AMIS-710216

AMIS-710216: 200dpi Two Level Digital Output Module Data Sheet 1.0 General Description The AMIS-710216 (PI216MC-DR) is a contact image sensor (CIS) module with an additional on board circuit that digitizes the analog pixels from the CIS image sensor to a “background-tracking”, two-level digital output signal. It is based on CIS module, the AMIS710209-A6 (PI209M-A6) manufactured by AMIS, but with a shorter read length of 88mm. Hence, its performance is equivalent to the AMIS-710209-A6 which uses MOS image sensor technology to gain its high-speed performance and high sensitivity. The AMIS-710216 is suitable for scanning documents with width of 88mm and with resolution of 8 dots per millimeter (dpm). It has broad applications, but it was especially designed for the following areas: • Where data compression is required, such as in data transmissions • Where component pin-out count must be kept to a minimum The background-tracking-digitizing circuits in the AMIS-710216 have been referred to as the “dynamic threshold” two-level A/D converter. For the purpose of describing the module’s characteristics this “dynamic threshold” processing circuit shall herein be referred to as the “tracking digitizer”. 2.0 Key Features • • • • • • • • • Light source, lens and sensor are integrated into a single module 8dpm resolution, 88mm scanning length Up to 176µsec/line scanning speed, with 4MHz pixel rate (See Table 3, Note 3) Wide dynamic range Two-level tracking digital output (“Dynamic Threshold Digitizer”) 660nm light source (other colors available) Compact size ≅ 13mm x 25.6mm x 102mm Low power Light weight 3.0 Module Description Figure 1: Block Diagram of AMIS-710216 AMI Semiconductor – May 06, M-20540-001 www.amis.com 1 AMIS-710216: 200dpi Two Level Digital Output Module Data Sheet The AMIS-710216 module consists of 11 sensors that are cascaded to provide 704 photo-detectors with their associated multiplex switches, and a digital shift register that controls its sequential readout. Mounted in the module is one-to-one graded-indexed micro lens array that focuses the scanned documents to image onto its sensing plane. A buffer amplifier amplifies the video pixels from the image sensors and passes them to analog digitizing circuit, where the video pixels are converted to digital signal and passed to output of the module. See Figure 1, the block diagram of the AMIS-710216 module. Illumination is accomplished by means of an integrated LED light source. All components are housed in a small plastic housing with a cover glass which acts as the focal point for the object being scanned and protects the imaging array, the micro lens assembly and the LED light source from dust. The pictorial of AMIS-710216 cross section is shown in Figure 2. Figure 2: Inside Pictorial of the Module I/O to the module is an 8-pin flex cable connector (see I/O Connector, under Specifications) located on one end of the module. The connector is on the top of the module with the glass window facing down and it is located on the opposite side of the module. See the Mechanical Housing under Mechanical Structure. AMI Semiconductor – May 06, M-20540-001 www.amis.com 2 AMIS-710216: 200dpi Two Level Digital Output Module 4.0 Circuit Description and Operation Data Sheet See Figure 3 for a simplified block diagram of the analog tracking digitizer. Fundamentally, the tracking digitizer transforms the signal output from a CIS module existing on the market today. It takes the analog signal from the CIS section of AMIS-710216 and derives a tracking background reference signal. Then this reference is compared against the output signals from the CIS section. The resulting signal from the comparison produces a two-level digital signal that is high when the pixel signal is brighter than the background and remains at zero as long as the signal is darker than the background signal. Figure 3: Analog Signal Reference Generator and a Single-bit Comparator Figure 1 depicts the two basic circuits, the CIS (image sensors and video amplifier) and the tracking digitizer. In the CIS section, the module has 11 serially concatenated AMIS-720234 (PI3034) image sensors, accordingly, the image sensors will span one scanningread line width that is 11 sensor times 64 pixel elements/sensor, or 704 pixel elements. In operation, the module produces the analog image pixel signals that are proportional to exposure on the corresponding picture element on the document (the video signal) then passes the signal to the tracking digitizer. In turn, the digitizer processes the analog image pixels to digital image pixels. The analog image pixels, at test point TV, are separated into two signals. One generates the reference signal and the other remains unmodified. These unmodified image pixels are applied to one of the input of the comparator. The reference signal is applied to the second input of the comparator. The results of the comparison are the digital image pixels. This digital output is produced in two levels, determined by the difference between the background reference signal and the analog image pixels. A digital pixel output of value “one” represents the analog image pixel that is brighter than the background and digital pixel level of value “zero” represents the image pixel that is darker than background. AMI Semiconductor – May 06, M-20540-001 www.amis.com 3 AMIS-710216: 200dpi Two Level Digital Output Module 5.0 Specifications The I/O connector pins and their functions is listed in Table 1. Table 1: Pin Configuration Pin Number 1 2 3 4 5 6 7 8 Symbol DIGOUT Vdd (+5V) Vn (-5V) SP GRD CLOCK GLED VLED Names and Functions Digital video output Ground; 0V Negative power supply Start pulse for the shift register Ground; 0V Clock for the shift register Return for the LED light source Power in for the LED light source. Data Sheet The connector is an 8-pin 1mm surface mount flex input, Molex 52207-0890. 5.1 Inputs There are five inputs: • • • • • Clock is on Pin 6 of the I/O connector. This is main clock input into the CIS module. SP is on Pin 4. This is the start clock input to the CIS module. VDD is on Pin 2. This is a +5V supply. VN is on Pin 3. This is a -5V supply. VLED is on Pin 8. This is a +5V supply for the LED light source. Note: Power return for the LED light source is GLED on Pin 7 and the ground return for the CIS modules is Pin 5. 5.2 Video Output DIGOUT is on Pin 1 of the I/O connector. This is the digital video output from the CIS module. Reflection off the dark target produces a digital signal of “0” level, while the white reflection off the white target produces a digital level of “one”. The amplitudes of the white and dark are listed in the table below: 6.0 Electro-Optical Characteristics (25°C) Table 2: Electro-Optical Characteristics (25 C) Parameter Number of photo detectors Pixel-to-pixel spacing Line scanning rate Clock frequency Bright output Dark output Note: 1. The tint is specified with a 2.0MHz clock frequency. In operation, the time constants in the reference generator is set to match the initial exposure time, hence the time constant will determine the optimum integration time. Note that the integration time is also a function of the clock frequency. Accordingly, it is highly recommended that the parameters be factory adjusted for the specific applications. Although the specification is shown nominally at 2.0MHz, the maximum clock frequency is 4.0MHz. ° Symbol Tint (1) Parameter 704 125 352 2.0 >3.5