SPRADN4B October 2024 – September 2025 AM62P , AM62P-Q1
The below FAQ includes recommendations on CAP_VDDSn capacitor value, and the effect of the capacitor assembly (mounted or shorted):
Refer below section Supply Connection for Partial IO (Low Power) Mode Configuration of user's guide for VDDSHV_CANUART supply connection.
The processor family supports x8 (eight) dual-voltage IO supply for IO groups (VDDSHVx [x = 0-3, 5-6]), IO supply for IO group CANUART (VDDSHV_CANUART) and IO supply for IO group MCU (VDDSHV_MCU). Each IO supply for IO group is connected (referenced) to a fixed set of IOs. Each IO supply for IO group can be connected to fixed (VDDSHV5, VDDSHV6 supports dynamic supply switching) 3.3V or 1.8V supply independently. The IO supply for IO group defines a common operating voltage for the entire set (fixed set) of IOs.
Processor pads (pins) designated as CAP_VDDSn [n = 0-3, 5-6], CAP_VDDS_CANUART, and CAP_VDDS_MCU connects the external capacitor to the internal IO supply for IO group regulator when the IO supply for IO groups connect to 3.3V supply (optional when IO supply for IO groups supplies connect to 1.8V). A 1μF (connected between the pins and VSS, see the processor-specific data sheet) capacitor is recommended. See the processor-specific data sheet for the recommended capacitor voltage rating and allowed capacitance range. When IO supply for IO groups are connected to 3.3V, the steady state DC output VDDSHVx/2, is the voltage to be considered for choosing the capacitor voltage rating considering the DC bias effect.
To minimize PCB loop inductance, place the capacitors on the back side of the PCB in the array of the BGA. The choice of capacitor voltage rating influences capacitor package (size) selection.
The recommendation is to select capacitor with ESR < 1Ω, keep the trace loop inductance < 2.5nH.