The ADuM31541 is an SPIsolator? digital isolator optimized for a serial peripheral interface （SPI） that includes support for up to four slave devices. Based on the Analog Devices， Inc.， iCoupler? chip scale transformer technology， the low propagation delay and jitter in the CLK， MO/SI， MI/SO， and SS SPI bus signals support SPI clock rates of up to 17 MHz. The ADuM3154 isolator also provides a slave select multiplexing system that allows up to four slave devices to be serviced from one isolator. When a target slave is selected， the slave select signal propagates to the desired output with low propagation delay， allowing tight timing control. The isolated SSx is addressed through a 250 kbps low speed， 2-channel address bus， allowing the target slave device to be changed in as little as 2.5 μs.