3.3.5.9 ZQ Calibration
This feature is applicable to DDR3 and LPDDR2/LPDDR3. The UDDRC controller uses the ZQ calibration command to calibrate SDRAM RON (Resistor On) and ODT (On-Die Termination) values over PVT (Process, Voltage, Temperature). DDR3 and LPDDR2/LPDDR3 SDRAMs need more time to calibrate RON and ODT at initialization and relatively less time to perform periodic calibrations. For more information, refer to the following specifications:
- DDR3 (JEDEC JESD79-3F)
- LPDDR2 (JEDEC JESD209-2E)
- LPDDR3 (JEDEC JESD209-3B)