 µV_RMS output noise (300 Hz–50 kHz) when using a 10-nF bypass capacitor. It serves as a precision, low-noise power supply for battery-powered portable electronics requiring stable 2.9 V rail generation.

For engineers reviewing the LP2985IM5X-2.9/NOPB datasheet, LP2985IM5X-2.9/NOPB pinout, LP2985IM5X-2.9/NOPB application, or LP2985IM5X-2.9/NOPB equivalent, key selection considerations include its SOT-23-5 package footprint, ON/OFF logic control interface, ceramic-capacitor compatibility down to 5 mΩ ESR, <1 µA shutdown quiescent current, and thermal/overcurrent protection - all critical for space-constrained, low-power embedded designs.

Technical Context

The LP2985IM5X-2.9/NOPB employs a vertically integrated PNP (VIP) pass transistor architecture enabling ultra-low dropout (280 mV max at 150 mA, –40°C to 125°C) and low ground current (850 µA typ. at 150 mA). Its internal reference and feedback loop deliver 1% initial output accuracy and maintain regulation across input voltages from 3.1 V to 16 V.

It integrates an active ON/OFF control pin with 1.6 V turn-on threshold and <0.15 V turn-off threshold, enabling precise enable/disable sequencing. The dedicated BYPASS pin connects to a 10-nF capacitor to shunt reference noise, reducing total output noise to 30 µV_RMS - a design feature confirmed for the LP2985-N family including this 2.9 V variant.

Key Specifications

Pinout & Package

SOT-23-5 (DBV) package: 2.90 mm × 1.60 mm body, 0.95 mm height, gull-wing leads, JEDEC MO-178AC compliant.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar low-noise, micropower LDO applications.

Compared with TCS2117-2.9 and MCP1703T-2902E/MB, the LP2985IM5X-2.9/NOPB uniquely combines 30 µV_RMS noise (via BYPASS), 280 mV max dropout, and <1 µA shutdown - making it optimal for battery-powered systems demanding both ultra-low noise and minimal quiescent consumption.

Availability

LP2985IM5X-2.9/NOPB is available at Aetrix Electronics and suitable for portable medical sensors, wearable health monitors, industrial handheld terminals, and smart meter communication modules requiring stable component supply, long-lifecycle support, and guaranteed traceability.

Supply support for LP2985IM5X-2.9/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 company specializing in analog and embedded processing technologies, with leadership in power management ICs since the 1980s.

The LP2985-N product line was designed specifically for micropower, ultra-low-noise, ultra-low-dropout regulation in space- and battery-constrained portable electronics - emphasizing ceramic-capacitor compatibility, precision output accuracy, and robust thermal protection.

FAQ

What is the minimum input voltage required for LP2985IM5X-2.9/NOPB to regulate 2.9 V output?

The LP2985IM5X-2.9/NOPB requires a minimum input voltage of 3.1 V under recommended operating conditions. This accounts for its maximum dropout voltage of 575 mV at 150 mA and –40°C to 125°C junction temperature. Below 3.1 V, regulation is not guaranteed, and output voltage will track input.

Can LP2985IM5X-2.9/NOPB operate without the BYPASS capacitor?

Yes, LP2985IM5X-2.9/NOPB functions without the BYPASS capacitor, delivering standard LDO performance. However, omitting the 10-nF ceramic capacitor on the BYPASS pin increases output noise to approximately 75 µV_RMS. For noise-sensitive applications, the BYPASS cap is essential to achieve the specified 30 µV_RMS.

Is LP2985IM5X-2.9/NOPB compatible with ceramic output capacitors below 2.2 µF?

No - the LP2985IM5X-2.9/NOPB requires a minimum 2.2 µF ceramic output capacitor for stability across its full 0–150 mA load range and –40°C to 125°C temperature range. Using smaller values risks oscillation or poor transient response, as confirmed in the device's ESR vs. load stability curves.

What happens to LP2985IM5X-2.9/NOPB during thermal shutdown?

When LP2985IM5X-2.9/NOPB junction temperature exceeds ~160°C, its internal thermal protection circuit disables the pass element. The output drops to near zero, power dissipation ceases, and the die cools. Once temperature falls ~15°C below the trip point, regulation resumes automatically - causing visible output cycling if sustained overload persists.

Does LP2985IM5X-2.9/NOPB support reverse input-output voltage conditions?

No - LP2985IM5X-2.9/NOPB contains an inherent IN-to-OUT diode. If output voltage exceeds input voltage by more than 0.3 V, reverse current flows from OUT to IN, potentially damaging upstream circuitry. External reverse-protection diodes or MOSFETs are required in systems where output may float above input.