Monolithic Power Systems Inc. MP8903DG-2.5-LF-Z

Overview

MP8903DG-2.5-LF-Z from Monolithic Power Systems is a fixed-output 2.5V, 150mA low-dropout linear regulator with 2% output accuracy, 100mV dropout at 100mA, and operation from 2.7V to 6.5V input. It features thermal shutdown protection, stable operation with low-ESR ceramic capacitors, and is packaged in a 2×2mm QFN8 for space-constrained mobile handset PLL and audio codec power rails.

For engineers reviewing the MP8903DG-2.5-LF-Z datasheet, MP8903DG-2.5-LF-Z pinout, MP8903DG-2.5-LF-Z application, or MP8903DG-2.5-LF-Z equivalent, key selection criteria include dropout voltage at full load, thermal resistance (θJA = 80°C/W), FB threshold tolerance (±0.025V), EN logic compatibility, and QFN8 thermal pad layout requirements.

Technical Context

The MP8903DG-2.5-LF-Z uses a PMOS pass transistor architecture enabling ultra-low dropout and inherent reverse-current blocking. Its internal 1.222V bandgap reference feeds a precision error amplifier that regulates output via feedback from the FB pin - fixed internally for 2.5V output or externally adjustable via resistor divider.

Thermal protection activates at 155°C junction temperature with 30°C hysteresis, and shutdown current is limited to 1μA max. PSRR is 50dB at 1kHz and 20dB at 1MHz, supporting noise-sensitive analog subsystems like audio codecs and RF PLLs.

Key Specifications

Pinout & Package

MP8903DG-2.5-LF-Z is housed in a thermally enhanced 8-pin QFN package (2mm × 2mm, 0.5mm pitch) with an exposed thermal pad. The package supports reflow soldering per JEDEC MO-229 VCCD-3 and requires PCB land pattern per datasheet Figure 5.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar low-dropout linear regulator applications.

Compared with XC6206P252MR-G and AP2210K-2.5TRG1, MP8903DG-2.5-LF-Z delivers superior thermal performance (80°C/W vs. >200°C/W), lowest dropout (100mV), and smallest footprint - making it optimal for thermally constrained, battery-sensitive portable designs.

Availability

MP8903DG-2.5-LF-Z is available at Aetrix Electronics and suitable for mobile handset PLL power, audio codec bias supply, and 802.11 PC card interface applications requiring stable component supply, RoHS-compliant packaging, and guaranteed long-term availability.

Supply support for MP8903DG-2.5-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.

The MP8903 belongs to MPS's low-noise, low-IQ linear regulator product line - engineered specifically for noise-sensitive analog subsystems in portable and wireless devices where size, thermal efficiency, and PSRR are critical.

FAQ

What is the minimum input voltage required to maintain 2.5V output at 150mA load?

The MP8903DG-2.5-LF-Z requires VIN ≥ VOUT + VDROP = 2.5V + 125mV = 2.625V at 150mA, based on the 125mV dropout specified at 150mA in the Electrical Characteristics table. At room temperature and typical conditions, 2.7V minimum input ensures reliable regulation across process and temperature variation.

Can the FB pin be left floating in the fixed 2.5V version?

Yes - the FB pin is internally connected to the fixed resistor divider network in MP8903DG-2.5-LF-Z. Datasheet Section "PIN FUNCTIONS" explicitly states FB is used only for adjustable configurations; leaving it unconnected has no effect on regulation or stability.

Is the exposed thermal pad electrically connected to GND?

Yes - the exposed pad on the QFN8 package is internally connected to GND (Pin 1). Per datasheet Package Information and PCB Layout Guide, it must be soldered to a dedicated GND plane with ≥4 thermal vias for optimal thermal performance and EMI suppression.

Does this part support ceramic output capacitors below 1μF?

No - the datasheet specifies 1μF to 10μF X5R/X7R ceramic capacitors for stable operation. Using <1μF violates the minimum capacitance requirement and risks oscillation, especially under load transients, as confirmed in Application Information section on Output Capacitor Selection.

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

Using PD(MAX) = (TJ(MAX) − TA) / θJA = (125°C − 70°C) / 80°C/W = 0.6875W. However, absolute maximum continuous power is limited to 1.6W at +25°C ambient; at +70°C, thermal derating reduces safe dissipation to ≤0.69W to prevent thermal shutdown.

How does EN pin logic interact with thermal shutdown?

EN is asynchronous and overrides thermal shutdown: pulling EN low forces immediate disable and reduces quiescent current to ≤1μA, even if junction temperature exceeds 155°C. Thermal shutdown only activates when EN is high and TJ exceeds threshold.

Is the 2.5V output trimmed at final test?

Yes - the Electrical Characteristics table lists output voltage accuracy as ±2.0% over temperature and load, and the Ordering Information confirms factory-trimmed fixed outputs. This is achieved via laser trimming of internal resistor dividers during wafer sort and final test.