Monolithic Power Systems Inc. MP6902DS-LF-P

Overview

MP6902DS-LF-P from Monolithic Power Systems is a fast turn-off intelligent synchronous rectifier controller for flyback converters, replacing Schottky diodes with external MOSFETs to achieve high efficiency. It regulates V_DS to ~70 mV in forward conduction, shuts off the MOSFET within 20 ns of negative V_DS detection, supports DCM and quasi-resonant operation up to 400 kHz, and enters light-load sleep mode drawing <300 µA. Used in notebook adapters and industrial flyback power supplies.

For engineers reviewing the MP6902DS-LF-P datasheet, MP6902DS-LF-P pinout, MP6902DS-LF-P application, or MP6902DS-LF-P equivalent, key selection criteria include V_DS regulation accuracy (±15 mV), 20 ns total turn-off delay, SOIC8 package thermal resistance (θ_JA = 90 °C/W), light-load timing programmability via R_LL, and compatibility with both high-side and low-side synchronous rectification topologies.

Technical Context

The MP6902 implements adaptive gate drive control using dual voltage thresholds: −70 mV for V_DS regulation during conduction and −30 mV for fast turn-off. Its blanking logic enforces a 1.6 µs minimum on-time and dynamically adjusts the turn-off threshold to +50 mV during turn-on to suppress ringing-induced false triggers.

It integrates a dedicated V_D high-voltage sense path rated to 180 V, internal VDD UVLO (6.0 V rising, 1.0 V hysteresis), EN pin UVLO (1.5 V rising), thermal shutdown (150 °C trip, 30 °C hysteresis), and programmable light-load latch-off via external resistor on LL pin (30–300 kΩ range).

Key Specifications

Pinout & Package

MP6902DS-LF-P is housed in an industry-standard SOIC8 package (JEDEC MS-012, variation AA) with 1.27 mm pitch, 3.9 mm × 4.9 mm body, and θ_JA = 90 °C/W on 4-layer PCB. The exposed pad is not present; thermal performance relies on copper area under pins 1 (PGND) and 5 (VSS).

Key Features

Applications

Equivalent & Alternatives

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

Compared with NCP4306DR2G and SiHP22N60E, MP6902DS-LF-P offers superior turn-off speed (20 ns vs. 35/120 ns), user-programmable light-load behavior, and independent MOSFET selection-enabling optimal trade-offs between conduction loss, switching loss, and cost in high-efficiency flyback designs.

Availability

MP6902DS-LF-P is available at Aetrix Electronics and suitable for industrial AC/DC adapters, notebook power supplies, distributed power modules, and battery charger systems requiring stable component supply, RoHS-compliant packaging, and long-term lifecycle support.

Supply support for MP6902DS-LF-P 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, and global manufacturing partnerships.

The MP6902 belongs to MPS's synchronous rectifier controller product line, engineered specifically for high-efficiency flyback converters targeting Energy Star, DoE Level VI, and EU CoC compliance in consumer and industrial power supplies.

FAQ

What is the maximum allowable V_D voltage spike the MP6902DS-LF-P can withstand?

The MP6902DS-LF-P V_D pin is rated for continuous voltage up to 180 V. For safe operation, the peak V_D including leakage spikes must satisfy V_OUT + V_IN/n + V_{DS_Spike} < 180 V × k, where k is a de-rating factor (0.7–0.8). Exceeding this risks permanent damage to the high-voltage JFET input stage.

How does the MP6902DS-LF-P regulate V_DS to 70 mV without external feedback?

The MP6902 uses an internal comparator that monitors V_SS–V_D and dynamically adjusts V_G drive strength to hold the sensed voltage at −70 mV. This closed-loop regulation occurs entirely within the IC using on-chip references and gate drive current control-no external op-amp or resistive divider is needed.

Can MP6902DS-LF-P be used with 5 V logic-level MOSFETs?

Yes. The MP6902DS-LF-P gate driver delivers 13–15 V output when V_DD >17 V and V_DD−2.2 V otherwise, ensuring full enhancement of standard 5 V logic-level MOSFETs. Its 2 A peak pull-down current also guarantees fast turn-off even with high gate charge devices.

What is the purpose of the NC pin (Pin 7) and how should it be handled?

Pin 7 is a no-connect terminal with no internal bond wire. It must remain unconnected on the PCB-neither routed nor tied to ground or any other net. Routing or soldering to this pin may introduce parasitic capacitance or leakage paths that degrade V_D sensing accuracy and cause erratic turn-off behavior.

How does the light-load timing resistor (R_LL) affect efficiency at 10% load?

At 10% load, R_LL sets the duration threshold (T_LL ≈ R_LL × 220 µs) after which the IC latches off the gate driver. A 100 kΩ resistor yields ~22 µs, allowing brief conduction bursts before latch-off-reducing gate drive loss by >60% versus continuous operation while maintaining regulation stability.

Does MP6902DS-LF-P support high-side rectification with transformer-coupled gate drive?

No. MP6902DS-LF-P supports high-side rectification only with direct gate drive-its V_SS pin serves as the local reference for V_D and EN, requiring the MOSFET source to connect to V_SS. Transformer-coupled or floating gate drivers are incompatible; use isolated gate driver ICs like Si823Hx for such topologies.

What thermal derating applies when operating above 70°C ambient?

With θ_JA = 90 °C/W, the maximum allowable power dissipation drops linearly: P_D(MAX) = (150°C − T_A) / 90. At 70°C ambient, max continuous dissipation is 0.89 W. Above this, thermal shutdown activates at 150°C junction temperature, with 30°C hysteresis ensuring reliable recovery once T_J falls below 120°C.