12N70 MOSFET — Specifications & Equivalents
About the 12N70
The 12N70 is an N-channel MOSFET with a drain–source voltage (VDS) rating of 700 V, a continuous drain current (ID) of 12 A and an on-resistance (RDS(on)) of 0.7 Ω. It can dissipate up to 225 W and is rated to a junction temperature of 150 °C. It is available in TO-220, TO-220F, TO-220F1 and TO-220F2 packages, so confirm the pinout of the exact variant you order.
At a glance
- Type: N-channel MOSFET
- Max drain–source voltage (VDS): 700 V
- Max continuous drain current (ID): 12 A
- On-resistance (RDS(on)): 0.7 Ω
- Power dissipation (PD): 225 W
- Max junction temperature (TJ): 150 °C
- Package: TO-220, TO-220F, TO-220F1, TO-220F2
Typical applications
With its 700 V drain–source rating the 12N70 sits in the high-voltage (offline) class of switching MOSFETs, typically found in primary-side switching in offline SMPS (flyback, forward and quasi-resonant), active PFC boost stages, half-bridge and full-bridge inverters, induction heating and electronic ballasts and BLDC and AC motor drives. The rating leaves usable margin above the ~325 V DC bus obtained by rectifying 230 VAC mains, which is why this class dominates offline power supplies.
Gate drive and switching notes
Keep gate–source voltage within the ±30 V maximum; exceeding it punctures the gate oxide and destroys the device permanently.
Switching behaviour is characterised by a rise time of 115 ns and an output capacitance (Coss) of 200 pF, which together with the gate drive determines switching loss and the practical upper frequency limit.
Choosing a replacement for the 12N70
A drop-in substitute for the 12N70 must be the same N-channel type and offer a drain–source rating of at least 700 V, a continuous drain current rating of at least 12 A and an on-resistance no higher than 0.7 Ω if efficiency and heat matter.
Mechanically, check the replacement against the TO-220, TO-220F, TO-220F1 and TO-220F2 footprint and confirm the pin order — parts sharing a package outline do not always share a pinout.
Where the application switches inductive loads or runs near the voltage limit, keep extra headroom rather than choosing a part that only just meets the original numbers.
Frequently asked questions
What is the 12N70?
The 12N70 is an N-channel MOSFET (metal-oxide-semiconductor field-effect transistor). It is rated for 700 V drain-source and 12 A continuous drain current.
What is the maximum voltage of the 12N70?
The 12N70 has a maximum drain-source voltage (Vds) of 700 V. Treat this as an absolute maximum and design with margin, especially when switching inductive loads.
How much current can the 12N70 handle?
It is rated for 12 A of continuous drain current, with power dissipation limited to 225 W. Real-world capability depends on your heatsinking and ambient temperature.
What is the on-resistance of the 12N70?
On-resistance (Rds(on)) is 0.7 Ω. Multiply by the square of your load current to estimate conduction loss.
What package does the 12N70 come in?
It is listed in TO-220, TO-220F, TO-220F1 and TO-220F2. Verify the pinout of the specific variant, as one outline can carry different pin assignments.
What can I use to replace the 12N70?
No verified equivalents are listed yet. Choose a part of the same polarity that meets or exceeds every rating above and shares a compatible package and pinout.
Key Specifications
| Type | MOSFET |
|---|---|
| Channel Type | N -Channel |
| Drain-Source Voltage (Vds) | 700 V |
| Gate-Source Voltage (Vgs) | 30 V |
| Drain Current (Id) | 12 A |
| Drain-Source On-Resistance (Rds) | 0.7 |
| Rise Time (tr) | 115 nS |
| Output Capacitance (Coss) | 200 pF |
| Junction Temperature (Tj) | 150 °C |
| Package | TO-220 TO-220F TO-220F1 TO-220F2 |
| Power Dissipation (Pd) | 225 W |
Equivalent & Replacement Parts
No verified equivalents are listed for 12N70 yet.