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)
.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)
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 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
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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
. 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
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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
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.
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?
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
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.
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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