The NXB family operates the same for both up and down translations. When driving a rising signal from side A to side B, the weak buffer drives the B-side high. The one-shot senses this rising edge and triggers the high-side PMOS device to accelerate the transition. For a falling signal from side A to side B, the upper one-shot switches off and the lower one-shot triggers to accelerate the falling transition. Since the device is symmetrical, rising or falling signals from the B-side to the A-side will operate in the same manner.