Monolithic Power Systems Inc. MP20045DQ-33-LF-Z

Overview

MP20045DQ-33-LF-Z 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 3.3V output (via external resistor divider), targeting power-sensitive portable electronics requiring high PSRR and precise voltage regulation.

For engineers reviewing the MP20045DQ-33-LF-Z datasheet, MP20045DQ-33-LF-Z pinout, MP20045DQ-33-LF-Z application, or MP20045DQ-33-LF-Z equivalent, key selection criteria include dropout performance at 1A, thermal shutdown threshold (150°C), open-drain PG status signaling, EN logic thresholds (1.5V high / 0.4V low), and QFN8 package thermal resistance (θJA = 50°C/W).

Technical Context

The MP20045DQ-33-LF-Z employs an internal PMOS pass transistor enabling ultra-low dropout and minimal quiescent current. Its feedback architecture uses a fixed 1.5V reference at the FB pin, allowing precise output setting via external resistive dividers - for 3.3V output, R1 ≈ 12kΩ and R2 = 100kΩ per design equations.

It integrates protection features including foldback current limiting (1.4–3.0A in-regulation limit), thermal shutdown with 20°C hysteresis, and open-drain power-good monitoring that asserts low when VOUT drops below 80–86% of nominal. The PG pin requires an external pull-up for proper logic-level interfacing.

Key Specifications

Pinout & Package

The MP20045DQ-33-LF-Z is housed in an 8-pin QFN package (3mm × 3mm, exposed thermal pad), optimized for compact PCB layouts and efficient heat dissipation when the pad is soldered to a solid GND plane.

Key Features

Applications

Equivalent & Alternatives

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

Compared with XC6210B332MR-G and ADM7172ACPZ-3.3-R7, the MP20045DQ-33-LF-Z uniquely balances ultra-low dropout (140mV), sub-15μV noise, and full system visibility via PG/EN - making it optimal for portable, battery-powered systems demanding both efficiency and robust power management.

Availability

MP20045DQ-33-LF-Z is available at Aetrix Electronics and suitable for notebook computers, handheld medical instruments, wireless communication modules, and industrial portable scanners requiring stable component supply with RoHS-compliant, lead-free packaging.

Supply support for MP20045DQ-33-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 in the US, China, and Taiwan, and global manufacturing partnerships.

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 extending runtime and preserving signal integrity.

FAQ

What is the minimum input voltage required to maintain 3.3V output at 1A load?

The MP20045DQ-33-LF-Z requires VIN ≥ 3.44V to sustain 3.3V output at 1A, based on its 140mV dropout specification. Below this, output voltage collapses linearly; operation down to 2.5V input is supported only at reduced load currents per the dropout vs. IOUT curve.

Can the MP20045DQ-33-LF-Z be used without the FB resistor divider?

No - the "DQ" suffix denotes the adjustable version, which requires an external resistor divider from VOUT to FB to set the output voltage. For 3.3V, typical values are R2 = 100kΩ and R1 = 12kΩ. Fixed-output variants (e.g., MP20045DQ-33) omit FB connection.

How should the exposed thermal pad on the QFN8 package be connected?

The exposed pad (Pin 6) must be soldered to a dedicated PCB copper pour tied directly to the system GND plane. At least 4 thermal vias (0.3mm diameter) connecting the pad to inner-layer GND planes are recommended to achieve θJA = 50°C/W and prevent thermal shutdown at full load.

Does the PG pin require an external pull-up resistor?

Yes - PG is open-drain and must be pulled up to a valid logic-high voltage (e.g., 3.3V or VOUT) via a 10kΩ resistor. Without pull-up, PG remains floating and cannot signal power-good status to host controllers or sequencers.

What is the maximum allowable power dissipation in the QFN8 package at 25°C ambient?

At TA = 25°C, the QFN8 package supports up to 2.0W continuous power dissipation before thermal shutdown activates, calculated as PD(MAX) = (TJ(MAX) − TA)/θJA = (125°C − 25°C)/50°C/W = 2.0W. Derate linearly above 25°C ambient.

Is the MP20045DQ-33-LF-Z compatible with ceramic output capacitors?

Yes - it is optimized for 2.2μF X5R/X7R ceramic capacitors with ESR < 0.9Ω. Larger values (e.g., 4.7μF) improve transient response but may affect stability if ESR falls outside the 0.1–0.9Ω window shown in Figure 2 of the datasheet.

What happens during thermal shutdown, and how does recovery work?

When junction temperature exceeds 150°C, the PMOS pass device turns off completely. Output drops to zero. After cooling by 20°C (to ~130°C), the device automatically resumes regulation. This hysteresis prevents oscillatory on/off cycling during sustained overload conditions.