Monolithic Power Systems Inc. MP6908GJ-Z

Overview

MP6908GJ-Z from Monolithic Power Systems is a fast turn-off intelligent rectifier IC designed to replace Schottky diodes in high-efficiency flyback converters. It regulates external SR MOSFET forward drop to ~40mV, enables self-powered operation down to 0V output, supports both high-side and low-side configurations without auxiliary winding, and features programmable ringing detection for DCM and quasi-resonant operation - deployed in USB PD quick chargers and ultra-low-voltage adapters.

For engineers reviewing the MP6908GJ-Z datasheet, MP6908GJ-Z pinout, MP6908GJ-Z application, or MP6908GJ-Z equivalent, key selection considerations include its 25–45ns turn-off delay, -86mV turn-on threshold, 100µA quiescent current, TSOT23-6 package constraints, and compatibility with logic-level and standard SR MOSFETs in energy-star-compliant designs.

Technical Context

The MP6908GJ-Z implements adaptive gate control using dual-threshold V_DS sensing: turn-on triggered at -86mV with slew-rate validation via external SLEW resistor, and turn-off initiated at -3mV with 25ns propagation delay. Its internal linear regulator generates VDD from either HVC or VD, supporting three VDD regulation modes (5V/9V/clamped) depending on input voltage levels.

It operates across DCM, CCM, and quasi-resonant flyback topologies, with built-in blanking timers (1.1µs turn-on, variable turn-off), body-diode conduction prevention, and no short-circuit current flow through the MOSFET body diode - critical for safe operation during output short conditions and zero-voltage start-up.

Key Specifications

Pinout & Package

MP6908GJ-Z is housed in a space-saving TSOT23-6 package with exposed pad for thermal enhancement. Pin layout follows standard top-view orientation with pin 1 marked by dot or bevel.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MP6907GJ-Z and SRK1001MTR, MP6908GJ-Z uniquely combines auxiliary-winding-free high-side operation, programmable ringing immunity, and sub-40ns turn-off - making it optimal for next-gen compact USB PD and zero-voltage battery charging supplies where layout density and transient robustness are critical.

Availability

MP6908GJ-Z is available at Aetrix Electronics and suitable for USB PD quick chargers, flyback adapters, and low-voltage battery charging supplies requiring stable component supply, RoHS-compliant packaging, and long-term production continuity.

Supply support for MP6908GJ-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 analog and power ICs, headquartered in Kirkland, WA, with global design and support centers.

The MP6908 belongs to MPS's intelligent rectifier product line, engineered specifically to eliminate Schottky diodes in flyback converters while enabling auxiliary-winding-free, high-efficiency synchronous rectification across wide output voltage ranges.

FAQ

What is the minimum output voltage supported by MP6908GJ-Z?

The MP6908GJ-Z supports operation down to 0V output voltage in low-side configurations. Its self-biasing architecture and absence of auxiliary winding dependency allow stable startup and regulation even when VOUT = 0V - essential for battery pre-charge and short-circuit-safe designs.

How does the SLEW pin prevent false turn-on in DCM operation?

The SLEW pin connects to an external resistor that sets a time window for V_DS to cross the -86mV turn-on threshold. If the dV/dt of ringing is too slow - as in DCM demagnetization - the threshold is not met within the programmed window, and the gate remains off. This avoids shoot-through caused by premature SR MOSFET activation.

Can MP6908GJ-Z be used in high-side synchronous rectification without an auxiliary winding?

Yes. The HVC pin accepts up to +150V and enables VDD generation directly from the secondary winding voltage, allowing fully self-powered high-side SR operation. Three VDD regulation modes (5V/9V/clamped) adapt automatically based on HVC voltage level, eliminating auxiliary winding requirements.

What is the maximum recommended R_DS(ON) for the external SR MOSFET?

MPS recommends selecting an SR MOSFET with R_DS(ON) ≥ 20/I_OUT (mΩ) - e.g., ≥4mΩ for a 5A output. This ensures the MOSFET remains fully enhanced for ≥50% of the conduction period while maintaining ~40mV forward regulation and avoiding excessive gate driver loss.

Does MP6908GJ-Z require external components for EMI suppression?

No dedicated EMI components are required, but MPS recommends a 100nF ceramic capacitor from VDD to VSS placed adjacent to the IC, and optional RC snubbers (RSN/CSN) across the SR MOSFET drain-source to dampen high-frequency ringing - especially in high-power or high-dV/dt applications.

Is MP6908GJ-Z compatible with both logic-level and standard-gate MOSFETs?

Yes. Its VG output delivers 4.9V high-level drive and 0.02V low-level pull-down, ensuring full enhancement of logic-level MOSFETs (V_GS(th) ≤ 2.5V) and reliable turn-off of standard MOSFETs (V_GS(th) ≤ 4V) without external level shifters or gate resistors.

What thermal derating applies to MP6908GJ-Z in TSOT23-6 package?

In TSOT23-6, θ_JA = 220°C/W. At 25°C ambient, maximum continuous power dissipation is 0.56W. For sustained operation above 70°C ambient, power must be reduced per PD_MAX = (125°C − T_A)/220. Internal thermal shutdown activates at 150°C junction temperature.