A Low Noise CMOS Low Dropout Regulator with an Area-Efficient Bandgap Reference

Sangwon HAN  Jongsik KIM  Kwang-Ho WON  Hyunchol SHIN  

Publication
IEICE TRANSACTIONS on Electronics   Vol.E92-C   No.5   pp.740-742
Publication Date: 2009/05/01
Online ISSN: 1745-1353
DOI: 10.1587/transele.E92.C.740
Print ISSN: 0916-8516
Type of Manuscript: LETTER
Category: Electronic Circuits
Keyword: 
low dropout regulator (LDO),  bandgap reference,  CMOS,  

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Summary: 
In a low dropout (LDO) linear regulator whose reference voltage is supplied by a bandgap reference, double stacked diodes increase the effective junction area ratio in the bandgap reference, which significantly lowers the output spectral noise of the LDO. A low noise LDO with the area-efficient bandgap reference is implemented in 0.18 µm CMOS. An effective diode area ratio of 105 is obtained while the actual silicon area is saved by a factor of 4.77. As a result, a remarkably low output noise of 186 nV/sqrt(Hz) is achieved at 1 kHz. Moreover, the dropout voltage, line regulation, and load regulation of the LDO are measured to be 0.3 V, 0.04%/V, and 0.46%, respectively.