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PGA460

Other Parts Discussed in Thread: TIDA-01597, PGA460

I am designing a parking assitance system based on the PGA460.  Reading the "slaa732.pdf" it sugests adding a tuning capacitor and a tunable transformer. But "TIDA-01597" deploys a standard fixed central tab transformer. The system I am designing is a 24V system for truck/traillers. Distances must range from 25cm to 2,5 m. How critical are those components fot matching the impedances? Depends on the ultrassnic sensores selected? I would like to avoid this tunning process at the end of the production. 

Thank you

  • Hello Ricardo,

    Thank you for your question. The tuning components as mentioned are a recommendation for better operation of your system such as when shorter distance measurements are needed. These components help reduce the decay period of the transducers ringing period in order to achieve those closer measurements or tune the transmission frequency in order to stabilize the output.

    For the transformer and dampening resistor depending on the transducer or the transformer selected it is possible that you might not be able to sense the lower end of your spectrum but that all depends on the ringing characteristics of the selected components. So testing your system is definitely key here to see if those components are needed. From experience with a frequency of about ~58kHz, 25cm is not usually a problem without using a tunable transformer and normally suggest just going with the dampening resistor as well as the tuning capacitor. These values can be tested with a specific transducer and transformer combination and behavior is pretty consistent beyond that which means they do not require any sort of tuning at the end of production.

    On TIDA-01597 that you referenced you can see there is a tuning capacitor (C1 1500pF) and dampening resistor (R2 2.7kOhm) being used. These are a pretty good starting point if you plan to use a similar frequency.

    Best,

    Isaac

  • Thank you Isaac , I will proceed as reccomended

    All the bet