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ads5560 warm problem

Filipe Alves
Prodigy 10 points
Other Parts Discussed in Thread: ADS5560, THS4502, CDCE72010

Hi

I'm trying to use the ADC ads5560 with my own PCB, but I'm having some problems.

I am connecting the ADC with an FPGA that is also responsible for generating theclock. When the clock is generated, the device begins to overheat.

Iam using CMOS parallel mode, and a ths4502 to convert single-ended todifferential input.

I do not know what I'm doing wrong, follow my attached schematic.

Thanks for the help!

6404.placa_adc.pdf 

  • 0
    TI__Guru 69564 points

    Hi Filipe,

    When the ADC input clock is stopped or is below 1MHz, the ADS5560 automatically enters low power mode. Once the clock starts again, the ADC power dissipation increases in order to convert the data. As long as you are designing your PCB with the correct thermal pad and take care of the thermal environments of the ADC, the device should operate correctly. 

    Typically, as long as the internal die junction temperature is within the specification (105C), your ADC should be fine. If the junction temperature exceed this, then you will need to change your PCB and layout in order to improve the thermal. You may visit www.ti.com/thermal for information and training regarding thermal. 

    For more information on the exposed thermal pads, please refer to the following app note: 

    http://www.ti.com/lit/an/sloa122/sloa122.pdf

    http://www.ti.com/lit/an/slua271a/slua271a.pdf

    On another note, typically, the FPGA will generate a clock with certain jitter content. This may affect your SNR performance of your ADC. You may want to consider some jitter cleaning clock devices such as the CDCE72010 or LMK04800 family.

    -KH