VCA824: VCA824 vs LMH6503

Dennis Brown

Part Number: VCA824
Other Parts Discussed in Thread: LMH6503, , VCA821, VCA822, VCA820

Would it be correct to say that the VCA824 is a direct replacement (assuming SOIC 14 pkg) for the LMH6503 VGA? Seems like the VAC824 is just an improved design but just betters the LMH6503 for bandwidth.

over 6 years ago

0 Michael Steffes over 6 years ago

Guru 48395 points

Sort of, there are two gain control types in the 4 part TI family. The VCA821 is a fast dB/V type control like the LMH6503 intended for servo loop type apps. The VCA824 is a similar speed, but the control is linear gain via the Vg control

And then there are slower versions in the LMH6503 region with the VCA820 dB/V type and VCA822 linear control

0 Dennis Brown over 6 years ago in reply to Michael Steffes

Prodigy 230 points

I need to replace a LMH6530 with a linear/linear device so it still looks like the VCA824 is the best option. The VCA822 has limited bandwidth of only 150M. I need to be able to process signals at 180MHz and have a VGA function.

0 Michael Steffes over 6 years ago in reply to Dennis Brown

Guru 48395 points

Sure looks like the LMH6503 (not the LMH6530 you mention above) is a dB/V adjustment device - so if you need to duplicate that in a faster device, the VCA821 is the one - if you need to switch to linear control, then yes the VCA824 is the one

0 Dennis Brown over 6 years ago in reply to Michael Steffes

Prodigy 230 points

Ah, I put in the wrong part. I do mean the LMH6503, not the LMH6530. Sorry about that.

0 Dennis Brown over 6 years ago in reply to Dennis Brown

Prodigy 230 points

The LMH6503 is linear V/V. This is what the VCA824 is as well. I want to compare similar and was not interested in dB/V devices.

0 Michael Steffes over 6 years ago in reply to Dennis Brown

Guru 48395 points

Yes you are right, it is linear in gain control - so yes the VCA824 is the upgrade

0 Dennis Brown over 6 years ago in reply to Michael Steffes

Prodigy 230 points

Ok. I am pretty certain that the VCA824 is the right part.

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VCA824: VCA824 vs LMH6503