Nowadays, portable imaging surveillance systems are widely used in military and civil fields. Such systems always need low power consumption to meet the requirements of long-term operation. These systems are in standby mode during most of the time and woken up at a regular interval for a very short time to perform a measurement. Accordingly, a low power oscillator as wake-up clock generator is needed. In this paper, a sub-μW low temperature sensitivity RC oscillator is presented. Unlike the traditional CMOS RC oscillator with double comparators, it contains only one hysteresis comparator and operates in subthreshold region to reduce current consumption. The oscillator has been designed and simulated in a standard 0.18 μm CMOS process, achieving a frequency of 100 kHz. The variation of frequency is ±1:65% over the temperature range from -10°C to 110°C. The current consumption is 332 nA under a supply voltage of 1.8 V at room temperature. The occupied area is merely 0.01 mm<sup>2</sup> without pads.
Design of a multispectral infrared focal plane array ROIC (readout integrated circuit) with TDI (time delay integration) is presented. A 3 SNR improvement can be achieved by a 3 pixels TDI implementation. The 3 pixel signals in each channel are firstly integrated by 3 CTIA structures, then the TDI action is in SC-AMP (switch capacitor amplifier) of each channel. A novel switch capacitor amplifier topology is proposed which can both reduce power dissipation by shutting down the AMP and realize offset voltage cancellation. Besides, bad pixel replacement is realized by an alternative gain of the SC-AMP. The proposed ROIC can work well both room and cryogenic temperature. Simulation results show that the CTIA input stage have a good linearity of 99.721% (post-layout sim) over 2.8V output span.
A scannerless ladar imaging system based on a unique frequency modulation/continuous wave (FM/cw) technique
is able to entirely capture the target environment, using a focal plane array to construct a 3D picture of the target. This
paper presents a low power trans-impedance amplifier (TIA) designed and implemented by 0.18 μm CMOS technology,
which is used in the FM/cw imaging ladar with a 64×64 metal-semiconductor-metal(MSM) self-mixing detector array.
The input stage of the operational amplifier (op amp) in TIA is realized with folded cascade structure to achieve large
open loop gain and low offset. The simulation and test results of TIA with MSM detectors indicate that the single-end
trans-impedance gain is beyond 100 kΩ, and the -3 dB bandwidth of Op Amp is beyond 60 MHz. The input common
mode voltage ranges from 0.2 V to 1.5 V, and the power dissipation is reduced to 1.8 mW with a supply voltage of 3.3 V.
The performance test results show that the TIA is a candidate for preamplifier of the read-out integrated circuit (ROIC)
in the FM/cw scannerless ladar imaging system.