A 4-channel 12-bit high-voltage radiation-hardened digital-to-analog converter for low orbit satellite applications

This paper presents a circuit design and an implementation of a four-channel 12-bit digital-to-analog converter (DAC) with high-voltage operation and radiation-tolerant attribute using a specific CSMC H8312 0.5-μm Bi-CMOS technology to achieve the functionality across a wide-temperature range from -55 °C to 125 °C. In this paper, an R-2R resistor network is adopted in the DAC to provide necessary resistors matching which improves the DAC precision and linearity with both the global common centroid and local common centroid layout. Therefore, no additional, complicated digital calibration or laser-trimming are needed in this design. The experimental and measurement results show that the maximum frequency of the single-chip four-channel 12-bit R-2R ladder high-voltage radiation-tolerant DAC is 100 kHz, and the designed DAC achieves the maximum value of differential non-linearity of 0.18 LSB, and the maximum value of integral non-linearity of -0.53 LSB at 125 °C, which is close to the optimal DAC performance. The performance of the proposed DAC keeps constant over the whole temperature range from -55 °C to 125 °C. Furthermore, an enhanced radiation-hardened design has been demonstrated by utilizing a radiation chamber experimental setup. The fabricated radiation-tolerant DAC chipset occupies a die area of 7 mm x 7 mm in total including pads (core active area of 4 mm x 5 mm excluding pads) and consumes less than 525 mW, output voltage ranges from -10 to +10 V

Reform and Practice of Analog Circuits

In the new century, education has become the focus of the reform. At present, cross, penetration and integration between basic courses are the key to improve the quality of teaching and the overall quality of students. University of Electronic Science and Technology of China (UESTC) combines "circuit analysi" and "fundamentals of analog circuits" as one course "electronic circuit", the curriculum reform follows the principles of strengthening the foundation, updating the structure, penetrating the interdisciplinary and simplifying the courses. This paper discusses the principles and ideas of reforms related to the "electronic circuit": the results show that the teaching can broaden the knowledge and vision of students, as a result, the students can better adapt to the requirements of learning and challenge of the new era

An external capacitor-less low-dropout voltage regulator using a transconductance amplifier

This paper presents an external capacitor-less NMOS low-dropout (LDO) voltage regulator integrated with a standard CSMC 0.6 μm BiCMOS technology. Over a -55 ∘C to +125 ∘C temperature range, the fabricated LDO provides a stable and considerable amount of 3 A output current over wide ranges of output capacitance COUT (from zero to hundreds of μF ) and effective-series-resistance (ESR) (from tens of milliohms to several ohms). A low dropout voltage of 200 mV has been realised by accurate modelling. Operating with an input voltage ranging from 2.2 V to 5.5 V provides a scalable output voltage from 0.8 V to 3.6 V. When the load current jumps from 100 mA to 3 A within 3 μs, the output voltage overshoot remains as low as 50 mV without output capacitance, COUT. The system bandwidth is about 2 MHz, and hardly changes with load altering to ensure system stability. To improve the load transient response and driving capacity of the NMOS power transistor, a buffer with high input impedance and low output impedance is applied between the transconductance amplifier and the NMOS power transistor. The total area of fabricated LDO voltage regulator chip including pads is 2.1 mm×2.2 mm

High-precision adaptive slope compensation circuit for DC-DC converter in wearable devices

This paper presents a high precision adaptive slope compensation circuit for for DC-DC converter in wearable devices. Compared with the traditional adaptive slope compensation circuit, the comparator is used to sample the output voltage and input voltage, which greatly improves the accuracy.In this paper, the circuit is designed in UMC 0.18-μm CMOS Technology and verified by Virtuoso Spectre Circuit Simulator. The simulation results show that the accuracy of the adaptive slope compensation circuit in this paper can reach more than 96%

Fast-transient radiation-hardened low-dropout voltage regulator for space applications

This paper presents a fast-transient radiation-hardened low-dropout (LDO) voltage regulator integrated in a standard CSMC 0.6 μm BiCMOS technology for space and other harsh radiation environments applications. The fabricated LDO consumes 150 μA quiescent current at 6 A maximum output current. A low dropout voltage of 300 mV which corresponds to an ultra-low RDS(ON) resistance of 50 mΩ is realized by accurate modeling. A separate fast-transient response circuit under narrow-bandwidth condition is proposed to improve the output voltage transient speed. It operates from an input voltage range of 2.8 V to 5.5 V and provides for output voltage of 2.5 V, with output voltage accuracy of ±2%. The proposed LDO achieves a successful line regulation of 1 mV/V, and a load regulation of 2.16 mV/A. Novel radiation-hardened layout techniques are applied to realise high area-efficient LDO chip, whose total area including pads is 5.35 mm2, only about one-third area of similar radiationhardened products. Total ionising dose (TID) experiments were conducted at China Academy of Engineering Physics, Mianyang of Sichuan province. Furthermore, a special set of single event latch-up (SEL) experiments were performed at the Heavy Ion Research Facility in Lanzhou (HIRFL), Institute of Modern Physics, Chinese Academy of Sciences, the most advanced heavy ion accelerator of China. The measurement results show that the LDO can tolerate up to a total ionising dose (TID) of 150 krad (Si) and SEL immunity at a linear energy transfer (LET) of 99.8 MeV/(mg/cm2) with proposed novel layout design