Hi Hippy,
this is the datasheet: http://www.produktinfo.conrad.com/datenblaetter/1100000-1199999/001116572-da-01-en-IC_LED_TREIB_PCA9633DP2_118_TSSOP_10_NXP.pdf
I've got the 10 pin version.
I connected the I2C bus to a 20X2. 2 pull up resistors of 10K each. A0 and A1 are connected to ground...