SFDR of DAC902 at wider range

Shinichi Inoue

Guru 21556 points

Other Parts Discussed in Thread: DAC902, DAC902EVM, THS5661EVM

Dear Specialists

MY customer is considering DAC902 for RF transceiver.

He wants to know SFDR with a window at wider range.

Datasheet spec says only 2MHz or 4MHz span.

Could you please provide me the spec following condition

conditions

CLK:125MHz

fout:50MHz

Span:20MHz

He needs to confirm the specs at the used case.

Similar condition is acceptable.

Best regards,

Shinichi

over 10 years ago

0 Ken C over 10 years ago

TI__Genius 12965 points

Shinichi,
Sorry for the delay. We will look at this and get back with you asap.

Ken.

0 jim s over 10 years ago in reply to Ken C

TI__Guru* 91947 points

Shinichi,

As soon as I can locate a DAC902EVM, I was planning on doing the following test:

1. Provide a 125MHz sample clock

2. Provide a 50MHz digital test input tone

3. Capture the output with a spectrum analyzer from 0 to 62.5MHz.

Is this what you are interested in?

Regards,

Jim

0 Shinichi Inoue over 10 years ago in reply to jim s

Guru 21556 points

Dear Jim

Thank you for your reply.

Your testing condition is OK.

In addition to 0 to 62.5MHz, the customer wants output data from 40MHz to 60MHz.

I am looking for the waveform.

I appreciate your great help.

Best regards,

Shinichi

0 jim s over 10 years ago in reply to Shinichi Inoue

TI__Guru* 91947 points

Shinichi,

Unfortunately, TI no longer provides evaluation modules for this device. Without this hardware, I will be unable to do any of these tests. I will try and contact the design team to see if they have any data I can share with you.

Regards,

Jim

0 Shinichi Inoue over 10 years ago in reply to jim s

Guru 21556 points

Dear Jim

Thank you for your reply.

Could you please confirm your design team and inform.

I appreciate your great help.

Best regards,

Shinichi

0 Shinichi Inoue over 10 years ago in reply to Shinichi Inoue

Guru 21556 points

Dear Jim

How is the situation of confirmation of design team as you mentioned.

I have to report the customer about it.

I am looking forward to your reply and the data.

I appreciate your great help.

Best regards,

Shinichi

0 jim s over 10 years ago in reply to Shinichi Inoue

TI__Guru* 91947 points

Shinichi,

Unfortunately, this part was designed by the old Burr Brown company which TI bought in 2000. All of the designers are no longer available. We are building new EVM's that will allow us to do future testing, but these boards will not be available for another 4 weeks. We have a THS5661EVM coming from the TI Estore that we will swap out the THS5661 with a DAC902. Hopefully we can have this board modified and running by late next week.

Regards,

Jim

0 Shinichi Inoue over 10 years ago in reply to jim s

Guru 21556 points

Dear Jim

Thank you for your reply.

That is a good news.

The customer and I are waiting for the data from you.

Best regards,
Shinichi

0 jim s over 10 years ago in reply to Shinichi Inoue

TI__Guru* 91947 points

Shinichi,

We did a test with a THS5661EVM sampling at 125MHz with a 50MHz tone. The data was captured with a 20MHz BW centered at 50MHz. The results are attached. We are expecting a DAC902 device tomorrow that we will install on to the EVM and repeat the test. Is this the type of data you are requesting?

Regards,

Jim

0 Shinichi Inoue over 10 years ago in reply to jim s

Guru 21556 points

Dear Jim

Thank you for your reply.

It's OK that you're setting.

I am looking for the data of DAC902.

Best regards,

Shinichi

0 jim s over 10 years ago in reply to Shinichi Inoue

TI__Guru* 91947 points

DAC902.pptxShinichi,

Attached are plots from a DAC902 sampling at 125MHz with 50MHz output tone. First two plots are with no filtering. The last two plots are with bandpass filters we had available in the lab.

Regards,

Jim

0 Shinichi Inoue over 10 years ago in reply to jim s

Guru 21556 points

Dear Jim

Thank you for your reply and measure.

I'll send the file to the customer.

I appreciate your great help.

Beat regards,
Shinichi

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SFDR of DAC902 at wider range