Texas Instruments LP5951MF-1.5

Overview

LP5951MF-1.5 from Texas Instruments is a micropower, 150-mA low-dropout CMOS voltage regulator in SC70-5 package, delivering fixed 1.5 V output with 250 mV dropout at 150 mA, 29 µA quiescent current, and ±2 mV line transient response - used to power low-voltage microcontrollers and RF sections in portable battery-powered systems.

For engineers reviewing the LP5951MF-1.5 datasheet, LP5951MF-1.5 pinout, LP5951MF-1.5 application, or LP5951MF-1.5 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-1.5 employs a PMOS pass device architecture enabling ultra-low quiescent current and reverse-current blocking capability. Its internal bias generator and reference circuit maintain regulation across –40°C to 125°C junction temperature while supporting fast 30 µs turn-on and controlled discharge during shutdown.

Enable control is active-high with guaranteed VIH = 0.9 V and VIL = 0.4 V over full temperature range; the NC pin is unconnected internally and must not be bonded. The regulator remains stable with no load and supports input voltages as low as 1.8 V - critical for single-cell Li-ion and coin-cell applications.

Key Specifications

Pinout & Package

LP5951MF-1.5 is packaged in SC70-5 (2.00 mm × 1.25 mm) - a space-constrained, surface-mount package optimized for portable electronics PCBs with tight layout constraints.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar low-quiescent-current LDO applications.

Compared with TPL720F15 and MCP1700T-1502E/MB, LP5951MF-1.5 uniquely combines sub-30 µA quiescent current, integrated thermal shutdown, active-high enable, and 200–250 mV dropout in SC70-5 - making it the only option qualified for wide-temperature, safety-aware portable medical and industrial designs.

Availability

LP5951MF-1.5 is available at Aetrix Electronics and suitable for wearable sensor nodes, BLE wireless modules, industrial IoT edge controllers, and medical diagnostic patches requiring stable component supply across long production lifecycles.

Supply support for LP5951MF-1.5 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 focused on analog and embedded processing technologies, serving industrial, automotive, and personal electronics markets with high-reliability components.

The LP5951MF-1.5 belongs to TI's micropower LDO family designed specifically for battery-powered portable systems demanding ultra-low IQ, fast transient response, and robust protection - not general-purpose regulation.

FAQ

What is the minimum input voltage required for LP5951MF-1.5 to regulate at full 150 mA output?

The LP5951MF-1.5 requires VIN ≥ VOUT + VDO = 1.5 V + 0.25 V = 1.75 V under nominal conditions. Per datasheet Section 7.4.2, the internal circuitry becomes functional only above 1.8 V, so 1.8 V is the practical minimum input voltage to ensure regulation at full load across temperature. At lower inputs, output voltage drops or regulation is lost.

Can the NC pin on LP5951MF-1.5 be connected to ground or left floating?

The NC pin on LP5951MF-1.5 is unconnected internally and must remain electrically floating - neither grounded nor tied to any voltage. Connecting it may cause unpredictable behavior or damage due to unintended internal coupling. The datasheet explicitly states "No internal connection" and warns against bonding or routing traces to this pin.

Does LP5951MF-1.5 support reverse current protection without external components?

LP5951MF-1.5 includes inherent reverse current blocking via its PMOS pass device parasitic body diode, limiting reverse current to ≤50 mA when VOUT exceeds VIN. For reverse currents above 50 mA, TI specifies an external Schottky diode (cathode to VIN, anode to VOUT) is mandatory - the IC itself does not provide active reverse-current shutdown.

What output capacitor types and values are validated for stable operation of LP5951MF-1.5?

LP5951MF-1.5 is validated for stable operation with 1 µF ceramic capacitors (X7R or X5R dielectric, 0402 or 0603 case) having ESR between 3 mΩ and 300 mΩ. TI confirms stability down to 0.7 µF and up to 47 µF, but recommends X7R for –40°C to 125°C operation due to ±15% capacitance tolerance versus >50% loss in Z5U/Y5V at temperature extremes.

How does the thermal shutdown feature behave in LP5951MF-1.5 during sustained overload?

LP5951MF-1.5 triggers thermal shutdown at TJ = 160°C (typ.) and re-enables at TJ = 140°C (20°C hysteresis). During continuous overload, this results in pulsed output voltage - the device cycles between regulation and shutdown - protecting against permanent damage but not sustaining steady output. Continuous operation must stay below 125°C junction temperature per specifications.