what is the difference between the LT1764EQ and LT1764AEQ? At first sight I can't see any differences, except pricing from the distributors.
LT1764A is stable with ceramic output capacitance with low ESR, while extra consideration must be given to use ceramic output capacitance. For LT1764, the recommended ESR is 50mOhm to 3Ohm. You can refer to datasheet for details under "output capacitors and stability" section.