Ultrasonic Sensing FAQ

Which device does this forum cover?

TDC1000 and TDC7200

What applications is the TDC1000 targeted for?

Fluid Level measurement

Fluid Identification/Concentration

Flow Metering: gas, water, heat

What frequency range does it operate at?

31.25 kHz to 4 MHz

How many transducers can the TDC1000 interface to?


Is it available is automotive (Q) grade?


Is the TDC1000 configurable?

Yes. It is configurable via a SPI interface

What is configurable?

TX frequency and number of pulses

RX chain gain

RX Blanking time

What is the minimum CLKIN Frequency for a specific TX frequency?

Minimum CLKIN = 2 x TX Frequency

Does the TDC1000 automatically sense the transducer center frequency?


What frequency transducer should I use?

Depends on the material you are measuring.

In general liquids/solids 1Mhz

Gases: 40Khz - 250Khz

What does TOF mean?

Time Of Flight : measuring the time it takes for a signal to travel through a material. 

In general TOF will be the time from the creation of  the first excitation pulse to the time the echo is received.

Is there any benefit to to driving the TDC1000 VDD rail at max operating voltage(5.5V)?

Yes, the higher the excitation voltage the stronger the transmit signal created by the transducer which will increase the size of the resulting echo. A larger echo means level measurements will be possible for larger tanks or tanks with more surface variance. 

What determines the transducer excitation voltage when using the TDC1000?

The TDC1000's VDD voltage rail is the voltage that gets driven to the transducer.

The 2 EVMs have different excitation voltages as they are targeted for different applications.

The TDC1000-C2000 EVM (http://www.ti.com/tool/TDC1000-C2000EVM)  has a VDD of 4.65V

while the TDC1000-TDC7200EVM (http://www.ti.com/tool/tdc1000-tdc7200evm) has a VDD of 3.7V

What determines the maximum tank level I can measure with the TDC1000?

Depending on:

1. the size (diameter) of your transducer (bigger is a better driver and more sensitive receiver)

2.  VDD voltage (closest to Vddmax (5.5) is best)

3. Does the tank have a "level guide" or a tube within the tank that minimizes signal loss the ultrasound pulse?  Ie: with a "level guide the TDC1000 can easily tanks up 1m. Without a "level guide" surface perturbations while filling, tank movement, or surface angle reduce the chance of detecting an echo. 

1 Reply