opamps used for unity gain - Page 3

banana · 27th November 2007, 03:11 AM

AD797 does need special care. 100R isolation resistor into inverting input is needed, and feedback lead cap should be less than 30pF. Datasheet have mentioned that.

THS4031 have similar requirement, though it's not writen in the datasheet.

peranders · 27th November 2007, 05:46 AM

An idea was to hear what Scott Wurcer has to say since he has designed the AD797. Persnally I would avoid the opamp for inuty gain due to the restless phase behaviour at 0 dB gain.

juma · 27th November 2007, 08:46 AM

Quote:

Originally posted by HiFiNutNut
Juma, would you mind sharing on how to properly implement it?

This worked great for me:
http://www.diyaudio.com/forums/attac...amp=1155331765

A successful application:

AUDIODH · 12th April 2011, 03:01 PM

Hi Guys,
a newbie here. Just wanted to say hello. I saw the comments on amplifiers. FYI, there is a really nice and inexpensive op amp by NJR model NJM4580. It's very fast, extremely low distortion and reasonable power drain. I've designed it into many successful products.

lineup · 12th April 2011, 03:23 PM

In my simulator I have SPICE model for NJM4580, too.
It is one dual opamp.

AUDIODH · 12th April 2011, 03:34 PM

Yes, it was designed for Audio. You will find in many Pro Audio devices because of it's price/performance. The last design I did with it, the Audio Precision Portable One, could not measure THD or IMD as it was below it's limits. While that doesn't always make a good sounding audio device, I find them to sound very good, with a very good audio slew rate.

27th November 2007, 05:46 AM	#22
peranders Electrons are yellow and more is better! diyAudio Member Join Date: Apr 2002 Location: Göteborg, Sweden Blog Entries: 4	An idea was to hear what Scott Wurcer has to say since he has designed the AD797. Persnally I would avoid the opamp for inuty gain due to the restless phase behaviour at 0 dB gain. __________________ /Per-Anders (my first name) or P-A as my friends call me

12th April 2011, 03:23 PM	#25
lineup diyAudio Member Join Date: Dec 2005 Location: the north	In my simulator I have SPICE model for NJM4580, too. It is one dual opamp. __________________ lineup

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27th November 2007, 03:11 AM	#21
banana diyAudio Member Join Date: Feb 2003 Location: Hong Kong	AD797 does need special care. 100R isolation resistor into inverting input is needed, and feedback lead cap should be less than 30pF. Datasheet have mentioned that. THS4031 have similar requirement, though it's not writen in the datasheet.

12th April 2011, 03:01 PM	#24
AUDIODH diyAudio Member Join Date: Apr 2011 Location: Mayberry RFD, Alabama	Hi Guys, a newbie here. Just wanted to say hello. I saw the comments on amplifiers. FYI, there is a really nice and inexpensive op amp by NJR model NJM4580. It's very fast, extremely low distortion and reasonable power drain. I've designed it into many successful products.

12th April 2011, 03:34 PM	#26
AUDIODH diyAudio Member Join Date: Apr 2011 Location: Mayberry RFD, Alabama	Yes, it was designed for Audio. You will find in many Pro Audio devices because of it's price/performance. The last design I did with it, the Audio Precision Portable One, could not measure THD or IMD as it was below it's limits. While that doesn't always make a good sounding audio device, I find them to sound very good, with a very good audio slew rate.

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