Datasheet

SLVA037A
18 Designing a USB Power Distribution System Using the TPS2014 and TPS2015 Power Distribution Switches
Notes:
1. Channel 1: Switched Port Output Voltage 1 V/div
2. Channel 2: Adjacent Output Port Voltage 1 V/div
3. Time Scale: 200 ns/div
Figure 12. Non-Ganged Hot-Insertion Transient
Figure 12 shows the circuit used in the hot-insertion transient test for the non-ganged
configuration. Testing shows that this circuit has a droop voltage of 280 mV, which is better than
the 330-mV requirement.
Figure 13. Ganged Transient Load Test Circuit
In the ganged configuration (see Figure 13 and Figure 14), the voltage droop for a hot-insertion
was approximately 1 V. This is unacceptable. Even with an additional 1000
µF added to the
output, the droop was still more than double the 330-mV limit. Since there is no impedance
between the ports, there is no filtering between them. Some impedance must be added between
the ports to meet the drop requirement.