Monolithic Power Systems Inc. MP6922LGS

Overview

MP6922LGS from Monolithic Power Systems is a dual-channel fast turn-off intelligent synchronous rectification controller for LLC resonant converters, driving two N-channel MOSFETs with 70mV V_DS regulation, 20ns total turn-off delay, and reverse current protection. It operates from 8V–24V V_DD, supports CCM/CrCM/DCM modes, and targets high-efficiency AC-DC adapters and telecom SMPS.

For engineers reviewing the MP6922LGS datasheet, MP6922LGS pinout, MP6922LGS application, or MP6922LGS equivalent, key selection criteria include forward-voltage regulation accuracy, light-load quiescent current (<600µA), RCP latch timing (100µs), SOIC8E thermal resistance (θ_JA = 50°C/W), and gate driver pull-down impedance (1–2Ω).

Technical Context

The MP6922LGS implements dual independent channel control with adaptive V_DS-sensing logic that regulates conduction to maintain ~70mV forward drop across each MOSFET, enabling precise synchronous rectification in both heavy and light load conditions. Its blanking architecture enforces minimum on-time (~1µs) and off-time (1.6µs) to prevent shoot-through in high-frequency LLC topologies.

It integrates an internal 5V reference for RCP monitoring, latches gate drivers during reverse current events for 100µs, and uses EN pin hysteresis (0.4V) with UVLO thresholds (rising: 2.5–3.5V) to ensure robust enable/disable sequencing. Light-load mode entry is triggered by sub-2.2µs conduction pulses, with 120µs delay before latching.

Key Specifications

Pinout & Package

MP6922LGS is packaged in SOIC8E (exposed pad), offering enhanced thermal performance over SOIC8/SOIC14 variants. The exposed PGND pad improves heat transfer and reduces junction temperature rise under sustained load.

Key Features

Applications

Equivalent & Alternatives

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

Compared with NCP4306DR2G and MP6902-based solutions, MP6922LGS delivers lower system-level component count, 46% faster turn-off response, integrated RCP latching, and SOIC8E thermal advantage-making it optimal for space-constrained, high-efficiency LLC adapters and telecom PSUs.

Availability

MP6922LGS is available at Aetrix Electronics and suitable for AC-DC adapters, LCD TV power supplies, and telecom SMPS requiring stable component supply, RoHS-compliant packaging, and long-term lifecycle support.

Supply support for MP6922LGS 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 over 20 years of expertise in DC-DC conversion, motor drivers, and power management.

The MP6922 product line was designed specifically for high-frequency LLC resonant converter synchronous rectification, emphasizing fast turn-off, multi-mode adaptability, and ultra-low standby power in compact consumer and telecom power supplies.

FAQ

What is the maximum recommended V_DS rating for external MOSFETs used with MP6922LGS?

The MP6922LGS VD1/VD2 pins are rated for –0.7V to +180V, allowing use with 200V-class N-channel MOSFETs. For reliable operation, select MOSFETs with V_DS ≥ 200V to accommodate voltage spikes in LLC resonant tanks, especially under transient line conditions or light-load burst mode.

How does the light-load latch-off function improve efficiency in AC-DC adapters?

When conduction time per cycle drops below 2.2µs, MP6922LGS enters light-load mode after a 120µs delay and latches both gate drivers off, reducing quiescent current to 600µA. This eliminates gate drive losses and MOSFET conduction losses during idle periods, directly enabling compliance with Energy Star 0.5W no-load requirements.

Can MP6922LGS operate with logic-level MOSFETs, and what is the minimum V_GS required for full enhancement?

Yes, MP6922LGS supports both standard and logic-level FETs. Its VG1/VG2 high-level output reaches V_DD–2.2V (min) when V_DD < 16V, ensuring >10V gate drive for logic-level MOSFETs with V_GS(th) ≤ 2.5V. Pull-down impedance of 1–2Ω guarantees rapid turn-off even with high gate charge devices.

What is the purpose of the exposed pad on the SOIC8E package, and how should it be connected on the PCB?

The exposed pad is electrically and thermally connected to PGND. It must be soldered to a dedicated PCB copper pour tied to power ground, with ≥4 thermal vias (0.3mm diameter) connecting to inner ground planes. This reduces θ_JA from 90°C/W (SOIC8) to 50°C/W, enabling 2.5W continuous dissipation without heatsink.

How does the Reverse Current Protection (RCP) function prevent shoot-through in center-tapped LLC topologies?

RCP monitors drain-source voltage via an external resistor divider to the RCP pin. When voltage exceeds 3V-indicating reverse current flow-the IC latches both gate drivers low for 100µs. This prevents simultaneous conduction of primary-side switches and secondary-side SR MOSFETs, eliminating shoot-through risk during high-frequency CCM transitions.

Is MP6922LGS compatible with CrCM (critical conduction mode) LLC operation, and how is timing managed?

Yes, MP6922LGS supports CrCM via adaptive blanking: its 1µs minimum on-time and 1.6µs minimum off-time align with CrCM valley-switching intervals. The controller detects zero-current crossing via V_DS polarity reversal and adjusts gate timing dynamically-no external CrCM controller or compensation components are required.

What is the recommended external component for setting light-load timing, and how does it affect operation?

Only the SOIC14 variant (MP6922DS) includes an LL pin for external resistor programming. MP6922LGS (SOIC8E) uses fixed internal timing: light-load enter delay = 120–150µs, pulse width = 2.2µs, and off-period threshold = 50µs. No external resistor is needed or supported on MP6922LGS.