FHP120N08D Reliable N-Channel MOSFET - ASIC PSU Repair

FHP120N08D 80V 120A N-Channel MOSFET TO-220 — Secondary-Side ASIC PSU Repair

The FHP120N08D is an N-channel enhancement-mode field-effect transistor in a TO-220 package, designed to replace faulty mid-voltage / high-current MOSFETs in ASIC miner power supplies and adjacent DC-DC sections. With 80V Vds, 120A continuous Id and a very low 0.008Ω Rds(on), it is well suited to the secondary-side synchronous rectification and DC-DC buck stages where high current and minimal conduction loss are critical.

For repair shops servicing the 12V / low-voltage output stage of mining PSUs, FHP120N08D is a versatile replacement part to keep in stock.

Specifications

Where the FHP120N08D fits in ASIC PSU repair

An 80V N-channel MOSFET in TO-220 with 120A rating and 8 mΩ Rds(on) is a textbook secondary-side device: synchronous rectifier on the low-voltage output of an ASIC PSU, high-current buck stage, OR-ing / hot-swap controller, or load switch on a 12V rail. In ASIC miner PSUs that deliver hundreds of amps at 12V (APW-class and Whatsminer-class units), this is precisely the class of MOSFET that handles the rectified output current.

Why low Rds(on) matters at hashboard-scale currents

At 100-200A output, conduction loss in the secondary MOSFETs is one of the biggest contributors to PSU heat. A 0.008Ω part keeps conduction loss low and protects the surrounding electrolytics and the PCB from thermal stress. When you replace a blown secondary MOSFET, matching or beating the original Rds(on) is far more important than going to a "stronger" voltage class.

Common failure symptoms

• PSU output voltage collapses under load — one or more secondary MOSFETs shorted
• One leg of the synchronous rectifier failed short → output rail clamped low
• Visible burn mark or cracked package on a TO-220 near the output inductor
• PSU works at low load but trips OCP / shuts down at high load
• Excessive heat on the secondary heatsink even when current is moderate

Frequently asked questions

Can FHP120N08D replace an 80V class TO-220 MOSFET in an ASIC PSU?

If the original device is an N-channel 80V class TO-220 with comparable Rds(on), Qg and Id ratings, FHP120N08D is a candidate replacement. Always cross-check the original part marking and the PSU schematic before substituting.

Is the TO-220 package fully isolated or does the tab need an insulator?

The TO-220 tab is electrically connected to the drain. When mounting to a shared heatsink, use the appropriate insulating pad and shoulder washer.

Do you keep stock for repair-shop quantities?

Yes — contact us for volume pricing and lead time on FHP120N08D in tray or tube quantities.

Will it handle the full 120A continuously?

120A is the datasheet maximum at the stated reference conditions. Real-world derating depends on Tj, heatsink, gate drive and switching frequency — see the specifications panel and contact us for application-specific confirmation.

Related products

• NTMFS5C430NL Secondary-Side MOSFET for Cryptominer PSU
• FQP30N06 60V 30A N-Channel MOSFET for PSU
• MD18623 Dual MOSFET Gate Driver
• HBR3200 / SS320 Schottky Diode
• K8 Universal Hashboard / PSU Tester

Contact contact@lys-sz.com for volume pricing or compatibility questions.

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