Low-power and area-optimized VLSI implementation of AES coprocessor for Zigbee system

A 10-bit 10MS/s low power consumption successive approximation register (SAR) analog-to-digital converter (ADC) using a straightforward capacitive digital-to-analog converter (DAC) is presented in this paper. In the proposed capacitive DAC, switching is always straightforward, and its value is half of the peak-to-peak voltage in each step. Also the most significant bit (MSB) is decided without any switching power consumption. The application of the straightforward switching causes lower power consumption in the structure. The input is sampled at the bottom plate of the capacitor digital-to-analog converter (CDAC) as it provides better linearity and a higher effective number of bits. The comparator applies adaptive power control, which reduces the overall power consumption. The differential prototype SAR ADC was implemented with 0.18μm complementary metal-oxide semiconductor (CMOS) technology and achieves an effective number of bits (ENOB) of 9.49 at a sampling frequency of 10MS/s. The structure consumes 0.522mW from a 1.8V supply. Signal to noise-plus-distortion ratio (SNDR) and spurious free dynamic range (SFDR) are 59.5 dB and 67.1 dB and the figure of merit (FOM) is 95 fJ/conversion-step.

In this paper the performance evaluation of operational amplifier (Opamp) is carried out in reference to the advantages of high supply rejection in 0.18µm CMOS (complementary metal oxide semiconductor) technology. This evaluation is carried out with Miller Compensation. This process involves nine step procedure in which various parameter such as transconductance, W/L ratio, beta, various current is evaluated. This process is carried out in SPICE platform using Tanner EDA tool. Miller compensation technique is used because with it a reduction in the compensation capacitor size is observed. It further reduces design area and improves the phase margin from the left hand plane zero.

A 19 mW highly integrated GPS receiver with a ΣΔfractional-N synthesizer is presented in this paper. Fractional-N frequency synthesizer architecture was adopted in this work, to provide more degrees of freedom in the synthesizer design. A high linearity low noise amplifier (LNA) is integrated into the chip. The radio receiver chip was fabricated in a 0.18 μm complementary metal oxide semiconductor (CMOS) process and packaged in a 48-pin 2 mm×2 mm land grid array chip scale package. The chip consumes 19 mW (LNA1 excluded) and the LNA1 6.3 mW. Measured performances are: noise figure<2 dB, channel gain=108 dB (LNA1 included), image rejection>36 dB, and −108 dBc/Hz @ 1 MHz phase noise offset from the carrier. The carrier noise ratio (C/N) can reach 41 dB at an input power of −130 dBm. The chip operates over a temperature range of [−40, 120] °C and ±5% tolerance over the CMOS technology process.

The tunneling magnetoresistance micro-sensors (TMR) developed by magnetic multilayer material has many advantages, such as high sensitivity, high frequency response, and good reliability. It is widely used in military and civil fields. This work presents a high-performance interface circuit for TMR sensors. Because of the nonlinearity of signal conversion between sensitive structure and interface circuit in feedback loop and forward path, large harmonic distortion occurs in output signal spectrum, which greatly leads to the reduction of SNDR (signal noise distortion rate). In this paper, we analyzed the main source of harmonic distortion in closed-loop detection circuit and establish an accurate harmonic distortion model in TMR micro-sensors system. Some factors are considered, including non-linear gain of operational amplifier unit, effective gain bandwidth, conversion speed, nonlinearity of analog transmission gate, and nonlinearity of polycrystalline capacitance in high-order sigma-delta system. We optimized the CMOS switch and first-stage integrator in the switched-capacitor circuit. The harmonic distortion parameter is optimally designed in the TMR sensors system, aiming at the mismatch of misalignment of front-end system, non-linearity of quantizer, non-linearity of capacitor, and non-linearity of analog switch. The digital output is attained by the interface circuit based on a low-noise front-end interface circuit and a third-order sigma-delta modulator. The digital interface circuit is implemented by 0.35μm CMOS (complementary metal oxide semiconductor) technology. The high-performance digital TMR sensors system is implemented by double chip integration and the active interface circuit area is about 3.2 × 2 mm. The TMR sensors system consumes 20 mW at a single 5 V supply voltage. The TMR sensors system can achieve a linearity of 0.3% at full scale range (±105 nT) and a resolution of 0.25 nT/Hz1/2(@1Hz).

