ISL54054, ISL54055 pdf datashe

The Intersil ISL54054 and ISL54055 devices consist of low
ON-resistance, low voltage, bi-directional SPST analog
switches designed to operate from a single +1.8V to +5.5V
supply. These devices have an unique architecture. They
have two signal pins (pin 1 and pin 3) that are
simultaneously connected or disconnected to a common pin
(pin 4) under the control of a single logic control pin (pin 6).
The ISL54054 switches are OFF when the logic is low and
ON when the logic is high. The ISL54055 switches are ON
when the logic is low and OFF when the logic is high. This
architecture allows these devices to be used as a single
SPST switch or as a distribution switch to distribute a single
source to two different loads.
SPST operation is achieved by using one of the signal pins
while floating the other signal pin or by externally connecting
the two signal pins together. When both signal pins are tied
together, the rON of the SPST is reduced by half, from 1Ω to
0.5Ω (when operated with a 5V supply).