Visible to Intel only — GUID: sam1398695694711
Ixiasoft
Visible to Intel only — GUID: sam1398695694711
Ixiasoft
2.4.3.1. OCT Calibration
Each calibration block comes with a pair of RUP and RDN pins.
During calibration, the RUP and RDN pins are each connected through an external 25 Ω, 34 Ω, 40 Ω, 48 Ω, or 50 Ω resistor for respective on-chip series termination value of 25 Ω, 34 Ω, 40 Ω, 48 Ω, and 50 Ω:
- RUP—connected to VCCIO.
- RDN—connected to GND.
The OCT calibration circuit compares the external resistors to the internal resistance using comparators. The OCT calibration block uses the comparators' output to dynamically adjust buffer impedance.
During calibration, the resistance of the RUP and RDN pins varies. To estimate of the maximum possible current through the external calibration resistors, assume a minimum resistance of 0 Ω on the RUP and RDN pins.