The objective of this work was to design a versatile readout circuit for patch-type wearable devices consisting of a Transimpedance Amplifier (TIA). The TIA performs Current to Voltage (I–V) conversion, the most widely used technique for amperometry and impedance measurement for various types of electrochemical sensors. The proposed readout circuit employs a digitally controllable feedback resistor (Rf) technique in the TIA to improve accuracy, which can be utilized in a variety of electrochemical sensors within a current range of 0.1 µA–100 µA. It is designed to accommodate multiple sensors simultaneously to track multiple target analytes for high accuracy and versatile usage. The readout circuit consists of low power operational amplifier (op–amp) and digital circuit blocks, is designed and fabricated with Magna 0.18 µm Complementary Metal Oxide Semiconductor (CMOS) technology, which provides low power consumption and a high degree of integration. The design has a small size of 0.282 mm2 and low power consumption of 0.38 mW with a 3.3 V power supply, which are desirable factors in wearable device applications.

A folded Gilbert cell mixer was implemented in 0.13 μm complementary metal oxide semiconductor (CMOS) technology. The downconversion mixer is designed for 5---6 GHz radio frequency (RF) band and an intermediate frequency (IF) of 500 MHz. A voltage conversion gain (CG) of 9 dB, a noise figure (NF) of 11 dB and an IIP3 of 2 dBm were demonstrated experimentally under very low power consumption conditions, only 4.2 mW for the mixer core. Considering the overall performance of the circuit, this paper shows that the folded mixer architecture is one of the most interesting frequency converter solutions for low-power mobile applications.

In this work, an efficient technique of clock and power gating is concurrently introduced in finite state machines (FSM) with a view to minimising the overall power dissipation. The proposed power gating concept works on the principle of shutting down the power supply to the FSM during periods of inactivity. The extraction of the inactivity criteria is based on the occurrence of self-loops within the FSM or an unchanged FSM output between successive clock pulses. Clock gating, on the other hand, disables the clock signal to the sequential blocks of the FSM during this inactive/idle periods. The idea of implementing the gating in both the state logic as well as output logic is introduced in this work. The proposed approach has been introduced in three benchmark FSM circuits, simulated and synthesised in Cadence digital design tool. The results indicate a maximum of 73% total power savings (dynamic and static) with an average penalty of 27% area (approx.).

This paper presents a 6 Gb/s 4-channel arrayed transimpedance amplifiers (TIA) with the gain control for 4-channel passive optical network in 0.13 ㎜ complementary metal oxide semiconductor (CMOS) technology. A regulated cascode input stage and inductive-series peaking are proposed in order to increase the bandwidth. Also, a variable gain control is implemented to provide flexibility to the overall system. The TIA has a maximum 98.1 ㏈Ω gain and an input current noise level of about 37.8 ㎀/㎐. The die area of the fabricated TIA is 1.9 ㎜ x 2.2 ㎜ for 4-channel. The power dissipation is 47.64 ㎽/1ch.

Direct conversion receiver (DCR) architecture is a promising candidate in the radio frequency (RF) front end because of its low power consumption, low cost and ease of integration. However, flicker noise and direct current (DC) offset are large issues. Owing to the local oscillator (LO) frequency, which is half of the RF frequency, and the absence of a DC bias current that introduces no flicker noise, the subharmonic passive mixer (SHPM) core topology front end overcomes the shortcoming effectively. When more and more receivers (RX) and transmitters (TX) are integrated into one chip, the linearity of the receiver front end becomes a very important performer that handles the TX and RX feedthrough. Another reason for the requirement of good linearity is the massive electromagnetic interference that exists in the atmosphere. This paper presents a linearity-improved RF front end with a feedforward body bias (FBB) subharmonic mixer core topology that satisfies modern RF front end demands. A novel complementary derivative superposition (DS) method is presented in low noise amplifier (LNA) design to cancel both the third- and second-order nonlinearities. To the best knowledge of the authors, this is the first time FBB technology is used in the SHPM core to improve linearity. A Volterra series is introduced to provide an analytical formula for the FBB of the SHPM core. The design was fabricated in a 0.13 μm complementary metal oxide semiconductor (CMOS) process with a chip area of 750 μm × 1270 μm. At a 2.4 GHz working frequency, the measurement result shows a conversion gain of 36 dB, double side band (DSB) noise figure (NF) of 6.8 dB, third-order intermodulation intercept point (IIP3) of 2 dBm, LO–RF isolation of 90 dB and 0.8 mW DC offset with 14.4 mW power consumption at 1.2 V supply voltage. These results exhibit better LO–RF feedthrough and DC offset, good gain and NF, moderate IIP3 and the highest figure of merit compared to the state-of-the-art publications.

