DS125DF1610: CTLE and DFE questions

Miranda Gu

Genius 15417 points

Part Number: DS125DF1610

Hi team,

Could you please answer below questions from customers about DS125DF1610? Many thanks.

1. What is the working principles of Adaptive CTLE?

2. How to determine the CTLE is suitable or not? By checking 0x8F register value?

3. Can we use 0x71~0x75 DFE registers to check whether the retimer is over equalization or over de-emphasis?

over 4 years ago

0 Rodrigo Natal over 4 years ago

TI__Mastermind 19235 points

Hi,

Please refer to datasheet section "7.3 Feature Description" for a detailed explanation
- aa
The user should read the vertical eye opening (VEO) and horizontal eye opening (HEO) values contained in channel registers 0x27 and 0x28, and check that VEO > 200mV and HEO > 0.4UI
Channel registers 0x71 thru 0x75 contain the DFE tap values. By themselves these DFE values do not tell you whether or not the retimer has over-equalized. You also need to read channel registers 0x27 and 28, and see whether the eye opening values exceed TI's recommended limits

The following equations are used to convert the contents of channel registers 0x27 and 0x28 into their appropriate units:

• HEO [UI] = ch reg 0x27 ÷ 64

• VEO [mV] = ch reg 0x28 x 3.125

Cordially,

Rodrigo Natal

HSSC Applications Engineer

0 Miranda Gu over 4 years ago in reply to Rodrigo Natal

TI__Genius 15417 points

Hi,

About your 3rd answer, 'Channel registers 0x71 thru 0x75 contain the DFE tap values. By themselves these DFE values do not tell you whether or not the retimer has over-equalized. You also need to read channel registers 0x27 and 28, and see whether the eye opening values exceed TI's recommended limits'

May I know what is TI's recommended limits?