Monolithic Power Systems Inc. MP6922DN-LF-Z

Overview

MP6922DN-LF-Z 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 supports CCM, CrCM, and DCM operation up to 300kHz and consumes <600µA in light-load latch-off mode.

For engineers reviewing the MP6922DN-LF-Z datasheet, MP6922DN-LF-Z pinout, MP6922DN-LF-Z application, or MP6922DN-LF-Z equivalent, key selection criteria include dual-channel gate drive timing accuracy, -30mV turn-off threshold, SOIC8E exposed-pad thermal performance, and RCP-enabled safe operation in high-frequency CCM LLC topologies.

Technical Context

The MP6922 implements adaptive voltage-sensing control per channel: it turns on each MOSFET when V_DS drops below -70mV (body diode conduction), regulates forward drop near -70mV during conduction via dynamic gate drive adjustment, and triggers turn-off at +30mV to prevent negative current flow. Blanking logic enforces minimum 1µs on-time and 1.6µs off-time to suppress noise-induced misfiring.

Its dual independent sensing paths (VD1/VS1 and VD2/VS2) support asymmetric secondary windings; the RCP pin enables external voltage-divider-based reverse-current detection with 3V threshold and 100µs latch duration; EN pin provides hierarchical enable control with 1.5V rising threshold and 2.5V UVLO.

Key Specifications

Pinout & Package

MP6922DN-LF-Z is packaged in SOIC8E (exposed pad), offering enhanced thermal dissipation (θ_JA = 50°C/W) versus standard SOIC8. The exposed PGND pad must be soldered to a large copper area for optimal junction temperature control.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MP6921DN-LF-Z, MP6922DN-LF-Z enables full-wave LLC topologies with independent channel control; versus UCC24612DR, it delivers 2× faster turn-off, integrated RCP, and 44% lower thermal resistance-critical for high-power, high-reliability telecom and industrial PSUs.

Availability

MP6922DN-LF-Z is available at Aetrix Electronics and suitable for AC-DC adapters, LCD/PDP TV power supplies, and telecom SMPS requiring stable component supply, RoHS-compliant packaging, and production-ready SOIC8E thermal performance.

Supply support for MP6922DN-LF-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, with over 20 years of expertise in DC-DC conversion, motor drivers, and power management solutions.

The MP6922 belongs to MPS's intelligent synchronous rectification controller product line, designed specifically to replace Schottky diodes in high-frequency resonant converters while delivering ultra-low quiescent current, precise V_DS regulation, and robust protection features.

FAQ

What is the purpose of the exposed pad on the MP6922DN-LF-Z SOIC8E package?

The exposed pad is electrically and thermally connected to PGND. It must be soldered to a large PCB copper area (≥200mm²) to achieve the specified θ_JA of 50°C/W and support 2.5W continuous power dissipation. Leaving it unconnected degrades thermal performance by ~40% and risks thermal shutdown under load.

How does the MP6922DN-LF-Z implement reverse current protection without external comparators?

It uses the dedicated RCP pin with an internal 3V reference. An external resistor divider scales the sensed voltage (e.g., from a sense resistor across the MOSFET) to this threshold. When exceeded, the IC latches both gate drivers low for 100µs-preventing shoot-through in high-frequency CCM-then automatically resumes normal operation.

Can the MP6922DN-LF-Z drive logic-level and standard-threshold MOSFETs interchangeably?

Yes. Its gate drivers deliver 14V high-side output when V_DD >16V and V_DD−2.2V otherwise, while sinking 3A to ensure fast turn-off. This accommodates both 4.5V logic-level FETs (e.g., SiR872DP) and 10V standard FETs (e.g., IRF7832), verified across 8V–24V V_DD range.

What triggers the light-load latch-off mode, and how quickly does it respond?

Light-load mode activates when MOSFET conduction time per cycle falls below 2.2µs (T_LL), with a 120–150µs entry delay (T_LL-Delay). The gate drivers latch off, reducing current to <600µA. Exit occurs within 1–2 switching cycles when body-diode conduction exceeds ~2.4µs, ensuring minimal latency on load step-up.

Is the EN pin compatible with microcontroller GPIOs operating at 3.3V logic levels?

Yes. The EN pin has a 1.5V rising threshold and 0.4V hysteresis, making it fully compatible with 3.3V CMOS outputs. Its internal 10–15µA pull-up ensures reliable high-state detection even with weak drive; no external pull-up is required for standard MCU interfacing.

How does the 70mV V_DS regulation improve efficiency compared to fixed-timing SR controllers?

Fixed-timing controllers turn MOSFETs on/off at predetermined points, causing variable V_DS and higher conduction loss at light loads. MP6922's regulation actively adjusts gate drive to hold V_DS near 70mV across all loads-reducing I²R losses by up to 35% at 10% load versus timing-based alternatives.

What is the maximum allowable V_D–V_S voltage the MP6922DN-LF-Z can sense, and how is it protected?

The VD1 and VD2 pins tolerate up to +180V relative to their respective VS pins, enabled by integrated high-voltage JFET input stages. Internal clamping limits input current if V_D–V_S exceeds −0.7V, and a small series resistor (recommended per datasheet) further protects against transients and ESD events.