PCIe Gen5 redrivers feature a continuous-time linear equalizer (CTLE) that applies a high-frequency boost and a low-frequency attenuation to help equalize the frequency-dependent insertion loss effects of the passive channel. The device has 20 available equalization (EQ) boost and 5 gain settings. The gain settings are Flat-Gain, increasing signal strength equally across the bandwidth. The overall data path Flat-Gain (DC and AC) can be programmed through SMBus/I2C registers. The default recommendation for most systems is 0 dB. The Flat-Gain and equalization of the redriver must be set such that the output signal swing at DC and high frequency does not exceed the DC and AC linearity ranges of the devices, respectively. Refer to the programming guide for more details.

Table 2-2 provides an idea of the EQ boosts offered by TI's PCIe Gen5 redriver architecture. The actual boosts in dB for each EQ Index setting are similar, but not identical between different PCIe Gen5 redriver devices. For full details, please refer to the tables in the Feature Description sections of the data sheets of the individual parts.

Table 2-2 is for illustrative purposes only — refer to part data sheets when designing.