LSK170 Cgd and Cgs?

[scott wurcer]

Has anyone actually played with these in a circuit where the capacitances matter? They say 20pF on their web site but the models they provide have 40pF for both Cgd and Cgs. I haven't checked the voltage variation either.

They also don't spec the excess gate current (Ig @ high Vgd).

For some reason they didn't ship me samples

[Charles Hansen]

Originally posted by scott wurcer
Has anyone actually played with these in a circuit where the capacitances matter? They say 20pF on their web site but the models they provide have 40pF for both Cgd and Cgs. I haven't checked the voltage variation either.

They also don't spec the excess gate current (Ig @ high Vgd).

For some reason they didn't ship me samples

Hi Scott,

As you probably know, the Toshiba originals are rated at a typical value of 30 pF with Vds = 10 VDC and Vgs = 0 Vdc at 1 MHz. In contrast, the Linear parts are rated at 15 VDC, which pretty much explains the reduction to 20 pF right off the bat.

It seems like Linear is picking and choosing the test conditions to give the best numbers. The seem like reasonably good parts. I haven't tried them for two reasons -- they don't make a complement, and the Toshibas are still in production for less than $.50 each.

On the other hand, I would love to purchase from an American manufacturer. If Analog wants to get into this area, please contact me, John Curl, and Ed Oxner, and we can get you pointed in the right direction. (On Semi has been making some noises about this also.)

Cheers,
Charlie Hansen