A 1/2-in, 1.3 M-pixel progressive-scan CCD image sensor employing0.25-μm gap single-layer poly-Si electrodes

A 1/2-in, 1.3 M-pixel progressive-scan interline-transfer charge coupled-device (IT-CCD) image sensor has been developed for low-power and high-sensitivity digital cameras. The image sensor uses 0.25-μm gap single-layer poly-Si for CCD transfer electrodes in order to reduce the power consumption and number of fabrication process steps. The image sensor achieved a low driving voltage (2.1 V) on a horizontal CCD (H-CCD) at a frequency of 24.5 MHz. An original pixel layout and a self-aligned photodiode structure make it possible to achieve a progressive scan pixel with well-controlled photodiode readout characteristics. An output three-stage source follower amplifier with new multioxide transistors, whose gate insulator thickness is thinner than that of a CCD register, is able to attain 17% higher gain than that of the conventional amplifier. The sensor provides low-power (100 mW) and high output sensitivity. The total number of steps for fabricating the sensor was reduced to 70% of that for conventional three-layer poly-Si electrodes     

Dynamic range improvement by narrow-channel effect suppression andsmear reduction technologies in small pixel IT-CCD image sensors

Technologies for narrow-channel effect suppression in photodiodes (PDs) and vertical CCDs (V-CCDs) and for smear reduction in PDs have been developed in order to improve dynamic range in small pixel interline-transfer CCD (IT-CCD) image sensors. The new technologies have been applied to a progressive-scan IT-CCD image sensor with 5 μm square pixels and have (1) increased the charge handling capability of its V-CCDs to 4500 electrons/V; (2) improved its smear value to -95 dB; and (3) increased the saturation charge of its PDs to 2.3×10⁴ electrons     

A 30 frames/s 2/3-in 1.3 M-pixel progressive scan IT-CCD imagesensor

A 30 frames/s 2/3-in 1.3 M-pixel progressive scan interline-transfer charge-coupled device (IT-CCD) image sensor has been developed for video and digital still-camera applications. To obtain high frame-rate images, a 49-MHz driving horizontal CCD (H-CCD) was developed. An 8-phase drive for vertical CCDs (V-CCDs) makes it possible to operate in a variety of modes, such as 1050 line progressive scan mode and 1049 line wide dynamic range interlaced scan mode. For digital still camera use, removing residual charges stored in the V-CCDs before exposure is essential, therefore new narrow-channel barrier over-flow drain (NCB-OFD) attached under the H-CCD was developed. The NCB-OFD automatically drains out extra charges and has the advantages of requiring neither an over-flow control gate nor any additional masks     

A 1/4-inch 380 k pixel IT-CCD image sensor employing gate-assisted punchthrough read-out mode

A newly developed 1/4-inch 380 k pixel IT-CCD image sensor features a novel cell structure in which signal charges are read out from a photodiode (PD) to a vertical-CCD (V-CCD) in a gate-assisted punchthrough mode. The cell structure, fabricated through the use of high energy ion implantation technology, enables both deep PD formation and transfer-gate (TG)/channel-stop (CS) length reduction. Deep PD formation helps increase sensitivity per PD unit area, and TG/CS length reduction widens both PD and V-CCD areas. Although the cell size is small (4.8 /spl mu/m (H)/spl times/5.6 /spl mu/m (V)), the sensor achieves both high sensitivity (35 mV/lx) and a high saturation signal (600 mV).<>     

A 1/3-in 1.3 M-pixel single-layer electrode CCD with ahigh-frame-rate skip mode

A 1/3-in 1.3 M-pixel interline-transfer charge-coupled-device (IT-CCD) image sensor has been developed for digital-camera applications. A 0.25-μm-gap single-layer poly-Si is used for the CCD electrodes. The vertical CCD (V-CCD) of the image sensor has ten-phase metal wiring to enable various charge-transfer modes. A high-frame-rate skip mode (75 frames/s) and an advanced 3:1 interlaced-scan mode were developed and tested. A method of separately implanting boron ions for the V-CCD and horizontal CCD in single-layer electrode CCDs with small pixels, to maintain high charge-transfer efficiency, was developed. However, reducing pixel size degrades the light-gathering capability of the on-chip microlens, which occurs especially obliquely incident light, thus, reducing the sensitivity for a given camera-iris aperture (f-number). A new thin flattened-layer (3.5 μm thickness) microlens improved the sensitivity of the device. At f-number 1.4, for example, there was an 18% increase in sensitivity compared to that of the thick flattened-layer (5.0 μm thickness) microlens     

