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ADS42XX EVM

Other Parts Discussed in Thread: THS4541, ADS4222EVM, THS4509

Hi,

I have few questions about ADS42XXEVM board:

1.What's the input voltage range? Can we have up to 80V?

2.Can this module handle both AC & DC coupling?

3.It supports Configurable Trigger IN and OUT?

4.What's the input impedence..1 Mohm?

5.What's the analog Bandwidth?

6.Built in Self-test to identify key problems?

7.Latest Schematic design availability with latest BOM..

Regards,

Venu

  • Venu,

    No, this EVM does not accept an 80V input. I will take a look at the schematics and answer your other questions later tonight after returning from travel. Kindly await a further response from me.

    Regards, Chase

  • Hi Venu,

    All of these questions can be answered from the datasheet of the specific product of the ADS42xx family.

    Regards,

    Rob

  • Venu,

    I already answered most of these questions in the previous thread you created, however see my comments below in red.

    1.What's the input voltage range? Can we have up to 80V? No. 80V is not acceptable. See previous thread. The EVM will have some front end input network losses, mainly due to baluns, so the voltage applied by a test source will be greater than what the ADC itself can actually accept in order to achieve full scale on the ADC.

    2.Can this module handle both AC & DC coupling? Yes, the EVM can be AC or DC coupled. The EVM has the THS4541 fully differential amplifier. This requires solder modifications to enable DC coupling.

    3.It supports Configurable Trigger IN and OUT? No, this EVM alone does not have trigger support. With the TSW1400EVM, a trigger in can be used to trigger a capture, which stores the captured data into RAM on the TSW1400EVM and then transfers to the PC over the USB2.0 cable. This is not fast enough for real time applications. This is meant to evaluation purposes only.

    4.What's the input impedence..1 Mohm? 50 ohm. 

    5.What's the analog Bandwidth? The bandwidth is limited to the bandwidth of the part itself (600MHz). The input balun are not limiting the bandwidth as they are 600MHz as well.

    6.Built in Self-test to identify key problems? No, the part itself does not have BIST and neither does the EVM.

    7.Latest Schematic design availability with latest BOM.. This is available online at the ADS4222EVM page, you can also download the files here: https://www.ti.com/lit/zip/slac459 

    Regards, Chase

  • Thanks Chase,

    1.What's the input voltage range? Can we have up to 80V? No. 80V is not acceptable. See previous thread. The EVM will have some front end input network losses, mainly due to baluns, so the voltage applied by a test source will be greater than what the ADC itself can actually accept in order to achieve full scale on the ADC.

    Venu:Is there a way to have a voltage divider network so that we can limit the voltage to accommodate up to 80V with divider on board?

    2.Can this module handle both AC & DC coupling? Yes, the EVM can be AC or DC coupled. The EVM has the THS4541 fully differential amplifier. This requires solder modifications to enable DC coupling.

    Venu:What are the mods required to have both AC & DC coupling on board with solder modification?

    4.What's the input impedence..1 Mohm? 50 ohm. 

    Venu:Is there a way to have at least 1 Mohm input impedance by changing  resisters?

    Venu:

    Regards,

    Venu

  • Venu,

    The input balun can only accept 1/4W input level. My suggestion is to work with Jacob Freet on the previous thread to find a suitable solution to attenuate the 80V down to a usable level. If we have such a device, you should obtain and use the EVM for attenuation before the ADC. Our EVM is not intended to be a SOM nor to provide massive flexibility like what you are asking for, it is meant to evaluate the ADC portion of a system, not RF attenuation blocks/stages, RF switches, etc.

    DC coupling is enabled by removing R93, R94, R97, R98, R119, R123, R141. R143 and populating R95, R96, R99, R114, R120, R129, R131, R132. This changes the front end to use the THS4509 amplifier path rather than the passive front end path. You will also have to remove WBC1-1 on both inputs and short pins 3,4 and pins 6,1 together on each balun in order to DC couple. You will also have to populate J9 or find out which modifications are required to allow the THS4509 to act in a single to differential mode rather than differential input and differential output. You will have to ask Jacob Freet about using the THS4509 device with a 1MΩ input source.

    Regards, Chase

  • Thanks Chase,

    I did send out an email to Jacob and yet to hear back.Not sure he is vacation..

    I will continue to work with him and try to find the best parts/circuitry suitable for our application.

    Regards,

    Venu