0.37-pJ/b/dB PAM-4 Transmitter and Adaptive Receiver with Fixed Data and Threshold Levels for 12-m Automotive Camera Link

This paper presents a transmitter and an adaptive receiver for the next-generation automotive camera link with four-level pulse amplitude modulation (PAM-4) signaling. The PAM-4 transmitter utilizes push-pull current drivers and a 3-tap feed-forward equalizer to improve impedance matching and eye margin, respectively. In order to cancel the sampler offset for a lower bit error rate (BER), instead of adjusting data and threshold levels, the gain of a programmable gain amplifier is adjusted adaptively under fixed data and threshold levels. The transmitter delivers 8-Gb/s PAM-4 signal to the adaptive receiver through a lossy 12-m cable (22-dB channel loss) with a BER of 1E-8, and the eye margin larger than 0.15 UI x 50 mV is measured for a BER of 1E-5. The prototype chips consume 65.2 mW (excluding PLL), exhibiting an FoM of 0.37 pJ/bit/dB.