I've read for some time that the E grade of KSC1845/KSA992 are no longer available.
I decided to look into this and found some thing a bit strange. Here are the grades
reported on a Fairchild data sheet:
P 200-400
F 300-600
FA 300-470
FB 430-600
E 400-800
There is obviously a lot of overlap here, and perhaps one was an old system and
the rest a newer system. With P and E the entire range from 200 to 800 is covered.
Strange that F overlaps P and E, if they are binning parts how do they decide when
there is overlap?
Wondering if FA and FB are a newer system since if we design to worst case FB is
better than E with a minimum of 430 as compared to a minimum of 400 for E. If we are
selecting parts I wonder if many in the FB grade end up above 500 or even close to 600.
Does the E grade serve any purpose when the minimum for FB is higher?
Did these parts ever yield an hFE higher than 600, anyone measure any above 600?
I believe that the FB grade is good enough, possibly better.
I decided to look into this and found some thing a bit strange. Here are the grades
reported on a Fairchild data sheet:
P 200-400
F 300-600
FA 300-470
FB 430-600
E 400-800
There is obviously a lot of overlap here, and perhaps one was an old system and
the rest a newer system. With P and E the entire range from 200 to 800 is covered.
Strange that F overlaps P and E, if they are binning parts how do they decide when
there is overlap?
Wondering if FA and FB are a newer system since if we design to worst case FB is
better than E with a minimum of 430 as compared to a minimum of 400 for E. If we are
selecting parts I wonder if many in the FB grade end up above 500 or even close to 600.
Does the E grade serve any purpose when the minimum for FB is higher?
Did these parts ever yield an hFE higher than 600, anyone measure any above 600?
I believe that the FB grade is good enough, possibly better.
https://www.fairchildsemi.com/produ...mall-signal-bjts/KSC1845.html?keyword=KSC1845
It may be too late to consider options. From a visit to Fairchild's website and a look at their current datasheet (rev.1.7) only F Hfe classification is still in full production. (KSC1845FTA) Obsolescence notices for other grades were issued in 2010-2011. Because the F classification originates from a Japanese Fab and the others apparently from elsewewhere, like Korea, the overlap of Hfe classifications could well have been due to sourcing matters. https://www.fairchildsemi.com/produ...ors/small-signal-bjts/KSC1845.html#exportComp
It may be too late to consider options. From a visit to Fairchild's website and a look at their current datasheet (rev.1.7) only F Hfe classification is still in full production. (KSC1845FTA) Obsolescence notices for other grades were issued in 2010-2011. Because the F classification originates from a Japanese Fab and the others apparently from elsewewhere, like Korea, the overlap of Hfe classifications could well have been due to sourcing matters. https://www.fairchildsemi.com/produ...ors/small-signal-bjts/KSC1845.html#exportComp
But F grade spans the full range of FA and FB so it just seems that they are no longer binning them. They probably don't yield anything outside of 300 to 600.
Forgot the attached snip from the data sheet in the first post.
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Looking good, however, for A992 only two options are available, so if one needs complimentary pairs, the choice is rather limited:
https://www.rocelec.com/parts/results/all/?s=KSA992
Thanks ...
My point was that you get 400-800 with E grade, FB gets you 430 min.
E is certainly better than F
And just what I need a min buy of qty 3334.
Any source for the 992 in E or FB?
Never heard of Rochester Electronics before, but reading a bit on their homepage and my own thinking lately it can't be far away into the future until the silicon fab goes the same route as PCB manufacturing have gone making professionally made PCB's available in very small quantities at affordable price for DIY'ers.
I wonder how much it would cost getting a reasonable small batch of some obsolete device made.
I wonder how much it would cost getting a reasonable small batch of some obsolete device made.
Thanks, I take it you are saying they make exceptions to this statement that came up on their site?
"Note: To meet the $100 line minimum the minimum order qty for this part is 3334."
Sounds like their line item minimum is $100. I'll just call them and see.
That's been my experience too. Nothing to select or match as every device on the piece of tape is near identical. It's actually a miracle of modern process control
Below the table of price quantity, "or, add to rfq" is there. Click on that and you can choose as many as you want. Then try another item etc. You will have a shopping cart.
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