DS280DF810: DFE/CTLE/TX FIR settings start point

Luke Sun

Intellectual 1830 points

Part Number: DS280DF810

Hi team,

My customer is using DS280DF810 and they don't have much experience on it.

They want to know what kind of settings on DFE/CTLE/TX FIR they could start tuning from.

The architecture is as below. There're 3 traces.

1st trace is from BSB to CDR0, 1.6~1.8inch

2nd trace is from CDR0 to CDR1, 1.9~4.4inch

3rd trace is from CDR1 to BSB, 1.6 inch

The length has some variation because between same trace but different channels, the length is not very constant.

The temperature range is -40~70C. And board material is TU862/EM370D.

Could you kindly help?

Thank!

over 7 years ago

0 Rodrigo Natal over 7 years ago

TI__Mastermind 19235 points

Hi,

These traces are very short. I don't expect much if any Retimer Tx FIR post-cursor would be necessary. Similarly, on the Rx side the retime Rx EQ will likely not need to do much work. My suggestions below:

Retimer FIR settings (for both CDR0 and CDR1)

Main = 15

Post = 0

Pre = -1

Retimer Rx setting

Adapt mode 1 -> channel register 0x31 = 0x20

You may also consider forcing a CTLE value of 0x00 given the low loss.

Table 43. Set CTLE Boost Value

STEP	SHARED/ CHANNEL REGISTER SET	OPERATION	REGISTER ADDRESS [HEX]	REGISTER VALUE [HEX]	WRITE MASK [HEX]	COMMENT
1	Channel	Write	2D	08	08	Enable CTLE boost override
2	Channel	Write	03	00	FF	Set CTLE boost to 0x00. Different input channel loss will require different CTLE settings.

Cordially,

Rodrigo Natal

HSSC Applications Engineer

Interface

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DS280DF810: DFE/CTLE/TX FIR settings start point