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TDC1000-Q1: Using TDC1000-Q1 with two layered 1.6mm thickness PTH PCB

Krunal Zala
Prodigy 120 points
Part Number: TDC1000-Q1
Other Parts Discussed in Thread: TDC1000, TUSS4470, PGA460

Hello,

I am considering TDC1000-Q1 in our my new product development.

Referring to chapter 11 of TDC1000-Q1 datasheet, I see the recommendation is for 4 layer PCB. Due to high volume low cost nature of the product, I am inclined to use TDC1000-Q1 with 2 layered PCB.

Could you please offer me guidance and necessary instructions so my use of two layered PCB with TDC1000-Q1 serves the end application purpose?

I will be using TDC1000-Q1 in mono static mode. If you anticipate performance issues due to use of two layered PCB with TDC1000-Q1 then request you to please share details on anticipated performance degradation.

Thank you for attending my support request.

Regards,

Krunal

  • 0
    TI__Expert 8016 points

    Hello Krunal, 

    Thank you for your question on the TDC1000.

    Do you know the transducer burst frequency you intend to use? I ask because the TDC1000 is now only recommended for applications using greater than 1MHz frequency.

    For applications at or less than 1MHz we recommend the TUSS44470, and applications requiring less than 480kHz, the PGA460. 

    The TDC1000 is no longer a recommended solution as the device can in some cases be difficult to use, and the device lacks the gain available in other devices. 

    Two layer boards can be developed for the TDC1000, but it is necessary to keep the externally routed analog traces far away from any noise inducing sources. 

    Section 11.1 of the TDC1000 datasheet covers the most important layout considerations for developing the PCB:

    Unfortunately, I do not have any test data on the performance difference between using a 4 layer vs. 2 layer board.

    If possible, I recommend using either the PGA460 or the TUSS4470 device. Both devices offer greater noise immunity, and are easier to develop with. 

    Here are links for the BOOSTXL-TUSS4470 EVM and the BOOSTXL-PGA460 EVM

    Please let me know if you have any questions,

    Thank you,

    Jacob

  • 0 in reply to Jacob Nogaj
    Prodigy 120 points

    Hello Jacob,

    Thank you for a quick reply.

    I appreciate you for sharing your know-how with me and helping me in selecting appropriate product for my ultrasonic transducer interfacing application.

    Considering the fact of cost constraints and limited measurement range(< 5 meter) requirement, I don't want to go with high frequency ultrasonic transducer. As you know, 40kHz ultrasonic transducer are the ones that is mostly used and therefore I would like to stay with whatever is available in market as long as it serves my end application requirement.(i.e. fluid level measurement for less than 5 meters of range)

    It appears PGA460 is a good solution but I am not sure if this is an active product. Looking at TI website, I see this product is out of stock. Any info you have about its availability, kindly share with me.

    Adding further, referring to PGA460 datasheet, I see it allows direct drive method and therefore I can eliminate the need of an external transformer. Of course PGA460 comes with a requirement of higher supply voltage of not less than 6V DC which could increase my BoM cost.

    I have additional queries pertaining to PGA460, and request you to help me:

    1. If I connect a 9V battery directly to Vvpwr, it should be okay. Isn't it? Of course, battery voltage will decrease as time elapses and PGA460 host circuit shall take care of battery voltage monitoring activity.
    2. Do you have a schematic with BoM details for direct drive method showing external high side MOSFET BoM?

    Please help me with following additional queries with respect to receiving ultrasonic signal echoed by ultrasonic transducer"

    1. Is there a document such as technical brief, application note from TI that shows design guide for receiving ultrasonic signal echoed by ultrasonic transducer?

    Thank you for your guidance and support in helping me in device selection - I sincerely appreciate your effort and attention to my queries.

    Awaiting your reply.

    Krunal

  • 0 in reply to Krunal Zala
    TI__Expert 8016 points

    Hi Krunal,

    Thank you for the additional details on the application. Do you expect the transducer to be mounted above the tank, or attached to the bottom of the tank? 

    You are correct, PGA460 can work well without use of a step-up transformer. 6V min supply is slightly higher than other devices, but features for this device make it suitable in most applications.

    Supply constraints are the primary factor for the out of stock nature of the device. I am not aware of any specific plans for the availability of the part, but it is easy to create restocking notifications on TI.com. 

    I do not see an issues with using a 9V battery to supply power to the device. Note, during burst operation, current to VPWR increases drastically. It is possible to program current limitations in device register settings, but it is still recommended to evaluate the current supply capable by the battery.

    Section 5 of the PGA460 EVM User's Guide includes schematics and BOM for the EVM design.

    I do not think we have any technical documents specifically on receiving ultrasonic echoes. Being that most of our ultrasonic devices contain integrated amplifiers and filters, our technical content is focused more on how the settings of the device can be used to realize design goals.   

    For PGA460 tuning, we recommend customers utilize the User's guide linked above, and the PGA460 Ultrasonic Module Hardware and Software Optimization Guide . Additionally, the PGA460 EVM FAQ is a great resource for general information on the device and EVM.

    Please let me know if you have any questions,

    Regards,

    Jacob

  • 0 in reply to Jacob Nogaj
    Prodigy 120 points

    Hello Jacob,

    Thank you for your reply.

    It does help. Appreciate for your attention and support.

    One query about sample request - please guide if you can.

    I have been placing sample request on TI website by creating a sample request case. In my both attempt, someone is closing my request by rejecting it but response does not provide any info why my request is getting rejected? Please see if you can help me here or redirect me to other contact where I can understand this issue further.

    Note: If my sample request is getting rejected because of no stock then the response shall mention such reason for a clarity purpose.

    Regards,

    Krunal

  • +1 in reply to Krunal Zala
    TI__Expert 8016 points

    Hi Krunal,

    Happy to offer assistance.

    I believe the request was in fact being rejected due to lack of sample units available. I am surprised the response did not mention anything related to why the request is being terminated. 

    I believe the most reasonable means for obtaining PGA460 devices are via setting up restock notifications on TI.com:

    Or via seeking an EVM such as the BOOSTXL-PGA460 EVM

    Please let me know if you have any questions.

    Thank you,

    Jacob