The TPS65235-1 device has a dedicated EN pin to disable and enable the LNB output. In a non-I²C application, when the EN pin is pulled high, the LNB output is enabled. When the EN pin is pulled low, the LNB output is disabled. In an I²C application, when the EN pin is either low or high, the I²C registers can be accessed, which allows users to change the default LNB output at system power-up. When the I2C_CON bit in the Control Register 1 is set to 1b, the LNB output enable or disable is controlled by the EN bit in the Control Register 2. By default, the I2C_CON bit of the control register is set to 0b, which makes the LNB output is controlled by the EN pin. Figure 7-3 and Figure 7-4 shows the detailed control behavior.

V(EN) = 0 V

I2C_CON = 1b

Figure 7-3 VLNB Output Controlled by bit EN of Control Register 2

I2C_CON = 0b

Figure 7-4 VLNB Output Controlled by EN Pin