Clock & timing

Clock & timing forum

State Resolved
Locked Locked
Replies 13 replies
Answers 2 answers
Subscribers 22 subscribers
Views 814 views
Users 0 members are here

Support feedback

Options

Options

Related

CDCM7005: LVPECL VOD maximum specification

Ella KIM

Expert 4232 points

Part Number: CDCM7005

Hi Team,

My customer is considering to reuse their previous CDCM7005 design into new project and urgently requesting to check the information below.

- What is LVPECL VOD max specification? Datasheet only specifies min spec 500mV.

- When calculating with VOH and VOL, its min value should be 0.37V (VCC-1.55-VCC+1.18) and its max value should be 1.19V (VCC-2-VCC+0.81), which are not corresponding to VOD spec 500mV.

Thank you for your support.

over 3 years ago

+1 Ajeet Pal over 3 years ago

TI__Genius 12690 points

Hi,

The Figure 5 in the CDCM7005 datasheet shows the typical VOD value over the frequency. Hence the minimum VOD in the above table shows the amplitude at higher operating frequency.

Thanks!

Regards,
Ajeet Pal

0 Ella KIM over 3 years ago in reply to Ajeet Pal

TI__Expert 4232 points

Hi Ajeet,

Thanks! I notice Fout for LVPECL is only upto 1500MHz. Why do we test VOD level way above 1500MHz in figure 5?

In addition, Customer is using 122.88MHz. It looks 880mVtyp. They want a max/min spec of CDCM7005. Do we usually not provide this data?

0 Ajeet Pal over 3 years ago in reply to Ella KIM

TI__Genius 12690 points

Hi,

Clock out in LVPECL mode supports up to 1500MHz, so for that Figure 5 should be read up to 1.5GHz only.

CDCM7005 datasheet shows only typical VOD value. I can have a look in the archive, if can find the max./min. values also.

Thanks!

Regards,
Ajeet Pal

0 Ella KIM over 3 years ago in reply to Ajeet Pal

TI__Expert 4232 points

Thank you, Ajeet. As Samsung is in rush, can I know the min/max value by tomorrow if you can find any?

0 Ajeet Pal over 3 years ago in reply to Ella KIM

TI__Genius 12690 points

Hi,

So far, I couldn't find the details and checking with internal team and will update you, if I got something on it.

Thanks!

Regards,
Ajeet Pal

0 Ella KIM over 3 years ago in reply to Ajeet Pal

TI__Expert 4232 points

Hi Ajeet,

Do you have something to hear back? Sorry for the rush!

0 Ajeet Pal over 3 years ago in reply to Ella KIM

TI__Genius 12690 points

Hi Ella,

It's pretty old part and I am afraid, we doesn't have max./min specs data of the LVPECL output.

Thanks!

Regards,

Ajeet Pal

0 Ella KIM over 3 years ago in reply to Ajeet Pal

TI__Expert 4232 points

Hi Ajeet,

Thank you for following up. Is there any guidance like such device has typically x % of max/min spec compared to the typical spec? (empirically)

0 Ajeet Pal over 3 years ago in reply to Ella KIM

TI__Genius 12690 points

Hi Ella,

I'll get back to you on this soon.

Thanks!

Regards,

Ajeet Pal

0 Ella KIM over 3 years ago in reply to Ajeet Pal

TI__Expert 4232 points

Hi Ajeet,

Gentle reminder. Thanks.

0 Ajeet Pal over 3 years ago in reply to Ella KIM

TI__Genius 12690 points

Hi Ella,

Sorry for the delay but I am awaiting to get the inputs from internal team. I'll update you as soon as I get the details.

Thanks!

Regards,

Ajeet Pal

+1 Ajeet Pal over 3 years ago in reply to Ajeet Pal

TI__Genius 12690 points

Hi Ella,

Thanks for your patience!

CDCM7005 LVPECL VOD can be higher up to 900mV at lower frequencies over the PVT. The variation can be +/-30mV over the VOD plot on Figure - 5.

Thanks!

Regards,

Ajeet Pal

0 Ella KIM over 3 years ago in reply to Ajeet Pal

TI__Expert 4232 points

Hi Ajeet,

Thank you for information!!

Sincerely,

Ella