Abstract: A high-speed SerDes transmitter which may reduce power supply introduced data dependent jitter. Instead of trying to make the output voltage of a power supply of a pre-driver constant, the output voltage of the power supply is returned to its normal level periodically, e.g., after each bit time to follow the data rate of an input data stream. A complementary pre-driver may be used to create a complementary data stream which may be at the same data rate as the input data rate. The complementary data stream may have a transition when there is no transition between two consecutive bits in the input data stream, but have no transition when there is a transition in the input data stream. As a result, there is a transition at the power supply during each bit time, and the power supply may be drawn back to its normal level during each bit time. Consequently, the power supply variation is periodic at the beat of the input data rate, and the power supply may have the same impact on each data bit.

Abstract: To reduce the effect of the phase shift error originated from the mismatch of the delay units of the clock generator, we propose to add one more set of averaging amplifiers and averaging impedances, such as resistors, into the circuit of the clock generator. In the clock generator, outputs of all delay units connect to inputs of all averaging amplifiers respectively, and the averaging impedances connect the corresponding outputs of two adjacent averaging amplifiers, so as to form a closed loop. When a phase shift error occurs in the delay units, the averaging current through the averaging impedances will decrease the phase shift error in each stage. Specifically, the output impedance of the averaging amplifiers approaches infinite, and thus the resistance of the averaging impedances is relatively small. Therefore almost all signal currents will go through the averaging impedances, and an optimal averaging effect is achieved.

Abstract: To reduce the effect of the phase shift error originated from the mismatch of the delay units of the clock generator, we propose to add one more set of averaging amplifiers and averaging impedances, such as resistors, into the circuit of the clock generator. In the clock generator, outputs of all delay units connect to inputs of all averaging amplifiers respectively, and the averaging impedances connect the corresponding outputs of two adjacent averaging amplifiers, so as to form a closed loop. When a phase shift error occurs in the delay units, the averaging current through the averaging impedances will decrease the phase shift error in each stage. Specifically, the output impedance of the averaging amplifiers approaches infinite, and thus the resistance of the averaging impedances is relatively small. Therefore almost all signal currents will go through the averaging impedances, and an optimal averaging effect is achieved.