Performance differences between THS4001 and OPA657

[Paul98]

Hi everyone, I bought an amplifier module. On the product page it was declared that it mounted an OPA657 but verifying upon arrival there is mounted a THS4001. I don't have much experience with these two opamps but comparing the datasheets, despite being electrically replaceable The OPA657 is newer and has better performance than the THS4001 (mainly bandwidth, gain and noise). I attach the technical sheets. Can you confirm or not that the THS4001 has lower performance than the OPA657? Thanks for your help.


OPA657

THS4001

 

[KlausST]

Hi,

lower performance regarding what?
(you already compared bandwidth, gain, noise)

Maybe it´s a good idea to tell us what you want to do with it. And what are your technical requirements on the application.

There´s a good reason why an OPAMP datasheet is that big with all the specifications: Because there are so many applications with different requirements.

Klaus

 

[Paul98]

Hi,
I suspect that a THS4001 was used only because it was much cheaper but in fact defrauding the sale. However, I will send it back and report it to the sales platform. Then knowing whether to use a real OPA657 instead of the THS4001 would get a higher gain with less noise. I need it as a first stage (with adjustable gain) to detect and quantify microsignals (microvolts) up to 100MHz. Consider some kind of scanner.

 

[FvM]

The two OP are completely different in many regards. It's impossible to compare their performance without referring to the actual application circuit and its requirements.

 

[FvM]

Here's a brief parameter comparison

	OPA657	THS4001
GBW	1600 MHz	270 MHz
Min. stable gain	7	1
Supply	8-12 V	5-30 V
Ibias	2 pA	2 uA
Vn	4.8 nV/rtHz	12.5 nV/rtHz
In	1.3 fA/rtHz	1.5 pA/rtHz
Price 1k	$ 6.5	$ 2

You better compare THS4001 with unity gain stable OPA656

 

[Paul98]

@FvM , this is what I meant, it is the confirmation of what I thought, that is, the 4001 is performing worse. I put the photo of the baord below.