Papers you can refer for VGA.
1)CMOS low-distortion high-frequency variable-gain amplifier
Rijns, J.J.F.;
Solid-State Circuits, IEEE Journal of
Volume 31, Issue 7, July 1996 Page(s):1029 - 1034
Digital Object Identifier 10.1109/4.508217
2)A temperature-stable CMOS variable-gain amplifier with 80-dB linearly controlled gain range
Yamaji, T.; Kanou, N.; Itakura, T.;
Solid-State Circuits, IEEE Journal of
Volume 37, Issue 5, May 2002 Page(s):553 - 558
Digital Object Identifier 10.1109/4.997847
3)CMOS current-mode exponential-control variable-gain amplifier
Chang, C.-C.; Lin, M.-L.; Liu, S.-I.;
Electronics Letters
Volume 37, Issue 14, 5 July 2001 Page(s):868 - 869
Digital Object Identifier 10.1049/el:20010593
4)Wideband 70dB CMOS digital variable gain amplifier design for DVB-T receiver's AGC
Chua-Chin Wang; Ching-Li Lee; Li-Ping Lin; Yih-Long Tseng;
Circuits and Systems, 2005. ISCAS 2005. IEEE International Symposium on
23-26 May 2005 Page(s):356 - 359 Vol. 1
Digital Object Identifier 10.1109/ISCAS.2005.1464598
5)Wideband high dynamic range CMOS variable gain amplifier for low voltage and low power wireless applications
Kwon, J.K.; Kim, K.D.; Song, W.C.; Cho, G.H.;
Electronics Letters
Volume 39, Issue 10, 15 May 2003 Page(s):759 - 760
Digital Object Identifier 10.1049/el:20030516
6)A CMOS Variable Gain Amplifier with Wide Dynamic Range and Accurate dB-Linear Characteristic
Ji-Hun Kim; Chang-Seok Chae; Young-Jin Woo; Gyu-Hyeong Cho;
Advanced Communication Technology, 2006. ICACT 2006. The 8th International Conference
Volume 1, 20-22 Feb. 2006 Page(s):831 - 835
7) Design of a 1.8 V high frequency CMOS variable gain amplifier with a novel dB-linear gain structure
Wei Hu; Seunghyun Song; Bongryul Choi; Jae-Whui Kim;
Circuits and Systems, 2004. MWSCAS '04. The 2004 47th Midwest Symposium on
Volume 1, 25-28 July 2004 Page(s):I - 125-8 vol.1
Digital Object Identifier 10.1109/MWSCAS.2004.1353913
8) A 50 dB variable gain amplifier using parasitic bipolar transistors in CMOS
Pan, T.-W.; Abidi, A.A.;
Solid-State Circuits, IEEE Journal of
Volume 24, Issue 4, Aug. 1989 Page(s):951 - 961
Digital Object Identifier 10.1109/4.34077