A 10 Gb/s/pin Single-Ended Transmitter With Reflection-Aided Duobinary Modulation for Dual-Rank Mobile Memory Interfaces

The dual-rank configuration is one of the parallelization methods to increase the memory capacity for mobile applications. However, the stub mainly composed of the redistribution layer causes resonance reflections and its reflection interval reaches the bit period, which distorts signal and limits the signal bandwidth. A single-ended duobinary transmitter that utilizes the reflection is presented for dual-rank mobile memory interfaces where reflections dominate. The reflection is included in the transfer function for duobinary modulation, which allows the transmitter to have a wide eye opening and high energy efficiency. Two-tap reverse feed-forward equalization and slew-rate control are used to support the duobinary modulation in combination with the reflection. A prototype chip fabricated in a 65 nm CMOS process has an area of 0.0378 mm
²
and consumes 1.24 pJ/bit. It is verified at data rates of 8, 9 and 10 Gb/s/pin where the flight time of the 9 mm stub is 55.6 ps.