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KSC2690A and KSA1220A
KSC2690A and KSA1220A
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Old 15th April 2019, 07:58 AM   #11
woofertester is offline woofertester  United States
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Quote:
Originally Posted by Bonsai View Post
+- 70 V rails.

The 2690/1220 are standard drivers hanging off the VAS, so they should be good.
At what Ic will they be biased?
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Old 15th April 2019, 08:37 AM   #12
knutn is offline knutn  Norway
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I am using the models attached without problems. But I don't remember where I got them.
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File Type: txt KSA1220.txt (688 Bytes, 29 views)
File Type: txt KSC2690.txt (688 Bytes, 19 views)
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Old 15th April 2019, 08:04 PM   #13
Bonsai is offline Bonsai  Europe
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Quote:
Originally Posted by woofertester View Post
At what Ic will they be biased?
30-50mA
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Old 15th April 2019, 11:56 PM   #14
woofertester is offline woofertester  United States
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Originally Posted by Bonsai View Post
30-50mA

For the KSC3503E/KSA1381E that I have, the gain is fairly flat out to 22mA-ish. By 30 mA, the gain is falling. Do you use the 3503/1381 at 30+mA bias?

I have not seen the gain curve for the KSC2690A/KSA1220A pair. ....and...it looks like the 1220 is out of stock at Digikey/Mouser/Newark.

Is there an Ic-Ib curve for these devices published anywhere?
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Old 16th April 2019, 02:44 AM   #15
gannaji is offline gannaji  India
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Quote:
Originally Posted by woofertester View Post
For the KSC3503E/KSA1381E that I have, the gain is fairly flat out to 22mA-ish. By 30 mA, the gain is falling. Do you use the 3503/1381 at 30+mA bias?

I have not seen the gain curve for the KSC2690A/KSA1220A pair. ....and...it looks like the 1220 is out of stock at Digikey/Mouser/Newark.

Is there an Ic-Ib curve for these devices published anywhere?
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File Type: pdf KSC2690.pdf (51.0 KB, 29 views)
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Old 16th April 2019, 04:34 AM   #16
sajti is online now sajti  Hungary
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Quote:
Originally Posted by woofertester View Post
it looks like the 1220 is out of stock at Digikey/Mouser/Newark.
It looks, that Fairchild must be overloaded with order, as I see 40 weeks lead time. I put order for 200xKSA1381 at Mouser, in January. It was promised to middle of March first, then middle of April, changed to middle of August(!), and now 2nd half of September.... 49 weeks lead time

Sajti
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Old 16th April 2019, 07:01 AM   #17
janusz is offline janusz  Australia
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Quote:
Originally Posted by knutn View Post
I am using the models attached without problems. But I don't remember where I got them.
Both are the same: ksc2690a. Could you please show ksa1220a?
Thanks.

cheers,
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Old 16th April 2019, 08:51 AM   #18
knutn is offline knutn  Norway
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Oh, I'm sorry, here it is.
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File Type: txt KSA1220.txt (676 Bytes, 16 views)
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Old 16th April 2019, 10:12 AM   #19
woofertester is offline woofertester  United States
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Default Gain Curves

In the original thread question, distortion of the 2690 vs the 3503 was called into question.

What I am showing is the datasheet curve of gain vs Ic for the 2690A on the left and my measurement of a 3503E on the right. The measured 3503E curve has some noise. The base current is uA and the cables and fixture are unshielded and unguarded. This measurement deserves shielding and guarding.

If you bias the 2690A at 30mA and Ic swings 60mA p-p, the gain of the 2690A will change by 50% (or possibly more, LOG curve difficult to read) p-p while the 3503E biased at 10mA and swinging 20mA p-p will experience a gain change of 4% p-p. If the 3503E current swings 10 mA p-p, the gain change is less than 1%.

If the 2690A is biased at 30 mA and only swings 10mA p-p, then possibly the linearity is very good. I would want to see the curve plotted with better resolution. 90% of the datasheet curve is useless white space.

It will depend on how much p-p current you want to get out of the 2690A as to whether it is more linear than the 3503.

This is just my musing of a linearity comparison of the two parts.
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File Type: jpg KSC3503E_vs_KSC2690.jpg (157.1 KB, 154 views)
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Old 16th April 2019, 02:50 PM   #20
rsavas is offline rsavas  Canada
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In stock at Arrow
https://www.arrow.com/en/products/se...ksa1381&r=true
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