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ADC12DJ3200EVM: DC coupling, external triggering, using TSW14J57EVM

Yoni Sher
Prodigy 150 points
Part Number: ADC12DJ3200EVM
Other Parts Discussed in Thread: ADC12DJ3200, , TSW14J57EVM

Hi, 

Two questions about the ADC12DJ3200 for LIDAR applications:

1. The chip specification says RF sampling - can the chip use DC coupling to sample LIDAR signals?

2. Can the EVM board be set to external triggering, and record a (relatively short, ~100 microsecond) trace at each trigger event to be read by USB at latency? 

The software can be set to arm, and then recording starts at the trigger, but the data has to be read and the device re-armed every trigger, which severely limits the number or events that can be recorded per second. 

Thanks, 

Yoni

  • 0
    TI__Mastermind 44680 points

    Hi Yoni

    1. The ADC12DJ3200 does support DC coupled inputs. For the ADC12DJ3200EVM to work in DC coupled mode requires minor reconfiguration of the board. The 0 ohm resistors connecting the balun outputs to the ADC inputs must be removed, and then 0 ohm resistors are installed to connect the differential input connectors to the ADC inputs.
    2. Triggering is not currently supported on the TSW14J57EVM firmware. That feature will be added as a future firmware upgrade. The TSW14J56EVM can be used with the ADC12DJ3200EVM and does support triggering. When using that capture board the ADC12DJ3200EVM will be limited to clock rates of 3000 MHz or less.

    When using triggering, the TSW14J56EVM capture event is gated by the next LMFC (Local MultiFrame Clock) edge. If the trigger requests are not synchronous to the internal LMFC then the latency from trigger request to actual data capture will be variable, with a maximum variation of one LMFC period.

    You are correct that after capture the data must be read to the PC and then the trigger re-armed. This will limit the number of capture events per second. Changing this behavior would require significant re-design of the TSW14J56EVM firmware and software control features of the system.

    Best regards,

    Jim B