Pin Diagrams Figure . 28-pin SPDIP, SSOP, SOIC Figure . 28-pin QFN, UQFN Note: It is recommended that the exposed bottom pad be connected to VSS, however it must not be the only VSS connection to the device. Figure . 40-pin PDIP Figure . 40-pin UQFN Note: It is recommended that the exposed bottom pad be connected to VSS, however it must not be the only VSS connection to the device. Figure . 44-pin TQFP Figure . 44-pin QFN Note: It is recommended that the exposed bottom pad be connected to VSS, however it must not be the only VSS connection to the device.