The SS pin is externally driven by another voltage source to achieve output voltage tracking. The application circuit is shown in Figure 7-1. The internal reference voltage follows the voltage at the SS pin with a fraction of 1.56 until the internal reference voltage of 0.8 V is reached. The device achieves ratiometric or coincidental (simultaneous) output tracking, as shown in Figure 7-2.

Figure 7-1 Output Voltage Tracking

Figure 7-2 Voltage Tracking Options

The R2 value should be set properly to achieve accurate voltage tracking by taking 7.5-µA soft start-up current into account. 1 kΩ or smaller is a sufficient value for R2.

For decreasing the SS pin voltage, the device does not sink current from the output when the device is in power save mode. So the resulting decreases of the output voltage may be slower than the SS pin voltage if the load is light. When driving the SS pin with an external voltage, do not exceed the voltage rating of the SS pin which is
7 V.