JCS15N70F N-Channel MOSFET for Whatsminer Power Supply repair

JCS15N70F N-Channel Power MOSFET | 700V / 15A High-Voltage Switching Transistor with Low Gate Charge for Whatsminer Power Supply Primary Stage Repair

The JCS15N70F is a 700V / 15A N-channel power MOSFET used in the primary switching stage of Whatsminer power supplies. Drop-in replacement when the original primary-side MOSFET fails: restores stable PSU operation and clears the dead-PSU, overcurrent-trip, or no-output symptoms that come from a degraded high-voltage primary switch.

Rated for 700V maximum drain-source voltage (Vds), 15A continuous drain current (Id), 62.5W power dissipation, and 150°C junction temperature. The low gate charge (Qg = 44.6 nC) and fast switching characteristics (rise time tr = 112 ns) minimise switching losses at the high frequencies modern PSU primary controllers run at. Improved dv/dt capability handles the sharp voltage transitions of resonant and quasi-resonant topologies without spurious turn-on. Every part undergoes 100% avalanche testing at production — the type of validation that matters when the PSU primary side sees the inevitable transient events of production mining duty.

When to Replace the JCS15N70F

• Whatsminer PSU primary stage dead — high-voltage MOSFET failed short or open, no switching activity.
• Overcurrent trip on PSU startup — short across drain-source pulling the primary controller into protection.
• Excessive heating at the MOSFET location — degraded internal Rds(on), conduction loss rising above safe envelope.
• Visible burn or thermal damage on the package — direct replacement, swap any paralleled MOSFETs on the same leg.
• Preventive PSU refurbishment — replace primary-stage MOSFETs alongside electrolytics during a complete rebuild.

JCS15N70F Specifications

FAQ — JCS15N70F MOSFET

Q: Why does 100% avalanche testing matter?
A: MOSFETs in PSU primary stages see brief over-voltage events during normal switching transitions and the inevitable surge events in production deployments. Avalanche-tested MOSFETs survive these events without damage; untested parts fail unpredictably. For mining PSU repair, the avalanche-rated grade is the right choice.

Q: How do I diagnose a failed JCS15N70F in-circuit?
A: Diode-test drain-source with the gate grounded — a healthy N-channel reads infinite drain-source resistance. Short across drain-source confirms a dead part. Visual inspection catches the obvious burn cases. Note: the part operates at 400V+ in the primary stage — discharge bulk capacitors before probing.

Q: Should I replace all paralleled MOSFETs on the affected leg?
A: For best long-term reliability replace all paralleled MOSFETs on the affected leg — the surviving parts have absorbed thermal stress from the failure event and have shortened service life.

Q: Bulk pricing for repair shops?
A: Yes — email contact@lys-sz.com with your monthly volume. Tube and tray quantities are stocked.

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Repair shops stocking JCS15N70F MOSFETs by the tray? Email contact@lys-sz.com for bulk pricing. Worldwide shipping from our Shenzhen warehouse.