A low driving voltage CCD with single layer electrode structure forarea image sensor

A new single layer electrode two-phase CCD was studied for the purpose of realizing low driving voltage operation in inter-line transfer CCD (IT-CCD) image sensor aiming for low power consumption. Conventional H-CCD with overlapping double layer electrode structure have not achieved signal charge transfer at very low driving voltage below 2 V due to appearance of potential pocket under the inter-electrode gap yet. The new CCD employs a new channel doping profile for potential pocket suppression at the inter-electrode gap. The new CCD also employs a stepped-oxide structure having a single layer transfer electrode covering both a thin gate oxide forming storage region and a thinner gate oxide forming barrier region. The inter-electrode gap of single layer electrode was decreased to as small as 0.3 μm. As a result of these measures, a fabricated 1/3 in format 270 K pixel IT-CCD image sensor reproduces a fine video image even when it is operated at a driving voltage as low as 1.8 V     

Computer model of an injection laser amplifier

Laser amplifiers can be used in two ways: as preamplifiers to enhance the sensitivity and improve the noise performance of detectors and, in a pulsed mode of operation, as modulators to boost and stabilize the output of an injection laser oscillator. Most mathematical models of injection lasers are based on time-dependent rate equations that ignore the spatial dependence of the electron and photon densities. The model discussed here is based on numerical solutions of traveling-wave equations. The noise output of the laser amplifier is treated by traveling-wave power equations, but the light signal is described by traveling-wave equations for its amplitude. The parameters responsible for spontaneous and stimulated emission are being related to each other by the requirement that the amplifier achieve optimal noise performance in the absence of internal losses and without gain saturation. The most important results obtained from this computer model of a laser amplifier are as follows. 1) The theory contains a heuristic electron injection efficiency parameter. To agree with experimental observations this parameter must be kept small and its value must decrease with increasing current. 2) Cavity amplifiers saturate more readily than amplifiers without feedback. 3) Because of internal loss mechanisms the amplifier supplies more noise than is required by quantum theory, but its noise performance is still surprisingly good. In particular, the optical signal-to-noise ratio prior to detection is insensitive to gain saturation by strong signals. It remains approximately 4 dB below the theoretical maximum value for weak to moderately strong input signals and drops dramatically only when the amplifier is almost completely saturated.     

A new CCD architecture of high-resolution and sensitivity for colordigital still picture

A new charged-coupled device (CCD) architecture developed for building high-resolution and high-sensitivity image sensors suitable for color digital still picture applications is presented. The sensor is based on the interline CCD structure. Both the interline pixels and the vertical charge transfer lines are utilized as light-sensing elements to improve simultaneously the resolution and sensitivity. This device is named the sea-of-photosensor array (SPA-CCD). A camera and supporting digital system were designed and built specifically to evaluate the device. Digital picture processing for white balance adjustment, chromatic correction, and high-frequency luminance was performed to improve color reproduction and picture resolution. An increased light sensitivity and limiting resolutions of 550 horizontal lines and 400 vertical lines on a TV screen were confirmed with an SPA-CCD of the same chip size as a conventional 190-k pixel IT-CCD. The new design of the SPA-CCD overcomes both the sensitivity and the resolution limitations of previous approaches     

A Handset Power Amplifier With High Efficiency at a Low Level Using Load-Modulation Technique

A new monolithic-microwave integrated-circuit power amplifier for cellular handsets has been implemented using the load-modulation concept of the Doherty amplifier, which has a high efficiency at a low power level. In order to get a compact module, the$lambda/4$transmission line for the load modulation is replaced by a passive high-pass$pi$-network, and the load-modulation circuit is also modified to function as a power-matching circuit of the main amplifier. The amplifier has two modes of operation, low- and high-power modes, controlled by a control voltage. At the high power mode, both the main and auxiliary amplifiers are operational and, at the low power mode, only the main amplifier generates output power enhancing the efficiency. For the code-division multiple-access environment, the amplifier at the low-power mode provides power-added efficiency (PAE) of 39.8% and an adjacent channel power ratio (ACPR) less than 49.8 dBc at 23.1 dBm, and the high-power mode PAE of 37.9% and ACPR of 46.4 dBc at 28 dBm. The efficiency is improved by approximately 18.8% at$ P_ out=23$dBm by the load-modulation technique. For the advanced mobile phone system-mode operation, the amplifier delivers 26.1 dBm with PAE of 53% and 30.8 dBm with 48.7% at the low and high modes, respectively.     

