Design of a LDO linear regulator with supply of low and high voltage

For the situation of slow linear response of traditional LDO(low dropout) linear regulator with supply of low voltage, a LDO linear regulator with supply divided to low and high voltage was proposed based on BICMOS 0.5 μm BCD process. The regulator was simulated by Hspice software. Results show that the regulator has high gain, high PSRR(Power Supply Rejection Ratio), low power consumption, fast response characteristics, the input voltage range of 0.5-28.0V, the output voltage of 5 V. This regulator achieves 86 d B of open-loop gain at low frequency, the phase margin is 68 o,power supply rejection ratio is –91 d B at low frequency and –2 d B at high frequency, the quiescent current is only 13.5 μA.