Bias in a classical current feedback amp - influence how?

[PMA]

Yes, I think SMD for DIY'ers is the next thing and also current feedback.....

Next step is to use 0204 parts 😀

.... or TAS5111 ... 😀

 

[bocka]

Well, I'm only using µBGA if they're available. Prevents my projects to be copied... 😉

0603 could be used by some DIYers, not small enough and can be soldered when using a fine tip.

 

[sonnya]

I have done some simulating on a SMD current feedback amp with Diamond buffer and the performance seems to be rather good. Bandwidth up to 25 MHz but how about real world influence? I expect over 1 MHz is very possible, maybe 10 MHz.

I notice that working point aren't very sensitive. 0.5 mA or 5 mA doesn´t mean much.

I'm very keen on making a small cute all SMD headphone amp, mayby with Jung Super Regulators.

I have attached the simulation files if somebody wants to fool around.

Bandwidth up to 1MHz is very possible, also in a poweramplifier. Just use Emitterfollower as output. Maybe use MOSFET's.

Try out other combinations of currentmirrors. As i have found out you can gain more phase margin than with the current mirrors you have used right know.

I my self would like high idle current, so it isn't jumping between class B and A when slewing fast.

 

[peranders]

If I choose to have 10pF I get 70 deg, 22pF, 64 deg, 47pF, 55 deg.

22pF = 14 MHz, 47pF = 6 MHz

Simulationwise I think Wilson mirrors aren't so bad.

I have adjusted the currents somewhat but I have kept them rather low so my poor pcb won't go into flames. Total power consumption for one channel is 0.8 Watt.

 

[peranders]

Here is the schematics which I'm working on. At the moment I have only one channel. First I'll make the pcb layout for one channel ready then I will duplicated it.

I wonder how good the temp stability will be? May I'll have to reduce the currents? I'll guess a prototype will give me the answer.

 

[peranders]

The CAD files have left the computer so I start a new thread here.