A low power-noise output driver with an adaptive characteristic applicable to a wide range of loading conditions

Semicustom IC design methodologies often assume a wide range of operating conditions. This requirement makes designing output drivers very difficult, as output ringing due to overdriving cannot be avoided. This problem becomes more tricky when power noise due to simultaneous switching of many output drivers at very high speed is also considered. A new output driver is proposed that adopts an innovative feedback mechanism to achieve an adaptive characteristic so that its performance will not vary under different loading conditions. The driver is also low in power noise as it works with a principle similar to a controlled slew rate output driver. Measurement from a test chip substantiates all those claims.