I'd like to use one of these parts for a sonar application, generally in the 40-80kHz range, and at high power. Equivalent load to the amp will be around 2 ohm (maybe 4 depending on how important that is). Running at BTL or PBTL is fine, we will probably use PBTL to accommodate a lower value load. We were planning on 24VDC power, 192kHz.
We've done some experiments with the 5756 but reaching published power levels in this frequency band has been difficult. It's pretty good though overall.
Which of these parts would be most suitable? It seems that the TAS5825 is a newer, smaller design with fewer external components, but fidelity isn't quite as good (though 0.03% THD vs 0.007% probably isn't a big deal). Rds is about the same, so I'd expect similar thermal properties, and power handling and efficiency seems to also be about the same. Switch frequency is the same. Flexibility with experimenting with modulation type on the 5825 is helpful for experimentation. Also the lack of external coupling of the DAC to power section of the 5825 (compared to the 5754/6) makes the circuitry a bit simpler.
Any other important differences I should be aware of? One unknown is how each amp responds to a non-speaker-load in this frequency range; while the equivalent is about 2 ohms, the piezo load is quite reactive, so both magnitude and phase change quickly with frequency, and it's unclear how the closed-loop control will respond.
Thanks for any guidance.
