http://www.ti.com/product/BUF634A
We've put a preliminary datasheet and prototype samples up on ti.com for a refresh of the classic BUF634. The new device is called BUF634A, and will be available first in the SOIC package (same pinout as the original), with other packages following afterwards.
A few notes on how BUF634A compares to the original device:
-Wider bandwidth: 210 MHz in full bandwidth mode, compared to 180 MHz
-Lower power consumption: 8 mA vs 15mA in full bandwidth mode
-Higher slew rate: 3750 V/us vs 2000 V/us
We've also made a new evaluation board for the new device, and it is designed specifically for customers to try different composite amplifier combinations with the BUF634A. There is a footprint on the PCB for the dual op amp of your choice (SOIC package), as well as RCA input connectors and a headphone jack at the output.
http://www.ti.com/tool/buf634adevm
We're a couple months away from the full release, but I thought there would be interest here in the preview information and proto samples. Enjoy!
We've put a preliminary datasheet and prototype samples up on ti.com for a refresh of the classic BUF634. The new device is called BUF634A, and will be available first in the SOIC package (same pinout as the original), with other packages following afterwards.
A few notes on how BUF634A compares to the original device:
-Wider bandwidth: 210 MHz in full bandwidth mode, compared to 180 MHz
-Lower power consumption: 8 mA vs 15mA in full bandwidth mode
-Higher slew rate: 3750 V/us vs 2000 V/us
We've also made a new evaluation board for the new device, and it is designed specifically for customers to try different composite amplifier combinations with the BUF634A. There is a footprint on the PCB for the dual op amp of your choice (SOIC package), as well as RCA input connectors and a headphone jack at the output.
http://www.ti.com/tool/buf634adevm
We're a couple months away from the full release, but I thought there would be interest here in the preview information and proto samples. Enjoy!
Hey John, interesting update. How do you feel the new IC compares to the LME49600? When would you prefer either one?
Btw, in the datasheet I can imagine more impressive candidates for a composite amplifier than the OPA2810.
PS: When are we getting the audio-specific version of the OPA2156?
Hey John, interesting update. How do you feel the new IC compares to the LME49600? When would you prefer either one?
Btw, in the datasheet I can imagine more impressive candidates for a composite amplifier than the OPA2810.
PS: When are we getting the audio-specific version of the OPA2156?
Comparing the two parts:
LME49600 Wide Bandwidth Mode: 180 MHz / 13.2 mA
BUF634A Wide Bandwidth Mode: 210 MHz / 8.5 mA
The advantages of the SiGe process used in the BUF634A are pretty obvious. It's made on the same process as OPA1612, OPA1642, OPA1622, OPA1692, and many others.
Funny you should ask about the audio version of OPA2156 (will be called OPA1656). I was literally sitting in the lab with the systems engineer for that part, measuring a composite amplifier made up of OPA1656 + BUF634A, when we saw your post. The OPA1656 prelim datasheet and prototype samples should be available on ti.com next week. I'll update this thread when it's online.
And don't discount the OPA2810! 100-MHz bandwidth, JFET-input, 190 V/us slew rate, with lower noise and distortion than an OPA627, and consumes only 3.6mA of supply current...
Very nice that you guys are still cranking out awesome parts for audio when others seem to have abandoned it.
OPA627 will definitely win in the 1/f noise comparison. Since it has a much lower gain bandwidth, the input JFETs can be massive, improving the low frequency noise. However, all that additional input capacitance will make the input current noise rise at high frequency.
I tend to worry about the significantly larger amount of audible bandwidth above 1kHz, than below it. Broadband noise is substantially more important than 1/f when integrating over a 20kHz bandwidth. Unless you're building a phono preamp and have tons of gain at low frequency, then I agree low frequency noise is critical.
That's good news John! I'm just waiting for PCB delivery on a composite with an AD797 (sorry...) and a BUF634, both SOIC, on a standard DIL08 footprint/socket.
I always felt the BUF534 has been neglected too much, it's a great product if you need a bit more kick than usual. Also, being open loop means it is quite stable even within a high speed loop. And the new lower Iq is also worthwhile!
I think I'll get some samples!
Jan
In the original BUF634 datasheet there was noticeable peaking in the frequency response in the wide bandwidth mode, even with no capacitive load. Is the new version similar or better in that regard? Just wondering if it can get away without a series output resistor in the same situations the original could for the most part.
I would still expect some peaking in the frequency response in high bandwidth mode. Since this is an emitter follower output, high impedance or inductive loads tend to cause peaking rather than capacitive loads.
With regards to your second question, if the original didn't require a series output resistor, I would not expect the new one to.
Jan, you should be able to get samples of the XBUF634A right now
http://www.ti.com/product/BUF634A/samplebuy
Please let me know if you are having trouble and I will look into it.
The "X" in XBUF634A just indicates that these are pre-release devices. There will be no change to the production release device coming in a month or two.
Hi Jan, have you posted a schematic on the forum by any chance?
No, not yet, still need to see that it works as advertised (it did on the breadboard, but you never know ... ;-)
Jan
Yes, worked, did have to sign the 'don't complain - it's a preproduction' thing. Fine with me! I'm sure it will be fully functional.
Jan