Receivers for HighSpeed LowSwing Signaling

1
Receivers for High-Speed Low-Swing Signaling

• Chinwuba D. Ezekwe

2
Outline

• Low-swing signaling basics
• Capacitively-coupled receiver
• Sense amplifier based receiver
• Pre-amplification
• Proposed receiver

3
Low-swing signaling basics

• Reduced swing
• Fast detection with low-swing receiver
• Termination for reflections

• Faster processing speeds demand faster links
• How to do links in power efficient way

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Capacitively-coupled receiver

• High CM Range
• High CM Rejection
• Uncoded data
• ESD stress
• Asymmetrical noise margins

X. Maillard, M. Kuijk, An 8Gb/s
Capacitive-Coupled Receiver with High Common-Mode
Rejection for Un-Coded Data, ISSCC Dig. Tech.
Papers, pp. 242-243, Feb. 2004.
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Sense amplifier based receiver

• Power efficient
• Use many in DEMUX
• Offset compensation
• Charge kickback

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Clocked pre-amp

• Like track and hold
• Improve kickback and CM-rejection with tail
  current
• Need two low skew clocks

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Receiver waveforms
Regenerative Sense Amplifier
Clocked pre-amp followed by regenerative Sense
Amplifier
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Proposed receiver

• Offset compensation
• Reduced charge kickback
• Single clock
• CM-rejection not great
• Can use CM rejection circuit from Maillard et al.

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Proposed receiver waveforms

• High CM content in kickback dissipated by source
  termination
• Reduced charge kickback

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Conclusion

• Unclocked amplifier is fine for low speed
• High-Speed requires a regenerative receiver
• Preamp is a nuisance at high speed
• Can reduce charge kickback with proposed circuit