34.6 Pin Driver Strength Figure 34-20. ATmega328PB: I/O Pin Output Voltage vs. Sink Current (VCC = 3V) Figure 34-21. ATmega328PB: I/O Pin Output Voltage vs. Sink Current (VCC = 5V) Figure 34-22. ATmega328PB: I/O Pin Output Voltage vs. Source Current (VCC = 3V) Figure 34-23. ATmega328PB I/O Pin Output Voltage vs. Source Current (VCC = 5V)