A fully-differential OTA in 28 nm UTBB FDSOI CMOS for PGA applications

• This paper presents a fully-differential operational transconductance amplifier (OTA) designed in a 28 nm ultra-thin box and body (UTBB) fully-depleted silicon-on-insulator (FDSOI) CMOS process. An overview of the features of the 28 nm UTBB FDSOI process which are relevant for the design of analog/mixed-signal circuits is provided. The OTA which features continuous-time CMFB circuits will be employed in the programmable gain amplifier (PGA) for a 9-bit, 1 kS/s SAR ADC. The reverse body bias (RBB) feature of the FDSOI process is used to enhance the DC gain by 6 dB. The OTA achieves rail-to-rail output swing and provides DC gain = 70 dB, unity-gain frequency = 4.3 MHz and phase margin = 68ï¿œ while consuming 2.9 μW with a Vdd = 1 V. A high linearity > 12 bits without the use of degeneration resistors and a settling time of 5.8 μs (11-bit accuracy) are obtained under nominal operating conditions. The OTA maintains satisfactory performance over all process corners and a temperature range of [-20oC +85oC].

Subject headings

TEKNIK OCH TEKNOLOGIER  -- Elektroteknik och elektronik -- Signalbehandling (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Electrical Engineering, Electronic Engineering, Information Engineering -- Signal Processing (hsv//eng)

Keyword

CMOS integrated circuits;analogue-digital conversion;mixed analogue-digital integrated circuits;operational amplifiers;silicon-on-insulator;PGA;SAR ADC;Si;UTBB FDSOI CMOS process;analog-mixed-signal circuits;continuous-time CMFB circuits;frequency 4.3 MHz;fully-differential OTA;gain 6 dB;gain 70 dB;operational transconductance amplifier;power 2.9 muW;programmable gain amplifier;reverse body bias;size 28 nm;temperature -20 degC to 85 degC;time 5.8 mus;ultrathin box and body fully-depleted silicon-on-insulator;voltage 1 V;word length 9 bit;Electronics packaging;Gain;Linearity;MOS devices;Resistors;Threshold voltage;Transistors

Publication and Content Type

ref (subject category)

kon (subject category)