| 摘要 |
A programmable logic device is equipped for various differential signaling schemes by providing a differential output buffer on the device that can be configured according to the needs of the particular differential signaling schemes that may be used. The buffer includes a differential output driver, an adjustable current limiting circuit between the supply voltage and the differential output driver, and an adjustable current limiting circuit between the differential output driver and ground. By selectively adjusting the two current limiting circuits, the output impedance and current, as well as the common mode output voltage and the differential output voltage can be controlled.
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