9.1 Application Information

The SN74HCS11 includes three 3-input AND gates with Schmitt-trigger inputs. These 3-input AND gates work independently, but can be combined to get up to a 7-input AND gate. It can be used with all three inputs active, or one input can be disabled by directly connecting them to V_CC to turn the device into a 2-input AND gate.

The SN74HCS11 is used to control the RESET pin of a motor controller. This system requires three input signals to all be HIGH before the controller is enabled, and should be disabled in the event that any one signal goes LOW. The 3-input AND gate combines the 3 individual reset signals into a single active-low reset signal.

Many power good signals utilize open-drain outputs which can produce slow input transition rates when they transition from LOW to Hi-Z mode. This makes the SN74HCS11 ideal for the application because it has Schmitt-trigger inputs that do not have input transition rate requirements.