SBVS233B January 2016 – June 2021 TPS7A84
At 3.0 A and 5.0 VOUT, the dropout of the TPS7A84 has a 340-mV maximum dropout over temperature, thus a 500-mV headroom is sufficient for operation over both input and output voltage accuracy. At full load and high temperature on some devices, the TPS7A84 can enter dropout if both the input and output supply are beyond the edges of their accuracy specification.
For a 5.0-V output. use external adjustable resistors. See the resistor values in listed Table 8-5 for choosing resistors for a 5.0-V output.
Input and output capacitors are selected in accordance with the Section 8.1.1 section. Ceramic capacitances of 47 µF for the input and one 47-µF capacitor in parallel with two 10-µF capacitors for the output are selected.
To satisfy the required start-up time and still maintain low noise performance, a 100-nF CNR/SS is selected. This value is calculated with Equation 14.
At the 3.0-A maximum load, the internal power dissipation is 1.5 W and corresponds to a 53.1°C junction temperature rise for the RGR package on a standard JEDEC board. With an 55°C maximum ambient temperature, the junction temperature is at 108.1°C. To further minimize noise, a feed-forward capacitance (CFF) of 10 nF is selected.