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PGA460-Q1: Datapath variation depending on the temperature

Pablo Martinez80
Intellectual 275 points
Part Number: PGA460-Q1
Other Parts Discussed in Thread: PGA460

Hi,

We are using the PGA460 in several devices but we have seen that the datapath value given by the device varies depending on the temperature. Decay time and object bounce is displaced right or left in case of a very low or very high temperature.

Is it possible that PGA460 fix this issue? Now we need to use 2 profiles in order to modify the threshold level in case of low temperatures but we cannot modify time varying gain, because there is just one.

  • 0
    TI__Mastermind 27950 points
    Hi Pablo,

    Unfortunately, the PGA460 is not able to perform any auto-compensation based on the temperature value. Your current workaround is the expected workaround, such that the master offsets the threshold, time varying gain, or other values based on the ambient temperature.

    The transducer behavior could be characterized across temperature for the master to have an approximate datapath mapping to aid in a predetermined threshold or TVG setting at specific temperatures.

    The PGA460 does include an integrated temperature sensor to help inform the master of the ambient temperature; however, the temperature sensor reading is of the device die temperature. To approximate the ambient temperature, a junction-to-ambient temperature conversion is required based on the value VPWR as described in section 7.3.11 "Temperature Sensor and Temperature Data-Path" of the datasheet.

    Having only one shared time-varying gain profile can definitely be an inconvenience in this case, so I would recommend using the two thresholds presets as you have suggested.