The XC9235/XC9236 series can be classified into four types including 1.2MHz PWM, 1.2MHz PFM/PWM, 3MHz PWM, or 3MHz  PFM/PWM. If the power conversion efficiency is critical in a customer’s design over the full range of load conditions, it is recommended that a 1.2MHz and PFM/PWM is selected. In this case, the part number is XC9236xxxC. If a main concern is board space, the 3MHz frequency version is recommended. The higher frequency allows a customer to use a smaller inductor. In this case, the XC9235xxxD or XC9236xxxD is recommended.