A 1µs Settling Time Fully Digital AGC System with a 1GHz-Bandwidth Variable Gain Amplifier for WiGig/IEEE802.11ad Multi-Gigabit Wireless Transceivers

Ryo KITAMURA  Koichiro TANAKA  Tadashi MORITA  Takayuki TSUKIZAWA  Koji TAKINAMI  Noriaki SAITO  

IEICE TRANSACTIONS on Electronics   Vol.E96-C    No.10    pp.1301-1310
Publication Date: 2013/10/01
Online ISSN: 1745-1353
DOI: 10.1587/transele.E96.C.1301
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Section on Emerging Technologies and Applications for Microwave and Millimeter-Wave Systems)
variable gain amplifier (VGA),  automatic gain control (AGC),  digitally-controlled,  wide-bandwidth,  wide gain range,  CMOS,  60GHz,  

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This paper presents an automatic gain control (AGC) system suitable for 60GHz direct conversion receivers. By using a two step gain control algorithm with high-pass filter cutoff frequency switching, the proposed AGC system realizes fast settling time and wide dynamic range simultaneously. The paper also discusses wide-bandwidth variable gain amplifier (VGA) design. By introducing digitally-controlled resistors and gain flattening capacitors, the proposed VGA realizes wide gain range while compensating gain variations due to parasitic capacitance of MOS switches. The AGC system is implemented in a transceiver chipset where RFIC and BBIC are fabricated in 90nm CMOS and 40nm CMOS respectively. The measurement shows excellent dynamic range of 47dB with +/-1dB gain accuracy within 1µs settling time, which satisfies the stringent requirements of the IEEE802.11ad standard.