Just a short message between hospital visits :
We have matched all regulator MOSFETs and will ship them in the next 5-10 days.
The mean Vgs for 2SJ618 at 4A is -2.79V, that for 2SK3497 is 2.56V.
There is not one single N-P pair of FETs where the P device will match the N device.
But N-N, P-P pair match is much better than 10mV in almost all cases.
For regulator use, this is totally overkilled, since the output voltage determining Zener diode has much more tolerance.
The P-N mismatch can be easily overcome by buying a bunch of Zener diodes and cherry picking.
Fitzfish will demonstrate this with an example in his test build report later.
Patrick
We have matched all regulator MOSFETs and will ship them in the next 5-10 days.
The mean Vgs for 2SJ618 at 4A is -2.79V, that for 2SK3497 is 2.56V.
There is not one single N-P pair of FETs where the P device will match the N device.
But N-N, P-P pair match is much better than 10mV in almost all cases.
For regulator use, this is totally overkilled, since the output voltage determining Zener diode has much more tolerance.
The P-N mismatch can be easily overcome by buying a bunch of Zener diodes and cherry picking.
Fitzfish will demonstrate this with an example in his test build report later.
Patrick
> @Patrick: the first GB was for how many F5X ??
22 pairs of 2SK3497, 22 pairs of 2SJ618.
> what do we need for 1 F5X?
If you use regulators as in the proto, you will need for 2 channels 1 pair of 2SK3497 and 1 pair of 2SJ618 (4 Mosfets in total).
> what parts what quantity
See above.
> how many more do we need to buy in order to get the required results?
I would suggest you allow for 10~20% matching reject if you are ordering less than 100 pairs.
Sorry for the late reply. Difficult times.
Patrick
22 pairs of 2SK3497, 22 pairs of 2SJ618.
> what do we need for 1 F5X?
If you use regulators as in the proto, you will need for 2 channels 1 pair of 2SK3497 and 1 pair of 2SJ618 (4 Mosfets in total).
> what parts what quantity
See above.
> how many more do we need to buy in order to get the required results?
I would suggest you allow for 10~20% matching reject if you are ordering less than 100 pairs.
Sorry for the late reply. Difficult times.
Patrick
You can use ANY complementary MOSFETs which have about the same Vgs at 4A.
The transconductance of these will determine the output impedance of the regulator.
The ones chosen have particularly high transconductances and positive tempco.
They are hence ideal for the purpose.
Patrick
.
The transconductance of these will determine the output impedance of the regulator.
The ones chosen have particularly high transconductances and positive tempco.
They are hence ideal for the purpose.
Patrick
.
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To all regulator MOSFET GB subscribers,
Please kindly email MarkLai via DIYA, copy to me, to reconfirm your postal address.
We have the FETs all packed, ready to go.
And we want to be sure :
a) Our record for your postal address is correct.
b) You are expecting it and not away on holiday or something.
Many thanks,
Patrick
Please kindly email MarkLai via DIYA, copy to me, to reconfirm your postal address.
We have the FETs all packed, ready to go.
And we want to be sure :
a) Our record for your postal address is correct.
b) You are expecting it and not away on holiday or something.
Many thanks,
Patrick
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