Using TDC1000-GASEVM to interface 1MHz transducer for flow application?

Steve1234

I am trying to use 1MHz transducer with TDC1000-GASEVM.

Since the resonance frequency has changed way above 58KHz~300KHz, I believe I have to change the input configuration from below circuit

Since the application is for water flow(in non intrusive way), with 1MHz, I will have to use capacitive feedback for LNA. How can I adjust from above circuit for my application?(By the way, I need higher voltage because signal attenuates significantly when changing layers of pipe, liquid and wedge)

over 9 years ago

0 Chris Oberhauser66 over 9 years ago

TI__Genius 14270 points

Hi Steve1234,

I would recommend you modify the TDC1000-GASEVM in the following manner. You will only change 4 caps as follows to shift the operation point to 1MHz:

1. On the BST-EVM move R3 to R4 position to allow for GUI-controlled boost power supply enable

2. On the BST-EVM replace C7 with a 300pf cap

3. On the TDC1000-GASEVM replace C27 and C32 with 51pf caps

4. Reduce the 5.6nF LNA-PGAIN cap to 1nF

Regards,

ChrisO

0 Matthew Minasi over 9 years ago in reply to Chris Oberhauser66

TI__Expert 4725 points

Steve1234,

You can skip step 1 above if you don't need to power cycle the 30V boost on the BST_EVM.

Regards,

Matt

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Using TDC1000-GASEVM to interface 1MHz transducer for flow application?