For the bidirectional clamping configuration (higher voltage to lower voltage or lower voltage to higher voltage), the EN input must be connected to V_{ref_B} and both pins pulled to HIGH side V_CCB through a bias resistor (typically 200 kΩ), as shown in Figure 9-1. This allows V_{ref_B} to regulate the EN input. A filter capacitor on V_{ref_B} is recommended. The controller output driver can be push-pull or open-drain (pull-up resistors may be required) and the peripheral device output can be push-pull or open-drain (pull-up resistors are required to pull the Bn outputs to Vpu).

If either output is push-pull, data must be unidirectional or the outputs must be tri-state and be controlled by some direction-control mechanism to prevent HIGH-to-LOW contention in either direction. If both outputs are open-drain, no direction control is needed.

In Figure 9-1, the reference supply voltage V_{ref_A} is connected to the processor core power supply voltage. V_{ref_B} is connected through a 200 kΩ resistor to a 3.3 V V_{B_Pullup} power supply and V_{ref_A} is set to 1.2 V. The output of A1 has a maximum output voltage equal to Vref_A, and the bidirectional interface on channel 2 has a maximum output voltage equal to V_PU1.