Monolithic Power Systems Inc. MP9989GS-P

Overview

MP9989GS-P from Monolithic Power Systems is a CCM/DCM flyback ideal diode IC integrating a 100V/10mΩ MOSFET, designed for high-side or low-side synchronous rectification in AC/DC adapters. It regulates forward voltage drop to 40mV, achieves 25ns turn-off delay, eliminates auxiliary winding need via self-powered VDD generation from SENSE, and supports USB PD/QC chargers delivering up to 4A at ≤20V output.

For engineers reviewing the MP9989GS-P datasheet, MP9989GS-P pinout, MP9989GS-P application, or MP9989GS-P equivalent, key selection criteria include its 100V drain-source breakdown, 110µA quiescent current, ringing detection for DCM/QR operation, and SOIC-8 package compatibility with standard flyback PCB layouts.

Technical Context

The MP9989GS-P implements intelligent gate control using slew-rate detection to prevent false turn-on during demagnetizing ringing in DCM/QR modes, with a 30ns slew-rate detection window and 1.2µs turn-on blanking time. Its internal linear regulator generates 6.7V VDD from SENSE (4.7V–180V input range), enabling operation without auxiliary windings.

It operates across CCM, DCM, and quasi-resonant flyback topologies, using dual-threshold sensing: -80mV turn-on threshold and -3mV turn-off threshold, with 20ns turn-on and 25ns turn-off delays. The integrated MOSFET features 10mΩ R_DS(ON) at 25°C and 20mJ single-pulse avalanche energy for robust transient handling.

Key Specifications

Pinout & Package

MP9989GS-P is housed in a RoHS-compliant SOIC-8 package (5.0mm × 6.2mm × 1.75mm), featuring exposed thermal pad connection on pins 5–8 (VD) and pin 3/4 (VS) for enhanced heat dissipation. Pin 1 (VDD) and pin 2 (SENSE) are isolated from power paths to minimize noise coupling.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar flyback synchronous rectifier applications.

Compared with NCP4306DR2G and SiHP20N60E, MP9989GS-P uniquely integrates control logic, VDD generation, and 40mV adaptive regulation in SOIC-8, enabling smaller adapters with higher efficiency and lower system-level BOM cost.

Availability

MP9989GS-P is available at Aetrix Electronics and suitable for laptop adapters, USB PD chargers, and industrial flyback PSUs requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant sourcing.

Supply support for MP9989GS-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 over 20 years of expertise in DC/DC converters, LED drivers, and intelligent power switches.

The MP9989 product line targets high-efficiency AC/DC adapter design, specifically addressing the need for auxiliary-winding-free synchronous rectification in compact, thermally constrained USB-C and laptop charging solutions.

FAQ

What is the maximum continuous output current supported by MP9989GS-P in SOIC-8 package?

The MP9989GS-P supports up to 4A continuous output current in typical 48W flyback adapters when mounted on a 2-layer PCB with ≥1.5cm² 2oz copper on VS/VD pads and ambient temperature ≤50°C. This is validated by thermal testing showing junction temperature remains below 125°C at 4A/20V output with 265VAC input.

Can MP9989GS-P operate in high-side rectification without an auxiliary winding?

Yes-MP9989GS-P generates its own VDD supply from the SENSE pin (4.7–180V range), eliminating the need for an auxiliary winding in both high-side and low-side configurations. In high-side setups, SENSE connects directly to the transformer secondary drain node, and VDD powers the IC through internal regulation to 6.7V.

How does the slew-rate detection prevent false turn-on during DCM ringing?

The MP9989GS-P monitors dV_DS/dt during the demagnetization phase; if V_DS crosses the -80mV turn-on threshold with slew rate below ~1V/ns (characteristic of ringing), the turn-on timer expires without triggering gate drive. Only primary-side turn-off events with fast dV_DS/dt (>1V/ns) initiate conduction.

What is the recommended external resistor value between SENSE and VD, and why is it needed?

A 100Ω–300Ω resistor is recommended between SENSE and VD to limit peak current into the SENSE pin during body-diode conduction events, protecting against exceeding the -1V absolute minimum rating. Values >300Ω risk insufficient VDD charging and degraded V_DS slew-rate detection performance.

Does MP9989GS-P support quasi-resonant (QR) flyback operation?

Yes-MP9989GS-P includes dedicated ringing detection and 1.2µs turn-on blanking to suppress false triggering during QR valley-switching waveforms. It has been validated in 65kHz–130kHz QR designs with 200kHz peak switching frequency and maintains <40mV forward regulation across all operating modes.

What thermal derating applies above 25°C ambient temperature?

Using θ_JA = 70°C/W, the MP9989GS-P must derate power dissipation by 14.3mW/°C above 25°C ambient. At 70°C ambient, maximum allowable power loss drops to 1.05W-corresponding to ~3.2A output at 20V with typical conduction and switching losses accounted.

Is there a difference in performance between MP9989GS-P (SOIC-8) and MP9989GV (QFN-8)?

Yes-the QFN-8 (MP9989GV) offers lower θ_JA (40°C/W vs. 70°C/W) and higher current rating (28.1A vs. 14.9A at T_C = 25°C), enabling 5A+ output in space-constrained designs. SOIC-8 provides easier rework and proven reliability in high-volume adapter manufacturing.