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

Overview

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

For engineers reviewing the MP8903DG-2.5-LF-P datasheet, MP8903DG-2.5-LF-P pinout, MP8903DG-2.5-LF-P application, or MP8903DG-2.5-LF-P equivalent, key selection criteria include dropout voltage under load, FB threshold stability across temperature, thermal resistance (θJA = 80°C/W), EN logic compatibility, and low-ESR capacitor stability requirements.

Technical Context

The MP8903DG-2.5-LF-P uses a PMOS pass transistor architecture enabling low dropout performance and inherent reverse-current blocking. Its internal bandgap reference sets a precise 1.222V feedback threshold, supporting both fixed-output (2.5V) and adjustable configurations via external resistor dividers.

Thermal protection activates at 155°C with 30°C hysteresis, and the device remains stable with X5R/X7R ceramic output capacitors ≥1μF. PSRR is 50dB at 1kHz and 20dB at 1MHz, making it suitable for noise-sensitive analog subsystems requiring clean local regulation.

Key Specifications

Pinout & Package

MP8903DG-2.5-LF-P is housed in a thermally enhanced QFN8 (2×2mm, 0.5mm pitch) package with exposed thermal pad. Pin 7 is NC; all other pins are electrically functional and validated per MPS Rev. 1.11 datasheet.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MCP1700T-2502E/TT and TLS850B2TE/V1, MP8903DG-2.5-LF-P uniquely balances 150mA capability, EN control, thermal protection, and QFN8 footprint-making it optimal for compact, thermally constrained portable electronics where headroom and safety margins matter.

Availability

MP8903DG-2.5-LF-P is available at Aetrix Electronics and suitable for mobile handset PLL power, audio codec analog supply, and 802.11 PC card core logic requiring stable component supply, RoHS-compliant packaging, and lead-free assembly compatibility.

Supply support for MP8903DG-2.5-LF-P 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 mixed-signal ICs for power management, motor drive, and interface applications.

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

FAQ

What is the minimum input voltage required for regulation at 2.5V output?

The MP8903DG-2.5-LF-P requires VIN ≥ VOUT + VDROPOUT. With a typical dropout of 100mV at 100mA, the minimum functional input is 2.6V. At full 150mA load, dropout rises to ~125mV, so 2.625V is the practical lower limit for guaranteed regulation.

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

No. Per the datasheet, the FB pin must be connected directly to the OUT pin in fixed-output configurations. Leaving FB floating violates bias conditions and may cause output instability or excessive quiescent current due to undefined internal node voltages.

Is the exposed thermal pad on the QFN8 package required to be soldered?

Yes. The exposed pad is internally connected to GND and serves as the primary thermal conduction path. It must be soldered to a dedicated PCB thermal pad with ≥4 thermal vias to an inner ground plane to achieve the specified θJA = 80°C/W and prevent thermal shutdown under 150mA load.

Does MP8903DG-2.5-LF-P support reverse polarity protection?

No. The device lacks built-in reverse-voltage protection. Applying negative voltage to IN or OUT relative to GND exceeds absolute maximum ratings (–0.3V) and risks permanent damage. External protection diodes or MOSFET-based circuits are required in systems prone to reverse connection.

What is the recommended output capacitor ESR range for stability?

The MP8903DG-2.5-LF-P is optimized for low-ESR ceramic capacitors (X5R/X7R) from 1μF to 10μF. It does not require a minimum ESR and remains stable down to <10mΩ. Tantalum or aluminum electrolytic capacitors with ESR >100mΩ are not recommended and may cause oscillation.

How does EN pin behavior affect startup time?

When EN is pulled high, the device enables within 50μs (typical), followed by output soft-start over ~100μs. No external soft-start capacitor is needed. If EN is toggled rapidly, the internal thermal protection and undervoltage lockout ensure safe re-enabling without latch-up or overshoot.

Can MP8903DG-2.5-LF-P be used in adjustable mode despite its fixed marking?

Yes. Though marked for 2.5V, the internal feedback network is disconnected in DG-package variants. The FB pin is fully accessible, allowing adjustment from 1.25V to 5V using an external resistor divider - provided R1 + R2 ≤ 100kΩ and R2 = 10kΩ ±1% for best accuracy.