DS90UB960-Q1: DS90UB960-Q1 maximum serial bit rate

Yes, the DS90UB960-Q1 typically can support full HD at 60fps for 4 cameras. The DS90UB960-Q1 can support output data rates up to max rate of 6.656Gbps.Please note the CSI-2 data rate from different image sensors can vary for full HD depending on number of exposures or bits/pixel.
The CSI-2 protocol also has some overhead based on the framing and packetization of the data.

Dear Liam,

Thank you very much for your explanations. I would though need some confirmations and additional explanations...

I am aware of the fact that different image sensors can have different CSI-2 data rate.

When you say that DS90UB960-Q1 can typically support full HD at 60fps for 4 cameras, do you mean that two CSI-2 outputs (4 Lanes each) should be used to support this? If one CSI-2 output can support up to 6.656Gbps two can support up to 13.312Gbps. Correct?

If image sensor gives 24-bits per pixes, for 1920 x 1080 px image, for 4 cameras, we would need the following rate (not counting the overhead):

1920x1080 px * 24b/px * 60f/s * 4 cameras = 11.95Gpbs

I'm afraid that if we count the overhead for framing and packetization of data, we will go beyound 13.321Gbps that we can have with two CSI-2 output.

Are my calculations OK or I'm missing something?

Can you recomend me some image sensors that can give me full HD image?

Thanks once again.

Sincerely,

Bojan.

On the other hand, if I have full HD image (1920 x 1020), the same frame rate of 60fps but 8-bits per pixel, and having in mind the overhead, I believe it will be possible to deserialize 4 cameras with just one CSI-2 MIPI output (using all 4 lanes). Correct ?

Hi Bojan,

your calculations are correct. So you can use each CSI-2 output for two Full-HD cameras.

if you use the 8-bit or 12-bit resolution then you can have all 4 cameras on one CSI-2 output.

Hello Hamzeh,

Thanks for your reply.

I'm afraid of overhead.

Two MIPI CSI-2 output ports can support 2 x 6.656Gbps = 13.312Gbps

My data rate for 4 cameras without overhead for packetization and framing included is 11.95Gbps

I'm afraid if we add the overhead to 11.95Gbps, we will be beyound 13.312Gbps. What is the amount of overhead I should take into consideration ?

Thanks in advance.

Sincerely,

Bojan.

Hello Bojan,

You are right; you need to calculate the imager data rate including the blanking period. The blanking is usually between 15% to 30%.
So if I calculate your example we will have data rate of the imager = 1920 x 1080 x 24 x 60 x 1.2 = 3,583 Gbps which is not supported by the Serializer (953).
So here you need to reduce either the blanking or the number of bits/pixel or number of fps.
You need to get this number to max. 3,2 Gbps. if you have this number for 4 cameras then the Deserializer can support that without worry about the overhead, because it is already included in the blanking period.

Hello Hamzeh,

Thank you for your explanations. 

What is 1.2 in your calculation? Is it 20% of the blanking ?

Concerning the blanking (that is usually between 15% and 30%), is it something that the user can set during the configuration?

If I understand you well, I should not get over 3.2Gbps when I multiply: Image size * bits per pixel * frames per second * blanking. Please confirm. 

Sincerely,

Bojan.

Hi Hamzeh,

would you mind to quickly address my questions ?

Thanks in advance,
Bojan.