About the SFDR and THD specification of AD3551R and LTC1668

Hi Benuyan,

We have not concluded the evaluation of the AD3551R above 100 kHz. The AD3551R is capable of generating tones up to half the update rate but overall performance depends on the amplifier, filter and configuration of the DAC.

From the amplifiers we have tested, the AD8065 would be close to meeting the 90 dBc THD requirement at 1 MHz. We are still testing other options aiming at improving DC and AC performance.

The main difference in performance between AD3551R and LTC1668 is the noise floor: 20 pA/√Hz vs 50 pA/√Hz. Our preliminary measurements show that the AD3551R would be on par with the LTC1668 in terms of THD at 1 MHz. However there are several adjustments we are testing to improve performance. We aim at publishing an application note with recommendations when the work is concluded.

Best regards,

Antonio

Hi Antonio,

Thank you! We are unsure about the performance of AD3551R within the frequency range of 800K ~ 1.2MHz, as these frequency bands are vital to our bio-impedance applications. So it is safe to design using AD3551R right now or we should wait for your application note?

Apart from the noise floor, we also found that AD3551R may have better temperature stabilities. This chip as well as its two-channel variant are very attractive for our applications. Could we order some samples or 10 pcs right now via a distributor in P. R. China?

Best

Benyuan

Hi Antonio,

Thank you! We are unsure about the performance of AD3551R within the frequency range of 800K ~ 1.2MHz, as these frequency bands are vital to our bio-impedance applications. So it is safe to design using AD3551R right now or we should wait for your application note?

Apart from the noise floor, we also found that AD3551R may have better temperature stabilities. This chip as well as its two-channel variant are very attractive for our applications. Could we order some samples or 10 pcs right now via a distributor in P. R. China?

Best

Benyuan

Hi Benuyan,

If your project has a stringent timeline, I suggest you proceed in parallel with our evaluation since it will take several months to complete. You may need to build your own circuit since the evaluation board may not achieve the required performance.

The purpose of EngineerZone is to provide communities with the support of select Analog Devices products. For additional information on pricing or product availability, we recommend contacting your FAE or local ADI salesperson.

Contact details for your local ADI salesperson are available via the following page on the Analog Devices website: Sales and Distribution | Analog Devices

Best regards,

Antonio