The voltage on the EN pin provides electrical ON/OFF control of the device. This input features precision thresholds, allowing the use of an external voltage divider to provide a programmable UVLO (see Section 7.3.6). Applying a voltage of V_EN ≥ V_{EN-LDO_H} causes the device to enter standby mode, powering the internal LDO, but not producing an output voltage. Increasing the EN voltage to V_EN-H fully enables the device, allowing it to enter start-up mode and begin the soft-start period. When the EN input is brought below V_EN-H by V_EN-HYS, the regulator stops running and enters standby mode. Further decrease in the EN voltage to below V_EN-LDO-L completely shuts down the device. Figure 7-2 shows this behavior. The values for the various EN thresholds can be found in Section 6.5.

Figure 7-2 Precision Enable Behavior

The EN pin cannot be open circuit or floating. The simplest way to enable the operation of the TPSM53603 is to connect the EN pin to VIN directly as shown in Figure 7-3. This allows self start-up of the TPSM53603 when VIN is within the operation range.

If an application requires controlling the EN pin, an external logic signal can be used to drive the EN pin as shown in Figure 7-4. Applications using an open-drain/collector device to interface with this pin require a pullup resistor to a voltage above the enable threshold.

Figure 7-3 Enabling the Device

Figure 7-4 Typical Enable Control