Crazy idea for the OPA860

Russ White · 26th July 2005, 01:00 PM

Ok, so this morning I read my email and I see one from TI touting this "new" opamp/buffer the OPA860.

Ok, it does not look at all like it was designed for audio, but it has some intersting features which made me wonder...

Could this thing be used for a headphone amp?

1) Excellent slew rate.
2) Awesome power bandwidth.
4) Very low output impedance.
5) Built in buffer with 65ma output.

Some downsides as well.

1) Small form factor (SO-8). Not a huge deal.
2) Small working voltage (max 6.5V). Not a big deal for headphones.
3) Bi-polar... And I am not sure how to design the circuit/feedback loop for this chip.

Any ideas?

Thanks,
Russ

DSP_Geek · 26th July 2005, 06:36 PM

The harmonic distortion increases a fair bit when it's loaded by less than 200 or 300 ohms, and the noise isn't particularly low. It's not a bad part - as a matter a bloody good one if you want to work at megahertz frequencies - but in my opinion not a great match to headphones.

Francois.

Russ White · 26th July 2005, 06:37 PM

Thank you for the response. I suspected as much. It does look like quite an IC.

26th July 2005, 01:00 PM	#1
Russ White diyAudio Member Join Date: Jan 2005 Location: Nashville, TN, USA	Crazy idea for the OPA860 Ok, so this morning I read my email and I see one from TI touting this "new" opamp/buffer the OPA860. Ok, it does not look at all like it was designed for audio, but it has some intersting features which made me wonder... Could this thing be used for a headphone amp? 1) Excellent slew rate. 2) Awesome power bandwidth. 4) Very low output impedance. 5) Built in buffer with 65ma output. Some downsides as well. 1) Small form factor (SO-8). Not a huge deal. 2) Small working voltage (max 6.5V). Not a big deal for headphones. 3) Bi-polar... And I am not sure how to design the circuit/feedback loop for this chip. Any ideas? Thanks, Russ __________________ Less pulp more juice Twisted Pear Audio.

26th July 2005, 06:37 PM	#3
Russ White diyAudio Member Join Date: Jan 2005 Location: Nashville, TN, USA	Thank you for the response. I suspected as much. It does look like quite an IC. __________________ Less pulp more juice Twisted Pear Audio.

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26th July 2005, 06:36 PM	#2
DSP_Geek diyAudio Member Join Date: Aug 2003 Location: Santa Cruz, California	The harmonic distortion increases a fair bit when it's loaded by less than 200 or 300 ohms, and the noise isn't particularly low. It's not a bad part - as a matter a bloody good one if you want to work at megahertz frequencies - but in my opinion not a great match to headphones. Francois.