Toshiba N-JFET 2SK2145 is a dual JFET containing 2x 2SK209 with their source wired together internally.
Since D-S are exchangable, it can be used in a LTP as well as souce follower.
However both applications will want matched devices.
Toshiba datasheet does not have any specification on matching.
So how well matched are they actually ?
I just matched 105x 2SK2145GR for Idss.
So maybe the statistics would be of interest.
This is only one sample of 105, so not necessarily perfectly representative.
Average Idss of the 2 JFETs in one device varies from 3mA to 5.3mA.
Delta Idss between the 2 varies from 1µA to 0.39mA (or 8%).
50 pieces have delta Idss within 1%.
18 pieces > 2%; 5 pieces > 4%.
For me, it always needs to be measured.
I would never want a 8% difference in a LTP or source follower.
And I would also not want to parallel one of 3mA with another of 5mA.
Cheers,
Patrick
.
Since D-S are exchangable, it can be used in a LTP as well as souce follower.
However both applications will want matched devices.
Toshiba datasheet does not have any specification on matching.
So how well matched are they actually ?
I just matched 105x 2SK2145GR for Idss.
So maybe the statistics would be of interest.
This is only one sample of 105, so not necessarily perfectly representative.
Average Idss of the 2 JFETs in one device varies from 3mA to 5.3mA.
Delta Idss between the 2 varies from 1µA to 0.39mA (or 8%).
50 pieces have delta Idss within 1%.
18 pieces > 2%; 5 pieces > 4%.
For me, it always needs to be measured.
I would never want a 8% difference in a LTP or source follower.
And I would also not want to parallel one of 3mA with another of 5mA.
Cheers,
Patrick
.
Attachments
HOw is the matching performed
Hi Patrick,may i ask how you matched the fet's? Did you combine pins or match the individual fet's?
Thanks, Hans.
Hi Patrick,may i ask how you matched the fet's? Did you combine pins or match the individual fet's?
Thanks, Hans.