Hi Masa-san, There may be some confusion with respect to how the AVSS switch (AVSS-SW) works. It is only useful if REFN0 is connected. Note the functional block diagram. The AVSS-SW will only break the connection to whatever is connected to REFN0. Normally this would be EXC- on a bridge circuit to break the excitation current. The action of the AVSS-SW is controlled through a register setting in the IDACMAG (0x06) register. The switch is default open. If the switch is set to closed, it will open when the device is set to power-down mode. See section 9.3.12 on page 55 of the ADS124S06 datasheet. There will not be a lot of switching that would affect REFN0 and this would also be in power-down as well. If REFN0 is not being used and is floating, then you could also float the AVSS-SW pin. The key point here is you don't want to connect AVSS-SW to AVSS and REFN0 to AVDD as the switch could inadvertently be closed in the register setting causing a supply short. Instead of floating AVSS-SW and REFN0 you could connect both pins to AVSS. Best regards, Bob B
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