Ultra-low-noise readout integrated circuit for uncooled microbolometers

A low-noise readout architecture for uncooled microbolometer focal plane arrays is described. A 40times30 uncooled microbolometer focal plane array based on the low-noise ROIC was implemented on silicon using a 0.5 mum CMOS technology. Total output noise voltage is 260 V RMS. Experimental values of voltage responsivities of 3.98 10⁵ V/W on average at 1 Hz modulation frequency have been achieved.     

Noise optimisation for the design of a reliable high speed X-ray readout integrated circuit

On the basis of the design of an X-ray readout integrated circuit, we present in this paper the noise analysis which has to be performed in order to implement a reliable system. In this context, we exploit the various noise sources originating both at the device and at the circuit level of the system. We present the crucial noise contributors, calculate the noise level and present optimisation methods to accommodate the best noise performance in readout circuits. The noise contribution of the input amplification stage to the overall system noise performance is treated in detail. The designer’s alternative choices regarding the input capacitance scaling (device level) and the feedback resistance (circuit level) are properly investigated. Other issues such as signal filtering and mixed signal design are also addressed.     

红外探测器高性能读出电路的研究

设计了一种高性能电容反馈跨阻放大器(CTIA)与相关双采样电路(CDS)相结合的红外探测器读出电路。该电路采用CTIA电路实现对微弱电流信号的高精度读出,并通过CDS电路抑制CTIA引入的固定模式噪声(FPN),最后采用失调校正技术减小CDS引入的失调,从而减小了噪声对电路的影响,提高了读出电路的精度。采用特许半导体(Chartered)0.35μm标准CMOS工艺对电路进行流片,测试结果表明:在20pA～10nA范围内该电路功能良好,读出精度可达10bit以上,线性度达97%,达到了设计要求。该读出电路可用于长线列及面阵结构红外探测系统。     

An ultra low noise readout integrated circuit for uncooled microbolometers

A low noise readout architecture for uncooled microbolometer focal plane arrays is described. The on-chip readout circuit contains an integration circuit in which the bolometer current is directed injected into a capacitor, and exhibits extremely low noise with no decrease in signal by using an ultra low noise capacitive transimpedance amplifier (CTIA). The simple configuration of the integration circuit makes it possible to operate more circuits in parallel, and increases the integration time and number of pixels. A 40 × 30 uncooled microbolometer focal plane array based on the low noise ROIC was implemented on silicon using a 0.5 μm CMOS technology. The total output noise voltage is 260 μV RMS. A noise at this level is so low that can loosen required TCR in the bolometer material. Experimental values of voltage responsivities of 3.98 × 10⁵ V/W on average at 1 Hz modulation frequency have been achieved.     

一种提高BOTDR系统信噪比的方法研究

提出了一种利用非线性反射镜提高布里渊光时域反射仪(BOTDR)系统信噪比的新型传感结构.通过将两根相同类型的传感光纤敷设在同一待测温度或应变环境下,结合光纤3 dB耦合器,可以形成非线性反射镜.利用非线性反射镜可以将传感系统输出信号的强度提高到只用一根传感光纤时的4倍,既能改善系统的信噪比及测量精度,也能提高传感系统的可靠性.     

快照模式紫外焦平面读出电路电容优化设计

快照模式焦平面读出电路的单元电路一般包括前置放大器、采样保持电路、多路开关传输器和缓冲跟随器.在有限的单元面积内完成较高性能的单元电路设计是快照模式焦平面读出电路的难点.考虑到积分电容、采样保持电容、运放补偿电容占据了CMOS电路版图中较多的面积,通过分析计算读出电路各级噪声以及电路总的输出噪声,探讨了上述各种电容对于电路噪声的影响.考虑到紫外探测器的特点,同时在固定其他设计参数的基础上,通过调整电容面积的分配比例,计算了电路可以得到最佳噪声水平的电容大小.结果表明,在目前的工艺和版图限制等条件下,在上述三种电容分别取1.1、0.4、1.2pF时,输出端噪声电压为最小,达172μV.     

混合式IRFPA读出电路参数测试系统

读出电路是红外焦平面阵列(IRFPA)的关键组成部分之一。它的质量直接影响到IRFPA的质量,因此读出电路参数的测试非常重要。本系统采用信号模仿的方法,对IRFPA读出电路注入电信号,调节电信号即可模拟不同的测试条件,利用读出电路的输出就可测试其主要参数的技术指标。系统采用虚拟仪器系统的精密数据采集卡(DAQ)和用于数据处理的软件(LabVIEW)来构建出混合式IRPFA读出电路参数测试系统。采集卡对读出电路输出信号进行采集,并利用软件的运算功能模块对采集的数据进行统计运算,就可定量得到各项参数指标,从而判断读出电路性能的好坏。采用本系统对128×128元读出电路进行测试,实验结果表明了系统的可行性,测试结果可以反映读出电路的质量。     

低信噪比情况下的微多普勒特征提取方法

如何在低信噪比条件下进行微多普勒目标特征提取一直是微弱信号雷达检测的难点问题,文中从增强信号的角度出发,在信号不失真条件下,研究了多重自相关函数与信号强度的关系,提出了基于多重自相关函数与短时傅里叶变换联合的微多普勒目标特征提取方法,实现了在低信噪比条件下微多普勒目标特征的提取。文中通过建立旋翼回波信号,并在信噪比为-5d B的情况下,利用所提出的方法进行微多普勒特征提取,仿真结果表明该方法可以在低信噪比条件下有效提取出目标微多普勒特征。     

