Texas Instruments LP2985AIM5X-3.3

Overview

LP2985AIM5X-3.3 from Texas Instruments is a micropower, ultra-low-dropout linear regulator delivering 150 mA output current with 3.3 V fixed output, 1% accuracy (A-grade), 300 mV typical dropout at full load, 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 voltage under light-to-moderate load.

For engineers reviewing the LP2985AIM5X-3.3 datasheet, LP2985AIM5X-3.3 pinout, LP2985AIM5X-3.3 application, or LP2985AIM5X-3.3 equivalent, key selection criteria include guaranteed 150 mA output with <1 µA shutdown current, compatibility with low-ESR ceramic capacitors (≥2.2 µF), SOT-23-5 package constraints, and ON/OFF logic control with 0.15 V low-threshold disable.

Technical Context

The LP2985AIM5X-3.3 uses an optimized vertically integrated PNP (VIP) process to achieve ultra-low dropout and minimal ground current across load range - 75 µA at 1 mA and 850 µA at 150 mA. Its internal reference and feedback loop ensure 1% output accuracy over –40°C to 125°C junction temperature, with line regulation of 0.014%/V and load regulation maintained within ±2.5% up to 150 mA.

It integrates active ON/OFF control with hysteresis: device enables when ON/OFF ≥1.6 V and disables below 0.15 V, reducing quiescent current to ≤2 µA. Stability is ensured with ceramic output capacitors down to 5 mΩ ESR, and noise performance is enhanced via dedicated BYPASS pin supporting external 10-nF capacitor for 30 µV_RMS noise reduction.

Key Specifications

Pinout & Package

SOT-23-5 (DBV) package: 2.90 mm × 1.60 mm body, 0.95 mm height, surface-mount, lead-free and RoHS-compliant.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar low-noise, 3.3-V LDO applications.

Compared with TCS2103-3.3 and MCP1703T-3302E/MB, the LP2985AIM5X-3.3 uniquely combines 1% accuracy, 30 µV_RMS noise (with BYPASS), and <2 µA shutdown in SOT-23-5 - making it optimal for noise-critical, battery-sensitive applications where performance trade-offs are unacceptable.

Availability

LP2985AIM5X-3.3 is available at Aetrix Electronics and suitable for cellular phones, USB peripherals, PDAs, and industrial sensor nodes requiring stable component supply, long-lifecycle support, and consistent parametric performance across production batches.

Supply support for LP2985AIM5X-3.3 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, industrial, and automotive markets.

The LP2985-N series was designed specifically for micropower, ultra-low-noise, ultra-low-dropout regulation in space-constrained battery-powered systems - emphasizing precision, efficiency, and ease of integration with minimal external components.

FAQ

What is the minimum input voltage required for LP2985AIM5X-3.3 to regulate 3.3 V at 150 mA?

The LP2985AIM5X-3.3 requires a minimum input voltage of 3.65 V to maintain regulation at 150 mA load, based on its maximum dropout voltage of 350 mV over temperature. At room temperature, typical dropout is 280 mV, so 3.58 V suffices. Input below this threshold causes output to track input linearly, losing regulation.

Can LP2985AIM5X-3.3 operate without the BYPASS capacitor?

Yes, the LP2985AIM5X-3.3 functions without the BYPASS capacitor, but output noise increases from 30 µV_RMS to approximately 75 µV_RMS (300 Hz–50 kHz). The BYPASS pin is optional for noise-critical applications; omitting it simplifies BOM but degrades noise performance - verify against system SNR requirements before removal.

Is LP2985AIM5X-3.3 compatible with ceramic output capacitors smaller than 2.2 µF?

No - the LP2985AIM5X-3.3 requires a minimum 2.2 µF ceramic output capacitor for guaranteed stability across all loads and temperatures. Using smaller values risks oscillation or poor transient response. Capacitance may be increased without limit, but ESR must remain ≤5 mΩ; X7R/X5R dielectrics are recommended.

What happens to LP2985AIM5X-3.3 if the ON/OFF pin is left floating?

If the ON/OFF pin is left floating, the LP2985AIM5X-3.3 may power up unpredictably due to noise coupling or internal leakage, leading to erratic enable behavior. TI specifies that the ON/OFF pin must be actively terminated - tie to IN for always-on operation or to a controlled GPIO for managed enable/disable. A pull-up resistor is not sufficient per datasheet guidance.

Does LP2985AIM5X-3.3 support reverse input-output voltage conditions?

No - the LP2985AIM5X-3.3 contains an internal diode between IN and OUT pins. If V_OUT exceeds V_IN by more than 0.3 V, reverse current flows, potentially damaging the device or causing latch-up. External reverse-voltage protection (e.g., series Schottky diode) is required in systems where output could be driven independently.