• Journal of the Institute of Electronics Engineers of Korea SD
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• v.48 no.1
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• pp.22-30
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• 2011

In this paper, we propose a memory efficient multi-rate Low Density Parity Check (LDPC) decoder for China Mobile Multimedia Broadcasting (CMMB). We find the best trade-off between the performance and the circuit area by designing a partially parallel decoder which is capable of passing multiple messages in parallel. By designing an efficient address generation unit (AGU) with an index matrix, we could reduce both the amount of memory requirement and the complexity of computation. The proposed regular LDPC decoder was designed in Verilog HDL and was synthesized by Synopsys' Design Compiler using Chartered $0.18{\mu}m$ CMOS cell library. The synthesized design has the gate size of 455K (in NAND2). For the two code rates supported by CMMB, the rate-1/2 decoder has a throughput of 14.32 Mbps, and the rate-3/4 decoder has a throughput of 26.97 Mbps. Compared with a conventional LDPC for CMMB, our proposed design requires only 0.39% of the memory.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.12B
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• pp.1380-1386
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• 2009

In this paper, we propose a CQS(Calendar Queue Scheduler) architecture which was designed for processing multimedia and timing traffic in home network. With various characteristics of the increased traffic flowed in home such as VoIP, VOD, IPTV, and Best-efforts traffic, the needs of managing QoS(Quality of Service) are being discussed. Making a group regarding application or service is effective to guarantee successful QoS under the restricted circumstances. The proposed design is aimed for home gateway corresponding to the end points of receiver on end-to-end QoS and eligible for supporting multimedia traffic within restricted network sources and optimizing queue sizes. Then, we simulated the area for each module and each memory. The area for each module is referenced by NAND($2{\times}1$) Gate(11.09) when synthesizing with Magnachip 0.18 CMOS libraries through the Synopsys Design Compiler. We verified the portion of memory is 85.38% of the entire CQS. And each memory size is extracted through CACTI 5.3(a unit in mm2). According to the increase of the memory’sentry, the increment of memory area gradually increases, and defining the day size for 1 year definitely affects the total CQS area. In this paper, we discussed design methodology and operation for each module when designing CQS by hardware.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.48 no.10
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• pp.72-81
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• 2011

In this paper, we proposed and designed a novel floating point converter which supports single and double precisions of IEEE754 standard. The proposed convertor supports conversions between floating point number single/double precision and signed fixed point number(32bits/64bits) as well as conversions between signed integer(32bits/64bits) and floating point number single/double precision and conversions between floating point number single and double precisions. We defined a new internal format to convert various input types into one type so that overflow checking could be conducted easily according to range of output types. The internal format is similar to the extended format of floating point double precision defined in IEEE754 2008 standard. This standard specifies that minimum exponent bit-width of the extended format of floating point double precision is 15bits, but 11bits are enough to implement the proposed converting unit. Also, we optimized rounding stage of the convertor unit so that we could make it possible to operate rounding and represent correct negative numbers using an incrementer instead an adder. We designed single cycle data path and 5 cycles data path. After describing the HDL model for two data paths of the convertor, we synthesized them with TSMC 180nm technology library using Synopsys design compiler. Cell area of synthesis result occupies 12,886 gates(2 input NAND gate), and maximum operating frequency is 411MHz.

• JSTS:Journal of Semiconductor Technology and Science
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• v.6 no.3
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• pp.154-161
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• 2006

This paper describes the new types of ngative differential resistance (NDR) IC applications which use a monolithic quantum-effect device technology based on the RTD/HBT heterostructure design. As a digital IC, a low-power/high-speed MOBILE (MOnostable-BIstable transition Logic Element)-based D-flip flop IC operating in a non-return-to-zero (NRZ) mode is proposed and developed. The fabricated NRZ MOBILE D-flip flop shows high speed operation up to 34 Gb/s which is the highest speed to our knowledge as a MOBILE NRZ D-flip flop, implemented by the RTD/HBT technology. As an analog IC, a 14.75 GHz RTD/HBT differential-mode voltage-controlled oscillator (VCO) with extremely low power consumption and good phase noise characteristics is designed and fabricated. The VCO shows the low dc power consumption of 0.62 mW and good F.O.M of -185 dBc/Hz. Moreover, a high-speed CML-type multi-functional logic, which operates different logic function such as inverter, NAND, NOR, AND and OR in a circuit, is proposed and designed. The operation of the proposed CML-type multi-functional logic gate is simulated up to 30 Gb/s. These results indicate the potential of the RTD based ICs for high speed digital/analog applications.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.4A
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• pp.447-457
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• 2004