An integrated readout circuit for personal dosimetry with phase-shift compensation technique to improve stability

In this paper an integrated CMOS readout circuit for a radiation detector in a personal dosimeter is presented. High counting rate and low power requirements make the stability of the conventional high-pass pulse shaper a big problem. A novel phase-shift compensation method is proposed to improve the phase margin. The principle of the compensation circuit and its influence on noise performance are analyzed theoretically. A readout chip with two channels of conventional structure and one channel of the proposed structure has been implemented in a 0.35 μm CMOS technology. It occupies an area of 2.113×0.81 mm². Measurement results show that the proposed channel can process up to 1 MHz counting rate and provide a conversion gain of about 170 mV/fC at a power dissipation of 330 μW with a 3.3 V power supply. Ac-coupled to a silicon PIN detector, it successfully detects β-rays.     

Development of a 64 × 64 CdZnTe array and associated readout integrated circuit for use in nuclear medicine

Previous work has shown that hybrid semiconductor detector arrays similar to those used in infrared focal-plane arrays are very attractive for use in nuclear medicine and other gamma-ray imaging applications. In this paper, we describe the development of a 64 × 64 readout multiplexer specifically for use in gamma-ray imaging; we also describe the construction of 64 × 64 CdZnTe hybrid detector arrays using the new readout. The readout and detector array are both about one inch square (2.5 cm × 2.5 cm) and have 380 μm pixel pitch. Some initial assembly problems have been resolved by stabilizing the hybrids with epoxy. Preliminary testing results are presented that verify that the 64 × 64 CdZnTe arrays perform as excellent imaging spectrometers.     

CMOS circuit for readout of microbolometer arrays

A CMOS circuit for the readout of microbolometer arrays is presented. It provides a pulsed bias for the microbolometers, signal amplification and multiplexing to a common output. The chip can be used with linear and small two-dimensional arrays of microbolometers realising a hybrid infrared sensor     

Time-constant-based CMOS readout circuit for DNA detection

An RC-to-time constant interface circuit was implemented in 0.18 mum CMOS to characterise the conductive polymer labelled deoxyribonucleic acid (DNA) hybridisation activity on nano-sensor micro-arrays. Measured results show that sub-picomolar DNA (0.1-10 pM) are able to be differentiated with respect to their electrical parameters of 1-23 GOmega resistances parallel with 2.8 down to 0.1 nF capacitances.     

An alternative derivation for the signal-to-noise ratio of a SSMAsystem

We present an alternative derivation for the signal-to-noise ratio (SNR) of a phase-coded spread-spectrum multiple access (SSMA) system by use of ensemble-average approach. We show that our formula can be explicitly expressed in terms of system parameters and the expression for the SNR derived by Pursley (1977) is just a special case when the user number is very large     

集成偏振近红外焦平面探测器研制与信噪比分析

面向近红外波段隐蔽目标识别应用,基于InGaAs近 红外焦平面阵列,利用焦平面像元分组方法,研 制了一种单片集成微偏振元阵列的InGaAs焦平面探测器。本文器件利用电子束直写与金属刻 蚀工艺制备的金 属纳米线阵列实现偏振态选择,实验测试平均消光比为8.05。研究结 果表明,光串扰在很大程度上降低了消 光比,对偏振图像的暗部细节的解析度也产生了不利影响;金属纳米线本身的不完整性不但 造成了信噪比(SNR)下降,也制约了光响应动态范围。     

Smart TDI readout circuit for long-wavelength IR detector

A smart time delay and integration (TDI) readout circuit is suggested which performs background suppression, cell-to-cell non-uniformity compensation, and dead pixel correction. Using the smart TDI readout circuit, the integration capacitor area occupying almost the whole area of a unit-cell can be reduced to one-fifth and transimpedance gain can increase by five times. From measurement results, it is found that the skimming current error for a few hundred nA background current is < 1.25 nA corresponding to LSB/2 of ADC and the non-uniformity introduced by cell-to-cell background current variation is reduced to 1.02 nA     

Noise bandwidth suppression for low noise readout circuit

A new noise reduction circuit that suppresses noise bandwidth of the output stage is proposed for the readout circuit of an infrared detector operating at a high pixel rate. Using this circuit, it is found that the rms noise voltage of the output stage is effectively reduced from 87 to 52 μV at a pixel rate of 10 pixel/μs     

半导体集成电路可靠性测试及数据处理方法

伴随着新材料与工艺技术的出现,半导体集成电力线宽逐渐减少,其集成度逐渐提高,对于集成电路可靠性要求逐渐严格.如今,集成电路生产加工突飞猛进,在一定程度上为集成电路可靠性研究奠定了基础.对此,笔者根据实践研究,就半导体集成电路可靠性测试与数据处理方法进行简要分析.     

A low noise readout detector circuit for nanoampere sensorapplications

A readout detector IC has been developed which is capable of detecting nanoampere photo-current signals of interest in a high (microampere) background illumination or dc noise level (SNR=80 dB). The readout detector sensor IC processes transient signals of interest from a separate photo-diode pixel array chip. Low noise signal conditioning, filtering, and signal thresholding implement smart sensor detection of only “active pixels.” This detector circuit can also be used to perform signal conditioning for other sensor applications that require detection of very small signals in a high background noise environment