Op_Amp_Booster_Circuit
Op_Amp_Booster_Circuit
(OP)
I'm trouble shooting a circuit for an R/D converter. One circuit is an op-amp booster. It takes a sine wave in differentially and drives it single-ended. It uses a booster stage to drive the signal at 10V peak. I'm not familiar with booster circuits using transistors. Can anyone tell me if this circuit is sufficient and what to what to watch out for? The load is about 120 ohms. Is there a better solution?





RE: Op_Amp_Booster_Circuit
The topology is similar to National's LH0033 buffer amp:
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TTFN
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RE: Op_Amp_Booster_Circuit
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RE: Op_Amp_Booster_Circuit
What is the frequency of your signal ?
What is the problem ?
RE: Op_Amp_Booster_Circuit
Have you looked at the output signal under load? What does it look like? What is the problem you are troubleshooting?
Gunnar Englund
www.gke.org
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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...
RE: Op_Amp_Booster_Circuit
Thanks
RE: Op_Amp_Booster_Circuit
Did the circuit work at some point in time, and stopped working when some component was changed?
TTFN
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RE: Op_Amp_Booster_Circuit
Also, the inductosyn coil looks like an inductor at the end of the cable.
RE: Op_Amp_Booster_Circuit
Cable capacitance can definitely affect stability but your (implied) bandwidth requirements mean you can use pretty much any of the standard compensation techniques. A capacitor across the 10k feedback resistor (say, 330pF to 680pF) will curtail the high frequency response somewhere north of 20kHz. More elaborate schemes can help tailor the pulse response, but it doesn't sound like you need to worry about this. At any rate, if you are getting obviously visual distortion at 20kHz with the amount of capacitance from a few feet of cable then you are hard up on the slew limit of something (e.g. - U1, the discrete output buffer or both).
RE: Op_Amp_Booster_Circuit
RE: Op_Amp_Booster_Circuit
Is it possible that there has been such a capacitor and that it is now missing? That could explain why you have problems with a device that seems to have worked once.
Gunnar Englund
www.gke.org
--------------------------------------
100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...
RE: Op_Amp_Booster_Circuit
Thanks for all the help.