Vp is shown as 7.5V to 25V for Id=100mA
That Vp is actually Vgs to set the drain current to 100mA.
If you know the normal bias current then you can measure the Vp or Vgs when the transistor is passing that current.
But the biggest problem you will have is controlling the Tj while you take your measurements.
To avoid some of that problem, one can connect drain to gate and apply a controlled voltage across Gate to Source and measure the Id. This allows a lower dissipation and lowers the swing in Tj as you take measurments.
But with Vgs being so high, it will still get hot very quickly unless you test at an unusably low Id.
A normal Vertical mosFET having a typical Vgs of 4V when Id=100mA will dissipate 400mW during the test/measurment. That still leaves a Tj problem where some form of cooling is required.
That Vp is actually Vgs to set the drain current to 100mA.
If you know the normal bias current then you can measure the Vp or Vgs when the transistor is passing that current.
But the biggest problem you will have is controlling the Tj while you take your measurements.
To avoid some of that problem, one can connect drain to gate and apply a controlled voltage across Gate to Source and measure the Id. This allows a lower dissipation and lowers the swing in Tj as you take measurments.
But with Vgs being so high, it will still get hot very quickly unless you test at an unusably low Id.
A normal Vertical mosFET having a typical Vgs of 4V when Id=100mA will dissipate 400mW during the test/measurment. That still leaves a Tj problem where some form of cooling is required.
Tim5,
don't do this:
k60/j18 are not enhanced mode devices (like vertical mosfets/hexfets) - they are depletion mode devices with triode-like output characteristic. The current through them is controlled by Vds and Vgs simultaneously.
N channel part (2sk60) should be connected to power source (source pin to - pole, drain pin to +pole, with Ampermeter in series) of same voltage as your intended circuit. This power source should have its current limited to, say, 1A.
Another power source is needed to establish the gate controlling voltage (Vgs) with - pole connected to gate and + pole connected to source pin. The more voltage you have between gate and source pins, the lower the current through the VFET. Start with -20V and turn it toward 0V slowly, looking at the Ampermeter that you put between the drain pin and the + pole of the first power source.
Read the Vgs and note the corresponding Id that equals the intended Id of your circuit. Repeat carefully for every device.
Turn all polarities upside down for P-channel part (2sj18) and please be very careful, those devices are extremely rare.
Take care to turn the Vgs on before the Vds in order to avoid catastrophic scenario.
Use the heatsink to avoid thermal overload of the devices but don't worry too much about thermal equilibrium, VFET are very tame in temperature domain - they don't go wild like BJT or MOSFETs.
don't do this:
because it will toast your precious VFETs.
k60/j18 are not enhanced mode devices (like vertical mosfets/hexfets) - they are depletion mode devices with triode-like output characteristic. The current through them is controlled by Vds and Vgs simultaneously.
N channel part (2sk60) should be connected to power source (source pin to - pole, drain pin to +pole, with Ampermeter in series) of same voltage as your intended circuit. This power source should have its current limited to, say, 1A.
Another power source is needed to establish the gate controlling voltage (Vgs) with - pole connected to gate and + pole connected to source pin. The more voltage you have between gate and source pins, the lower the current through the VFET. Start with -20V and turn it toward 0V slowly, looking at the Ampermeter that you put between the drain pin and the + pole of the first power source.
Read the Vgs and note the corresponding Id that equals the intended Id of your circuit. Repeat carefully for every device.
Turn all polarities upside down for P-channel part (2sj18) and please be very careful, those devices are extremely rare.
Take care to turn the Vgs on before the Vds in order to avoid catastrophic scenario.
Use the heatsink to avoid thermal overload of the devices but don't worry too much about thermal equilibrium, VFET are very tame in temperature domain - they don't go wild like BJT or MOSFETs.
Last edited:
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.