由于电阻精度引起差分放大电路误差的分析

差分放大电路的最大特征就是放大差模信号,抑制共模信号。使用差分放大电路放大信号时,在选择共模抑制比高的集成运放的情况下,为了使输出误差尽可能小,就要保证电阻元件有较高的精度。通过具体计算来说明电阻精度对差分放大电路误差的影响。电阻精度越高误差越小,相反电阻精度越低误差越大。     

An InGaP-GaAs HBT MMIC smart power amplifier for W-CDMA mobile handsets

We demonstrate a new linearized monolithic microwave integrated circuit smart power amplifier of extraordinary high power-added efficiency (PAE), especially at the most probable transmission power of wide-band code-division multiple-access handsets. A PAE of 21% at 16 dBm of output power, which is the maximum bound of the most probable transmission power in IS-95 systems, was obtained, as well as 40% at 28 dBm, the required maximum output power, with a single-chip MMIC power amplifier. The power amplifier has been devised with two InGaP-GaAs heterojunction bipolar transistor amplifying chains parallel connected, each chain being optimized for a different P/sub 1dB/ (1-dB compression point) value: one for 16 dBm for the low-power mode, targeting the most probable transmission power, and the other for 28 dBm for the high-power mode. The high-power mode operation shows 40% of PAE and -30 dBc of adjacent channel leakage power ratio (ACLR) at the maximum output power of 28 dBm. The low-power mode operation exhibits -34 dBc of ACLR at 16 dBm with 14 mA of a quiescent current. This amplifier improves power usage efficiency and, consequently, the battery lifetime of the handset by a factor of three.     

13 Gb/s Si-bipolar AGC amplifier IC with high gain and wide dynamicrange for optical-fiber receivers

A complete linear automatic-gain-control (AGC) amplifier for a 10 Gb/s optical-fiber link was integrated on a single chip, using a Si-bipolar production technology with f_T≈22 GHz. It is characterized by a high gain of 37 dB, linear operation over a wide input dynamic range of 47 dB, a maximum data rate of 13 Gb/s, and a gain-independent 3-dB cut off frequency of 10 GHz. The circuit consumes 850 mW at a single supply voltage of -6.5 V. It can be operated in both a single-ended and differential mode. A novel 50-Ω input matching circuit with only small return loss is used. Two separate output buffers with a constant output voltage swing of 500 mV_p-p allow splitting up the output signal without use of external components     

Over-30-GHz limiting amplifier ICs with small phase deviation foroptical communication systems

For a high-speed limiting amplifier with small phase deviation, a new design technique using a uniplanar passive balun and a narrow-band matching network is proposed. It is revealed that a device with small bias-dependence of parasitic capacitances, such as a high electron mobility transistor (HEMT), and a differential operation using passive baluns enables phase deviations at very high frequency to be reduced. Furthermore, suppressing harmonics can reduce phase deviation in a limiting amplifier, which operates in the highly nonlinear region. To verify these design techniques, two types of limiting amplifier ICs using an InP HEMT and AlGaAs/GaAs BCT technology were designed and fabricated. These IC's feature narrow-band matching circuits for input and output using transmission lines and uniplanar CPW-slot transition baluns for differential signals. The devices achieved high frequency operation of over 30 GHz with small phase deviations     

Experimental Studies of Transmission Bit-Rate for Teletext Signal in the 525-Line Television System

In order to investigate the optimum transmission bit-rate for teletext signals in the 525-line television system, laboratory and field tests were carried out using binary NRZ digital data signals of several bit-rates to 5.73 Mbit/s ( 364fH, 8/5fsc). In these tests, the bit-errors and eye-openings of PN signals were measured and subjective evaluation of teletext signals was also made under various receiving conditions. The results have indicated that a digital data signal of 5.73 Mbit/s could be utilized for teletext in the 525-line television system. The Japanese teletext system now being developed employs this bit-rate for transmitting and displaying the signals.     

