High‐speed mobile memory I/O interface using multi‐modulation signalling

The proposed multi‐band multi‐modulation I/O (MMI) for mobile memory interface consists of two RF‐band and 4‐PAM (pulse‐amplitude modulation) transceivers for simultaneous bidirectional read/write operations on a shared single‐ended 5 cm off‐chip transmission line. A novel band‐selective transformer is introduced to combine and split two amplitude shift keying modulated RF‐bands with a 4‐PAM baseband for transmitting and receiving multiple data concurrently. The MMI interface consumes 2.8 pJ/b from a 1.2 V supply voltage. Testing results show that the MMI interface achieves an overall data rate of 14 Gb/s/pin. It is implemented in a 65 nm CMOS process with chip area of 0.25 mm 2 .