An Outside-Rail Opamp Design Targeting for Future Scaled Transistors

2011 IEEE International Symposium of Circuits and Systems (ISCAS)

Zhang

et al. 2011

This paper describes a high-voltage-enabling circuit technique for enhancing the gain precision and linearity of OpAmp-based analog circuits. Without resorting from specialized devices, a 2xV DD -enabled recycling folded cascode (RFC) OpAmp optimized in 1V GP 65-nm CMOS achieves, when compared with its 1xV DD counterpart, 25-dB higher open-loop DC gain and 30-dB higher IM3 (in closed loop), under a similar power budget. These joint improvements save the need of a 2 nd stage in the OpAmp when high precision and high linearity are the priorities. A voltage-conscious bias scheme and gate-drain-source engineering ensure that all devices are consistently operated within the reliability limits.

Section: Circuit Reliability Considerationsmentioning

confidence: 98%

A high-voltage-enabled recycling folded cascode OpAmp for nanoscale CMOS technologies

Liu

2011 IEEE International Symposium of Circuits and Systems (ISCAS)

Zhang

et al. 2011

“…From September 2008, after the reform of the UM Charter, he was nominated after open international recruitment as Vice-Rector (Research) until August 31, 2013. Within the scope of his teaching and research activity he has taught 20 bachelor and master courses and has supervised 21 theses, Ph.D. (9) and Masters (12). He has published: 13 books, co-authoring (3) and co-editing (10), plus 5 book chapters; 176 refereed papers, in scientific journals (34) and in conference proceedings (142); as well as other 70 academic works, in a total of 264 publications, in the areas of microelectronics, electrical and electronics engineering, engineering and university education.…”

Section: Acknowledgmentmentioning

confidence: 99%

“…A 3.3-V 0.18-mm CMOS two-stage operational amplifier (OpAmp) was demonstrated in [12]. The concept of extending the voltage is related with the addition of extra cascode transistors, boosting the voltage-withstand capability from 1.8 to 3.3 V. The input stage is of particular interest as it is based on a high-voltage-enabled differential pair using a current mirror load.…”

Section: E Operational Amplifi Er (High-v Dd + Thin-oxide Transistor)mentioning

confidence: 99%

High-/Mixed-Voltage RF and Analog CMOS Circuits Come of Age

IEEE Circuits Syst. Mag.

Martins

2010

Instead of blindly tracking the rapid downsizing of supply voltage (V DD ) in technology scaling, high-/mixed-voltage radio-frequency (RF) and analog CMOS circuits have emerged as a prospective alternative comes of age. An elevated V DD , or a hybrid use of I/O and core V DD 's, in conjunction with thinand thick-oxide MOS transistors open up many possibilities in defining circuit topologies, while maintaining the speed and area benefits of advanced processes. Circuit reliability can be guaranteed through advanced circuit techniques. This paper aims to provide a glimpse of the basic concept, system design considerations and circuit examples. A wide variety of RF and analog CMOS circuits designed based on such techniques are examined and new topologies are proposed. Those circuit topologies comprise the RF power amplifier, the low-noise amplifier, the mixer, operational-amplifier-based analog circuits, the sample-and-hold amplifier and, finally, the line driver. Reliability considerations such as oxide breakdown, hot carrier injection (HCI), time dependent dielectric breakdown (TDDB), and bias temperature instability (BTI) will be discussed, and their implications in different types of circuits will be justified. The outlined principles are extendable to other RF and analog circuits, motivating the adoption of new voltage-conscious topologies in ultrascaled CMOS processes.

“…In view of that, the voltage-oriented OpAmp becomes more prospective [8], [9]. As shown in Figure 1, a high V DD along with technology downscaling can directly enlarge the voltage headroom with respect to the threshold voltage (V T ), which will not be scaled much due to variability, matching and leakage issues.…”

Section: Introductionmentioning

confidence: 99%

Enhancing the performances of recycling folded cascode OpAmp in nanoscale CMOS through voltage supply doubling and design for reliability

Liu

Zhao

et al. 2012

Circuit Theory & Apps

Current-oriented operational amplifier (OpAmp) design has been common for its orderly current-to-speed tradeoff. However, for high-precision or high-linearity applications, increasing the current does not help much, as the supply voltage (V DD ) and intrinsic gain of the MOSFETs in ultra-scaled CMOS technologies are very limited. This paper introduces voltage-oriented circuit techniques to address such limitations. Specifically, a 2xV DD -enabled recycling folded cascade (RFC) OpAmp is proposed. It features: (1) current recycling to enhance the effective trans conductance by 4x with no extra power; (2) transistor stacking to boost the output resistance by one to two orders of magnitude; and (3) V DD elevating to enlarge the linear output swing by 4x. Comparing with its 1xV DD RFC and FC counterparts, the proposed solution achieves 20-dB higher DC gain (i.e. 72.8 dB) in open loop and 20-dB lower IM3 (i.e., -76.5 dB) in closed loop, under the same power budget of 0.6 mW in a 1-V General Purpose 65-nm CMOS process. In many applications, these joint improvements in a single stage are already adequate, being more power efficient (i.e. less current paths), stable (i.e. more phase margin), and compact (i.e. no frequency compensation) than multi-stage OpAmps. Voltage-conscious biasing and node-voltage trajectory check ensure the device reliability in both transient and steady states. No specialized high-voltage device is necessary.