DAC38J84: NCO only config: output attenuates with frequency

Anjana Sharma

Prodigy 70 points

Part Number: DAC38J84

Hi,

I am using DAC38J84 EVM. Its setup for NCO only config, DAC input is set to 1GHz

input is constant, and DAC CLK is 10MHz. PLL is locked.

following are p2p value at differetn frequencies.

40mV p2p at 200MHz. 100mv p2p at 100MHz, 250mV p2p at 10MHz.

is this behavior expected?

config values are attached. termination is 50 ohms.dac_config.cfg

Regards,

Anjana

over 7 years ago

0 Yusuf%20Agoro over 7 years ago

TI__Expert 4880 points

Hey Anjana,

This is not typical behavior for the DAC38J84. What are you using to measure the output voltages? Can you verify that the probe you are using is suitable for measuring such high frequencies?

Yusuf

0 Anjana Sharma over 7 years ago in reply to Yusuf%20Agoro

TI__Prodigy 70 points

probe is indeed the issue. thanks.

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DAC38J84: NCO only config: output attenuates with frequency