Monolithic Power Systems Inc. MP8903DJ-3.3-LF-P

Overview

MP8903DJ-3.3-LF-P from Monolithic Power Systems is a 150mA low-dropout linear regulator in TSOT23-5 package, delivering fixed 3.3V output with ±2% accuracy across –40°C to +85°C. It operates from 2.7V to 6.5V input, achieves 100mV dropout at 100mA, and integrates thermal shutdown for protection in space-constrained power rails such as mobile handset PLL supplies.

For engineers reviewing the MP8903DJ-3.3-LF-P datasheet, MP8903DJ-3.3-LF-P pinout, MP8903DJ-3.3-LF-P application, or MP8903DJ-3.3-LF-P equivalent, key selection criteria include dropout voltage at full load, thermal resistance (θJA = 220°C/W), FB threshold (1.222V), EN logic compatibility, and stability with low-ESR ceramic capacitors.

Technical Context

The MP8903DJ-3.3-LF-P uses a PMOS pass transistor architecture enabling low dropout performance and inherent reverse-current blocking. Its internal bandgap reference (1.222V) feeds a precision error amplifier that regulates output via feedback from the FB pin.

Enable control is active-high with 1.5V logic threshold and sub-1μA shutdown current; thermal protection activates at 155°C with 30°C hysteresis, ensuring safe operation under sustained overload or poor PCB thermal design.

Key Specifications

Pinout & Package

MP8903DJ-3.3-LF-P is housed in a RoHS-compliant TSOT23-5 package (2.9mm × 1.6mm × 1.0mm), featuring exposed pad-less construction optimized for low-cost assembly and moderate thermal dissipation (θJA = 220°C/W).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MCP1700T-3302E/TT and TLS850B2TE/V1, MP8903DJ-3.3-LF-P uniquely balances 150mA capability, 100mV dropout, EN control, thermal protection, and TSOT23-5 size-making it optimal for consumer portable electronics where space, efficiency, and reliability are co-constrained.

Availability

MP8903DJ-3.3-LF-P 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 compliance, and lead-free assembly support.

Supply support for MP8903DJ-3.3-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, motion control, and interface applications.

The MP8903 product line delivers compact, thermally robust LDOs targeting portable and space-constrained systems where low dropout, precision output, and integrated protection are essential.

FAQ

What is the maximum allowable input voltage for MP8903DJ-3.3-LF-P?

The absolute maximum input voltage is +7.0V, but the recommended operating range is 2.7V to 6.5V. Exceeding 6.5V may cause excessive power dissipation or trigger thermal shutdown, especially at high ambient temperatures or heavy load conditions.

Can MP8903DJ-3.3-LF-P be used in adjustable-output configuration?

No - MP8903DJ-3.3-LF-P is factory-trimmed for fixed 3.3V output and has FB pin internally connected to the internal resistor divider. For adjustable operation, select MP8903DJ-XX versions marked "X.X" or use MP8903DX variants with accessible FB pin.

Is an input capacitor required, and what type is recommended?

Yes - a minimum 1μF X5R or X7R ceramic capacitor must be placed between IN and GND, located as close as possible to the device. Larger values up to 10μF improve line transient response but increase board area.

What is the thermal resistance (θJA) of the TSOT23-5 package?

The junction-to-ambient thermal resistance is 220°C/W on a standard 4-layer JEDEC test board. Actual θJA depends heavily on PCB copper area and layout; adding thermal vias under the GND pad can reduce effective θJA by up to 40%.

Does MP8903DJ-3.3-LF-P require an output capacitor, and why?

Yes - a 1–10μF X5R/X7R ceramic capacitor is mandatory between OUT and GND to ensure loop stability, suppress load transients, and reduce output noise. Omitting it risks oscillation, overshoot, or failure to regulate under dynamic load changes.

How does the EN pin behave during power-up sequencing?

The EN pin is active-high with 1.5V threshold and <1μA bias current. When tied directly to IN, the device powers up immediately upon input application. For controlled sequencing, drive EN with a delayed logic signal to coordinate with other rails or reset controllers.

What is the FB pin function in MP8903DJ-3.3-LF-P?

In this fixed-output variant, the FB pin is internally connected and not accessible externally. It must be left unconnected (NC) per datasheet guidance - applying external components or voltage to FB may disrupt regulation or damage the device.