An EMI-Immune PAM-4 Transmitter With Input Level Shifter in 130-nm BiCMOS Technology

This work presents a design of an electromagnetic interference (EMI)-immune pulse amplitude modulation-4 (PAM-4) transmitter. The traditional PAM-4 transmitters are prone to failing in the presence of EMI, which is experimentally verified. The proposed PAM-4 shows superior performance over the traditional PAM-4 transmitter, in the presence of EMI, by using an Input Level Shifter (ILS). ILS minimises the effect of EMI on a PAM-4 signal by reducing the input common-mode level of the transmitter and renders it compatible with the previous logic state. The proposed PAM-4 transmitter is fabricated in 130-nm BiCMOS technology with a chip area of 580 $\mu \text{m}\,\,\times $ 915 $\mu \text{m}$ . EMI-immunity measurements are aligned with the IEC 62132-2 standard by using a transverse electromagnetic (TEM) cell for radiated EMI-immunity. In the presence of a wide range of EMIs, the proposed PAM-4 transmitter operates at a data rate of 6.5 Gbps and maintains the minimum required eye-opening of 70 mV as per the standard IEEE 802.2bs. The proposed EMI-immune transmitter can withstand EMI powers of 0–16 dBm in frequencies ranging from 1 MHz to 1.5 GHz.