• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.18 no.4
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• pp.15-21
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• 2004

The optical characteristics; luminous flux, correlated color temperature, and CIE -chromaticity coordinate etc., of HB LED(high brightness light emitting diode) of yellow/green/white SMD(surface mounted device) type were tested with integrating sphere photometer and monochromator, and the results were comparatively evaluated And, for the white LED, color rendering indices were considered to analyze.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.43 no.4 s.310
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• pp.45-52
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• 2006

In his paper, we have developed the SMD(surface mounted device) type PECL(positive emitter-coupled logic) VCXO of the $5{\times}7mm$ size for gratifying the requested specifications and the multilayer ceramic SMD(surface mounted device) package technology. The VCXO wired with the PECL(positive emitter coupled logic) package take place a stray inductance and a parasitic capacitance by the length and the inner pattern of the VCXO and the amplitude attenuation and signal loss due to the reflection of power source and the noise component. We have developed the Zig system to analyze the precise spectrum and evaluate the performance. The basic operating voltage is the 3.3 V and have the frequency range of 120MHz-180MHz. The Q factor is over 5K and it has the low jitter characteristics of 3.5 ps and low phase noise.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.04b
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• pp.6-7
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• 2008

The purpose of this study was to investigate heat resistance for union type SMD inductor core. The samples was produced with process 5 step. In this study, it analysis heat resistance of SMD(Surface Mounted Device) inductor core and it get electric field only exist inside of SMD core. Therefore electric fields do not affect any device and equipments. These results are very important to design data acquisition system(several test equipments such as temperature, impedance, and current test), because data acquisition system can place under the SMD Inductor core. So, it can be decrease their test error due to electric field.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.2A
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• pp.107-113
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• 2005

In this paper, we have developed the miniature ceramic PECL(positive emitter-coupled logic) VCXO of the $5{\times}7mm$ size for gratifying the requested specifications and the multilayer ceramic SMD(surface mounted device) package technology. The ceramic SMD PECL VCXO designed by the inverted Mesa type HFF is operating at the 3.3 Voltage and have the frequency range of 120MHz-180MHz. The Q factor is over 5K and it has the low jitter characteristics of 3.5 ps and low phase noise.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.11a
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• pp.221-221
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• 2006

The SMD type P-N junction diode with ceramic package for diode case were fabricated. It was made this diode with simple process from $Al_2O_3$ ceramic chip, solder preform, diode chip, coating reagent and conductive paste for chip terrmination. Its merit is small size, easy manufacture. fast cooling with ceramic case. The electric characteristics of the diode such as reverse recovery time, breakdown voltage, forward voltage, and leakage current were 5 28ns, 1322V, 1.08V, $0.45{\mu}A$.

• Journal of the Korean Ceramic Society
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• v.49 no.5
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• pp.432-437
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• 2012

Electrical properties of the laminated SMD-type PTC thermistor for microcircuit protection were investigated as a function of calcination and sintering temperature. $BaTiO_3$ with $Y_2O_3$ and $MnO_2$ were calcined at 1000 to $1150^{\circ}C$ for 2h and the laminated SMD-type PTC thermistor was sintered at 1350 to $1400^{\circ}C$ for 2h in a reduced atmosphere (1% $H_2/N_2$). Sintered density of the sample was dependent on the calcination and sintering temperature. Electrical properties of the sintered samples were strongly dependent on the densities of samples. For the samples with density below 4.6 g/$cm^3$, the insulator characteristics were observed, while PTC jump characteristics (R150/R30) were disappeared for the sample with density above 5.05 g/$m^3$. Optimal PTC characteristics were obtained for the sintered samples with density of 5.05 g/$m^3$. The laminated SMD-type PTC thermistor prepared by calcination at $1100^{\circ}C$ for 2h and sintering at $1270^{\circ}C$ for 2h showed the room temperature resistivity of $11{\Omega}{\cdot}cm$ and PTC jump characteristics of $10^2$ order.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.42 no.1
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• pp.23-31
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• 2005

Recently, the multimedia and high speed telecommunication systems needs a high frequency and high stability oscillator. The VCXO(voltage controlled -crystal oscillator) have continually downsized to gratify a thin and small size of the telecommunication systems. In his paper, we have developed the small ceramic PECL(positive emitter-coupled logic) VCXO of the 5×7 mm size for gratifying the requested specifications from user, and then use the multilayer ceramic SMD(surface mounted device) package technology. The ceramic SMD PECL VCXO is operating at the 3.3 Voltage and have the frequency range of 120MHz～180MHz. The Q factor is over 5K and it has the low jitter characteristics of 3.5 ps and low phase noise.

• Korean Journal of Materials Research
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• v.22 no.12
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• pp.658-663
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• 2012

The electrical properties of a laminated SMD type PTC thermistor for microcircuit protection were investigated as a function of polymer blowing agent addition. Green ceramics for multilayered $BaTiO_3$-based PTCRs were formed by doctor blade method of barium titanate powders; we successfully laminated the sintered ceramic chips to obtain 10 layer chip PTCRs with PTC effect. The sintered density increases with increasing sintering temperature. The electrical properties of the sintered samples were strongly dependent on the calcination and addition of a polymer blowing agent. When $BaTiO_3$ powders containing 0.2 mol% of $Y_2O_3$ were calcined at $1000^{\circ}C$ for 2 hrs, the resistivity jump was of 1-2 orders of magnitude. The resistivity at room temperature increases according to the polymer blowing agent addition. Also, the sample using the calcined powder showed a lower resistivity than that of the sample prepared using powders without calcinations. With an increase in the OBSH, the magnitude of the resistivity jumped as a function of the temperature increase. The resistivity of the sintered bodies after the addition of 0.5 wt% polymer blowing agent at $1290^{\circ}C$ for 2 h was shown to be about $8.5{\Omega}{\cdot}cm$; the jump order of the sintered bodies was shown to be on the order of $10^2$.

• Fire Science and Engineering
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• v.19 no.2 s.58
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• pp.75-80
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• 2005

This dissertation is about the development of PTC(Positive Temperature Coefficient) thermistor by composition method. A multilayer-type PTC samples were fabricated under optimal conditions after setting the experimental composition equation as $(0.90Ba+0.05Sr+0.05Ca)TiO_3+0.01TiO_3+0.01SiO_2+0.0008MnO_2+0.0018Nb_2O_5$ and their testing results were analyzed. The fabrication method of SMD(Surface Mounted Device) multilayer -type sample based on the composition ratio has the advantages in lowering its resistivity at room temperature, considerably, and increasing maximum current level, as needed. Although there is a disadvantage of peak resistivity drop by the multilayer, causing the increasement of thermal capacity. and thereby, increasing the switching delay time, a high applying voltage can increase the peak resistivity and shorten the switching delay time. The voltage-current characteristic showed that the more multilayers increased the initial maximum current and the transition voltage that increased the resistivity abruptly according to the curie point. The element it could be applied with the sensor for the fire detector.