Chirn Chye Boon

Design and Analysis of Ultra Low Power True Single Phase Clock CMOS 2/3 Prescaler

In this paper the power consumption and operating frequency of true single phase clock (TSPC) and extended true single phase clock (E-TSPC) frequency prescalers are investigated. Based on this study a new low power and improved speed TSPC 2/3 prescaler is proposed which is silicon verified. Compared with the existing TSPC architectures the proposed 2/3 prescaler is capable of operating up to 5 GHz and ideally, a 67% reduction of power consumption is achieved when compared under the same technology at supply voltage of 1.8 V. This extremely low power consumption is achieved by radically decreasing the sizes of transistors, reducing the number of switching stages and blocking the power supply to one of the D flip-flops (DFF) during Divide-by-2 operation. A divide-by-32/33 dual modulus prescaler implemented with this 2/3 prescaler using a chartered 0.18 ¿m CMOS technology is capable of operating up to 4.5 GHz with a power consumption of 1.4 mW.

A Subthreshold Low-Noise Amplifier Optimized for Ultra-Low-Power Applications in the ISM Band

The IEEE 802.15.4 standard relaxes the requirements on the receiver front-end making subthreshold operation a viable solution. The specification is discussed and guidelines are presented for a small area ultra-low-power design. A subthreshold biased low-noise amplifier (LNA) has been designed and fabricated for the 2.4-GHz IEEE 802.15.4 standard using a standard low-cost 0.18-mum RF CMOS process. The single-stage LNA saves on chip area by using only one inductor. The measured gain is more than 20 dB with an S11 of -19 dB while using 630 muA of dc current. The measured noise figure is 5.2 dB.

Design of a CMOS Broadband Transimpedance Amplifier With Active Feedback

In this paper, a novel current-mode transimpedance amplifier (TIA) exploiting the common gate input stage with common source active feedback has been realized in CHRT 0.18 ¿m -1.8 V RFCMOS technology. The proposed active feedback TIA input stage is able to achieve a low input impedance similar to that of the well-known regulated cascode (RGC) topology. The proposed TIA also employs series inductive peaking and capacitive degeneration techniques to enhance the bandwidth and the gain. The measured transimpedance gain is 54.6 dB¿ with a -3 dB bandwidth of about 7 GHz for a total input parasitic capacitance of 0.3 pF. The measured average input referred noise current spectral density is about 17.5 pA/¿{Hz} up to 7 GHz. The measured group delay is within 65 ± 10 ps over the bandwidth of interest. The chip consumes 18.6 mW DC power from a single 1.8 V supply. The mathematical analysis of the proposed TIA is presented together with a detailed noise analysis based on the van der Ziel MOSFET noise model. The effect of the induced gate noise in a broadband TIA is included.

A Wideband Low Power Low-Noise Amplifier in CMOS Technology

A T-coil network can be implemented as a high order filter for bandwidth extension. This technique is incorporated into the design of the input matching and output peaking networks of a low-noise amplifier. The intrinsic capacitances within the transistors are exploited as a part of the wideband structure to extend the bandwidth. Using the proposed topology, a wideband low-noise amplifier with a bandwidth of 3-8 GHz, a maximum gain of 16.4 dB and noise figure of 2.9 dB (min) is achieved. The total power consumption of the wideband low-noise amplifier from the 1.8 V power supply is 3.9 mW. The prototype is fabricated in 0.18 ¿m CMOS technology.

A 57.9-to-68.3 GHz 24.6 mW Frequency Synthesizer With In-Phase Injection-Coupled QVCO in 65 nm CMOS Technology

A fully integrated 60 GHz frequency synthesizer with an in-phase injection-coupled quadrature voltage-controlled oscillator (IPIC-QVCO) is proposed. Through a particular symmetrical coupling network formed by diode-connected transistors, the in-phase coupling is realized in the IPIC-QVCO, which reduces both phase noise and phase error. A compact inductor-less divider chain is designed to reduce power consumption. A self-correcting low spur charge pump is employed to reduce reference spur. A standalone 60 GHz IPIC-QVCO and a fully integrated PLL are implemented in standard 65 nm low power CMOS technology. The measurement results show that the QVCO covers a frequency range from 57.88 to 68.33 GHz while consuming 11.4 mW power from a 1.2 V supply. The phase noise of the QVCO is -92 ~ -95 dBc/Hz at 1 MHz offset. The FOM and FOM T of the QVCO are -178.1 ~ -179.7 and -182.5 ~ -184.1 dBc/Hz respectively. The tuning range of the frequency synthesizer is from 57.9 to 68.3 GHz, and the power consumption is 24.6 mW. The phase noise of the frequency synthesizer is -89.8 ~ -91.5 dBc/Hz at 1 MHz offset across the frequency band.

