DS250DF230: About DS250DF230 Datarate configuration

Haiming Shen

Part Number: DS250DF230
Other Parts Discussed in Thread: DS110DF111

I want to configure the chip's datarate as 8.5G,Is it supported? Or it only can be configured as the datarates listed in programmer' guide? BTW, we use 25-MHz Calibration Clock.I can configure the datarate as 4.25G, but BER is very bad; and with 8.5G, CDR can not be locked.

21 days ago

0 Drew Miller1 21 days ago

TI__Mastermind 40163 points

Hi Haiming,

The device only supports locking to rates as specified in the data sheet. 4.25G and 8.5G are not within the CDR lock range of this device. You could use DS250DF230 in CDR bypass to support 8.5G.

If you need to lock to 8.5G signal, have you considered DS110DF111?

Thanks,

Drew

0 Haiming Shen 20 days ago

Prodigy 20 points

Hi, Drew,

Got that, and very Thanks!

Haiming

0 Haiming Shen 20 days ago in reply to Drew Miller1

Prodigy 20 points

Hi,Drew,

I have another questions about datarate of chip DS250DF230, 6.25Gbps,which not involed in the CDR lock range, can be supported. Why?

Thanks and BRs,

Haiming

0 Drew Miller1 19 days ago in reply to Haiming Shen

TI__Mastermind 40163 points

Hi Haiming,

Please take another look at supported data rates.

Thanks,

Drew

+1 Haiming Shen 15 days ago in reply to Drew Miller1

Prodigy 20 points

Hi，Drew，

OK，I see。

I only have the table from program guide as below。

Thanks again，

BRs，
Haiming

0 Drew Miller1 15 days ago in reply to Haiming Shen

TI__Mastermind 40163 points

Hi Haiming,

Please follow calculation detailed here. Note that the formulas here do not account for div-4 (i.e. quarter rate). Full rate, half rate, and quarter rate use a different divider in the calculation below. I've added a table to help clarify the value to use for div-4.

Rate Scalar	Equation Divider
Full rate (div-1)	64
Half rate (div-2)	32
Quarter rate (div-4)	16

Thanks,

Drew

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DS250DF230: About DS250DF230 Datarate configuration