I am planning to use the SDSDUN4-128G-GN6IN SD card in my design. As higher bus speeds require low-level signaling, UHS-1 adopts a 1.8 V signaling level for SDCLK, CMD and data lines [3:0].

To change to 1.8 V signaling, the microcontroller (MIMXRT1024CAG4B) NVCC_SDD power pin has to be changed from 3.3 V to 1.8 V. To switch the voltage from 3.3 V to 1.8 V, I am planning to use the SD power switch BD2204GUL-E2, which has a continuous load current of 0.5 A and an absolute maximum current of 1 A. The maximum current consumption of SD card in UHS104 mode is 800 mA and I'm planning to operate the SD card at 60 MB/s.

Can I use this SD power switch, as my continuous load current of this switch is only 0.5 A, but my SD card current consumption could be 800 mA (as per physical layer simplified specification V9.00 on sdcard.org)? enter image description here


1 Answer 1


The "Absolute Maximum" ratings are not an operating spec.
They tell you what the part should be able to survive without permanent damage, but there's no guarantee that it will behave properly if you exceed the "Recommended Operating Conditions".
Using a 500mA part to switch 800mA is not a good design decision.


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