Monolithic Power Systems Inc. MP20045DQ-25-LF-Z

Overview

MP20045DQ-25-LF-Z from Monolithic Power Systems is a low-noise, 1A fixed-output (2.5V) linear regulator with 140mV dropout at full load, 110μA ground current, and 13μVRMS output noise. It uses an internal PMOS pass element and operates from 2.5V to 5.5V input, targeting power-sensitive battery-operated systems requiring stable, clean voltage rails.

For engineers reviewing the MP20045DQ-25-LF-Z datasheet, MP20045DQ-25-LF-Z pinout, MP20045DQ-25-LF-Z application, or MP20045DQ-25-LF-Z equivalent, this device delivers verified low-noise regulation, open-drain power-good signaling, thermal/overcurrent protection, and QFN8 package compatibility for space-constrained portable electronics design.

Technical Context

The MP20045DQ-25-LF-Z integrates a PMOS pass transistor enabling ultra-low dropout (140mV @ 1A) and minimal quiescent current (110μA). Its feedback threshold is fixed at 1.5V internally for the 2.5V version, eliminating external resistor networks while retaining precision via ±2.5% output voltage accuracy over temperature and line/load conditions.

It features an open-drain PG output that asserts low when VOUT drops below 80–86% of nominal, with 1.1–1.3V trip hysteresis and <0.4V output low voltage. Thermal shutdown activates at 150°C with 20°C hysteresis, and current limiting holds output at 1.4–3.0A depending on input voltage and regulation state.

Key Specifications

Pinout & Package

MP20045DQ-25-LF-Z is housed in an 8-pin QFN package (3mm × 3mm, exposed thermal pad), optimized for thermal performance and PCB area efficiency. The exposed pad must be soldered to a GND plane for effective heat dissipation and electrical stability.

Key Features

Applications

Equivalent & Alternatives

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

Compared with XC6210B252MR-G and ADM7172ACPZ-2.5-R7, MP20045DQ-25-LF-Z uniquely balances ultra-low noise (13μVRMS), minimal IQ (110μA), and QFN8 thermal performance-making it optimal for compact, battery-limited designs where both runtime and signal fidelity are critical.

Availability

MP20045DQ-25-LF-Z is available at Aetrix Electronics and suitable for wireless handheld instruments, Li-ion powered microcontroller systems, Bluetooth audio transceivers, and portable medical sensors requiring stable component supply, RoHS-compliant packaging, and tape-and-reel delivery for automated assembly.

Supply support for MP20045DQ-25-LF-Z 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 a focus on energy-efficient, miniaturized solutions for consumer, industrial, and automotive markets.

The MP20045 belongs to MPS's low-noise LDO product line, engineered specifically for battery-powered portable electronics demanding ultra-low dropout, sub-20μVRMS noise, and integrated protection-without sacrificing small-footprint manufacturability.

FAQ

What is the minimum input voltage required for MP20045DQ-25-LF-Z to maintain regulation at 1A load?

The minimum input voltage is calculated as VOUT + dropout = 2.5V + 0.14V = 2.64V. At 1A load and 25°C, regulation is maintained down to 2.64V; however, the absolute minimum input per absolute ratings is 2.5V, and UVLO triggers at 2.0–2.3V rising, so operation below 2.64V results in unregulated output.

Can MP20045DQ-25-LF-Z be used without an external output capacitor?

No. A minimum 2.2μF ceramic capacitor with ESR ≤0.9Ω is mandatory for stability and transient response. Omitting it causes oscillation, excessive noise, and potential thermal runaway under load. The datasheet explicitly specifies this as a hard requirement-not optional.

How does the power-good (PG) output behave during startup and fault conditions?

PG remains high-impedance until VOUT reaches ~80–86% of 2.5V (~2.0–2.13V), then pulls low after a brief delay. During overcurrent or thermal shutdown, PG goes high-impedance (open-drain), signaling loss of regulation. It does not actively drive high-external pull-up is required.

Is the EN pin internally pulled up, and what happens if it's left unconnected?

No internal pull-up exists. Leaving EN floating risks unpredictable enable/disable behavior due to noise coupling, potentially causing intermittent output or latch-up. The datasheet mandates tying EN to VIN (for always-on) or a controlled logic source-never floating.

Does MP20045DQ-25-LF-Z require a specific PCB layout for thermal performance?

Yes. The exposed thermal pad (Pin 6) must be soldered to a solid GND copper pour ≥100 mm² with ≥4 thermal vias (0.3mm diameter) connecting to inner/ground planes. Without this, junction temperature exceeds 125°C at 1A, triggering thermal shutdown even at 25°C ambient.

What is the maximum allowable power dissipation in the QFN8 package at 60°C ambient?

Using θJA = 50°C/W and TJ(MAX) = 125°C, PD(MAX) = (125 − 60)/50 = 1.3W. At 1A and 2.64V input, power dissipation is (2.64 − 2.5) × 1 = 0.14W-well within limit. But at VIN = 5.5V, PD = (5.5 − 2.5) × 1 = 3.0W, exceeding rating and requiring derating or forced cooling.

How does load regulation affect system accuracy in precision analog applications?

Load regulation is specified as −0.3% from 1mA to 1A, meaning VOUT shifts by ≤7.5mV across full load. For a 2.5V rail feeding a 16-bit ADC reference, this introduces ≤0.05 LSB error-acceptable for most industrial sensing, but critical designs may add post-regulation filtering.