A 5 Gb/s Voltage-Mode Transmitter Using Adaptive Time-Based De-Emphasis

隨著CMOS製程持續進步，資料傳輸的速度也跟著快速成長。但隨著傳輸速度的提升，許多問題也開始出現，相對於傳輸資料的速度，傳輸通道的有限頻寬就是其中的一個問題，這問題會造成訊號失真與嚴重的符際干擾，在通訊系統中，會將等化器放置於傳送器或是放置於接收器以解決符際干擾問題。因為傳輸通道的材質和長度會隨著應用而有所不同，因此等化器會搭配一個可適性的演算法，使電路可工作在不同的通道。 本論文提出一個使用時間模式去加強法的可適性電壓模式傳送器。此時間模式去加強法是使用功率平衡法來決定責任週期，並利用脈波寬度調變來控制所需的補償增益。我們提出的可適性演算法不需要額外的輔助傳輸線，並且可以忍受製程變異。此電路實現於40奈米製程，其傳送器和接收器的面積各為0.075mm2和0.105mm2。在每秒50億位元的傳輸速率下，此傳送器能操作在通道損耗為15 dB的環境，且量測到的方均根抖動為12.25 ps，其位元錯誤率小於10-12。此電路的校正時間為2.048 us。在1.1伏特電壓操作下，此傳送器功率消耗9.3mW，而接收發器整體的功率消耗為17.5mW。With the CMOS technology continues to progress, the data rate is also fast growing in different applications. As data rate keeps rising, many significant problems appear. One of the problem is that the channel bandwidth limits compared with the data rate. It will result in a significant inter symbol interference (ISI) and cause signal distortion. In communication systems, equalizers are widely adopted in transmitter side or receiver side to deal with ISI. The length or the material of the transmission channel may be different for various applications. Therefore, an equalizer with the adaptive algorithm is widely adopted in communication systems. A 5-Gb/s adaptive voltage-mode (VM) transmitter using time-based de-emphasis is presented. The duty cycle of the pulse width modulation is adjusted by the spectrum-balancing technique. For different cable lengths, the duty cycle of the PWM data is adaptively adjusted. The proposed adaptive VM transmitter does not require any auxiliary channels. The proposed adaptive VM transmitter can tolerate the process variations. This adaptive transmitter is fabricated in a 40-nm CMOS process. The active areas of the transmitter and the receiver are 0.075mm2 and 0.105mm2, respectively. For a 5-Gb/s PRBS of 27-1 passing through a 9-m coaxial cable with a 15.35-dB loss, the measured root-mean-square jitters of the recovered data is 12.25 ps. The measured bit error rate is less than 10-12. The settling time for adaptive time-based de-emphasis is 2.048us. For a 1.1V supply voltage, the power of the transmitter is 9.3mW and the total power of the transceiver is 17.5mW