The SN3257-Q1 is an automotive qualified 2:1 (SPDT) 4-channel switch with powered-off protection up to 3.6 V. Wide operating supply of 1.5 V to 5.5 V allows for use in applications where different supply voltages are available. The device supports bidirectional analog and digital signals on the source (SxA, SxB) and drain (Dx) pins. The wide bandwidth of this switch allows little or no attenuation of high-speed signals with minimum propagation delay.

The enable (EN) pin is an active-low logic pin that controls the connection between the source (SxA, SxB) and drain (Dx) pins of the device. The select pin (SEL) controls the state of all four channels of the SN3257-Q1 and determines which source pin is connected to the drain. Fail-Safe Logic circuitry allows voltages on the logic control pins to be applied before the supply pin, protecting the device from potential damage. All logic control inputs have 1.8 V logic compatible thresholds, ensuring both TTL and CMOS logic compatibility when operating in the valid supply voltage range.

Powered-off protection up to 3.6 V on the signal path of the SN3257-Q1 provides isolation when the supply voltage is removed (V_DD = 0 V). Without this protection feature, the system can back-power the supply rail through an internal ESD diode and cause potential damage to the system.