Other Parts Discussed in Thread: DS250DF210, DS250DF410, DS250DF810, , DS280DF810
Tool/software:
Across all 25-28G retimers (DS250DF210, DS250DF230, DS250DF410, DS250DF810, DS280DF810) there are 255 total CTLE boost settings. A subset of these settings, spanning the full range of the CTLE, makes up the CTLE boost table. Most 25-28G retimers use the same CTLE boost table, which includes 16 indexes spanning from 9.2 dB @ 13 GHz to 26.4 dB @ 13 GHz. DS250DF230 uses a unique CTLE boost table, which includes 20 indexes spanning from 0.6 dB @ 13 GHz to 26.4 dB @ 13 GHz.
CTLE Boost Table (DS250DF210, DS250DF410, DS250DF810, DS280DF810)
| EQ Table Index |
CTLE Boost Settings Reg_0x03[7:0] [Hex] |
High-Frequency Boost (10 MHz vs. 13 GHz) [dB] |
| 0 | 00 | 9.2 |
| 1 | 40 | 13.0 |
| 2 | 50 | 15.0 |
| 3 | 80 | 14.6 |
| 4 | 90 | 16.6 |
| 5 | C0 | 16.0 |
| 6 | D0 | 17.9 |
| 7 | D1 | 18.9 |
| 8 | D5 | 20.3 |
| 9 | D8 | 20.9 |
| 10 | EA | 23.5 |
| 11 | F7 | 23.8 |
| 12 | FD | 24.3 |
| 13 | EE | 24.5 |
| 14 | EF | 25.3 |
| 15 | FF | 26.4 |
CTLE Boost Table (DS250DF230 only)
| EQ Table Index |
CTLE Boost Settings Reg_0x03[7:0] [Hex] |
High-Frequency Boost (10 MHz vs. 13 GHz) [dB] |
| 0 | 00 | 0.6 |
| 1 | 01 | 2.0 |
| 2 | 02 | 3.2 |
| 3 | 03 | 5.4 |
| 4 | 00 | 9.2 |
| 5 | 40 | 13.0 |
| 6 | 50 | 15.0 |
| 7 | 80 | 14.6 |
| 8 | 90 | 16.6 |
| 9 | C0 | 16.0 |
| 10 | D0 | 17.9 |
| 11 | D1 | 18.9 |
| 12 | D5 | 20.3 |
| 13 | D8 | 20.9 |
| 14 | EA | 23.5 |
| 15 | F7 | 23.8 |
| 16 | FD | 24.3 |
| 17 | EE | 24.5 |
| 18 | EF | 25.3 |
| 19 | FF | 26.4 |
On the DS250DF230, the first three stages of the CTLE can be bypassed so that a very small amount of gain can be applied in the fourth stage only. This is why the DS250DF230 CTLE boost table includes 4 additional indexes and the minimum boost is much lower than other retimers. For short channel/low insertion loss use cases, DS250DF230 may be a better choice than other 25-28G retimers because of its minimum CTLE boost.
For all 25-28G retimers, the boost values for CTLE indexes 0-15 are programmed in channel registers 0x40 -- 0x4F, respectively. For DS250DF230, the boost values for CTLE indexes 16-19 are programmed in channel registers 0x50 -- 0x53, respectively. These registers are reserved for all other 25-28G retimers. TI strongly does not recommend making any changes to the boost values for each CTLE index.
If DS250DF230 is being configured through an external EEPROM, 4 bytes need to be included in the EEPROM hex file for registers 0x50 -- 0x53. These should be inserted between bytes which program channel registers 0x4F and 0x60. These 4 bytes are not included in the EEPROM hex file for all other 25-28G retimers.
EEPROM Register Map Excerpt (DS250DF210, DS250DF410, DS250DF810, DS280DF810)
| EEPROM Address Byte | Bit 7 | Bit 6 | Bit 5 | Bit 4 | Bit 3 | Bit 2 | Bit 1 | Bit 0 |
| 46 (0x2E) | 0x4E[7] | 0x4E[6] | 0x4E[5] | 0x4E[4] | 0x4E[3] | 0x4E[2] | 0x4E[1] | 0x4E[0] |
| 1 | 1 | 1 | 0 | 1 | 1 | 1 | 1 | |
| 47 (0x2F) | 0x4F[7] | 0x4F[6] | 0x4F[5] | 0x4F[4] | 0x4F[3] | 0x4F[2] | 0x4F[1] | 0x4F[0] |
| 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | |
| 48 (0x30) | 0x60[7] | 0x60[6] | 0x60[5] | 0x60[4] | 0x60[3] | 0x60[2] | 0x60[1] | 0x60[0] |
| 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | |
| 49 (0x31) | 0x61[7] | 0x61[6 | 0x61[5] | 0x61[4] | 0x61[3] | 0x61[2] | 0x61[1] | 0x61[0] |
| 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
EEPROM Register Map Excerpt (DS250DF230 only)
| EEPROM Address Byte | Bit 7 | Bit 6 | Bit 5 | Bit 4 | Bit 3 | Bit 2 | Bit 1 | Bit 0 |
| 46 (0x2E) | 0x4E[7] | 0x4E[6] | 0x4E[5] | 0x4E[4] | 0x4E[3] | 0x4E[2] | 0x4E[1] | 0x4E[0] |
| 1 | 1 | 1 | 0 | 1 | 0 | 1 | 0 | |
| 47 (0x2F) | 0x4F[7] | 0x4F[6] | 0x4F[5] | 0x4F[4] | 0x4F[3] | 0x4F[2] | 0x4F[1] | 0x4F[0] |
| 1 | 1 | 1 | 1 | 0 | 1 | 1 | 1 | |
| 48 (0x30) | 0x50[7] | 0x50[6] | 0x50[5] | 0x50[4] | 0x50[3] | 0x50[2] | 0x50[1] | 0x50[0] |
| 1 | 1 | 1 | 1 | 1 | 1 | 0 | 1 | |
| 49 (0x31) | 0x51[7] | 0x51[6] | 0x51[5] | 0x51[4] | 0x51[3] | 0x51[2] | 0x51[1] | 0x51[0] |
| 1 | 1 | 1 | 0 | 1 | 1 | 1 | 0 | |
| 50 (0x32) | 0x52[7] | 0x52[6] | 0x52[5] | 0x52[4] | 0x52[3] | 0x52[2] | 0x52[1] | 0x52[0] |
| 1 | 1 | 1 | 0 | 1 | 1 | 1 | 1 | |
| 51 (0x33) | 0x53[7] | 0x53[6] | 0x53[5] | 0x53[4] | 0x53[3] | 0x53[2] | 0x53[1] | 0x53[0] |
| 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | |
| 52 (0x34) | 0x60[7] | 0x60[6] | 0x60[5] | 0x60[4] | 0x60[3] | 0x60[2] | 0x60[1] | 0x60[0] |
| 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | |
| 53 (0x35) | 0x61[7] | 0x61[6 | 0x61[5] | 0x61[4] | 0x61[3] | 0x61[2] | 0x61[1] | 0x61[0] |
| 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |