A fast transient response low-dropout regulator with all-NPN push–pull buffer in 0.6-μm bipolar process

This paper presents a fast transient response low-dropout (LDO) regulator with all-NPN push–pull buffer in 0.6-μm bipolar process. In order to improve the transient response, an all-NPN push–pull buffer is proposed. Based on single Miller capacitance (SMC), the use of the all-NPN push–pull buffer overcomes the shortcomings of the equivalent series resistance (ESR) that requires strict output capacitor types. Besides, the proposed merging structure of bandgap reference and error amplifier not only improves the transient response, but also simplifies the circuit and reduces the output noise. Implemented and fabricated in a 0.6-μm bipolar process, the proposed LDO regulator occupies an active area of 1.6 mm2. The measured maximum load current is 200 mA, and the circuit can work at the load current of 300 mA. Moreover, the measured line regulation and load regulation are 0.8 mV/V and 0.09 mV/mA, respectively.