We met some trouble when design a special LDO power as follow.
This specific LDO circuit is placed right after power-in port (battery or adaptor) and is aimed to suppress 800KHZ switching noise generated from other DC/DC modules in system.
(1)Vin = 14.4V(battery) or 19V(adaptor),
(2)Vout is required to approximately follow Vin: Vout = Vin - V_drop, V_drop should be small to reduce power loss, and is expected to limite within (0.2~0.4V), the exact number is not important, but we sat its typical. = 0.3V.
(3)I_load max = 1A or so.
(4) PSRR > 40dB at 800KHZ
We built an LDO prototype with discrete components (mosfet and amplifier) , but the PSRR is not as good as expected. And we think better to use off-the-shell LDO IC to do this. Hope TI experts could help on this. Thanks very much!