Monolithic Power Systems Inc. MP62551DJ-LF-P

Overview

MP62551DJ-LF-P from Monolithic Power Systems is a precision programmable current-limited power distribution switch with active-high enable, 1.5A continuous output current capability, ±10% current-limit accuracy over 60mA–1.7A (typ), 88mΩ R_DS(on) (TSOT23-6 package), and integrated thermal shutdown, reverse-voltage protection, and deglitched FLAG fault reporting. It operates from 2.5V to 5.5V input and is used in USB power distribution and portable GPS device power rail control.

For engineers reviewing the MP62551DJ-LF-P datasheet, MP62551DJ-LF-P pinout, MP62551DJ-LF-P application, or MP62551DJ-LF-P equivalent, key selection criteria include programmable current limit via ILIM resistor, fast 2μs over-current response, soft-start timing (0.5–1.5ms VOUT rise), open-drain FLAG behavior under fault conditions, and TSOT23-6 thermal performance (θ_JA = 220°C/W).

Technical Context

The MP62551DJ-LF-P integrates an N-channel MOSFET with internal charge pump for gate drive above VIN, enabling full enhancement down to 2.5V input. Its current-limit circuit uses a precision amplifier with external R_ILIM (12.4kΩ–210kΩ) to set threshold with ±10% tolerance across temperature.

Thermal protection employs dual independent sensors: one triggers at 135°C during current-limit operation, the other at 155°C unconditionally, both with ~10°C hysteresis. The FLAG pin is open-drain, deglitched for over-current (3.5–10ms), undeglitched for over-temperature, and unaffected by UVLO transitions.

Key Specifications

Pinout & Package

MP62551DJ-LF-P is housed in a 6-pin TSOT23 package (2.9mm × 1.6mm × 1.1mm), featuring exposed thermal pad internally connected to GND for PCB heat sinking. Pin 1 is lower-left when reading top marking left-to-right.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar programmable current-limiting power switch applications.

Compared with TPS2557DRBR and NCP45520MUTBG, MP62551DJ-LF-P uniquely combines resistor-programmable current limit, reverse-voltage protection, and native auto-retry functionality in a 6-pin TSOT23 package-reducing component count and layout complexity for portable USB and GPS power architectures.

Availability

MP62551DJ-LF-P is available at Aetrix Electronics and suitable for USB power distribution, portable GPS devices, notebook PC subsystems, and smartphone peripheral rail management requiring stable component supply, RoHS-compliant packaging, and long-term lifecycle continuity.

Supply support for MP62551DJ-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 power ICs, with design centers in the US, China, and Taiwan, and global manufacturing partnerships.

The MP6255x series belongs to MPS's precision power distribution switch product line, engineered specifically for compact, battery-sensitive applications demanding accurate current limiting, robust fault handling, and minimal external components.

FAQ

What is the minimum recommended R_ILIM value for MP62551DJ-LF-P?

The minimum recommended R_ILIM is 12.4kΩ (1% tolerance), corresponding to a typical current limit of 1.7A. Using lower resistance risks exceeding the 1.7A upper bound and may reduce accuracy due to amplifier offset effects at extreme programming ranges.

Does MP62551DJ-LF-P support automatic recovery after thermal shutdown?

Yes-MP62551DJ-LF-P features automatic-on recovery after fault removal. Once junction temperature drops ~10°C below the 155°C shutdown threshold, the internal switch re-enables without requiring external reset or EN toggling.

Can FLAG be used to trigger an external retry circuit without microcontroller involvement?

Yes-by connecting FLAG (open-drain) to EN through an RC network, the device implements autonomous retry: FLAG pulls low during fault, discharging the capacitor; after deglitch timeout, capacitor recharge raises EN voltage, re-enabling the switch until fault clears.

Is reverse-voltage protection active when EN is low?

Yes-reverse-voltage protection remains fully functional regardless of EN state. If V_OUT exceeds V_IN by >135mV, the MOSFET turns off within 5ms even with EN=0V, preventing backfeed into the input supply.

What is the maximum allowable power dissipation for MP62551DJ-LF-P at +85°C ambient?

At T_A=+85°C, maximum continuous power dissipation is 0.57W (per datasheet absolute ratings). This assumes θ_JA=220°C/W and T_J(MAX)=125°C; actual derating depends on PCB copper area and airflow.

How does UVLO interact with FLAG reporting during input brownout?

FLAG remains unchanged during UVLO activation or deactivation-it only asserts low for over-current or over-temperature faults. This ensures system fault monitoring stays decoupled from input supply transients.

What is the purpose of the exposed thermal pad on the TSOT23-6 package?

The exposed pad is internally connected to GND and serves as the primary thermal path. It must be soldered to a dedicated PCB copper pour tied to GND to achieve rated θ_JA=220°C/W and prevent thermal shutdown under 1.5A continuous load.