This paper presents a novel bandgap reference (BGR). Nine pairs of bipolar transistors are used to produce a voltage that is proportional to absolute temperature (PTAT), and three base-emitter voltages of bipolar transistors are used to produce a voltage that is complementary to absolute temperature (CTAT). The BGR of this structure can obtain a lower temper-ature coefficient with first-order temperature compensation. In the simulation, a voltage reference of 3.63 V with a temperature coefficient of 6.73 ppm/vC is achieved for a temperature range of - 45°C to 125°C at a 5 V supply voltage.

Quartz Flexible Accelerometer (QFA) system has gained extensive utilization in related navigation system due to the high precision, exceptional stability, and rapid response. The operational amplifier as the pivotal component of the analog servo circuit intricately relative to the performance of the QFA system. In this paper, the electrical mechanism of the QFA readout system and the influence of operational amplifier noise on the noise of QFA readout system is studied, a low-noise Class AB amplifier for the servo circuit of QFA readout system designed and fabricated by 180 nm BCD process, and the QFA readout system with the designed amplifier is simulated. The experimental results show that the low-noise amplifier achieved equivalent input current and voltage noise of 5.75pA/sqrt (Hz) and 12.7nV/sqrt (Hz) separately. Simulation results shows the designed QFA servo circuit has achieved resolution of 35 μ g and noise of 2.1 μ g/sqrt (Hz) @1Hz.

This paper presents a Spread spectrum clock oscillator for the DC-DC converter. In this design, digital logic control is added based on the RC relaxation oscillator, which makes the charging and discharging current of the oscillator change randomly in the set range. This random change of current can achieve the corresponding spread spectrum to achieve the purpose of reducing EMI. In addition, this oscillator design can achieve four different operational modes through the external control signal: 7 -bit output mode and 8 -bit output mode without spread spectrum, 7-bit output mode and 8-bit output mode with spread spectrum. The simulation results show that the oscillating frequency of the oscillator is 16.7MHz without the spread spectrum under 7-bit output mode, after spreading spectrum, the depth of spread spectrum is $54.4 \%$, which the peak energy is reduced by 24dB compared with that before spreading spectrum. Under 8-bit output mode, the oscillator oscillates at 19.6MHz without spreading spectrum, after spreading spectrum, the depth of spread spectrum is $58 \%$ with the 22dB peak energy reduction.

This paper introduces a slew-rate enhancement (SRE) circuit for CLASS AB Operational Transconductance Amplifier (OTA). The enhancement is achieved by two auxiliary amplifiers. Simulation results show that CLASS AB OTA with the proposed SRE circuit is achieved 60. 25MV/s positive and 30. 6MV/s symmetric slew rate with a load capacitance of2pF. The positive and negative slew rate of the CLASS AB OTA with the proposed SRE circuit have increased by a factor of 7.03 and 3.23 respectively. The SRE circuit only work during fast signal transitions with the power consumption increased by 8.06%.

This paper presents a low-noise low-input base current amplifier with both low-voltage and high voltage output capability. The amplifier has low frequency noise and input base current by employing a BJT input stage with a novel base current compensation structure, and has low and high voltage output capability by setting the input stage of it at low voltage supply (VDDL), the third and the output stage at high voltage supply (VDDH). Simulation results show the input base current of the amplifier is around 0.1nA, and the temperature coefficient of input current is around 6pA/°C over −45°C to 125°C, the equivalent input noise of the amplifier is 5.3nV/rt Hz at 1Hz, 8.2nV/rt Hz at 0.001Hz, and the output voltage range can be from 4V to 50V with VDDL=5V, VDDH=55V. The current consumption of the amplifier is 150$\mu$A with VDDL, 450$\mu$A with VDDH. Besides, with capacitor load condition of 20pF, the bandwidth of the proposed amplifier is 24MHz, the slew rate is 11. 29MV/s. The amplifier is implemented in 180 nm BCD process. It occupies an active area of 0.504mm 2 .