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A question about evaluation module(THS4509)

Beomyu Park
Prodigy 30 points
Other Parts Discussed in Thread: THS4509, THS4551, THS4541, THS4509EVM

Hi,

I'm Beomyu Park, in RF developement team, Samsung electronics.

I have a question about evaluation module(THS4509).

 

I'm finding a evaluation kit for measurement of analog baseband circuit, and I find a evaluation module (name : THS4509 evaluation module).

To minimize a loading effect of evaluation module, i will use higher register values of RG and RF for high input impedance.

In your datasheet, a RG and RF values are 100ohm and 348ohm respectively(10dB gain), 

but i want to use RG register values of 2.2Kohm and RF register value of 2.2Kohm(0dB gain) or 4.4Kohm(6dB gain).

And the evaluation module will drive a differential 150ohm register load.

 

In this case, i want to get a below performance.

1. up to 200MHz 3dB BW.

2. up to -60dBc 2nd and 3rd order-harmonic distortion in 160MHz.

3. up to -60dBc 2nd and 3rd order-intermodulation distortion in 160MHz.

4. under 25nV/root(Hz) Input noise voltage density in 100kHz.

 

In addition, a VCM of DUT is 500mV ~ 600mV, so i will use a Vs+ of 2.5V and Vs- of -2.5V.

Is there any problem using evaluation module??

 

If you know higher performance evaluation module, please recommoned it.

Power consumption is don't care.

 

Best Regard.

Thank you.

 

Beomyu Park.

  • 0
    TI__Mastermind 19046 points

    Hello Beomyu,

    Could you share what your input device into the EVM would be?  Are you using a signal generator, sensor, lab equipment, etc?  Why is there a need for a high impedance input?

    I will check and see if your requested configuration is operable for the part; I do not immediately see a reason why the PCB of the EVM would not be able to handle your desired frequencies and low gains.  There may be portions of the EVM designed for datasheet specifications (as to replicate them as close as possible).

    I do not think we have a generic EVM for FDAs in the RGT package; I can recommend the THS4541 & THS4551 RGT EVMs as alternatives for testing the THS4509.  Please investigate these EVMs and their user guides to determine the best choice for you.

    https://www.ti.com/tool/THS4541RGTEVM

    www.ti.com/.../THS4551RGTEVM

    Best,

    Alec

  • 0 in reply to Alec Saebeler
    Prodigy 30 points

    Hello Alec,

    I want to measure an performance of analog baseband(ABB) circuit, and the ABB circuit has a high output impedance(diffenreitla 1Kohm).

    Because the impedance of most lab equipment is 50 ohms, a buffer having high input impedance and low output impedance is needed.

    The input of buffer will be connected output of ABB circuit and the output of buffer will be connected input of mearuement equipment.

    Thank you.

    Beomyu Park

  • 0 in reply to Beomyu Park
    TI__Mastermind 19046 points

    Hello Beomyu,

    Thank you for providing an update on the setup for your testing and lab work.  I am going to look into any recommendations I may have for you; please look at the two FDA EVMs I shared above if you would like to consider an alternative EVM to the THS4509EVM in the RGT package.

    Best,

    Alec

  • 0 in reply to Alec Saebeler
    TI__Mastermind 19046 points

    Hello Beomyu,

    The only thing I recommend checking is whether your selected Rf values will cause the THS4509 to oscillate.  This is not an EVM issue; all three of the EVMs mentioned can handle the target specs you shared above.  The actual device, the THS4509, could have stability issues if the Rf values are too high.  This would not be cause by the EVM, but rather how the THS4509 is designed.

    Best,

    Alec