SLLA565 September 2021 TUSB1044
The CFG[1:0] can be used to adjust the TUSB1044 output voltage swing linear range and receiver equalization DC gain. Table 2-4 details the available options. For best performance, operate the TUSB1044 within its defined VOD linearity range. Keep the gain of the incoming VID to less than or equal to the TUSB1044 VOD linear range setting. This can be determined using Equation 1:
where
For example, for a VOD linearity range setting of 1200 mV, the maximum incoming VID signal at 5 GHz with a UEQ[1:0] setting of 5.2 dB is 1200 x (10–(5.2/20)) = 659 mVpp. The TUSB1044 can be operated outside its VOD linear range but jitter will be higher.
| Setting # | CFG1 Pin Level | CFG0 Pin Level | Downstream DC Gain(dB) | Upstream DC Gain (dB) | Downstream VOD Linear Range (mVpp) | Upstream VOD Linear Range (mVpp) |
|---|---|---|---|---|---|---|
| 0 | 0 | 0 | 1 | 0 | 900 | 900 |
| 1 | 0 | R | 0 | 1 | 900 | 900 |
| 2 | 0 | F | 0 | 0 | 900 | 900 |
| 3 | 0 | 1 | 1 | 1 | 900 | 900 |
| 4 | R | 0 | 0 | 0 | 1100 | 1100 |
| 5 | R | R | 1 | 0 | 1100 | 1100 |
| 6 | R | F | 0 | 1 | 1100 | 1100 |
| 7 | R | 1 | 2 | 2 | 1100 | 1100 |
| 8 | F | 0 | Reserved | Reserved | Reserved | Reserved |
| 9 | F | R | Reserved | Reserved | Reserved | Reserved |
| 10 | F | F | 0 | 0 | 1300 | 1300 |
| 11 | F | 1 | Reserved | Reserved | Reserved | Reserved |
| 12 | 1 | 0 | Reserved | Reserved | Reserved | Reserved |
| 13 | 1 | R | Reserved | Reserved | Reserved | Reserved |
| 14 | 1 | F | Reserved | Reserved | Reserved | Reserved |
| 15 | 1 | 1 | Reserved | Reserved | Reserved | Reserved |
In the I2C mode, VOD can be controlled through I2C register 0x0C. For this reason, CFG[1:0] can be left unconnected.