4-Bit Parallel-Input Exponential Digital-to-Analog Converter in CMOS 0.18 μm Technology

In this paper, a new digitally controlled linear-in-dB CMOS variable gain amplifier is proposed. The circuit employs the proposed novel approach in achieving a wide-range true-exponential transfer function e2X using a traditional pseudo-exponential amplifier followed by a variable gain stage, to expand the output dynamic range. A single digitally controlled variable resistor is used to tune the circuit accordingly by controlling X with a digital word. The result is a digitally controlled data conversion that yields a new type of non-linear digital-to-analog converter. Finally, a 4-bit converter is implemented in a TSMC 0.18 μm CMOS technology and displays a gain from about −21 dB to 36 dB in steps of 3.89 dB with an output linear error in [−0.66,0.45] dB and a static power consumption of 2.34 mW.

[1]  Wouter A. Serdijn,et al.  A Low-Voltage Low-Power Fully-Integratable Automatic Gain Control for Hearing Instruments , 1993, ESSCIRC '93: Nineteenth European Solid-State Circuits Conference.

[2]  R. Jacob Baker,et al.  CMOS Circuit Design, Layout, and Simulation , 1997 .

[3]  Cheng-Chieh Chang,et al.  Pseudo-exponential function for MOSFETs in saturation , 2000 .

[4]  T. Pimenta,et al.  A low-voltage CMOS exponential function circuit for AGC applications , 1998, Proceedings. XI Brazilian Symposium on Integrated Circuit Design (Cat. No.98EX216).

[5]  Brent Maundy,et al.  An improved pseudo-exponential, pseudo-logarithmic circuit , 2007, Canadian Journal of Electrical and Computer Engineering.

[6]  Michael M. Green,et al.  A 1.5 V CMOS VGA based on pseudo-differential structures , 2000, 2000 IEEE International Symposium on Circuits and Systems. Emerging Technologies for the 21st Century. Proceedings (IEEE Cat No.00CH36353).

[7]  Shen-Iuan Liu,et al.  CMOS exponential function generator , 2003 .

[8]  Brent Maundy,et al.  Improved dynamic range, digitally-controlled linear-in-dB CMOS variable gain amplifier , 2011, 2011 IEEE International Symposium of Circuits and Systems (ISCAS).

[9]  A. M. Soliman,et al.  Variable gain amplifiers based on a new approximation method to realize the exponential function , 2002 .

[10]  David A. Johns,et al.  Analog Integrated Circuit Design , 1996 .

[11]  Brent Maundy,et al.  Novel pseudo-exponential circuits , 2005, IEEE Transactions on Circuits and Systems II: Express Briefs.

[12]  Behzad Razavi,et al.  Design of Analog CMOS Integrated Circuits , 1999 .

[13]  David Harris,et al.  Integrated circuit design , 2011 .

[14]  Ramesh Harjani,et al.  A low-power CMOS VGA for 50 Mb/s disk drive read channels , 1995 .

[15]  Aria Nosratinia,et al.  HIGH-DRIVE CMOS BUFFER FOR LARGE CAPACITIVE LOADS , 1991 .

[16]  Chorng-Kuang Wang,et al.  A 3.3-V CMOS wideband exponential control variable-gain-amplifier , 1998, ISCAS '98. Proceedings of the 1998 IEEE International Symposium on Circuits and Systems (Cat. No.98CH36187).

[17]  Mohammed Ismail,et al.  Digitally controlled dB-linear CMOS variable gain amplifier , 1999 .

[18]  G.S. Sahota,et al.  High dynamic range variable-gain amplifier for CDMA wireless applications , 1997, 1997 IEEE International Solids-State Circuits Conference. Digest of Technical Papers.

[19]  R. Engelbrecht,et al.  DIGEST of TECHNICAL PAPERS , 1959 .