Attention to Internet Explorer users: ROHM website does not recommend browsing in IE 11. Please use latest browser to ensure the best performance on ROHM website.
The BU2099 supports cascade connection by inputting the serial data output pin (SO) of the 1st stage IC to the data of the second stage IC. SO changes at the falling timing of the CLK, so the second stage takes in the SO output as data at the rising clock edge, similar to the first stage.