DAC37J84EVM: DAC1 and DAC2 output single tone signal phase reversal

liukun627

Part Number: DAC37J84EVM
Other Parts Discussed in Thread: DAC38J84

Hi Ti,

Currently, TI's DAC3XJ8X EVM is used to output a 49.9MHz Tone(Created by High Speed Data Converter Pro GUI), and then ADCxxQJxx00 is used for data capture.

The data transmission and capture board paired with two EVMs is both TSW14J57.

Under the default DAC configuration, the signals output by two channels (1 and 2, or 3 and 4) of the DAC are phase reversed. May I ask where to modify the configuration so that all DAC channels can output in-phase signals.

Please refer to the attachment for the DAC configuration page, ADC data acquisition interface, and oscilloscope display interface.

Thanks!

10 months ago

0 Kang Hsia 10 months ago

TI__Guru 70509 points

Hi,

To optimize the DAC38J84 EVM layout, the balun and the DAC output between CH A and CH B are routed with different polarity output. This is the reason for 180 degree phase shift

0 liukun627 10 months ago in reply to Kang Hsia

Prodigy 20 points

Thank you for your reply.

Also, I would like to ask another question. If using this EVM board to achieve DAC differential output, are the following modifications to the components feasible.

1. remove T1 and T2
2. connect the 4th pin of T1 to the 6th pin of T2 using a zero ohm resistor.
3. connect the 6th pin of T1 to the 4th pin of T2 using a zero ohm resistor.

Thanks!