SLVSBC6C March 2013 – December 2019 TPS84A20
When configured as shown in the front page schematic, the TPS84A20 produces a regulated output voltage following the application of a valid input voltage. During the power-up, internal soft-start circuitry slows the rate that the output voltage rises, thereby limiting the amount of in-rush current that can be drawn from the input source. Figure 27 shows the start-up waveforms for a TPS84A20, operating from a 5-V input (PVIN = VIN) and with the output voltage adjusted to 1.8 V. Figure 28 shows the start-up waveforms for a TPS84A20 starting up into a pre-biased output voltage. The waveforms were measured with a 5-A constant current load.