• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.22 no.7
• /
• pp.729-736
• /
• 2011

In this paper, we propose a varactor-diodeless voltage-controlled oscillator operating at X-band, and verify the possibility of applying to a receiver for microwave radar signal detection applications. The proposed VCO is realized by only single RF BJT device as a varactor diode is substitued by a intrinsic collector-base PN-junction of the active device which is used to generate negative resistance. The fabricated VCO meets the specification of the receiver, which has a 11.20~11.75 GHz tuning bandwidth with respect to the tuning voltage, 1.0~7.0 V, output power of 9.0~12.0 dBm and linear frequency tuning performance.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2016.05a
• /
• pp.775-777
• /
• 2016

In this paper presents an analysis of pulsed radiation effects of unit devices. Unit devices are the nMOSFET, pMOSFET, NPN Transistor and those fabricated by the 0.18um CMOS process. Pulsed radiation test results in nMOSFET, the photocurrent of tens nA was generated in $2.07{\times}10^8rad(si)/s$. For the pMOSFET, a photocurrent generation was not observed in $3{\times}10^8rad(si)/s$. For the NPN transistor, the photocurrent was generated with about 1uA. Therefore, the MOSFET must be used than BJT transistor when radhard IC design.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.45 no.3
• /
• pp.54-59
• /
• 2008

A highly accurate wide swing BiCMOS cascode current mirror is proposed. It uses the base-current compensated BJT current mirror. It increases both output impedance and output voltage range by using the npn-NMOS cascode instead of the NMOS-NMOS cascode. The npn transistor copies the input current and the NMOS transistor increases the output impedance for the accurate current mirroring. The proposed current mirror achieves highly constant current for wide output voltage range. Simulation results were verified with measurements performed on a fabricated chip using a 5/16V 0.5um BCD process. It has only $-2.5%{\sim}1.0%$ current error for $0.3V{\sim}16V$ output voltage range.

• Journal of Sensor Science and Technology
• /
• v.24 no.5
• /
• pp.353-357
• /
• 2015

A new SPICE-compatible model for a gate/body-tied PMOSFET photodetector (GBT PD) with an overlapping control gate is presented. The proposed SPICE-compatible model of a GBT PD with an overlapping control gate makes it possible to control the photocurrent. Research into GBT PD modeling was proposed previously. However, the analysis and simulation of GBT PDs is not lacking. This SPICE model concurs with the measurement results, and it is simpler than previous models. The general GBT PD model is a hybrid device composed of a MOSFET, a lateral bipolar junction transistor (BJT), and a vertical BJT. Conventional SPICE models are based on complete depletion approximation, which is more applicable to reverse-biased p-n junctions; therefore, they are not appropriate for simulating circuits that are implemented with a GBT PD with an overlapping control gate. The GBT PD with an overlapping control gate can control the sensitivity of the photodetector. The proposed sensor is fabricated using a $0.35{\mu}m$ two-poly, four-metal standard complementary MOS (CMOS) process, and its characteristics are evaluated.

• Journal of IKEEE
• /
• v.23 no.1
• /
• pp.338-341
• /
• 2019

In this paper, we propose a novel ESD device with improved characteristics of LVTSCR, which is a representative ESD protection device, and verify the N-stack technology for design optimized for each required voltage of a specific application. The characteristics of the holding voltage and the trigger voltage, which are the main parameters, are examined and the temperature characteristic, which is an indicator of the tolerance characteristic, is also verified. well region and a parasitic NPN to form a series-connected structure. We used synopsys' T-cad simulation tool for characterization.

• Journal of IKEEE
• /
• v.26 no.3
• /
• pp.520-523
• /
• 2022

In this paper, an ESD protection device with a simpler structure than the existing ESD protection device is proposed. The proposed new structure operates an additional NPN parasitic bipolar transistor by adding an N+ diffusion region and connecting it to the bridge region, thereby lowering the current gain. As a result, it was confirmed that the proposed ESD protection device has a trigger voltage of 10.8V and a holding voltage of 6.1V. It is expected to have reliability for 5V applications and is expected to have high tolerance characteristics.

