Will linear deliver on promised lsj74

[scott wurcer]

So basically $8 and change per complementary pair. If you can only buy 8 transistors per month, how can you get good matches?

In some circuits you need to explore trimming, you would be surprised at how little the OCD matching matters.

 

[hitsware]

Some one should dare to be great and thermally connect
the complementary pair and see what happens !

 

[jez]

I hope the price will come down!! They're really expensive!
Maybe Paul N can answer this but can we expect to see them at a similar price as the N channel part when on full release via normal distributors?

 

[mlloyd1]

price usually drops when yields go up. i think they have been struggling with the yields for a while.

mlloyd1

 

[udailey]

I want to make an F4. Which IDSS grade A B C or D should I be purchasing?

 

[Zen Mod]

comparative to Toshiba's BL range

 

[udailey]

Ok. Made the purchase and dual 5U chassis plus boards. Talk about making a commitment! Thanks Zen for pointing in the right direction. Looks like people love your Pumpkin with the F4. Might be next on the list. We'll see.

 

[paul n]

LSK170A=GR (green)
LSK170B=BL (blue)
LSK170C=V (violet)
LSK170D=toshiba never offered this grade of idss
LSK170E=toshiba never offered this grade of idss

LSJ74A=GR (green)
LSJ74B=BL (blue)
LSJ74C=V (violet)
LSJ74D=toshiba never offered this grade of idss
LSJ74E=toshiba never offered this grade of idss

 

[udailey]

Grade A (Idss 2.6 - 6.5): Basically Toshiba's GR
Grade B (Idss 6 - 12): Basically Toshiba's BL
Grade C (Idss 10 - 20): Basically Toshiba's V

Shoot.. I think I bought the wrong ones... Gotta check my order

 

[udailey]

Found links to request help. Nevermind.

 

[Variac]

I want to make an F4. Which IDSS grade A B C or D should I be purchasing?

Pass said:

"The B through D and most of the A would not be a problem
for the ACA, and a slight adjustment would allow down to the
2.5 mA figure without problems.

Most of my projects would want a B or C grade as most desirable,
but it’s not a big deal."

 

[sakellogg]

So basically $8 and change per complementary pair. If you can only buy 8 transistors per month, how can you get good matches?

i just got my 8 today they match up pretty good.

 

[Triodethom]

i just got my 8 today they match up pretty good.

Not to be rude. However how close ?

 

[sakellogg]

Not to be rude. However how close ?

3 within 10mv. 4 within 3mv. 1 was way off.
so a easy 3 matched pairs.

i used a huge batt bank with 6 cells.
so 13.4v ish
a 1k source resistor.

and, not rude. good question. had i been thinking i would have added that in the first place.

ill post the current of them maybe tomarrow.
i only needed two good matched pairs. so if someone else has some that are close and wanna trade or whatever let me know.

 

[MASantos]

So can these be used as a drop in replacement for the toshibas? I've seen some comments saying that while being good, they are not exactly the same as original toshibas and that some value adjustment might be needed

 

[NicMac]

3 within 10mv. 4 within 3mv. 1 was way off.

mv? Is that Idss in mA or measured voltage drop over 1K in mV?

 

[SY]

So can these be used as a drop in replacement for the toshibas?

In some circuits, yes, in others, no. They are NOT direct one-for-one replacements.

 

[sakellogg]

mv? Is that Idss in mA or measured voltage drop over 1K in mV?

V drop of the fet. to ill have to do the math on the current. ill post my test results in ma. i used the same jig i use for mosfets.

 

[sakellogg]

V drop of the fet. to ill have to do the math on the current. ill post my test results in ma. i used the same jig i use for mosfets.

just to make sure i know what i think i know...... what i did, as long as i match the v drop of the jfets thats the same thing as current matching.... just a diffrent test point... right? current in series right?

 

[flg]

I beleive the standard measurement is; 10Vds, Gate shorted to Source, measure current. However you set up your "jig" or "test fixture", you should acheive the 10Vds and Gate shorted to the Source. Current source, 1K whatever. The 1K is convenient for measureing the current but you should adjust the Vds for 10V. The temp at which you do this is not always specified but generally understood by some to be 25C. Very difficult to achieve without an automated set-up, doing the measurement within about 500uSec of power-up.