Monolithic Power Systems Inc. MP6924GS

Overview

MP6924GS from Monolithic Power Systems is a dual-channel, fast turn-off synchronous rectifier IC for LLC resonant converters operating in CCM, CrCM, and DCM modes. It drives two N-channel MOSFETs with 35ns total turn-off delay, regulates forward voltage drop to 45mV (MP6924), and latches gate drivers under light-load conditions to limit quiescent current to 175µA. Used in high-efficiency AC/DC adapters and PC power supplies.

For engineers reviewing the MP6924GS datasheet, MP6924GS pinout, MP6924GS application, or MP6924GS equivalent, key selection criteria include forward voltage threshold (45mV), turn-off blanking time (210ns), VDD operating range (4.2V–35V), SOIC-8 package compatibility, and support for both high-side and low-side rectification in resonant topologies.

Technical Context

The MP6924GS implements adaptive voltage-sensing control to maintain MOSFET conduction near V_fwd = 45mV by dynamically adjusting gate drive strength during the conduction phase. Its fast turn-off logic triggers at +40mV V_DS threshold with 35ns total propagation delay, enabling reliable operation across discontinuous and continuous conduction modes without shoot-through risk.

Light-load mode is activated via external resistor on LL pin, initiating latch-off after 0.5–1.52ms delay (MP6924) to reduce driver loss. Anti-bounce logic prevents cross-conduction between channels by blanking one gate driver when the other turns off - a feature present in MP6924 but disabled in MP6924A.

Key Specifications

Pinout & Package

MP6924GS is housed in a SOIC-8 package with exposed thermal pad (PGND-connected) and standard pin pitch. Pin functions are validated per MPS Rev. 1.02 datasheet and confirmed on official Monolithic Power Systems documentation.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual-channel LLC synchronous rectifier applications.

Compared with MP6924AGS, MP6924GS trades 16mV higher V_fwd for 1.54µs shorter blanking time and anti-bounce logic-critical for ruggedness in cost-driven PC power supplies. Against NCP4306DR2G, MP6924GS delivers true dual-channel integration, light-load optimization, and single-chip reliability in LLC secondary-side designs.

Availability

MP6924GS is available at Aetrix Electronics and suitable for AC/DC adapters, PC power supplies, and LCD/LED TV power stages requiring stable component supply, long-term lifecycle support, and RoHS-compliant sourcing.

Supply support for MP6924GS 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.

The MP6924GS belongs to MPS's synchronous rectifier product line, engineered specifically for high-frequency LLC resonant converters targeting >94% efficiency, low standby power, and simplified secondary-side design in consumer and computing power applications.

FAQ

What is the maximum drain voltage rating for VD1 and VD2 pins?

The VD1 and VD2 pins are rated for continuous operation up to +180V relative to VSS, with internal JFET clamping to protect against overvoltage transients. This enables direct connection to MOSFET drains in 12V–48V output LLC converters without external voltage dividers or level shifters.

How does the anti-bounce logic function in MP6924GS?

When either VG1 or VG2 transitions low, the corresponding gate driver output is blanked until the opposite channel completes its turn-off transition. This prevents simultaneous conduction (shoot-through) in dual-MOSFET configurations, especially critical in center-tapped LLC secondaries where body diode conduction timing overlaps.

Can MP6924GS operate with logic-level MOSFETs?

Yes - MP6924GS provides up to 13V gate drive (at VDD > 10V) and 0.5A peak source current, sufficient to fully enhance logic-level MOSFETs with V_GS(th) ≤ 2.5V and Q_g ≤ 25nC. Its adaptive gate drive adjusts voltage based on V_DS, ensuring optimal R_DS(ON) utilization without overdriving.

What is the recommended minimum R_DS(ON) for the SR MOSFETs used with MP6924GS?

Per Equation (2) in the datasheet, R_DS(ON) should be ≥ V_fwd/I_OUT. For a 10A output with V_fwd = 45mV, minimum R_DS(ON) is 4.5mΩ. Selecting significantly lower values reduces gate drive effectiveness and yields diminishing efficiency returns due to increased Q_g-related switching loss.

Does MP6924GS require external components for basic operation?

Only three external components are mandatory: a ≥1µF VDD decoupling capacitor, a resistor on LL for light-load timing (optional if omitted), and optional RC filters on VD1/VD2 for noise immunity. No bootstrap capacitors, timing resistors, or external references are needed - enabling minimal BOM count and compact layout.

How does light-load mode affect startup and transient response?

Upon exiting light-load mode, MP6924GS waits until the next complete LLC switching cycle begins before re-enabling gate drivers - preventing partial-cycle activation that could cause instability. The light-load enter delay (0.5–1.52ms) ensures brief load spikes do not trigger unnecessary mode transitions.

Is MP6924GS pin-compatible with MP6924AGS?

Yes - MP6924GS and MP6924AGS share identical SOIC-8 pinout, absolute maximum ratings, and functional block diagram. They differ only in internal thresholds (V_fwd, blanking time, thermal shutdown) and anti-bounce logic presence, allowing direct substitution with performance trade-offs verified in final system testing.