SN74LVC1G3157: What is the maximum current consumption (worst case) of this switch that see power rail attached to Vcc.

Hi Adam,

The max current consumption of the SN74LVC1G3157 is not 500uA or 100mA.  The max current consumption is 35uA given by the Icc spec:

It is recommended to drive the control logic pin S to Vcc or ground.  With the test condition S pin S= Vcc-0.6 V (Delta Icc spec), there can be excess current consumption or supply-current change up to 500uA.   This is common in many logic devices which is why it is recommended to drive the control pins to Vcc or ground. If you drive the S pin to Vcc or ground this will not be an issue.  This application note Implications of Slow or Floating CMOS Inputs has more information on this topic.  

 The absolute max ratings are not recommended operating conditions and are the specifications that may cause permanent damage to the IC.  Under normal operation there will be at most 35uA current consumption with Vcc = 5V through Vcc.  But under abnormal operation, such as exposing the device I/O pins to voltages greater than Vcc (which is out of spec) larger currents can be driven from the signal path to Vcc.  If these large currents driven from the signal path to Vcc are in excess of 100mA the device could be permanently damaged.  

Thanks

Saminah