The F75909 is a 2 bidirectional voltage level shifter with enable (EN) input. It is operational from 1.1 V to [V_CC(H)C(H)75909 is a 2 bidirectional voltage level shifter with enable (EN) input. It is opVCC(L) with 5V tolerant. When F75909 is disabled, both port L and port H I/O pins became high-impedance.

The bus port H are compliant with any digital signals, the standard I²C-bus or SMBus I/O levels, while port L uses a current sensing mechanism to detect the input or output LOW signal which prevents bus lock-up. This results in a LOW on the port L accommodating smaller voltage swings. The output pull-down on the port L internal buffer LOW is set for approximately 0.2 V, while the input threshold of the internal buffer is set about 50 mV lower than that of the output voltage LOW. When the port L I/O is driven LOW internally, the LOW is not recognized as a LOW by the input. This prevents a lock-up condition from occurring. The output pull-down on the port H drives a hard LOW and the input level is set at 0.3 of SMBus or I²C-bus voltage level which enables port H to connect to any other I²C-bus devices or buffer.

The F75909 is not enabled unless V_CC(L)is above 0.8 V and V_CC(H)is above 2.5 V. The enable (EN) pin can also be used to turn the drivers on and off under system control. Caution should be observed to only change the state of the EN pin when the bus is idle.