A highly-integrated Doherty amplifier for CDMA handset applications using an active phase splitter

A highly-integrated "extended" Doherty-type amplifier has been developed for code-division multiple access (CDMA) applications. In order to overcome the size limit of the Doherty amplifiers for reduced form-factor applications such as handsets, bulky input quadrature coupler and output /spl lambda//4-line transformers have been replaced with an active phase splitter and lumped-element networks, respectively. The active phase splitter provides inherent gain and isolation. All the components except for the output circuits have been integrated on a single chip with a size of 1.1 mm/spl times/1.4 mm. The measured data of the proposed Doherty amplifier showed better than -45 dBc adjacent channel power ratio (ACPR) over the entire power range, and 16% and 38% efficiencies at 16 and 28 dBm, respectively. The average current consumption calculated using urban compact disk game (CDG) usage profile was reduced from 76 mA (conventional class-AB amplifier) to 31 mA using our approach. This concept can be applied to a variety of wireless TX applications requiring small form factors and enhanced efficiencies.     

Optical demultiplexing at 6 Gb/s using a semiconductor laser amplifier as an optical gate

A semiconductor laser amplifier (SLA) has been employed successfully for optical demultiplexing in two-channel optical time division multiplexed system experiments at 6 and 2 Gb/s. Demultiplexing of 6-Gb/s (2-Gb/s) signals was demonstrated with a power penalty of 1.6 dB (3.0 dB) at bit error rates of 10/sup -9/. It is also shown that a reduction of the generated amplified spontaneous emission can be obtained by optical gating/demultiplexing for systems incorporating inline amplifiers. A 0.5-dB improvement in sensitivity was achieved as a result of using an SLA for demultiplexing from 2.0 to 1.0 Gb/s in a system with one inline Er/sup 3+/-doped fiber amplifier.<>     

一种增益可控音频前置放大器电路的设计

设计了一种基于0.5μm CMOS工艺的增益可控音频前置放大器电路。该电路采用直流音量控制方式控制前置放大器的增益,进而实现整体音频放大器的音量控制。外部输入的直流模拟电压经过片内模数转换器转换成数字控制信号,控制前置放大器的输入电阻与反馈电阻的比值,从而实现前置放大器的增益控制。该放大器能够实现32档的音量控制范围,增益从-50 dB变化到25 dB,电路版图面积为1.2 mm×0.8 mm。     

A Parallel Power Amplifier With a Novel Mode Switching Control

Two parallel operating power amplifiers (PAs) are controlled by a novel mode switch for high efficiencies at both the back-off power region and high power region. The mode switch is realized by the base-collector (BC) junction diode which reuses the dc current of the low power mode amplifier. A 836 MHz CDMA PA has been demonstrated using InGaP/GaAs heterojunction bipolar transistor with fully integrated matching component for small package and low cost. It shows a 13 mA idle current, 15.4% power added efficiency (PAE), ACPR1 at 16 dBm of the low power mode operation and a 40.5% PAE, ACPR1 at 28 dBm of the high power mode operation.     

Design procedure of class-E amplifier for off-nominal operation at 50% duty ratio

Design equations for satisfying the off-nominal operating condition [i.e., only the zero-voltage switching (ZVS) condition] of the Class-E amplifier with a linear shunt capacitance at a duty ratio D=0.5 are derived. A new parameter s (V/s), called the slope of switch voltage when the switch turns on is introduced to obtain an image of the distance from the nominal conditions. By examining off-nominal Class-E operation degree of the design freedom of the Class-E amplifier increases by one. In addition various amplifier parameters such as operating frequency, output power, and load resistance range can be set as design specifications. For example, the peak switch voltage and switch current can be taken into account in the design procedure. Examples of a design procedure of the Class-E amplifier for off-nominal operation are given. The theoretical results were verified with PSpice simulation and experiments.     

W-band waveguide-packaged InP HEMT reflection grid amplifier

This letter presents a 79-GHz broadband reflection-type grid amplifier using spatial power combining to combine the power of 64 unit cells. Each unit cell uses a two-stage cascade configuration with InP HEMTs arranged as a differential pair. A broadband orthogonal mode transducer (OMT) separates two orthogonally polarized input and output signals over a 75 to 85GHz range. In conjunction with the OMT, a mode converter with quadruple-ridged apertures was designed to enhance the field uniformity over the active grid. Measurements show 5-dB small signal gain at 79GHz and an 800-MHz 3-dB bandwidth. The amplifier generates an output power of 264mW with little evidence of saturation.