LMH0024: Lmh0024

Janek Janek

Part Number: LMH0024

Tool/software:

Hello!

I'm using lmh0024 as cable equalizer and adn2818 as clock and data recovery. And I found that at short cables (about 30-50 meters coax cable) IC's works properly. When coax cable is long (about 200 meters) adn2818 doesn't recovery clock signal. SDI datarate is 270 Mbits/s SMPTE-259M.

When I'm using clc014 + clc016 + clc011 there is no problem with long cables.

Is there problem with lmh0024 or adn2818?

11 months ago

0 Nick Peabody 11 months ago

TI__Genius 9209 points

Hi Janek,

We will be following up on this shortly.

Best,

Nick

0 Nick Peabody 11 months ago in reply to Nick Peabody

TI__Genius 9209 points

Hi Janek,

What cable type are you using?

This could be an ADN issue because it is not recovering the clock.

Best,

Nick

0 Janek Janek 11 months ago in reply to Nick Peabody

Prodigy 10 points

Hello!

I'm using Belden 1694A. On dataout pins of adn2818 there is some data, but on clkout pins there is nothing.

On dataout pins of lmh0024 there is equlized signal. But I don't know this equlized signal right or wrong. What is right voltage between pins aec+ and aec- lmh0024 with 200 m cable?

0 Shane Hauser 11 months ago in reply to Janek Janek

TI__Mastermind 33615 points

Hi Janek,

It sounds like the LMH0024 is able to equalize your signal. To confirm whether it is operating correctly, can you measure the voltage on the CLI output?

This should correspond to the cable length on the receiving end of the LMH0024. For example, if you are using a 200m cable, the CLI voltage should be around 2.27V:

Best,

Shane

0 Janek Janek 11 months ago in reply to Shane Hauser

Prodigy 10 points

Hello!

I measured voltage on CLI pin. With 3 m cable voltage is 2.53 V, with 150 m cable voltage is 2.32 V. Does it means that lmh0024 works correctly and trouble is in adn2818??

0 Shane Hauser 11 months ago in reply to Janek Janek

TI__Mastermind 33615 points

Hi Janek,

I believe lmh0024 is working correctly. The CLI measurement looks correct and you are seeing an equalized signal at the output.

This seems like an issue with the ADN2818 recovering your clock. I suggest reaching out to the manufacturer of this part to check whether they've seen this behavior before.

Best,

Shane

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LMH0024: Lmh0024