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# TCA9534A: Max. Current consumption

Part Number: TCA9534A

Hi,

As we want to check the maximum power consumption for the device, we want to check the current consumption for TCA9534A.

But only continuous current is mentioned in the datasheet. We want to know what is the max power that can be consumed by the chip if in case all the blocks are working.

Based on the recommended operating denotation "Each P-port I/O configured as a high output must be externally limited to a maximum of 10 mA, and the total current sourced by all I/Os (P-ports P7-P0) through VCC must be limited to a maximum current of 80 mA."

You can calculate the power by P=I*V(drop) where IoL = 10mA and VoL at 10mA is 0.7V thus P = 7mW (If we used VoH, the dissipated power would be less so this gives us our worst case)

There are 8 GPIO channels to this device so the total power is 7mW*8= 56mW.

The operating mode and standby mode currents are measured in uA so this is negligible when compared to the GPIO power dissipation, so I will choose to ignore it.

SDA is limited as denoted as "The SDA pin must be externally limited to a maximum of 12 mA" and VoL of 0.4V at a 3mA IoL. If I assume linearity then at at 12mA 1.6V would be the VoL (likely not as we build for higher margin and may even see saturation depending on Vcc.... but I will assume worst case again)...

P=1.6V*.012A= 19.2mW

Total power = 19.2mW + 56mW. = 75.2mW

-Bobby