Texas Instruments LP5951MGX-1.5/NOPB

Overview

LP5951MGX-1.5/NOPB from Texas Instruments is a micropower, 150-mA low-dropout CMOS voltage regulator with fixed 1.5 V output, 1.8–5.5 V input range, 29 µA typical quiescent current, and active-high enable control - designed for space-constrained portable battery-powered systems requiring stable low-noise supply for microcontrollers, sensors, and RF ICs.

For engineers reviewing the LP5951MGX-1.5/NOPB datasheet, LP5951MGX-1.5/NOPB pinout, LP5951MGX-1.5/NOPB application, or LP5951MGX-1.5/NOPB equivalent, key selection considerations include dropout voltage at 150 mA (200 mV for VOUT < 2.5 V), ±2 mV line transient response, –60 dB PSRR at 1 kHz, shutdown current < 1 nA, and compatibility with 1-µF ceramic output capacitors in SC70-5 or SOT-23-5 packages.

Technical Context

The LP5951MGX-1.5/NOPB employs a PMOS pass device architecture enabling ultra-low quiescent current and inherent reverse-current blocking. Its internal bias generator and LDO core are optimized for stability with minimal 1-µF ceramic capacitors without requiring ESR tuning.

Enable functionality is implemented as a logic-controlled gate driver with defined VIH = 0.9 V and VIL = 0.4 V thresholds across –40°C to 125°C, supporting direct connection to GPIOs of 1.8-V and 3.3-V microcontrollers. Thermal shutdown engages at 160°C (typ.) with 20°C hysteresis, and short-circuit protection limits peak output current to 400 mA.

Key Specifications

Pinout & Package

LP5951MGX-1.5/NOPB is housed in a 5-pin SC70 package (2.00 mm × 1.25 mm body size, 0.65 mm pitch), optimized for thermal performance and board area efficiency in portable designs.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LP5951MGX-1.5/NOPB, TPL7407LPGQ integrates switching functionality but sacrifices output current and standalone regulation capability, while MCP1700T-1502E/MB achieves lower quiescent current but lacks enable control and has significantly higher dropout - making LP5951MGX-1.5/NOPB optimal for battery-powered systems requiring both low IQ and active power management.

Availability

LP5951MGX-1.5/NOPB is available at Aetrix Electronics and suitable for wearable electronics, BLE modules, industrial transmitters, and smart metering applications requiring stable component supply with guaranteed long-term manufacturability.

Supply support for LP5951MGX-1.5/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 delivering analog and embedded processing solutions, with decades of expertise in power management IC design and manufacturing reliability.

The LP5951 product line targets ultra-low-power portable systems, emphasizing micropower operation, small-footprint packaging, and robust transient performance for battery-constrained edge devices.

FAQ

What is the minimum input voltage required for LP5951MGX-1.5/NOPB to regulate 1.5 V at 150 mA?

The LP5951MGX-1.5/NOPB requires VIN ≥ VOUT + VDO = 1.5 V + 0.2 V = 1.7 V to maintain regulation at 150 mA. However, the absolute minimum operating input voltage is specified as 1.8 V per recommended conditions - so 1.8 V is the practical lower limit for guaranteed performance across temperature and process variation. Below 1.8 V, internal bias circuitry may not function reliably.

Can LP5951MGX-1.5/NOPB operate without an output capacitor?

No - LP5951MGX-1.5/NOPB requires a minimum 0.7 µF ceramic output capacitor (1 µF recommended) for stability, as confirmed in Section 6.8 of the datasheet. Omitting the capacitor causes oscillation and loss of regulation. The device is optimized for 1-µF X7R/X5R ceramics with ESR between 3 mΩ and 300 mΩ; tantalum or electrolytic types are not recommended due to ESR and aging effects.

Is the NC pin on LP5951MGX-1.5/NOPB safe to connect to ground or leave floating?

The NC pin (Pin 4) on LP5951MGX-1.5/NOPB has no internal connection and must remain unconnected - neither grounded nor tied to any net. Connecting it risks parasitic coupling or unintended current paths that could degrade noise performance or cause erratic enable behavior. TI's Pin Functions table explicitly states "No internal connection", and layout guidelines require this pad to be left unpopulated.

How does LP5951MGX-1.5/NOPB behave when the output is forced above the input voltage?

LP5951MGX-1.5/NOPB contains a PMOS pass device with an inherent body diode. If VOUT exceeds VIN, reverse current flows through this diode. The datasheet specifies safe reverse current is limited to 50 mA. Exceeding this risks thermal overstress; TI recommends adding an external Schottky diode (cathode to VIN, anode to VOUT) for applications where VOUT may exceed VIN - such as backup battery switchover or hot-swap scenarios.

Does LP5951MGX-1.5/NOPB support 1.8-V logic-level enable signals?

Yes - LP5951MGX-1.5/NOPB has VIH = 0.9 V (max) and VIL = 0.4 V (min) across –40°C to +125°C, making it fully compatible with 1.8-V GPIO outputs. A 1.8-V logic high (≥1.35 V) exceeds the 0.9-V threshold with ample margin, ensuring robust enable signaling even with PCB trace resistance or I/O voltage droop. The EN pin must never be left floating and should be pulled to VIN or GND via ≥1 MΩ resistor if unused.