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KSC2690A and KSA1220A
KSC2690A and KSA1220A
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Old 14th April 2019, 05:53 PM   #1
Bonsai is offline Bonsai  Europe
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Default KSC2690A and KSA1220A

Anybody had sim problems with the models for the above? When I sim with 3503/1381 I get good distortion results. When I sim with the models below, its about 5x worse.



.MODEL KSC2690A_k NPN ( IS=1.7783E-13 BF=132.5 NF=1.0 BR=8.495 NR=1.005 ISE=1.9953E-13 NE=1.5 ISC=1.5849E-9 NC=1.98 VAF=580.75 VAR=18.15 IKF=4.0271 IKR=0.0120 RB=2.98 RBM=0.001 IRB=0.6396 RE=0.0909 RC=1.4705 QCO=0 RCO=0 VO=6.587 GAMMA=2.8216E-7 CJE=4.0082E-10 VJE=0.6696 MJE=0.3296 FC=0.5 CJC=6.0404E-11 VJC=0.5 MJC=0.4266 XCJC=0.4955 XTB=1.2590 EG=1.2277 XTI=3.0 Tf=830p Vceo=160 Icrating=1.2A mfg=Fairchild)
.MODEL KSA1220A_k PNP (IS=4.7863E-13 BF=289.3 NF=1.0 BR=9.76 NR=1.006 ISE=5.2481E-12 NE=2 ISC=2.4909E-11 NC=1.5 VAF=98.5 VAR=6.7 IKF=2.7061 IKR=0.0759 RB=2.26 RBM=0.2308 IRB=0.001 RE=0.1908 RC=1.1748 QCO=0.02 RCO=3.9811 VO=11.078 GAMMA=5.01187E-8 CJE=3.4786E-10 VJE=0.9575 MJE=0.4694 FC=0.5 CJC=1.1224E-10 VJC=0.5761 MJC=0.4365 XCJC=0.4955 XTB=1.7978 EG=1.2255 XTI=3.0 Tf=970p Vceo=160 Icrating=1.2A mfg=Fairchild)
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Old 14th April 2019, 06:13 PM   #2
sajti is online now sajti  Hungary
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In which position are You using the transistors? KSC2690/KSA1220 has about 10 times higher Ccb.

Sajti
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Old 14th April 2019, 06:13 PM   #3
Ian Finch is offline Ian Finch  Australia
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Aren't the 2690A/1220A pair actually drivers rather than VAS types? I would have thought the higher Cob alone would have had an adverse affect on the THD in simulation too. Apart from that, linearity of the 3503/1381 pair is quite outstanding, by all accounts.
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Old 14th April 2019, 06:35 PM   #4
Bonsai is offline Bonsai  Europe
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I am not using in the VAS - I am using 3503 and 1381.

I am using these as pre-drivers in an EF3.

I am making a few small changes to the e-Amp so I can release the PCB's for DIY. The amp has very good performance, but I used 3503/1381 for the pre-drivers but as you know these are getting more difficult to source, and besides, the 1290/1220 on paper make much better drivers (about 10x the Ic capability). I've looked on Bob Cordell's site, but he does not cover the 2690/1220. Maybe these models are just bad.


Here is the original link to the e-Amp thread FYI

Ovation e-Amp is Completed

Last edited by Bonsai; 14th April 2019 at 06:38 PM.
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Old 14th April 2019, 06:55 PM   #5
sajti is online now sajti  Hungary
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I'm in same situation, and my plan is to try Toshiba TTC/TTA004B as predriver. They have somewhat less internal capacitance.

Sajti
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Old 14th April 2019, 07:18 PM   #6
Bonsai is offline Bonsai  Europe
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I don't think its the internal capacitance Satji - this is not in the VAS position but the pre-driver location. The models are just not right.

Maybe keantoken has some ideas.

I will try the sim with some other pre-driver transistors and see what happens.
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Old 14th April 2019, 07:29 PM   #7
rsavas is offline rsavas  Canada
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I recall a long time ago I was having problems with those ksc2690/a1220 models too. I have no idea where I got them, same place as you :-).
I can look to see if I can find 2sc2690/2sa1220 modles

I agree that ksc2690/a1220 should be fine as pre-drivers since they can put out a lot more current than the c3503/a1381.

As said above, Toshiba TTA004B,TTC004B, similar to ksc2690/a1220. I did not look if Toshiba has models, nor have I tried them. Something to try one day too.

Spice models for 2SC2690

Last edited by rsavas; 14th April 2019 at 07:55 PM.
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Old 15th April 2019, 12:57 AM   #8
woofertester is online now woofertester  United States
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Quote:
Originally Posted by Bonsai View Post
I am not using in the VAS - I am using 3503 and 1381.

I am using these as pre-drivers in an EF3.

I am making a few small changes to the e-Amp so I can release the PCB's for DIY. The amp has very good performance, but I used 3503/1381 for the pre-drivers but as you know these are getting more difficult to source, and besides, the 1290/1220 on paper make much better drivers (about 10x the Ic capability). I've looked on Bob Cordell's site, but he does not cover the 2690/1220. Maybe these models are just bad.


Here is the original link to the e-Amp thread FYI

Ovation e-Amp is Completed


I just bought 50 pcs of KSC3503E from Summit Electronics. I ran them through the curve tracer and they appear genuine. The price was $0.90 each for 50 pcs. I consider that a bargain for how good they are. I will probably buy some more of those to match the number of KSA1381E that I already have.

That said, I bought quantities of three other devices and they were all not up to datasheet spec so I consider those fakes or mislabeled lower rank parts. Either way those are going back.

Buyer beware
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Old 15th April 2019, 01:55 AM   #9
woofertester is online now woofertester  United States
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Quote:
Originally Posted by Bonsai View Post
I am not using in the VAS - I am using 3503 and 1381.

I am using these as pre-drivers in an EF3.

I am making a few small changes to the e-Amp so I can release the PCB's for DIY. The amp has very good performance, but I used 3503/1381 for the pre-drivers but as you know these are getting more difficult to source, and besides, the 1290/1220 on paper make much better drivers (about 10x the Ic capability). I've looked on Bob Cordell's site, but he does not cover the 2690/1220. Maybe these models are just bad.


Here is the original link to the e-Amp thread FYI

Ovation e-Amp is Completed
At what Vce and Ic will you be biasing these transistors? I would want to see the Ic - Ib curve to see if these transistors are as good as the KSC3503/KSA1381.

I will order some of each and run them through my curve tracer.
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Old 15th April 2019, 07:20 AM   #10
Bonsai is offline Bonsai  Europe
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+- 70 V rails.

The 2690/1220 are standard drivers hanging off the VAS, so they should be good.
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