The SN3257-Q1 is an automotive grade complementary metal-oxide semiconductor (CMOS) switch that supports high speed signals with low prop delay. The SN3257-Q1 offers a 2:1 (SPDT) switch configuration with 4-channels making it ideal for various protocols such as SPI and I2S. The device supports bidirectional analog and digital signals on the source (SxA, SxB) and drain (Dx) pins and can pass signals above supply up to VDD x 2, with a maximum input/output voltage of 5.5 V.
The SN3257-Q1 has an active low EN pin that is used to enable/disable all channels simultaneously. When the EN pin is LOW, one of the two switch inputs is selected based on the state of SEL pin.
Powered-off protection up to 3.6 V on the signal path of the SN3257-Q1 provides isolation when the supply voltage is removed (VDD = 0 V). Without this protection feature, switches can back-power the supply rail through an internal ESD diode and cause potential damage to the system.
Fail-safe logic circuitry allows voltages on the logic control pins to be applied before the supply pin, protecting the device from potential damage. Both logic control inputs have 1.8 V logic compatible thresholds, ensuring both TTL and CMOS logic compatibility. Integrated pull down resistor on the logic pins removes external components to reduce system size and cost.
