The LM74501-Q1 has an SW pin to enable battery voltage monitoring in automotive systems. When the device is enabled, an internal switch connects the SW pin to SOURCE. This connection enables monitoring battery voltage using an external resistor divider connected from SW pin to GND. When LM74501-Q1 is put in shutdown mode by pulling down the EN pin to ground, an internal switch between SW and SOURCE pin is disconnected. This disconnection ensures there is no quiescent current drawn by the resistor ladder when system is put into low power shutdown mode. When not used, the SW pin can be left floating.

Figure 8-2 LM74501-Q1 SW Functionality