Monolithic Power Systems Inc. MP20045DQ-15-LF-Z

Overview

MP20045DQ-15-LF-Z from Monolithic Power Systems is a low-noise, 1A adjustable-output linear regulator with 140mV dropout at full load, 13μVRMS output noise, and 56dB PSRR at 1kHz. It operates from 2.5V to 5.5V input, delivers fixed 1.5V output in QFN8 (3mm × 3mm), and integrates PMOS pass element, open-drain power-good (PG), and enable (EN) control - used in battery-powered handheld instruments requiring stable low-noise bias.

For engineers reviewing the MP20045DQ-15-LF-Z datasheet, MP20045DQ-15-LF-Z pinout, MP20045DQ-15-LF-Z application, or MP20045DQ-15-LF-Z equivalent, key selection criteria include dropout voltage under 1A load, ground current ≤110μA, FB accuracy ±2.5%, thermal shutdown at 150°C, and compatibility with 2.2μF ceramic output capacitors.

Technical Context

The MP20045DQ-15-LF-Z employs an internal PMOS pass transistor enabling ultra-low dropout (140mV @ 1A) and minimal quiescent current (110μA). Its feedback architecture uses a precise 1.5V reference with ±2.5% FB accuracy, supporting both fixed 1.5V output and adjustable configurations via external resistor divider.

It integrates multiple protection functions: thermal shutdown (trip at 150°C, 20°C hysteresis), short-circuit current limiting (1.6A typical), and open-drain PG output asserting low when VOUT drops below 80–86% of nominal. EN pin logic thresholds (1.5V high / 0.4V low) ensure robust digital control without floating.

Key Specifications

Pinout & Package

MP20045DQ-15-LF-Z is housed in an 8-pin QFN package (3mm × 3mm, exposed thermal pad), optimized for compact, thermally efficient layouts in space-constrained portable devices.

Key Features

Applications

Equivalent & Alternatives

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

Compared with XC6210B152MR-G and ADM7172ACPZ-1.5-R7, MP20045DQ-15-LF-Z uniquely balances ultra-low dropout (140mV), ultra-low IQ (110μA), and integrated PG/EN - making it optimal for space- and energy-constrained portable instrumentation where supply headroom and sequencing reliability are non-negotiable.

Availability

MP20045DQ-15-LF-Z is available at Aetrix Electronics and suitable for notebook computers, handheld instruments, portable medical sensors, and wireless sensor nodes requiring stable component supply with guaranteed long-term manufacturability and RoHS-compliant packaging.

Supply support for MP20045DQ-15-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 design centers across Asia and North America and global manufacturing partnerships.

The MP20045 product line targets battery-powered portable electronics demanding ultra-low noise, low dropout, and minimal quiescent current - specifically engineered for handheld test equipment, medical wearables, and industrial data loggers where power integrity directly impacts measurement fidelity.

FAQ

What is the minimum input voltage required for MP20045DQ-15-LF-Z to regulate 1.5V output at 1A?

The minimum input is 1.64V (1.5V + 140mV dropout), but per absolute maximum ratings and recommended operating conditions, VIN must be ≥2.5V. Below 2.5V, UVLO activates at 2.0–2.3V, disabling regulation - so functional minimum is 2.5V for guaranteed 1A operation.

Can MP20045DQ-15-LF-Z be used with ceramic output capacitors smaller than 2.2μF?

No - the datasheet specifies 2.2μF ceramic with ESR <0.9Ω as the minimum stable value. Using smaller capacitance risks instability, as shown in Figure 2's ESR vs. output current stability boundary; 1μF or less may cause oscillation under load transients.

Is the exposed thermal pad on the QFN8 package electrically connected to GND?

Yes - Pin 6 (GND) and the exposed pad are internally connected and must be soldered to a PCB ground plane. This dual-path grounding provides both electrical reference integrity and thermal conduction, enabling the rated 2.0W power dissipation at TA=25°C.

Does the PG pin require an external pull-up resistor, and what value is recommended?

Yes - PG is open-drain and requires an external pull-up. A 10kΩ resistor to 1.8–3.3V is typical; values from 4.7kΩ to 100kΩ are acceptable depending on rise time and bus loading. Do not leave PG unconnected - it will float high and falsely indicate "good" during fault conditions.

How does the EN pin behave during power-up, and is an external pull-up needed?

The EN pin has an internal 550kΩ to 1.1MΩ pull-up to VIN, so it defaults to ON at power-up if VIN rises cleanly. However, for deterministic startup in noisy environments or when VIN ramps slowly, an external 100kΩ pull-up to VIN is recommended to ensure EN exceeds 1.5V before regulation begins.

What is the accuracy of the 1.5V output under varying load and temperature?

Output voltage accuracy is ±2.5% over load (1mA–1A) and temperature (−40°C to +85°C), per the "Output Voltage Accuracy" row in Electrical Characteristics. At 25°C and 1mA load, tolerance tightens to ±2.5%; worst-case deviation remains within ±2.5% across full operating range.

Can MP20045DQ-15-LF-Z replace adjustable versions like MP20045DQ in existing designs?

Yes - pin-compatible with MP20045DQ (adjustable version), but FB must be connected directly to VOUT (not a resistor divider) for correct 1.5V operation. No other schematic changes are needed; thermal and layout requirements remain identical due to shared QFN8 package and electrical specs.