Texas Instruments LP2985AIM5-3.6

Overview

LP2985AIM5-3.6 from Texas Instruments is a micropower, ultra-low-dropout linear regulator (LDO) delivering 150 mA output current with 3.6 V fixed output voltage, 1% accuracy (A-grade), and 300 mV typical dropout at full load. It features ON/OFF control, low-noise operation via BYPASS pin, and stable operation with ceramic capacitors as low as 2.2 µF (COUT) and 0.01 µF (CBYPASS), targeting battery-powered portable electronics.

For engineers reviewing the LP2985AIM5-3.6 datasheet, LP2985AIM5-3.6 pinout, LP2985AIM5-3.6 application, or LP2985AIM5-3.6 equivalent, key selection criteria include dropout voltage at 150 mA, shutdown quiescent current (<1 µA), output noise (30 µVRMS), thermal performance in SOT-23, and compatibility with low-ESR ceramic output capacitors.

Technical Context

The LP2985AIM5-3.6 uses a vertically integrated PNP (VIP) process to achieve ultra-low dropout (280–575 mV at 150 mA over temperature) and low ground current (850 µA typical at 150 mA). Its internal reference and feedback loop ensure 1% output voltage accuracy across –40°C to 125°C junction temperature and load range 1–150 mA.

It integrates logic-controlled enable (ON/OFF pin), foldback current limiting, thermal shutdown, and stability with output capacitor ESR as low as 5 mΩ. The BYPASS pin enables noise reduction by connecting a 10 nF capacitor to GND, lowering RMS noise to 30 µV in 300 Hz–50 kHz bandwidth.

Key Specifications

Pinout & Package

SOT-23 (DBV) package: 5-pin surface-mount, body size 2.90 mm × 1.60 mm, thermally enhanced for PCB trace-sink mounting.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MCP1700T-3602E/TT and TLS850F3BTV50, the LP2985AIM5-3.6 delivers superior noise performance and tighter voltage accuracy in a smaller footprint, making it optimal for space-constrained, battery-powered analog-intensive systems where quiescent current and dropout are primary constraints.

Availability

LP2985AIM5-3.6 is available at Aetrix Electronics and suitable for cellular handsets, wearable sensors, industrial data loggers, and portable medical monitors requiring stable component supply, long-term lifecycle support, and guaranteed traceability.

Supply support for LP2985AIM5-3.6 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 headquartered in Dallas, Texas, specializing in analog, embedded processing, and power management ICs for industrial, automotive, and consumer markets.

The LP2985-N product line was designed specifically for micropower, ultra-low-dropout regulation in space- and battery-constrained portable electronics, emphasizing low noise, minimal external components, and robust thermal behavior in SOT-23 packaging.

FAQ

What is the minimum input voltage required for LP2985AIM5-3.6 to regulate 3.6 V at 150 mA?

The LP2985AIM5-3.6 requires a minimum input voltage of 4.175 V under worst-case conditions: 3.6 V output + 575 mV maximum dropout (specified at 150 mA and –40°C to 125°C). At room temperature and 1 mA load, dropout drops to 7 mV, allowing VIN as low as 3.607 V. Designers should maintain ≥4.2 V headroom for margin across temperature and production variation.

Can LP2985AIM5-3.6 operate without the BYPASS capacitor?

Yes, the LP2985AIM5-3.6 functions normally without the BYPASS capacitor, delivering 3.6 V output with standard LDO performance. However, omitting the 0.01 µF ceramic capacitor on the BYPASS pin increases output noise from 30 µVRMS to approximately 100 µVRMS. For noise-sensitive applications like ADC references or RF synthesizers, the BYPASS capacitor is mandatory to achieve specified low-noise operation.

What output capacitor value and type are required for stable operation of LP2985AIM5-3.6?

The LP2985AIM5-3.6 requires a minimum 2.2 µF ceramic output capacitor with ESR ≥5 mΩ for stability across all loads and temperatures. X5R or X7R dielectrics are recommended for stable capacitance over temperature. Tantalum or aluminum electrolytic capacitors are not recommended due to higher ESR and potential instability. Capacitor placement must be adjacent to the OUT and GND pins with short, low-inductance traces.

How does the ON/OFF pin behave during power-up and shutdown sequences?

The ON/OFF pin of LP2985AIM5-3.6 is active-high with hysteresis: device enables when voltage exceeds 1.6 V and disables when voltage falls below 0.15 V (–40°C to 125°C). During power-up, tying ON/OFF to VIN ensures immediate regulation. During shutdown, pulling ON/OFF to GND reduces quiescent current to <1 µA. Floating the pin is not allowed - it must be actively terminated to avoid erratic enable/disable behavior.

Is LP2985AIM5-3.6 compatible with ceramic input capacitors, and what is the minimum value?

Yes, LP2985AIM5-3.6 is fully compatible with ceramic input capacitors. A minimum 1 µF X5R or X7R ceramic capacitor is required between IN and GND, placed within 1 cm of the IN pin. Larger values (e.g., 2.2 µF or 4.7 µF) improve high-frequency PSRR and transient response but are not required for stability. No ESR restrictions apply to the input capacitor, unlike the output capacitor.