单晶体管 46dB 通过减少 LDO 噪音

单晶体管 46dB 通过减少 LDO 噪音
Maxim > App Notes > AMPLIFIER AND COMPARATOR CIRCUITS POWER-SUPPLY CIRCUITS

Keywords: Low-dropout regulator, LDO, RC filter Nov 23, 2005

APPLICATION NOTE 3656
Single Transistor Reduces LDO Noise by 46dB

Abstract: A simple RC filter with an external transistor driver rejects LDO noise. A plot of noise density vs.
frequency shows that the filter rejects LDO noise by more than 46dB, and achieves a noise floor of 7nV/ .

Of the many low-dropout (LDO) regulators providing voltage regulation for electronic systems, some are
specifically designed for low noise. The voltage regulator in Figure 1, for example, achieves an RMS noise
voltage of about 115V. Some ultra-low-noise applications such as instrumentation and high-qualit