Monolithic Power Systems Inc. MP20045DN-LF-P

Overview

MP20045DN-LF-P from Monolithic Power Systems is a low-noise, 1A adjustable-output linear regulator with 140mV dropout at full load, 110μA ground current, and 13μVRMS output noise. It operates from 2.5V to 5.5V input and delivers stable output from 1.5V to 5V via external feedback resistors. Designed for battery-powered handheld instruments and portable communications equipment requiring high PSRR (56dB @ 1kHz) and precise power-good signaling.

For engineers reviewing the MP20045DN-LF-P datasheet, MP20045DN-LF-P pinout, MP20045DN-LF-P application, or MP20045DN-LF-P equivalent, key selection criteria include dropout voltage under 1A load, thermal shutdown threshold (150°C), open-drain PG output behavior, and SOIC8E package compatibility with legacy PCB layouts.

Technical Context

The MP20045DN-LF-P uses an internal PMOS pass transistor enabling ultra-low dropout and minimal quiescent current. Its feedback architecture centers on a fixed 1.5V reference at the FB pin, supporting both adjustable and fixed-output configurations without external compensation.

It integrates protection functions including foldback current limiting (1.4–3.0A in-regulation limit), thermal shutdown with 20°C hysteresis, and UVLO with 2.3V turn-on threshold and 160mV hysteresis - all implemented in a single-die analog design without digital control logic.

Key Specifications

Pinout & Package

MP20045DN-LF-P is housed in an SOIC8E package (5.0mm × 6.2mm × 1.75mm height) with exposed pad connected to GND for thermal management. Pin 1 is marked by a notch or index area; the exposed pad must be soldered to a PCB ground plane for optimal θJA = 50°C/W performance.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar low-noise, 1A LDO applications.

Compared with XC6210B182MR-G and ADP1740ACPZ-1.8-R7, MP20045DN-LF-P uniquely combines adjustable output, open-drain PG, ultra-low noise, and 110μA IQ in SOIC8E - making it the only option supporting flexible voltage scaling and robust power sequencing in space-constrained portable designs.

Availability

MP20045DN-LF-P is available at Aetrix Electronics and suitable for notebook computers, cordless telephones, cellular phones, and modems requiring stable component supply across extended production lifecycles.

Supply support for MP20045DN-LF-P 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

Monolithic Power Systems (MPS) is a fabless semiconductor company specializing in high-performance analog and power ICs, with design centers in the US, China, and Taiwan.

The MP20045 belongs to MPS's low-noise LDO product line, engineered specifically for battery-powered portable electronics where ultra-low dropout, minimal quiescent current, and high PSRR are essential for analog signal integrity.

FAQ

What is the minimum input voltage required for MP20045DN-LF-P to regulate a 2.5V output?

The minimum input is determined by dropout voltage plus output: 2.5V + 0.14V = 2.64V. However, the device's UVLO activates at 2.3V (rising), so stable regulation begins at 2.64V, and startup occurs at ≥2.3V. Below 2.64V, output drops linearly with input.

Can MP20045DN-LF-P be used with ceramic capacitors smaller than 2.2μF?

No - the datasheet specifies 2.2μF minimum capacitance with ESR < 0.9Ω for stability. Using smaller values risks oscillation, especially under load transients, due to insufficient phase margin in the control loop.

How does the power-good (PG) pin behave during thermal shutdown?

During thermal shutdown, VOUT collapses, causing PG to assert low within microseconds. PG remains low until VOUT recovers to ≥92% of nominal (e.g., ≥2.3V for 2.5V output), ensuring host systems detect fault conditions before resuming operation.

Is the EN pin internally pulled up or down?

There is no internal pull-up or pull-down on EN. The datasheet explicitly warns against floating the pin. External biasing is mandatory: tie to VIN for always-on operation or drive actively with a GPIO capable of ≥1.5V high and ≤0.4V low.

What is the maximum allowable power dissipation in SOIC8E at 70°C ambient?

Using θJA = 50°C/W and TJ(MAX) = 125°C: PD(MAX) = (125 − 70) / 50 = 1.1W. Exceeding this causes thermal shutdown. Layout with full-exposed-pad grounding improves real-world dissipation margin.

Does MP20045DN-LF-P support reverse polarity protection?

No - the device lacks reverse-input protection. Applying negative voltage to VIN or reverse-biasing VOUT relative to VIN can damage the internal PMOS and ESD structures. External diode protection is required in systems prone to polarity reversal.

How does load regulation performance change between 1mA and 1A output current?

Load regulation is specified as −0.3% across 1mA–1A, meaning VOUT deviates no more than ±7.5mV for a 2.5V output. This tight regulation is enabled by the high-gain error amplifier and low-impedance PMOS pass element.