Monolithic Power Systems Inc. MP20045DN-33-LF

Overview

MP20045DN-33-LF 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–5.5V input and delivers stable 3.3V output in SOIC8E package for power-sensitive portable electronics.

For engineers reviewing the MP20045DN-33-LF datasheet, MP20045DN-33-LF pinout, MP20045DN-33-LF application, or MP20045DN-33-LF equivalent, key selection criteria include dropout voltage under 1A load, PSRR of 56dB at 1kHz, open-drain power-good signaling, thermal shutdown at 150°C, and compatibility with 2.2μF ceramic output capacitors.

Technical Context

The MP20045DN-33-LF uses an internal PMOS pass transistor to achieve ultra-low dropout and quiescent current. Its feedback loop references a precise 1.5V internal bandgap, enabling accurate output regulation across temperature and load.

It integrates protection features including current limiting (1.4–3.0A), thermal shutdown with 20°C hysteresis, and undervoltage lockout with 160mV hysteresis. The open-drain PG pin asserts low when VOUT drops below 94% of nominal, supporting system-level power sequencing.

Key Specifications

Pinout & Package

MP20045DN-33-LF is housed in an SOIC8E package (5.0mm × 6.2mm × 1.75mm) with exposed pad thermally connected to GND. The 8-pin layout supports standard PCB assembly and provides dedicated pins for input bypass, output filtering, feedback, enable, and power-good status.

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 ADP1740ACPZ-3.3-R7, MP20045DN-33-LF uniquely balances ultra-low noise (13μVRMS), low IQ (110μA), and integrated PG functionality in a single SOIC8E package-making it optimal for space-constrained, battery-powered systems requiring verified rail integrity and analog-clean power.

Availability

MP20045DN-33-LF is available at Aetrix Electronics and suitable for wireless LAN modules, industrial hand-held meters, medical wearables, and smart POS terminals requiring stable component supply, RoHS-compliant packaging, and long-term production continuity.

Supply support for MP20045DN-33-LF 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.

The MP20045 series belongs to MPS's low-noise LDO product line, engineered specifically for battery-powered portable electronics demanding ultra-low dropout, sub-150μA quiescent current, and high PSRR in compact packages.

FAQ

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

The MP20045DN-33-LF requires VIN ≥ 3.44V to sustain 3.3V output at 1A, based on its 140mV typical dropout voltage. At worst-case 280mV dropout (per datasheet max), VIN must be ≥ 3.58V. Input under-voltage lockout activates below 2.0V, but regulation fails well before that threshold.

Can the MP20045DN-33-LF be used with ceramic output capacitors smaller than 2.2μF?

No-MP20045DN-33-LF requires a minimum 2.2μF ceramic output capacitor with ESR ≤ 0.9Ω for stability, as confirmed by Figure 2 in the datasheet. Using smaller capacitance risks oscillation or degraded transient response, especially under 500mA–1A load steps.

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

The PG pin remains high-impedance until VOUT reaches 94% of target (3.102V for 3.3V). It then pulls low only if VOUT drops below 94% due to overload, thermal shutdown, or input collapse. During normal operation, PG stays high via external pull-up; no internal pull-up is provided.

Is the EN pin internally pulled up, and what happens if left floating?

Yes-the EN pin has an internal pull-up resistor of 550kΩ to 1.1MΩ, ensuring default ON state when unconnected. However, the datasheet explicitly warns against floating EN: noise or leakage may cause erratic enable/disable behavior. Tie to VIN for always-on use or drive actively with GPIO.

Does MP20045DN-33-LF support adjustable output voltages, or is it fixed-only?

MP20045DN-33-LF is a fixed 3.3V version. The "DN" suffix denotes SOIC8E package with factory-trimmed output; adjustable variants use "DN" without voltage suffix (e.g., MP20045DN) and require external FB resistors. This part's FB pin is internally connected to VOUT and must not be reconfigured.

What thermal derating applies when operating above +25°C ambient?

With θJA = 50°C/W, maximum power dissipation drops linearly: PD(MAX) = (125°C − TA)/50. At TA = 70°C, PD(MAX) = 1.1W. For 3.3V output and 1A load, VIN must stay ≤ 4.4V to keep power ≤ 1.1W (1.1V × 1A), avoiding thermal shutdown.