TDC1000-TDC7200EVM: Can 300kHz transducer be used for TDC1000 / TDC1000-TDC7200EVM?

Hello,

The maximum detectable distance will remain the same compared to a higher frequency, while the minimum distance will increase because it will take more time to excite the transducer and the ringdown period will be longer. Your precision will be limited by the period of the excitation pulse (in this case 3.3us), and in water (speed of sound 1400m/s) that equates to about 4mm.

This will certainly work, but I would suggest this frequency for longer range measurements that do not need much precision.

To change the frequency, select the CPU clock enable and choose a frequency of 1.2Mhz in the GUI. On the TDC1000 page, change the frequency divider to "divide by 4". You will also need to set the jumper JP6 on the EVM to CPU.

One other thing to note is that the bandpass filter on the EVM is designed for transducers centered at 1Mhz. 300Khz is outside of this passband, so you will need to adjust the filter. The full schematic of the EVM is in the User's Guide here: www.ti.com/.../sniu021a.pdf

The bandpass filter is located between the PGAOUT and COMPIN pins.

Regards,