Texas Instruments LP2985IM5X-1.8/NOPB

Overview

LP2985IM5X-1.8/NOPB from Texas Instruments is a micropower, low-noise, ultra-low-dropout linear regulator delivering 150 mA at fixed 1.8 V output with ±1% accuracy (A-grade), 280 mV typical dropout at full load, and 30 µV_RMS output noise when using a 10-nF bypass capacitor - designed for battery-powered portable electronics requiring stable, quiet voltage rails.

For engineers reviewing the LP2985IM5X-1.8/NOPB datasheet, LP2985IM5X-1.8/NOPB pinout, LP2985IM5X-1.8/NOPB application, or LP2985IM5X-1.8/NOPB equivalent, key selection considerations include its SOT-23-5 package, ON/OFF logic control interface, ceramic-capacitor compatibility down to 5 mΩ ESR, sub-1-µA shutdown current, and guaranteed operation across –40°C to +125°C junction temperature.

Technical Context

The LP2985IM5X-1.8/NOPB employs a vertically integrated PNP (VIP) process to achieve ultra-low dropout (≤600 mV max over temperature at 150 mA) and exceptionally low ground pin current (825 µA typ. at full load). Its internal bandgap reference feeds a precision error amplifier driving a PNP pass transistor, enabling tight line and load regulation (0.014%/V line reg, ±2.5% load reg over 1–150 mA).

It integrates active ON/OFF control with TTL-compatible thresholds (ON ≥1.6 V, OFF ≤0.15 V), foldback current limiting (400 mA short-circuit current), 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

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

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar low-noise, 150-mA LDO applications.

Compared with TCS2101-1.8 and MCP1700T-1802E/MB, the LP2985IM5X-1.8/NOPB uniquely combines ON/OFF control, BYPASS-driven ultra-low noise, and ultra-low dropout in a standard 5-pin SOT-23 - making it optimal for space-constrained, battery-sensitive designs demanding both precision and silence.

Availability

LP2985IM5X-1.8/NOPB is available at Aetrix Electronics and suitable for cellular phone power management, wearable sensor node supply, industrial handheld terminals, and automotive infotainment displays requiring stable component supply across production lifecycles.

Supply support for LP2985IM5X-1.8/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 leader specializing in analog, embedded processing, and connectivity technologies, with decades of expertise in power management ICs.

The LP2985LV-N product line targets ultra-low-power, low-noise portable electronics - delivering high-accuracy, ceramic-stable LDOs optimized for single-cell battery systems and noise-sensitive mixed-signal applications.

FAQ

What is the minimum input voltage required for LP2985IM5X-1.8/NOPB to maintain regulation?

The LP2985IM5X-1.8/NOPB requires a minimum input voltage of 2.05 V at 25°C and 2.2 V across –40°C to +125°C to sustain 1.8 V output regulation. This is defined by its ultra-low dropout: at 150 mA load, typical dropout is 280 mV, so VIN must exceed VOUT + V_DO - i.e., ≥2.08 V - with margin for temperature and tolerance. The datasheet specifies 2.2 V as the guaranteed minimum under worst-case conditions.

Does LP2985IM5X-1.8/NOPB require an external bypass capacitor to achieve its rated 30 µV noise performance?

Yes, the LP2985IM5X-1.8/NOPB achieves its specified 30 µV_RMS output noise (300 Hz–50 kHz) only when a 10-nF ceramic capacitor is connected between the BYPASS pin and GND. Without this capacitor, noise rises significantly - typically ~120 µV_RMS. The BYPASS pin connects directly to the internal bandgap reference, and the external cap filters high-frequency noise without loading the reference node.

Can LP2985IM5X-1.8/NOPB be used with ceramic output capacitors smaller than 2.2 µF?

No - the LP2985IM5X-1.8/NOPB requires a minimum 2.2 µF ceramic output capacitor for guaranteed stability across all load and temperature conditions. Using a smaller value risks oscillation or poor transient response. The device is optimized for ceramic caps with ESR as low as 5 mΩ, and the 2.2 µF minimum ensures phase margin remains sufficient even at 150 mA load and –40°C.

What happens to LP2985IM5X-1.8/NOPB when the ON/OFF pin is left floating?

If the ON/OFF pin of the LP2985IM5X-1.8/NOPB is left floating, the device may power up unpredictably due to noise coupling or internal leakage, leading to erratic enable behavior. TI explicitly states that the ON/OFF input must be actively terminated - either pulled high to VIN via a resistor or tied directly to VIN if enable functionality is unused. A floating pin violates recommended operating conditions and can cause intermittent regulation failure.

Is LP2985IM5X-1.8/NOPB compatible with lead-free reflow soldering processes?

Yes, the LP2985IM5X-1.8/NOPB is RoHS-compliant and qualified for standard lead-free reflow soldering per JEDEC J-STD-020. Its SOT-23-5 (DBV) package has a moisture sensitivity level (MSL) of 1, meaning it is not moisture-sensitive and can be subjected to multiple reflow cycles without baking. Peak reflow temperature up to 260°C is supported, consistent with industry-standard Pb-free assembly.