An Energy-Aware CMOS Receiver Front End for Low-Power 2.4-GHz Applications

A receiver front end designed in 0.18- μm CMOS consisting of a low-noise amplifier and IQ mixers is presented. The front ends power consumption is controllable from 5.0 down to 1.4 mA. It is proposed to push the receiver requirements to the front end in order to efficiently control the overall power consumption based on the real-time required noise performance. We show that, under good channel conditions, this front end can save up to 70% of its nominal power consumption.

A Low-Power Single-Phase Clock Multiband Flexible Divider

In this paper, a low-power single-phase clock multiband flexible divider for Bluetooth, Zigbee, and IEEE 802.15.4 and 802.11 a/b/g WLAN frequency synthesizers is proposed based on pulse-swallow topology and is implemented using a 0.18-μm CMOS technology. The multiband divider consists of a proposed wideband multimodulus 32/33/47/48 prescaler and an improved bit-cell for swallow (S) counter and can divide the frequencies in the three bands of 2.4-2.484 GHz, 5.15-5.35 GHz, and 5.725-5.825 GHz with a resolution selectable from 1 to 25 MHz. The proposed multiband flexible divider is silicon verified and consumes power of 0.96 and 2.2 mW in 2.4- and 5-GHz bands, respectively, when operated at 1.8-V power supply.

Cell-Based Variable-Gain Amplifiers With Accurate dB-Linear Characteristic in 0.18 µm CMOS Technology

A simple and robust “cell-based” method is presented for the design of variable-gain amplifiers (VGAs). The proposed unit cell utilizes a unique gain compensation method and achieves accurate dB-linear characteristic across a wide tuning range with low power consumption and wide bandwidth. Several such highly dB-linear unit cells can be cascaded to provide the required gain range for a VGA. To prove the concept, single-cell, 5-cell, 10-cell and 15-cell reconfigurable VGAs were fabricated in a standard 0.18 μm CMOS technology. The measurement results show that the 10-cell VGA achieves a gain range of 38.6 dB with less than 0.19 dB gain error. The 15-cell VGA can either be used as reconfigurable VGA for analog control voltage or tunable PGA for digital control stream, with the flexibility of scaling gain range, gain error/step and power consumption. For the VGA at highest gain setting, it consumes 1.12 mW and achieves a gain range of 56 dB, gain error less than 0.3 dB.

Fully integrated CMOS fractional-N frequency divider for wide-band mobile applications with spurs reduction

A spurs reduction fractional-N frequency divider with a frequency range which is 3.5 times larger than that of a conventional fractional-N divider is presented in this paper. A 1.2-GHz quadrature voltage-controlled oscillator (VCO) is designed as the input source of the frequency divider. The circuit was fabricated using the 0.25-/spl mu/m CMOS technology. The power consumption of the frequency divider and the quadrature VCO are 3 and 6 mW, respectively, at a 2-V supply.

A 57.9-to-68.3GHz 24.6mW frequency synthesizer with in-phase injection-coupled QVCO in 65nm CMOS

Under the influence of increasing demand for high-data-rate communication systems such as 60GHz band applications, the requirements of PLLs keep getting higher. In a mm-Wave direct-conversion transceiver, the quadrature LO signal generation is challenging. The conventional techniques to generate quadrature LO signals suffer from many problems. The method of using a divide-by-2 divider after a VCO with double LO frequency is popular in multi-GHz designs, but it is difficult to be realized at mm-Wave frequencies. Employing passive RC complex filters is another way to generate quadrature signals, but high power is required to compensate its loss. The conventional parallel-coupled QVCO seems to be a good choice for mm-Wave application. However, the approach suffers from poor phase noise. This work presents a fully integrated 57.9-to-68.3GHz frequency synthesizer, which employs an in-phase injection-coupled QVCO (IPIC-QVCO) to produce low-phase-noise quadrature signals with low power.