Texas Instruments LP5951MF-1.8

Overview

LP5951MF-1.8 from Texas Instruments is a micropower, 150-mA low-dropout CMOS voltage regulator in SC70-5 package, delivering a fixed 1.8 V output with 29 µA typical quiescent current, 250 mV dropout at 150 mA, and ±2 mV line transient response - deployed in battery-powered microcontroller core rails and sensor biasing circuits.

For engineers reviewing the LP5951MF-1.8 datasheet, LP5951MF-1.8 pinout, LP5951MF-1.8 application, or LP5951MF-1.8 equivalent, key selection criteria include shutdown current (<1 nA), PSRR (–60 dB @ 1 kHz), thermal protection (160°C trip), enable logic thresholds (0.4 V/0.9 V), and stability with 1-µF ceramic output capacitors.

Technical Context

The LP5951MF-1.8 uses a PMOS pass device architecture enabling ultra-low quiescent current and inherent reverse-current blocking. Its internal bias generator and reference circuitry operate down to 1.8 V input, supporting direct Li-ion or single-cell alkaline supply interfacing without external support circuitry.

Enable control is implemented as an active-high digital input with guaranteed 0.4 V low threshold and 0.9 V high threshold across –40°C to 125°C, ensuring robust noise immunity in noisy portable environments. The device enters shutdown with <1 nA ground current and resumes regulation in 30 µs typical turnon time.

Key Specifications

Pinout & Package

LP5951MF-1.8 is packaged in SC70-5 (2.00 mm × 1.25 mm), optimized for space-constrained portable PCBs. Pin functions are validated per TI SNVS345G Rev G.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LP5951MF-1.8, TPL7407LPGEDR integrates switching drivers unsuitable for precision analog rails, while MCP1700T-1802E/TT omits enable control and exhibits poorer transient response - making LP5951MF-1.8 the optimal choice for dynamically controlled, noise-sensitive 1.8-V loads.

Availability

LP5951MF-1.8 is available at Aetrix Electronics and suitable for wearable electronics, medical diagnostic patches, industrial wireless sensors, and IoT edge microcontroller designs requiring stable component supply, long-term lifecycle assurance, and consistent parametric performance across temperature.

Supply support for LP5951MF-1.8 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 connectivity technologies for industrial, automotive, and consumer markets.

The LP5951 product line delivers micropower, low-noise LDO regulators optimized for battery-powered portable systems - emphasizing ultra-low IQ, small-footprint packaging, and robust transient performance in space- and energy-constrained applications.

FAQ

What is the minimum input voltage required for LP5951MF-1.8 to regulate at full 150 mA?

The LP5951MF-1.8 requires VIN ≥ VOUT + VDO = 1.8 V + 250 mV = 2.05 V to maintain regulation at 150 mA. Below this, output voltage drops linearly with input; the absolute minimum operating VIN is 1.8 V, but regulation is not guaranteed until the dropout condition is met. This allows direct use with partially discharged single-cell Li-ion (2.5–4.2 V) or two-cell alkaline (2.0–3.2 V) sources.

Can LP5951MF-1.8 be used without connecting the EN pin?

Yes - the EN pin of LP5951MF-1.8 can be tied directly to VIN to force permanent enable mode. Doing so bypasses shutdown control but ensures continuous regulation. Leaving EN floating is prohibited: it may cause erratic behavior or increased ground current due to undefined logic state. If dynamic control isn't needed, hard-wiring EN to VIN is a valid, widely adopted configuration.

Does LP5951MF-1.8 require an input capacitor, and what type is recommended?

Yes, LP5951MF-1.8 requires a minimum 1-µF ceramic input capacitor placed within 1 cm of the IN pin and returned to clean analog ground. X7R or X5R dielectrics are preferred for stable capacitance across temperature and bias. Tantalum capacitors are acceptable but must meet surge current ratings; film capacitors are viable alternatives. No ESR requirement exists for the input cap, but tolerance and DC bias derating must ensure ≥0.7 µF under worst-case conditions.

How does thermal shutdown behave on LP5951MF-1.8 during sustained overload?

LP5951MF-1.8 triggers thermal shutdown at TJ ≈ 160°C (typical), turning off the PMOS pass device. After junction temperature falls by ~20°C (hysteresis), the device automatically recovers and resumes regulation. Under continuous overload, this results in pulsed output - a self-protecting oscillation that prevents permanent damage while maintaining system awareness. Full recovery occurs once ambient and layout allow TJ to drop below 140°C.

Is LP5951MF-1.8 compatible with 0402-size 1-µF ceramic output capacitors?

LP5951MF-1.8 supports 1-µF ceramic output capacitors, but 0402 case size requires careful DC bias validation: typical 0402 X5R 1-µF caps drop below 0.7 µF above ~2.5 V bias, violating the minimum 0.7 µF spec. TI recommends 0603 or larger (e.g., C1608X5R1A105K) for guaranteed stability across full VIN range. Always verify manufacturer's DC bias curve for the selected capacitor before final layout.