ABSTRACTThe rapid growth of scaling and integration of nano-scale digital circuits is hardly tracked by the analog circuits which require additional passive components for fabrication. Mixed-signal Complementary Metal Oxide Semiconductor (CMOS) technologies are released with some delays after digital CMOS technologies, due to the issues related to integration of analog components. This urges the designers to consider using the same digital CMOS technology for integration of advanced analog circuits like continuous-time filters. As such, this article presents an area-efficient Gm–C filter made from MOS devices only. Instead of classical metal–insulator–metal capacitors, the proposed filter exploits the available compact-size MOS devices as capacitor. This modification makes the filter design compatible to any low-cost digital CMOS process. Besides, the 3-dB cut-off frequency of the filter can now be changed by varying the size of MOS capacitors. The effectiveness of the new design approach is validated through simulation of a fifth-order elliptic low-pass filter with a cut-off frequency of 1 MHz in 90-nm CMOS technology. The new filter dissipates around 115 µW from a 1.0 V power supply, and the sensitivity of its cut-off frequency is kept as low as 6% over various process and temperature corners.

This paper proposes an area and power efficient frequency divider used in frequency synthesisers, which operates in 2.4 GHz IEEE 802.15.4/ZigBee frequency band. The proposed frequency divider consists of a multi-modulus pre-scaler and integrated P&S counter. In order to reduce the power consumption and area, swallow counter has been replaced by a simple digital circuit. Simulation results show 30% of area and power is reduced when compared to the previous design. All of the circuits can be designed in 0.18 µm complementary metal oxide semiconductor technology with a single 1.8 V DC voltage supply.

In today’s technology, optical networking plays a vital role in reducing data losses, thereby providing higher data rates between the transreceivers. The very large scale integration circuits in the modulator–demodulator (MODEM) usually fabricated using complementary metal oxide semiconductor (CMOS) technology have serious scaling limitations; hence, device scaling beyond 65 nm technology becomes highly challenging. Quantum-dot cellular automata (QCA) is one of the most promising nanotechnologies that enable areas of smaller size, i.e. 60% less design area than the CMOS technology, with capability to produce high speed by taking less cycles compared with the other CMOS designs to reduce scaling issues. The QCA-based designs are considered as the best alternative solutions to the transistor-based (CMOS) designs. This paper deals with the implementation of the logic gates NOT, AND, OR, NAND, NOR, XOR and XNOR using both CMOS and QCA technologies, while the QCA allows more possible design structures for each logic gate to enable optimization of the area. Finally, the proposed QCA-based logic gate design and CMOS-based designs are compared in terms of the design area, cell count and the speed of the designs. QCA designer 2.0.3 and virtuoso CADENCE Computer-Aided Design tools are used for carrying out the work.

A multi-algorithm Crypto-Co-Processor called Celator is presented. Celator architecture is based on a 4times4 Processing Elements systolic array, a Sequencer with a Finite State Machine (FSM) and a local memory, the Celator RAM (CRAM). Data are encrypted or decrypted by the PE array. The whole system architecture around Celator includes a Central Processing Unit (CPU) and an Interface unit between the CPU and Celator. The Sequencer controls the PE array and manages all the data transfers between the PE array and the CPU. Three multiplexers per PE allow the reconfigurability of the data path. The FSM instructions are stored in the CRAM and can be changed by the CPU: therefore the FSM is also reconfigurable. This paper focuses on the implementation of the Advanced Encryption Standard (AES) transformations on Celator. Celator can perform an AES encryption in 580 clock cycles in Electronic Codebook mode, which is less than with a general purpose processor. Finally we report performance comparisons among Celator, ARM 7 TDMI, ARM 9 and AVR microprocessors, as well as with some AES dedicated and dynamically reconfigurable circuits.

This letter introduces a method to optimize the temperature offset drift and noise efficiency factor (NEF) for chopper and auto-zero instrumentation amplifiers. In order to optimize offset drift and NEF, our proposed amplifier exploits a threshold voltage (Vth) tracking reference. A prototype of the proposed amplifier was fabricated using a standard 0.35μm complementary metal oxide semiconductor technology and occupies 0.174 mm2. Using the Vth tracking reference, an offset drift of 80 nV/℃ is achieved. The measured NEF was 2.45 with a supply current of 1.1 mA.

In this study, a high‐frequency floating‐type memristor emulator has been presented. The proposed emulator circuit uses a current conveyor transconductance amplifier, second generation current conveyor, three resistors and a grounded capacitor. The presented floating‐type memristor can be configured in both incremental and decremental configurations and performs well up to 5 MHz. The equivalent memristor equation is verified by theoretical analysis of the proposed circuit which also includes non‐ideal analysis. The theoretical proposition has been verified through personal simulation program with integrated circuit emphasis simulations using TSMC 0.25 μm complementary metal oxide semiconductor technology parameters. Moreover, non‐volatility and Monte Carlo simulation have been performed to check the robustness of the circuit. The effectiveness of the presented memristor emulator design has been verified by printed circuit board prototype using commonly available integrated circuits AD844 and CA3080. The experimental results are included, which show good agreement with the theoretical and simulation results. To test the functionalities of the proposed designs, their applications as parallel and serial combinations, high‐pass filter and Chua's oscillator have been presented.