AD9681
Recommended for New Designs
The AD9681 is an octal, 14-bit, 125 MSPS analog-to-digital converter (ADC) with an on-chip sample-and-hold circuit that is designed for low cost, low power...
Datasheet
AD9681 on Analog.com
Dear ADI engineers,
I am using AD9681.
The balun stage in AD9681 is MABA-007159-000000 with the frequency region 4.5-3000MHz.
I would like to work with lower frequency. Could I change this balun stage to another one?
If possible. Could you recommend me some options?
Thank you very much,
HOANG
Hi Hoang,
Thanks for your interest in AD9681. Even though that balun's datasheet rating is 4.5MHz, it works well at lower frequency. How low of a frequency do you need?
Thanks,
Doug
I test with 500kHz square of arbitrary signal generator. I met the low frequency loss and phase shift.
How is about 500kHz or 1MHz?
Hi,
I thought 500kHz would be OK, but if you have tried it and it does not meet your need, the AD9681 evaluation board also has pads that can accommodate a Mini-Circuits ADT1-1WT+, which is rated down to 400kHz.
You would need to remove the two MABA-007159-000000 and install the Mini-Circuits ADT1-1WT+.
The AD9681 evaluation board schematic is here: wiki.analog.com/.../08_039100b_cam.zip
Thanks,
Doug
Thank you Dougl. Is there any examination you test with it?
Hi,
We use single tone sinusoid as an initial test signal for many of our tests. I don't have specific test conditions for the Mini-Circuits balun but you could try a 500kHz single tone test as a starting point.
At some point the impedance of the 0.1uF AC coupling capacitors could be an issue for you to be aware of.
Doug
Hi Dougl,
I replace the balun stage to Mini - circuits but the result I got was the same with the older one at 500kHz.
Here is my result. square waveform at 500kHz.
I try to see the voltage spectrum.
Could you tell me the problem and recommend what should I do?
Thank you.
HOANG
Hi Hoang,
How does the waveform look if you apply a 500kHz sinusoid?
Thanks,
Doug
Hi Dougl,
Sinunoid looks well.
Another question. Why was my signal voltage probe at SMA connector pin decreased by 2? example: 2Vp-p Sinunoid signal generator --> at SMA connector pin: 1.2Vp-p
Thanks,
HOANG
Hi Dougl,
Sinunoid looks well.
Another question. Why was my signal voltage probe at SMA connector pin decreased by 2? example: 2Vp-p Sinunoid signal generator --> at SMA connector pin: 1.2Vp-p
Thanks,
HOANG