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PGA460: BOOSTXL-PGA460-MATCHING daughtercard design file availability

Karl Grueschow
Prodigy 90 points
Part Number: PGA460

Hello,

I'm wondering if there's any update on the matching daughtercard outlined in the EVM user guide (p44-45). It doesn't appear as any design file anywhere on the PGA460 page that I can see, nor is there a menu in the EVM GUI for it yet. 

I have our hardware talking to the launchpad through the EVM GUI, and the reference design using the Murata closed-top 58kHz transducers (bistatic mode) works well, but I have 4 other transducer brands and frequencies to tune and I was hoping the daughtercard was available to simplify that process. 

In lieu of that, is there a recommended process for tuning C_tune and R_damp? My current thought is to build a few of our boards with large steps in capacitances and test them, then note which ranges appeared to perform best, then rebuild the boards with finer steps until a match converges. Is the GUI the correct tool for this? Or is it more efficient to use an external microphone and a scope? Mostly just looking for a sanity check here. 

Thanks,

Karl

  • 0
    TI__Mastermind 27950 points
    Hi Karl,

    Unfortunately, the Matching Daughtercard's design files are not yet available as we are still optimizing its performance for official release.

    Yes, your thought process of manually sweeping through the matching component values will help you to optimize the ring-decay. The process and typical range of the matching components is discussed in the PGA460 Ultrasonic Module Hardware and Software Optimization app note ( www.ti.com/.../slaa732.pdf ) section "3.4 Passive Tuning".

    You can use the GUI to check how the matching components impact the ring-decay time and the peak amplitude of an object at a fixed distance. The goal is to minimize or clean-up the ring-decay without significantly reducing the peak amplitude of the object. I recommend you start with the tuning capacitor, and then move the damping resistor. It is possible that both, only one of the two, or neither of the matching components will make an improving difference .
  • 0 in reply to Akeem Whitehead
    Prodigy 90 points

    Akeem,

    Thanks for your reply. Would the diagnostics section of the GUI be a better way to measure ring decay and resonance frequency, as opposed to visually evaluating the echo dump in the data monitor? 

    Karl

  • 0 in reply to Karl Grueschow
    TI__Mastermind 27950 points
    Hi Karl,
    I primarily recommend that you use the echo data dump as a means to monitor the ring decay and echo peak strength for the optimization of the transducer's matching components. The system diagnostic features of frequency, decay time, and excitation voltage serve more as health checks for the transducer when the system is running (post optimization of the matching circuit).