This paper proposes a RSA crypto-processor for embedded systems. The architecture of the RSA crypto-processor should be used relying on Big Montgomery algorithm, and is supported by configurable bit size. The RSA crypto-processor includes a RSA control signal generator, an optimal Big Montgomery processor(adder, multiplier). We use diverse arithmetic unit (adder, multiplier) algorithm. After we compared the various results, we selected the optimal arithmetic unit which can be connected with ARM core-processor. The RSA crypto-processor was implemented with Verilog HDL with top-down methodology, and it was verified by C language and Cadence Verilog-XL. The verified models were synthesized with a Hynix 0.25${\mu}{\textrm}{m}$, CMOS standard cell library while using Synopsys Design Compiler. The RSA crypto-processor can operate at a clock speed of 51 MHz in this worst case conditions of 2.7V, 10$0^{\circ}C$ and has about 36,639 gates.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.27 no.10
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• pp.917-925
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• 2016

Schmitt Trigger logic is a gate level design method to have hysteresis characteristics to improve noise immunity in digital circuits. Dynamic Threshold voltage MOS(DTMOS) Schmitt trigger circuits can improve noise immunity without adding additional transistors but by controlling substrate bias. The performance of DTMOS Schmitt trigger logic has not been verified yet in standard CMOS process through measurement. In this paper, DTMOS Schmitt trigger logic was implemented and verified using Magna $0.18{\mu}m$ MPW process. DTMOS Schmitt trigger buffer, inverter, NAND, NOR and simple digital logic circuits were made for our verification. Hysteresis characteristics, power consumption, and delay were measured and compared with common CMOS logic gates. EM Immunity enhancement was verified through Direct Power Injection(DPI) noise immunity test method. DTMOS Schmitt trigger logics fabricated using CMOS process showed a significantly improved EM Immunity in 10 M~1 GHz frequency range.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.122-122
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• 2008

Recently, Metal/Alumina/Silicon-Nitride/Silicon-Oxide/Silicon (MANOS) structures are one of the most attractive candidates to realize vertical scaling of high-density NAND flash memory [1]. However, as ANO layers are miniaturized, negative and positive bias temperature instability (NBTI/PBTI), such as the flat band voltage shift, ${\Delta}V_{FB}$, the interfacial trap density increase, ${\Delta}D_{it}$, the gate leakage current, ${\Delta}I_G$. and the retention characteristics, in MONOS capacitors, becomes an important issue in terms of reliability. It is well known that tunnel oxide degradation is a result of the oxide and interfacial traps generation during FN (Fowler-Nordheim) stress [2]. Because the bias temperature stress causes an increase of both interfacial-traps and fixed oxide charge could be a factor, witch can degrade device reliability during the program and erase operation. However, few studies on NBTI/PBTI have been conducted on improving the reliability of MONOS devices. In this work, we investigate the effect of post-annealing gas on bias temperature instability (BTI), such as the flat band voltage shift, ${\Delta}V_{FB}$, the interfacial trap density shift, ${\Delta}I_G$ retention characteristics, and the gate leakage current characteristics of MANOS capacitors. MANOS samples annealed at $950^{\circ}C$ for 30 s by a rapid thermal process were treated via additional annealing in a furnace, using annealing gases $N_2$ and $N_2-H_2$ (2 % hydrogen and 98 % nitrogen mixture gases) at $450^{\circ}C$ for 30 min. MANOS samples annealed in $N_2-H_2$ ambient had the lowest flat band voltage shift, ${\Delta}V_{FB}$ = 1.09/0.63 V at the program/erase state, and the good retention characteristics, 123/84 mV/decade at the program/erase state more than the sample annealed at $N_2$ ambient.