DS90UB953-Q1: Clocking Modes

Adrian Palumbo

Part Number: DS90UB953-Q1

Hi team,

I have a system with the DS90UB953/954 pair and I am currently working on a redesign of the 953 PCB. I have a question about the clock signal going into the DS90UB953.

The DS90UB953 has the option to accept the different clock modes according to the following table, configuring two resistors:

So, my question is:

What is the best option for my design, eliminating the issue of costs, number of components and prioritizing functionality?

Also, that the data sheet says that the operation in synchronous mode offers the advantage that the receiver and all of the sensors in a multi-sensor system are locked to a common clock in the same clock domain, which reduces or eliminates the need for data buffering and resynchronization. The synchronous clocking mode also eliminates the cost, space, and potential failure point of a reference oscillator within the sensor module.

Why would you select another working mode?

over 2 years ago

0 Lucas Wolter over 2 years ago

TI__Mastermind 27800 points

Hi Adrian,

DVP mode can only be used with 913 and 933 SERs. The other 3 clock modes are equally functional and I can't recommend a specific mode without knowing more about your design.

Best,

Lucas

0 Adrian Palumbo over 2 years ago in reply to Lucas Wolter

Prodigy 40 points

Hi Lucas, thanks for the quick reply.

My design is based on a camera module with the DS90UB953, which is connected via a coaxial cable (FPD-Link III) to another module with the DS90UB954 that takes the image from the camera sensor.

0 Lucas Wolter over 2 years ago in reply to Adrian Palumbo

TI__Mastermind 27800 points

Hi Adrian,

In synchronous mode, the forward channel and back channel are synchronized, meaning if the back channel is lost then the forward channel is lost as well. In non-synchronous modes the forward channel and back channel operate independently, meaning if the back channel is lost then the forward channel can continue transmitting without issues.

Best,

Lucas

0 Adrian Palumbo over 2 years ago in reply to Lucas Wolter

Prodigy 40 points

Hi Lucas,

Ok, I understand the difference and therefore I would be gaining robustness in my system, being more immune to external noise, right?

Currently, I am working with a 954 six serializer module that will connect to 6 individual cameras that have the 953 serializer. The 953 are set to synchronous mode.

If I choose to switch to Non-Synchronous External Clock mode with a 50 Mhz external clock, do I lose any functionality or features? Or would it work the same and I get more robustness in my system?

0 Lucas Wolter over 2 years ago in reply to Adrian Palumbo

TI__Mastermind 27800 points

Hi Adrian,

By switching to non-synchronous external clock mode, you are losing the ability to keep all serializers and the DES in the same clock domain. If you switch to non-synchronous mode, make sure to change the mode on the serializers as well.

Best,

Lucas

0 Adrian Palumbo over 2 years ago in reply to Lucas Wolter

Prodigy 40 points

I understand and will take it into consideration.

But I need to know what is best for my design and what criteria to take for the decision between one mode or the other.

I always need to transmit video images and never lose the transmission, in the worst possible situation.

0 Lucas Wolter over 2 years ago in reply to Adrian Palumbo

TI__Mastermind 27800 points

Hi Adrian,

We can't recommend a specific clocking mode to you. You will need to choose one based on your system design.

Best,

Lucas

0 Adrian Palumbo over 2 years ago in reply to Lucas Wolter

Prodigy 40 points

Ok, I'll do some tests to see which mode is the best.

Thanks for your time.

0 Lucas Wolter over 2 years ago in reply to Adrian Palumbo

TI__Mastermind 27800 points

Hi Adrian,

I'll be closing this thread. If you have any additional questions don't hesitate to open a new thread.

Best,

Lucas

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DS90UB953-Q1: Clocking Modes