Moo Young Kim

10-bit 100-MS/s Pipelined ADC Using Input-Swapped Opamp Sharing and Self-Calibrated V/I Converter

A 31 mW, 10-bit 100-MS/s pipelined analog-to-digital converter (ADC), which alleviates the memory effect occurring in the opamp-sharing technique, and automatically corrects the current error of the V/I converter, has been developed. The proposed ADC achieves low-power consumption, high noise immunity, and has a small area, by employing an input-swapped opamp-sharing technique that switches the summing node in an multiplying digital-to-analog converter and a V/I converter with a process, supply voltage, and temperature condition detector. The ADC shows a differential nonlinearity of less than 0.48 LSB, and an integral nonlinearity of less than 0.95 LSB. Also, an signal-to-noise-and-distortion ratio of 56.2 dB is measured with a 1 MHz input frequency. This has been implemented in a 0.18-μm CMOS process, and occupies 1.6 × 0.8 mm2 of active area.

A 0.004-mm

A portable multiphase clock generator capable of adjusting its clock phase according to input clock frequencies has been developed. It consists of a full-digital CMOS circuit that leads to a simple, robust, and portable IP. One-cycle lock time enables clock-on-demand circuit structures. The implemented low power clock generator tile occupies only 0.004mm2 and operates at variable input frequencies ranging from 625MHz to 1.2GHz

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A portable multiphase clock generator, independent of input duty ratio, has been developed. The proposed open-loop and full-digital architecture has a fast lock time of two clock cycles and is a simple, robust and portable IP. In addition, the complementary delay line is implemented to achieve high phase resolution at a wide frequency range. The generator has been implemented in a 0.18 um CMOS process and operates at variable input frequencies ranging from 800 MHz to 1.6 GHz.

Portable Multiphase Clock Generator Tile for 1.2-GHz RISC Microprocessor

A DLL-based clock generator for dynamic frequency scaling is fabricated in a 0.35 /spl mu/m CMOS technology. It generates clock signals ranging from 120MHz to 1.8GHz. The frequency can be dynamically changed. If the clock generator scales its output frequency dynamically by programming with the same last bit, it takes only one clock cycle to lock. The proposed clock generator has a jitter of /spl plusmn/6.6ps/sub pp/ at 1.3GHz.

A Low-Jitter Open-Loop All-Digital Clock Generator With Two-Cycle Lock-Time

A current source with a small current error has been proposed to maintain the bandwidth of the system without an increase in power consumption for a margin. It minimizes the current error under process, supply voltage, and temperature (PVT) variations. Because the on-resistance of the nMOS array is self-calibrated digitally by an on-chip digital PVT detector, a current error of only ±2% is achieved. The current source has been implemented in an 80-nm CMOS process, occupies 0.018 mm2 and consumes 94.9 μW at a supply voltage of 1.0 V.

A CMOS DLL-based 120MHz to 1.8GHz clock generator for dynamic frequency scaling

A portable multiphase clock generator capable of adjusting its clock phase according to input clock frequencies has been developed. It consists of a full-digital CMOS circuit that leads to a simple, robust, and portable IP. One-cycle lock time enables clock-on-demand circuit structures. The implemented low power clock generator tile occupies only 0.004mm2 and operates at variable input frequencies ranging from 625MHz to 1.2GHz

PVT Variation Tolerant Current Source With On-Chip Digital Self-Calibration

A portable clock generator, which solves the duty ratio and jitter problems of the input clock, has been developed. In the proposed clock generator, the complementary delay line generates a series of multiphase clocks. The 0-to-1 transition detector finds the 2 pi phase delayed position among the multiphase clocks produced by the complementary delay line, and then, the select signal generator chooses the proper path to generate the delayed output clock. As a result, the proposed open-loop and full-digital architecture achieves a fast lock time of two clock cycles. Also, it is a simple, robust and portable IP and consumes only 17 mW at an input clock frequency of 1.6 GHz. In addition, a complementary delay line is implemented to achieve high phase resolution over a wide frequency range. The proposed clock generator is implemented in a 0.18-mum CMOS process and, occupies an active area of 170 mum times 120 mum. Also, it operates at various input frequencies ranging from 800 MHz to 1.6 GHz.

A 0.004mm/sup 2/ Portable Multiphase Clock Generator Tile for 1.2GHz RISC Microprocessor

A 6-bit, 1.6-GS/s, flash ADC with a low-power architecture is presented. The proposed low-power architecture based on an analog input pre-processing method reduces the total number of comparators to almost two-thirds of that required in a conventional 6-bit, flash ADC. The advantages of the analog input pre-processing method include the low power consumption and small area due to the reduced number of comparators. The proposed flash ADC consumes 240mW at a supply voltage of 1.8V when implemented in a 0.18-µm CMOS technology. The simulated SNDR is 32dB at an input frequency of 200MHz.

A Low-Jitter Open-Loop All-Digital Clock Generator with 2 Cycle Lock-Time

A 31 mW, 10-bit 100 MS/s pipelined ADC has been developed. The proposed ADC achieves low power consumption, high noise immunity, and small area by employing a new opamp sharing technique that switches the summing node in an MDAC and a current source with a PVT condition detector. The ADC shows a DNL of less than 0.48 LSB and an INL of less than 0.95 LSB. Also, a SNDR of 56.2 dB is measured with a 1 MHz input frequency. It has been implemented in a 0.18 um CMOS process and it occupies 1.6 x 0.8 mm2 of active area.

Low-power architecture for A 6-bit 1.6GS/s flash A/D converter

In many VLSI chips, the power dissipation of the clocking system that includes clock distribution network and flip-flops is often the largest portion of total chip power consumption. In the near future, this portion is likely to dominate total chip power consumption due to higher clock frequency and deeper pipeline design trend. Traditionally, two approaches have been used: (1) to reduce power consumption in the clock tree, several low-swing clock flip-flops and double-edge flip-flops have been introduced; (2) to reduce power consumption in flip-flops, conditional capture, clock-on-demand, data-transition look-ahead techniques have been developed. Recently, pulsed latch type flip-flops are introduced in several high-performance microprocessors to reduce E × D. In this paper, these flip-flops are described with their pros and cons. Then, a new circuit technique is described along with simulation results. The proposed pulsed latch reduces E × D by 82.6% to 95.4% compared to conventional flip-flops.