QDR Point-to-Point termination | Cypress Semiconductor
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QDR Point-to-Point termination
Is it required to terminate the lines when QDR is driving the bus for a point-to-point link?
No, QDR has a feature that can adjust the output impedance to match that of the trace impedance. This can be accomplished by adding a resistor five times that of trace impedance to pin ZQ. ZQ will control the impedance of all outputs when the QDR is driving the bus. This method has a tolerance of ~10%. The output impedance can be adjusted between 35 ohms to 70 ohms.