• Journal of IKEEE
• /
• v.26 no.1
• /
• pp.119-123
• /
• 2022

This paper propose a new ESD protection device suitable for 12V class applications by adding a self-biasing structure to an ESD protection device with high holding voltage due to additional parasitic bipolar BJT. To verify the operating principle and electrical characteristics of the proposed device, current density simulation and HBM simulation were performed using Synopsys' TCAD Simulation, and the operation of the additional self-biasing structure was confirmed. As a result of the simulation, it was confirmed that the proposed ESD protection device has a higher level of holding voltage compared to the existing ESD protection device. It is expected to have high area efficiency due to the dual structure and sufficient latch-up immunity in 12V-class applications.

• Journal of Radiation Protection and Research
• /
• v.48 no.3
• /
• pp.124-130
• /
• 2023

Background: When bipolar junction transistors (BJTs) are used as switches, their switching characteristics can be deteriorated because the recombination time of the minority carriers is long during turn-off transient. When BJTs operate as low frequency switches, the power dissipation in the on-state is large. However, when BJTs operate as high frequency switches, the power dissipation during switching transients increases rapidly. Materials and Methods: When silicon (Si) BJTs are irradiated by fast neutrons, defects occur in the Si bulk, shortening the lifetime of the minority carriers. Fast neutron irradiation mainly creates displacement damage in the Si bulk rather than a total ionization dose effect. Defects caused by fast neutron irradiation shorten the lifetime of minority carriers of BJTs. Furthermore, these defects change the switching characteristics of BJTs. Results and Discussion: In this study, experimental results on the switching characteristics of a pnp Si BJT before and after fast neutron irradiation are presented. The results show that the switching characteristics are improved by fast neutron irradiation, but power dissipation in the on-state is large when the fast neutrons are irradiated excessively. Conclusion: The switching characteristics of a pnp Si BJT were improved by fast neutron irradiation.

• Transactions on Semiconductor Engineering
• /
• v.2 no.2
• /
• pp.10-14
• /
• 2024

This paper presents a circuit design aimed at generating the required reference voltage and temperature sensor voltage in conjunction with an ADC, utilizing the current generated by temperature characteristics of BJT components for sensor data conversion. Additionally, two control methods are introduced to reduce the standard deviation of the circuit, resulting in over a ten-fold decrease in standard deviation. The proposed circuit occupies an area of 0.057mm² and was implemented using 55nm RF process.

• Journal of Dental Rehabilitation and Applied Science
• /
• v.24 no.3
• /
• pp.269-281
• /
• 2008

Fatigue or overload can result in mechanical problems of implant components. The mechanical strength in the implant system is dependent on several factors, such as screw and fixture diameters, material, and design of the fixture-abutment connection and abutment. In these factors, the last rules the strength and stability of the fixture-abutment assembly. There have been some previous reports on the mechanical strength of the fixture-abutment assembly with the compressive bending test or short-term cyclic loading test. However, it is restrictive to predict the long-term stability of the implant system with them. The purpose of this study was to evaluate the influence of the design of the fixture-abutment connection and abutment on the mechanical strength and failure mode by conducting the endurance limit test as well as the compressive bending strength test. Tests were performed according to a specified test(ISO/FDIS 14801) in 4 fixture-abutment assemblies of the Osstem implant system: an external butt joint with Cemented abutment (group BJT), an external butt joint with Safe abutment (group BJS), an internal conical joint with Solid abutment (group CJO), and an internal conical joint with ComOcta abutment (group CJT). The following conclusions were drawn within the limitation of this study. Compressive bending strengths were decreased in order of group BJS(1392.0N), group CJO(1261.8N), group BJT(1153.2N), and group CJT(1110.2N). There were no significant differences in compressive bending strengths between group BJT and group CJT(P>.05). Endurance limits were decreased in order of group CJO(600N), group CJT(453N), group BJS(360N), and group BJT(300N). 3. Compressive bending strengths were influenced by the connection and abutment design of the implant system, however endurance limits were affected more considerably by the connection design.