50 KSC1845 tested

[pdp11]

Hello

I have tested 50 KSC1845 from the same tape for find matched transistor.

The test condition was Ib 51.6 uA for approximate Ic2mA
I have found

Beta
Average 260.9
min 252.6 -3.1%
max 277.1 +6.2%
std dev 6.84 -> 2.6%

Vbe
Average 622mV
min 617mV
max 625mV
std dev 1.67mV

What do you think?
Is the firs time that i do a so extensive matching test.
I expected a more accurate production.

Best regards,

Pietro

 

[Elvee]

Well, let's be realistic about it: some matched devices aren't even up to that standard, so don't be to unhappy about it.
And if your application needs better matching, my advice is to change to a more tolerant one: it will probably have been better engineered.

 

[pdp11]

I'm going to finish my last design.
This amplifier needs, as most of amilifer, quite matched parts in the input stage, and before closing the pcb I tested some transistor.
I prefer use the smd version of ksc1845, but I found quite difficult test sot23 transistor.
I have tested some ksa1845 for evaluating the repeatability of fairchild production, and i decided to use the to92 version for avoding mismatch when simmetry is needed.

I haven't done a similar test on other transistor and i have no idea if other suppliers are better than fairchild.

Pietro