Little GEM

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dadod

dadod

Member
Joined 2006
dadod said:
The mosfet operation (depletion mode) was discussed in mine other thread. It is just CCS and it gives combination of CCS and bootstrap VAS, and I never saw anything similar used before.
If you like to build this amp here is last layout in pdf. In my prototype I used older layout, so it needs check and you can change mosfet from TO220 to TO92 type.
Damir
Click to expand...

I've found some layout error in that PCB, Ian will have gerbers for new layout if someone interested.
Damir
 
dadod

dadod

Member
Joined 2006
T117 said:
Congratulations, you're design is very good amplifier. This amp can do a bit better. Look at R5L1. This circuit will add depth NFB.
Click to expand...

Thank you for your comment and suggestion. I simulated it with added RL between LP emitters and I've got some marginal THD20k improvement, but with some Phase Margin loss. I tried to optimize RL but still not to big difference. To get better result, I suppose I have to optimize whole LP and it's not worth the effort as distortion is already very low.
 
P

petr_2009

Banned
Joined 2009
petr_2009 said:
Little GEM_(Damir Dadod).pdf
Click to expand...
tPD = Gain*tPD(Gain=+1)

Propagation Delay, nS and Unity Gain Frequensy (UGF), MHz for some operational amplifiers:
LM6172 – 1,0 (100); THS4041 - 1,7 (89); LT1363 (64) - 2,0 (70); EL2044 – 2,5 (38); AD817 - 3,0 (50); AD843 – 4,6 (34); LM837 - 7,0 (25); AD744 - 8,0 (13); OPA627 - 10,0 (16); OPA2132 - 13,9 (8,7); NE5532 – 16,2 (9); TL072 – 53,6 (2,7)
 
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