The main difference between the CY2546 and CY2547 is that the CY2547 has I2C and the CY2546 does not have I2C. So accordingly, the CK3/FS0 (pin 8) and PD#/OE/FS1 (pin 9) of the CY2546 gets replaced by SCL and SDAT respectively. Pin 5 is DNU in CY2547 and is NC in CY2546. The CY2547 has 8 outputs and CY2546 has 9 outputs resulting into shuffling of the output numbers. Rest, they are the same parts in form fit and functionality. So the CY2547 is the I2C version of the CY2546 with one less output having the important, VDD, GND, XTALIN and XTALOUT pins at the same locations.