How to Read & Describe MOSFET Specification Parameters

1. Core Voltage Ratings (Absolute Maximum Ratings)

1.1 VDS – Drain-Source Voltage

The maximum allowable voltage between drain and source under normal operation. Exceeding this value will cause avalanche breakdown and permanent damage to the MOSFET.

Example marking: VDS = 60V, 100V, 200V, 600V

1.2 VGS – Gate-Source Voltage

Maximum safe voltage applied to gate and source. Gate oxide layer is extremely thin; overvoltage leads to gate punch-through.

Standard range: ±20V for most silicon MOSFETs

1.3 VGS(th) / VGS(off)

Enhancement MOS: VGS(th) = Threshold voltage, minimum VGS to form conductive channel
Depletion MOS: VGS(off) = Pinch-off voltage, negative bias to cut off native channel

2. Current Parameters

2.1 ID – Continuous Drain Current

Maximum steady-state drain current the device can carry at specified case temperature, the main current rating for power applications.

2.2 IDM – Pulsed Drain Current

Peak transient current allowed for short pulse durations, much higher than continuous ID.

2.3 ISD – Source-Drain Diode Current

Forward current rating of the internal body diode inside MOSFET.

3. On-State Conduction Parameters

3.1 RDS(on) – Drain-Source On-Resistance

Key performance index: resistance between drain and source when MOS is fully turned on at specified VGS and ID.

Lower RDS(on) = less conduction loss, lower heat generation.

3.2 Qg, Qgs, Qgd – Gate Charge

Total gate charge required to switch the MOSFET on/off, determines switching speed and drive power consumption.

Qgd (Miller charge) dominates switching loss in high-frequency circuits.

3.3 Ciss, Coss, Crss – Parasitic Capacitances

Input capacitance, output capacitance, reverse transfer capacitance; critical for high-frequency SMPS, BLDC inverter designs.

4. Switching Time Parameters

4.1 td(on), tr, td(off), tf

Turn-on delay time, rise time, turn-off delay time, fall time.

Smaller values support higher operating switching frequency.

5. Thermal & Derating Parameters

5.1 TJ – Maximum Junction Temperature

Max internal chip temperature, typical 150°C / 175°C.

5.2 RthJC / RthJA

Thermal resistance junction-to-case, junction-to-ambient; used to calculate required heat sink size.

6. Body Diode Parameters

6.1 VSD – Body Diode Forward Voltage

Forward voltage drop of internal parasitic diode.

6.2 trr – Reverse Recovery Time

Reverse recovery speed of body diode, important for synchronous rectifier circuits.

7. Standard Product Description Template

7.1 General Template For Product Page

N-channel enhancement power MOSFET, VDS 100V, continuous ID 80A, low RDS(on), low gate charge, low parasitic capacitance, wide operating junction temperature range, suitable for BLDC motor drive, DC-DC converters and battery management systems.

7.2 Short Single-Sentence Introduction Example

This N-channel MOSFET features 60V drain-source voltage rating, 120A continuous drain current, ultra-low on-resistance and fast switching speed, optimized for high-current switching power supply applications.