Other Parts Discussed in Thread: TPS7A85A, , TPS7A52, TPS7A84
I am currently looking at my options for filtering out some 900KHz supply ripple using an LDO. The application requires that the LDO be able to source >= 2.2A (>3A preferred for derating), and be able to output 5.0V (external resistors OK).
I found the TPS7A84A and TPS7A85A in your catalog and they seems OK, but using the parallel capacitor combination suggested in 8.1.1.7 it seems I only get ~20dB of power supply rejection at 900KHz on either part.
Can I use the capacitor values I choose and the boost circuit described in 8.1.3.1 of both datasheets (http://www.ti.com/lit/ds/symlink/tps7a84a.pdf & http://www.ti.com/lit/ds/symlink/tps7a85a.pdf) to steer the PSRR transfer function to have more rejection at 900KHz? Do you have and application notes / reference designs about how to do this? Or should I look for other high current LDOs with wider bandwidth?