SNLU269 User guide

SNLU269 april 2023 SN75LVPE3410

3.3 Set CTLE Gain Level

The SN75LVPE3410 requires manual CTLE tuning. The CTLE gain level can be changed by modifying the value of each CTLE stage (EQ1 and EQ2) or by bypassing the EQ1 stage. The CTLE level may be set individually for each channel or broadcast to all channels. Table 3-3 shows an example sequence to set the CTLE gain level to 3.3dB at 4 GHz (CTLE Index 2: EQ1 = 001'b; EQ2 = 000'b).

Table 3-3 Sequence to Set CTLE Level

Step	Register Set	Operation	Register Address [HEX]	Register Value [HEX]	Write Mask [HEX]	Comment
1	Share	Write	0xFF	0x03	0xFF	Select channel registers and enable broadcast write to all channels.
2	Share	Write	0xFC	0x01	0xFF	Select only register set channel 0 for read back.
3	Channel	Write	0x04	0x00	0x01	Disable EQ1 bypass.
4	Channel	Write	0x03	0x01	0x07	Set EQ1 to Index 1.
5	Channel	Write	0x03	0x00	0x38	Set EQ2 to Index 0.

Table 3-4 gives a sub-sequence (Steps 3 - 5) to set a range of CTLE gain levels (CTLE Index 0 - 15). The sub-sequence should be preceded with the steps 1 and 2 as described in Table 3-3.

Table 3-4 Sub-Sequence to Set CTLE Level as a Function of CTLE Index

CTLE Index	CTLE Gain at 4 GHz (dB)	Step / Operation	Register Address [HEX]	Register Value [HEX]	Write Mask [HEX]
0	-0.3	3 / Write 4 / Write 5 / Write	0x04 0x03 0x03	0x01 0x00 0x00	0x01 0x07 0x38
1	0.4	3 / Write 4 / Write 5 / Write	0x04 0x03 0x03	0x01 0x00 0x18	0x01 0x07 0x38
2	3.3	3 / Write 4 / Write 5 / Write	0x04 0x03 0x03	0x00 0x01 0x00	0x01 0x07 0x38
3	3.8	3 / Write 4 / Write 5 / Write	0x04 0x03 0x03	0x00 0x01 0x10	0x01 0x07 0x38
4	4.9	3 / Write 4 / Write 5 / Write	0x04 0x03 0x03	0x00 0x02 0x08	0x01 0x07 0x38
5	5.2	3 / Write 4 / Write 5 / Write	0x04 0x03 0x03	0x00 0x02 0x10	0x01 0x07 0x38
6	5.4	3 / Write 4 / Write 5 / Write	0x04 0x03 0x03	0x00 0x02 0x18	0x01 0x07 0x38
7	6.5	3 / Write 4 / Write 5 / Write	0x04 0x03 0x03	0x00 0x03 0x10	0x01 0x07 0x38
8	6.7	3 / Write 4 / Write 5 / Write	0x04 0x03 0x03	0x00 0x03 0x18	0x01 0x07 0x38
9	7.7	3 / Write 4 / Write 5 / Write	0x04 0x03 0x03	0x00 0x04 0x18	0x01 0x07 0x38
10	8.7	3 / Write 4 / Write 5 / Write	0x04 0x03 0x03	0x00 0x05 0x18	0x01 0x07 0x38
11	9.1	3 / Write 4 / Write 5 / Write	0x04 0x03 0x03	0x00 0x05 0x20	0x01 0x07 0x38
12	9.4	3 / Write 4 / Write 5 / Write	0x04 0x03 0x03	0x00 0x05 0x28	0x01 0x07 0x38
13	10.3	3 / Write 4 / Write 5 / Write	0x04 0x03 0x03	0x00 0x06 0x28	0x01 0x07 0x38
14	10.6	3 / Write 4 / Write 5 / Write	0x04 0x03 0x03	0x00 0x06 0x30	0x01 0x07 0x38
15	11.8	3 / Write 4 / Write 5 / Write	0x04 0x03 0x03	0x00 0x07 0x38	0x01 0x07 0x38