Monolithic Power Systems Inc. MP9989GS-Z

Overview

MP9989GS-Z from Monolithic Power Systems is a CCM/DCM flyback ideal diode controller with integrated 100V/10mΩ MOSFET, designed for high-side or low-side synchronous rectification in AC/DC adapters. It regulates forward voltage drop to 40mV, achieves 110µA quiescent current, supports energy-efficient operation down to 0V output, and eliminates need for auxiliary winding. Used in USB PD and QC chargers delivering up to 4A at high efficiency.

For engineers reviewing the MP9989GS-Z datasheet, MP9989GS-Z pinout, MP9989GS-Z application, or MP9989GS-Z equivalent, key selection criteria include its 100V drain-source breakdown, -80mV turn-on threshold, 25ns turn-off delay, ringing detection for DCM/QR stability, and SOIC-8 package thermal performance (θJA = 70°C/W).

Technical Context

The MP9989GS-Z implements intelligent gate control using slew-rate detection and blanking timers to prevent false turn-on during demagnetizing ringing in DCM and quasi-resonant flyback topologies. Its internal linear regulator generates 6.7V VDD from SENSE without auxiliary winding, enabling compact high-side rectifier designs.

It operates across CCM, DCM, and QR modes by dynamically regulating VGS to maintain ~40mV forward drop (VFWD) during conduction and triggering turn-off when VS–VD exceeds +3mV. The integrated 10mΩ RDS(ON) MOSFET delivers 14.9A continuous drain current at TC = 25°C in SOIC-8.

Key Specifications

Pinout & Package

MP9989GS-Z is housed in a standard SOIC-8 package (JEDEC MS-012, variation AA) with exposed pad not present; thermal dissipation relies on copper area under pins 5–8 (VD) and pins 3–4 (VS). Pin functions are electrically identical between SOIC-8 and QFN variants, with pin numbering aligned per top-marking orientation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with NCP4307DR2G and SiHP065N10AD-ND, MP9989GS-Z uniquely integrates control logic, 10mΩ MOSFET, and self-powered operation-enabling higher efficiency, smaller footprint, and simplified high-side rectifier designs without auxiliary windings.

Availability

MP9989GS-Z is available at Aetrix Electronics and suitable for laptop adapters, USB PD chargers, and high-efficiency flyback converters requiring stable component supply, RoHS-compliant sourcing, and long-term production continuity.

Supply support for MP9989GS-Z 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 MP9989 belongs to MPS's intelligent rectifier product line, engineered specifically for high-density, high-efficiency AC/DC flyback converters where auxiliary winding elimination and robust DCM/CCM/QR operation are critical.

FAQ

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

The MP9989GS-Z supports 14.9A continuous drain current at T_C = 25°C and 9.42A at T_C = 100°C in SOIC-8. For 4A-output USB PD adapters, thermal design using ≥2 oz copper on VD/VS pads and ≥4 thermal vias keeps junction temperature below 125°C under full load.

Does MP9989GS-Z require an external gate driver?

No. MP9989GS-Z integrates a fully autonomous gate driver optimized for its internal 100V/10mΩ MOSFET. The driver dynamically adjusts gate voltage to regulate forward voltage drop to ~40mV and provides 25ns turn-off delay-no external components or timing circuits are needed.

How does the SENSE pin function without an auxiliary winding?

The SENSE pin serves dual roles: it supplies the internal LDO (outputting regulated 6.7V VDD) and senses V_DS for control. When SENSE voltage exceeds 4.7V, the LDO limits charging current to 63mA; below 4.7V, a 40mA current source charges VDD-enabling self-startup from output rectifier voltage alone.

Can MP9989GS-Z be used in high-side rectifier configurations?

Yes. MP9989GS-Z is explicitly validated for high-side rectification (Figure 4 in datasheet), where VD connects to transformer secondary and VS connects to output positive. Its floating architecture and SENSE-to-VD sensing allow direct integration without level-shifting circuitry.

What is the purpose of the external resistor between SENSE and VD?

A 100–300Ω resistor limits peak current into the SENSE pin during body-diode conduction events, protecting against -1V absolute minimum rating violation. It also damps ringing but must remain ≤300Ω to avoid degrading VDD charge time and V_DS slew-rate detection accuracy.

Is MP9989GS-Z compatible with quasi-resonant (QR) flyback controllers?

Yes. Its built-in ringing detection and 30ns slew-rate validation prevent false turn-on during QR valley switching. The 1.2µs turn-on blanking time and -3mV turn-off threshold ensure stable operation across QR frequencies up to 150kHz without external timing components.