LMK00301: LVDS output frequency range

Gajendiran A

Part Number: LMK00301

Tool/software:

Hi,

The datasheet feature says the LVDS frequency range is DC to 2100MHz, but the specification table says 1.0GHz to 1.6GHz, and Figure 7-2 shows the LVDS Output Swing (VOD) vs. Frequency range as 100MHz to 1.3GHz. So, which one is the correct frequency range?

Our output frequency range is 150MHz to 200MHz LVDS signaling at this frequency. Will it cause any problems?

We have bought your EVB and tested it with 150MHz to 200MHz LVDS output, and it works fine.

3 months ago

0 vicente flores prado 3 months ago

TI__Mastermind 22491 points

Hello Gajendiran,
DC to 3.1GHz is the frequency range.

Best regards,

Vicente

0 Gajendiran A 3 months ago in reply to vicente flores prado

Prodigy 225 points

The input clock range is OK, but I'm more concerned about the output frequency range.

0 vicente flores prado 3 months ago in reply to Gajendiran A

TI__Mastermind 22491 points

Hi Gajendiran,
For LVDS it's as follows:

Depends on your swing.

Best regards,

Vicente

0 Gajendiran A 3 months ago in reply to vicente flores prado

Prodigy 225 points

The above table shows the maximum output swing. What about the output frequency for LVDS?

In the image below, I see a swing at 153.25MHz. This means it works at 150MHz, right? What is the output frequency range of LVDS?

It looks like it is work from 100MHz to 1GHZ, but not clear data in datasheet, please confirm

0 vicente flores prado 3 months ago in reply to Gajendiran A

TI__Mastermind 22491 points

Hi Gajendiran,
No, the table I attached is the maximum output frequency for LVDS.
The reason they're two values is due to the maximum output frequency varies depending on the output swing.

1.6GHz is LVDS output frequency maximum with the output swing (VOD) being larger than or greater than 250mV.
2.1GHz is LVDS output frequency maximum with output swing (VOD) being greater than or equal to 200mV.

Best regards,

Vicente

0 vicente flores prado 3 months ago in reply to vicente flores prado

TI__Mastermind 22491 points

150MHz to 200MHz LVDS output will work just fine.

0 vicente flores prado 3 months ago in reply to vicente flores prado

TI__Mastermind 22491 points

If you have any worries - you can also simulate using IBIS model.

Best regards,

Vicente

0 Gajendiran A 3 months ago in reply to vicente flores prado

Prodigy 225 points

I got it. This is the maximum output frequency. What about the minimum frequency of LVDS?

Our frequency range is 150MHz to 200MHz. Will the range be ok with LVDS output?

0 vicente flores prado 3 months ago in reply to Gajendiran A

TI__Mastermind 22491 points

Gajendiran,
I think I see you confusion now.
I believe you're confused as to why the DS lists 1GHz & 1.5GHz as the mins.
The DS is a bit confusing in this regard what we are assuring is the swing for a certain frequency range
So in other words 250mV VOD is guaranteed from 1GHz to 1.5GHz.
Refer to this thread for more info I believe you're asking the same question but for LVDS. If that's the case - I am sorry for not having catched that until now.

(+) LMK00301: support Lvpecl frequency - Clock & timing forum - Clock & timing - TI E2E support forums

Functionally, LVDS works from DC to 2.1GHz.
If this answers your question i would appreciate if you could press the "This Resolved my question" button :)
Best regards,

Vicente

0 Gajendiran A 3 months ago in reply to vicente flores prado

Prodigy 225 points

I assume the output LVDS works from DC to 2.1GHz?

Additionally, the maximum swing of 250mV VOD is guaranteed to range from 1GHz to 1.5GHz. What about less than 1GHz? I assume with less than 1GHz, the swing voltage won't be the problem, right? especially 150MHz to 200MHz?

below graphs says is >350mV

0 vicente flores prado 3 months ago in reply to Gajendiran A

TI__Mastermind 22491 points

That is correct - LVDS works from DC to 2.1GHz.
As you pointed out in figure 7-2 the swing from 150MHz to 200MHz is not a problem either and should be larger than 350mV.

Best regards,

Vicente

0 Gajendiran A 3 months ago in reply to vicente flores prado

Prodigy 225 points

The LVDS output swing voltage is 350mV, one single-ended (P or N), right? Not a differential output swing voltage(Vod), right?

Which is Vod=(Vout+) - (Vout-)

vod=(350mv)-(-350mV) =750mV right? as per LVDS std.

+1 Michael Srinivasan 2 months ago in reply to Gajendiran A

TI__Expert 3880 points

That is correct. The single-ended output swing is 350 mV.

Thanks,

Michael