TX517EVM: How many mili seconds pulse is generated?

Hey Sajad,

As to whether or not that pulse length is sufficient for your application is completely dependent on what you are trying to do. I would bet there is a setting some where that will control this value as you would like to. Everything that I am saying would seem to indicate that OUT A and OUT B are a differential pair, thus you should probably be using both of them to get the full signal levels that you want.

Best Regards,
Nick

If this answered your questions than please verify the answer below with the green button.

Alright, after some digging I think I've figured out what's going on. Currently I think you have your system set up as follows: The computer that you use is feeding the ultrasound pulse train to the control logic of the TX517EVM. This EVM has circuitry that converts this control logic to a high voltage differential signal on the OUTA and OUTB pins. You currently ignore OUTB and feed only OUTA to the TX810 switch. I'm not sure how you have connected TX801, but it should be to the transducer.

Now on to what is wrong, below I have attached a photo of a high level block diagram of an ultrasound system.

If we look at your signal chain we notice a key section that seems to be missing; the high voltage pulser. This section is the part you still need to convert that signal from the differential of OUTA and OUTB to the single ended Tx that enters the TX801 chip. To understand what is going on, here is a more deatailed scehmatic of the drive side of a system:

The output XDCR that is on the right hand side of the pulsar FETs would go to the Tx channel on the TX801.

However in reality, the EVM you have does the pulser too, it's just not obvious. If we go to the datasheet of the TX517 IC, we see in the block diagram that OUTA is really the circuitry for the high side pulsar and the OUTB is actually just the circuitry for the low side pulsar driver. 

With that known, how would you want to connect OUTA and OUTB given the other info I've posted? (I encourage you to actually stop and think about it)

If you look at the "Schematic Block Diagram" then you'll notice that the high (TC6320) and low (TC2320) side pulsar drivers are tied together at the "HVout" node. In turn, we now know that the OUTA and OUTB signals should be tied together and then fed to the Tx pin on the TX801 chip. We can confirm this too by looking at the application seciton of the TX517. The only difference is that they have a pulse transformer or some other type of coupled inductor attached to for surge protection of the output. 

I hope this helps in understanding how and why you connect OUTA and OUTB for your EVM. 

If this answered your question please verify the answer below using the green button so I know that I provided accurate info. If you have additional question let me know.

Best Regards,

Nick

Sajad,

I just answered the OUTA and OUTB question for you but I suspect you might have a follow up on the TX801 input so I will quickly address that. The purpose of this chip is to make sure that your low voltage receiver and LNA will not get harmed by high voltage transmission pulses. Essentially just a fancy surge protector that allows you to have multiple channels (8 in your case). Page two of the LM96530 datasheet (similar part to TX801) does a better job at describing the application of such a switch. Below, I have attached another diagram that should let you see how to connect the switch input as well. Node X3 below can be treated as the  M1-N2 output node in the TX517 application photo in my previous post. The MD0200 is comparable to the TX801.

If this helped solve your problem please verify the answer using the green button below. 

Best Regards,

Nick