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I tested a few different N channel switches on my test rig. The test rig is set up as follows, 60uS TX width, 3Kpps rate, 12.5v fully charged LiPo battery,10R series resistor,the mosfets are driven by a dedicated mosfet driver chip,and the coil is the TX winding of the schiebel coil that I bought on ebay, 248uH, 1.1R series resistance.
I took the measurements via 2K3 resistor,and diode clamps non amplified on 200mv scale.
1. irf 740 could be damped well enough for the flyback voltage to decay to zero in almost 8uS,but required 558R to do so.
2.igbt irfg4bc10ud is nice and flat at 8uS with 640R-650R I have been using this switch for some time,it is hard to beat.
3.Cree Wolfspeed c3m0280090d is flat at 8uS with 600R-630R and has a slightly flatter curve near zero volts.
4.stp2n80k5 mosfet is flat at 8uS with 670R but its only a 2A switch. I'm using 1.09A so it was warm. Probably be ok though.
I'm not an expert on the switching specs of mosfets,but I thought the cree looked pretty great. And in a respect it is,it is a t0247 package,and it has
11.5A rating. So its bigger and stronger,but just as fast. It cost almost 4 dollars though. Also on the SiC switch the Vgs threshold comes down as temperature goes up. They actually want you to pull the gate negative to turn it off. Vgs-th at 150c on my device is 1.5V
I selected quite a few low capacitance diodes to do a coil isolation test. You see this circuit in the hammerhead 2 detector. I have tested with what I had on hand previously and there are gains to be had. After I sort my diodes Ill do that test and post it as well.
I took the measurements via 2K3 resistor,and diode clamps non amplified on 200mv scale.
1. irf 740 could be damped well enough for the flyback voltage to decay to zero in almost 8uS,but required 558R to do so.
2.igbt irfg4bc10ud is nice and flat at 8uS with 640R-650R I have been using this switch for some time,it is hard to beat.
3.Cree Wolfspeed c3m0280090d is flat at 8uS with 600R-630R and has a slightly flatter curve near zero volts.
4.stp2n80k5 mosfet is flat at 8uS with 670R but its only a 2A switch. I'm using 1.09A so it was warm. Probably be ok though.
I'm not an expert on the switching specs of mosfets,but I thought the cree looked pretty great. And in a respect it is,it is a t0247 package,and it has
11.5A rating. So its bigger and stronger,but just as fast. It cost almost 4 dollars though. Also on the SiC switch the Vgs threshold comes down as temperature goes up. They actually want you to pull the gate negative to turn it off. Vgs-th at 150c on my device is 1.5V
I selected quite a few low capacitance diodes to do a coil isolation test. You see this circuit in the hammerhead 2 detector. I have tested with what I had on hand previously and there are gains to be had. After I sort my diodes Ill do that test and post it as well.