RE028 [Updated 3/03. 9 Pages] The RE028 is a Low Drop Out (LDO) voltage regulator macrocell with a fixed 4.5V output voltage. rated for loads up The RE028 is a Low Drop Out (LDO) voltage regulator macrocell with a fixed 4.5V output voltage, rated for loads up to 300 mA. It is designed to supply radio frequency synthesizers and used as a controller for the antenna switch.