Texas Instruments LP2985IM5-3.1/NOPB

Overview

LP2985IM5-3.1/NOPB from Texas Instruments is a micropower, ultra-low-dropout linear regulator delivering 150 mA output current with 3.1 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 3.1 V rail generation.

For engineers reviewing the LP2985IM5-3.1/NOPB datasheet, LP2985IM5-3.1/NOPB pinout, LP2985IM5-3.1/NOPB application, or LP2985IM5-3.1/NOPB equivalent, key selection criteria include its SOT-23-5 package compatibility, ON/OFF logic-controlled shutdown (<2 µA quiescent), ceramic-capacitor stability down to 5 mΩ ESR, and guaranteed 150 mA output across −40°C to 125°C junction temperature.

Technical Context

The LP2985IM5-3.1/NOPB employs a vertically integrated PNP (VIP) pass transistor architecture enabling ultra-low dropout (7 mV at 1 mA, 575 mV max at 150 mA over temperature) and low ground current (75 µA at 1 mA, 850 µA at 150 mA). Its internal reference and feedback loop are optimized for 1% output accuracy across line, load, and temperature.

It integrates active ON/OFF control with precise enable thresholds (ON ≥1.6 V, OFF ≤0.15 V), foldback current limiting (400 mA short-circuit, 350 mA peak), thermal shutdown, and stability with ceramic output capacitors as small as 2.2 µF and ESR as low as 5 mΩ - eliminating need for tantalum or electrolytic types.

Key Specifications

Pinout & Package

LP2985IM5-3.1/NOPB is housed in a 5-pin SOT-23 package (2.90 mm × 1.60 mm body size) with exposed pad not electrically connected. The package supports reflow soldering per JEDEC J-STD-020 and provides R_θJA = 169.0°C/W on standard PCB layout.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TLC7603-31 and MCP1703T-3102E/MB, LP2985IM5-3.1/NOPB uniquely combines 1% accuracy, 30 µV_RMS noise via BYPASS pin, and guaranteed stability with 2.2 µF ceramic caps - making it optimal for space-constrained, battery-sensitive, precision analog systems.

Availability

LP2985IM5-3.1/NOPB is available at Aetrix Electronics and suitable for portable medical sensors, wearable fitness trackers, industrial handheld scanners, and smart home doorbell cameras requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for LP2985IM5-3.1/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 designing analog ICs, embedded processors, and system solutions for industrial, automotive, and personal electronics markets.

The LP2985-N product line delivers micropower, ultra-low-dropout regulators optimized for battery-powered portable devices demanding low noise, high accuracy, and ceramic-capacitor compatibility - targeting cellular phones, PDAs, camcorders, and other compact consumer electronics.

FAQ

What is the minimum input voltage required for LP2985IM5-3.1/NOPB to regulate 3.1 V at 150 mA?

The LP2985IM5-3.1/NOPB requires a minimum input voltage of 3.675 V to maintain regulation at 150 mA load, based on its maximum dropout voltage of 575 mV across −40°C to 125°C. At room temperature and 1 mA load, dropout drops to 7 mV, allowing operation from 3.107 V. Always verify headroom against worst-case temperature and load conditions in final design.

Can LP2985IM5-3.1/NOPB operate without the BYPASS capacitor?

Yes, LP2985IM5-3.1/NOPB functions normally without the BYPASS capacitor; however, output noise increases from 30 µV_RMS to approximately 75 µV_RMS. The BYPASS pin is optional and may be left unconnected or tied to GND if low-noise performance is not required. Omitting the 10 nF capacitor simplifies BOM but sacrifices noise-sensitive applications.

Is LP2985IM5-3.1/NOPB compatible with ceramic output capacitors below 2.2 µF?

No - LP2985IM5-3.1/NOPB requires a minimum of 2.2 µF ceramic output capacitance for guaranteed stability across all loads and temperatures. Using smaller values risks oscillation or poor transient response. The device is specifically characterized for stability with 2.2 µF to 10 µF ceramics having ESR ≥5 mΩ; reducing capacitance below spec invalidates stability assurance.

How does the ON/OFF pin behave during power-up of LP2985IM5-3.1/NOPB?

The LP2985IM5-3.1/NOPB enters shutdown mode when ON/OFF is <0.15 V and begins regulation when ON/OFF rises above 1.6 V. During power-up, if VIN ramps before ON/OFF, the device remains disabled until ON/OFF exceeds threshold. No external pull-up is required, but tying ON/OFF to VIN ensures immediate enable - critical for systems needing deterministic startup timing.

What thermal derating applies to LP2985IM5-3.1/NOPB in SOT-23 package at 85°C ambient?

With R_θJA = 169.0°C/W, LP2985IM5-3.1/NOPB's junction temperature rise is 26°C at 150 mA (150 mW dissipation). At 85°C ambient, T_J = 111°C - within its −40°C to 125°C rating. Derating is not required at this condition, but continuous operation near thermal limit reduces reliability; consider heatsinking or reducing load if ambient exceeds 85°C or power dissipation increases.