Xenics has designed and manufactured a 1280*1024 pixel, 17 µm pitch InGaAs array for SWIR imaging in the [0.9 - 1.7 µm] range. It will report on the first characterization results of the device. As usual for this type of room temperature operated SWIR image sensors, the detector interface is based on a CTIA stage, yielding excellent linearity, a low detector bias and hence a low and stable dark current combined with low image lag. The charge to voltage conversion factor is 40 µV/e<sup>-</sup>. The pixel interface scheme contains a CDS circuit in order to reduce the kTC noise and common mode effects. The noise is expected to be below 30 e<sup>-</sup><sub>rms</sub> in linear mode, resulting in a dynamic range < 60 dB. Additionally the linear dynamic range is complemented with a high dynamic range logarithmic response with a saturation level < 5 nA/pixel. The information in the pixel matrix can be read via 2, 4 or 8 outputs, yielding a maximum full frame rate between 50 and 200 Hz. Each output is operating at 40 MHz pixel rate. The outputs are differential with a common mode voltage of 0.9 V and an adjustable output swing of 2 V<sub>ptp</sub>. Nevertheless the power dissipation shall be below 330 mW.
KEYWORDS: Signal to noise ratio, Transmitters, Modulation, Interference (communication), Amplifiers, Receivers, Telecommunications, Antennas, Analog electronics, Orthogonal frequency division multiplexing
Ultra-Wideband systems is the collective term for wireless devices with a large spectral footprint and a low transmission power. The extreme low power spectral density of the UWB system forms a vast difference with classic communication systems that employ a large power within a small frequency band. Implementation approaches of Ultra-Wideband enclose classical carrier-based OFDM systems and pulse-based systems, each with their play trumps and disadvantages. Depending on the final application, cost, power or bandwidth can be the key target. Deep-submicron technologies allow to extend the limiting boundaries of analog building blocks but also introduce new challenges. Furthermore, new problems with respect to analog design deserve our attention: The high bandwidth of the signals involved in wideband systems obliges to migrate to a broadband receiver chain: LNA's (Low Noise Amplifier), mixers and ADC's with a wideband in- and output have to be designed, while commonly used techniques such as inductive peaking in the power amplifier cannot be used any more. Both advantages and disadvantages of OFDM and pulse-based transceiver architectures will be compared, together with simulation data, in order to give an overview of important design aspects of an Ultra-Wideband application.