Wideband 70dB CMOS digital variable gain amplifier design for DVB-T receiver´s AGC

Author

Wang, Chua-Chin ; Lee, Ching-Li ; Lin, Li-Ping ; Tseng, Yih-Long

Author_Institution

Dept. of Electr. Eng., Nat. Sun Yat-Sen Univ., Kaohsiung, Taiwan

fYear

2005

fDate

23-26 May 2005

Firstpage

356

Abstract

This paper presents a novel VGA (variable gain amplifier) design which is applied in the AGC (automatic gain control) loop of DVB-T receivers. A total of three tunable gain stages are cascaded to provide a 70 dB dynamic range. Each gain stage is based on a DVGA (digital variable gain amplifier) which is composed of a plurality of GB (gain block) and a fully differential degeneration amplifier (FDDA). The GB are digitally controlled current mirrors which are used to determine the gain of the DVGA. A CMFB (common-mode feedback) circuitry is used to stabilize the FDDA. The bandwidth of the proposed design verified by HSPICE post-layout simulations is better than 95 MHz at every PVT corner which is sufficient for the DVB-T IF mixed-signal processing.

Keywords

CMOS integrated circuits; automatic gain control; cascade networks; circuit simulation; circuit stability; circuit tuning; current mirrors; differential amplifiers; digital control; digital video broadcasting; feedback amplifiers; intermediate-frequency amplifiers; mixed analogue-digital integrated circuits; radio receivers; radiofrequency amplifiers; AGC; CMFB; CMOS; DVB-T receivers; DVGA; FDDA; HSPICE post-layout simulations; IF mixed-signal processing; PVT corner; automatic gain control loop; cascaded tunable gain stages; common-mode feedback circuitry; digital variable gain amplifier; digitally controlled current mirrors; fully differential degeneration amplifier; gain block; stabilization; Bandwidth; Broadband amplifiers; Differential amplifiers; Digital control; Digital video broadcasting; Dynamic range; Feedback circuits; Gain control; Mirrors; Tunable circuits and devices;

fLanguage

English

Publisher

ieee

Conference_Titel

Circuits and Systems, 2005. ISCAS 2005. IEEE International Symposium on

Print_ISBN

0-7803-8834-8

Type

conf

DOI

10.1109/ISCAS.2005.1464598

Filename

1464598