Monolithic Power Systems Inc. MP5981GLU-P

Overview

MP5981GLU-P from Monolithic Power Systems is a monolithic hot-swap Intelli-Fuse IC integrating a 1.1mΩ R_DS(ON) high-side MOSFET, current mirror, on-die temperature sensor, and fault reporting logic. It delivers up to 50A continuous current at 25°C (60A with airflow), operates from 4V–16V input, and limits inrush during live insertion into backplane systems-used in server power distribution units and modular telecom line cards.

For engineers reviewing the MP5981GLU-P datasheet, MP5981GLU-P pinout, MP5981GLU-P application, or MP5981GLU-P equivalent, key selection criteria include its integrated current/temperature sensing, programmable over-current threshold via CLREF, soft-start timing control via SS capacitor, latch/hiccup mode selection via MODE pin, and parallel operation capability for >50A load protection.

Technical Context

The MP5981GLU-P implements a closed-loop gate-control architecture that regulates the integrated MOSFET's V_GS to enforce current limiting during both start-up and steady-state operation. Its current-sense path uses an internal current mirror (g_CS = 10 µA/A) referenced to external RCS, while CLREF voltage sets the trip threshold with dynamic clamping (635 mV at V_OUT < 80% V_IN, 1.6 V otherwise).

Thermal management integrates die-temperature sensing via VTEMP (8.7 mV/°C), over-temperature shutdown at 143°C, and real-time fault reporting through open-drain GOK (latched) and D_OC (over-current indicator). The device supports dual operational modes: standalone (via ON/PD control) or controller-coordinated (e.g., with MP5920), with built-in insertion delay (1.8 ms) and PD-mode pull-down (500 Ω, 2.1 ms delay).

Key Specifications

Pinout & Package

The MP5981GLU-P is housed in a thermally enhanced LGA-32 (5mm × 5mm) package with exposed thermal pad, optimized for low θ_JA (23.4°C/W) on 4-layer PCBs.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar hot-swap e-fuse applications.

Compared with TPS2491RGER and LTC4215IMS#PBF, the MP5981GLU-P uniquely integrates MOSFET, current mirror, and die-temperature sensor in one LGA-32 package-reducing component count by ≥6 parts while enabling higher current density and faster short-circuit response (200 ns vs. >1 µs).

Availability

MP5981GLU-P is available at Aetrix Electronics and suitable for server blade power distribution, telecom line card protection, enterprise storage enclosures, and industrial PC expansion modules requiring stable component supply across multi-year production cycles.

Supply support for MP5981GLU-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 power management ICs, with design centers in the US, China, and Taiwan, and global manufacturing partnerships.

The MP5981GLU-P belongs to MPS's Intelli-Fuse product line, engineered specifically for high-current hot-swap protection in datacenter, networking, and industrial infrastructure-emphasizing integration, thermal resilience, and system-level telemetry.

FAQ

What is the maximum continuous current rating for MP5981GLU-P under natural convection?

The MP5981GLU-P delivers 50A continuous current at 25°C ambient temperature with no forced airflow. This rating assumes proper PCB layout per MPS AN-123, including 2 oz copper, thermal vias under the exposed pad, and ≥4 cm² of copper pour connected to VOUT/VIN pins.

How does the CLREF pin function during soft-start versus normal operation?

During soft-start, CLREF is internally clamped to ~635 mV (V_BE) when V_OUT < 80% of V_IN, limiting inrush current. Once V_OUT ≥ 80% V_IN, the clamp releases to 1.6 V, allowing full current limit set by external CLREF voltage and RCS resistor.

Can MP5981GLU-P operate without an external hot-swap controller?

Yes - MP5981GLU-P supports standalone operation using the ON/PD pin for direct logic-level control. It implements built-in insertion delay, soft-start, over-current, short-circuit, and over-temperature protection without external coordination.

What is the purpose of the VTEMP pin, and how is it calibrated?

VTEMP provides a ratiometric analog voltage proportional to junction temperature (8.7 mV/°C), with 370 mV output at 25°C. It requires no external calibration and connects directly to an ADC input for real-time thermal monitoring and system-level throttling decisions.

How does parallel operation ensure balanced current sharing between multiple MP5981GLU-P devices?

During soft-start, all paralleled MP5981GLU-P units actively share gate drive and current-sense feedback, achieving <±5% current imbalance at 50A per device. Layout symmetry (matched trace length, impedance, and thermal coupling) is required to maintain balance under steady-state conditions.

Is the GOK output latched or auto-recovering after a fault event?

GOK is a latched open-drain output that remains low until the device is power-cycled or ON/PD is held low for >100 ms to force reset. In hiccup mode (MODE pin grounded), GOK asserts low but automatically recovers after ~560 ms if the fault clears.

What is the recommended minimum value for the SS capacitor to achieve full 270 ms soft-start time?

A 100 nF capacitor on the SS pin yields ~270 ms maximum soft-start time. Smaller values reduce ramp duration linearly (e.g., 47 nF ≈ 127 ms); larger values extend it but increase risk of thermal shutdown if load capacitance is excessive.