SPRUIS4E March 2022 – January 2024
The J721E SOM has 4GB of LPDDR4 using single 32Gb x 8-bit wide memory devices arranged in an 32-bit wide bus. The LPDDR4 interface can operate up to 3733 Mb/s speed. The LPDDR4 device is connected using T-branched routing for the clock and address/command lines and point-to-point connection for the data bus.
The Micron’s LPDDR4 memory chip MT53D1024M32D4DT is used on the SoM, it requires 1.8 V for Core (VDD1), 1.1 V for Core2 (VDD2) and 1.1 V or 0.6 V for I/O buffer power (VDDQ). The VDDQ supplies are selected using a dip switch SW1 on the SoM. For more details, see Section 4.5.3.