AMIS-721250

AMIS-721250: Contact Image Sensor Data Sheet 1.0 General Description AMI Semiconductor’s AMIS-721250 (PI6050D) contact image sensor (CIS) is a selectable 600 or 1200 dot per inch (dpi) resolution linear image sensor, which employs AMI Semiconductor’s proprietary CMOS image sensing technology. The sensor contains an onchip output amplifier, power-down circuitry and parallel transfer features that are uniquely combined with the present-day active-pixelsensor technology. The image sensors are designed to be cascaded end-to-end on a printed circuit board (PCB) and packaged in an image sensing module. Applications for the sensor array includes facsimiles, PC scanners, check readers, and office automation equipment. Figure 1 is a block diagram of the sensor. Each sensor consists of 688 active pixels, their associated multiplexing switches, buffers, and an output amplifier circuit with a power down feature. The sensors pixel-pixel spacing is approximately 21.15µm. The size of each sensor without the scribe lines is 14560µm by 425µm. 2.0 Key Features • • • • • • • • • • • • 600 or 1200dpi selectable resolutions 344 or 688 image sensor elements (pixels) 21.15µm (1200dpi) pixel center-to-center spacing (47.24dots/mm) On-chip amplifier Single 5.0V power supply 3.3V input clocks 3.0MHz maximum pixel rate Parallel / integrate and transfer Power-down circuit High sensitivity Low power Low noise 14560µm 21.15µm 1 1 2 2 3 3 4 4 Row of 688 Pixels (1200dpi) or Selectable Row of 344 Pixels (600dpi) and Video Line Multiplexer 342 686 343 687 344 688 Parallel Transfer, Storage Cells and Readout Registers 425µm Amplifier, PowerDown and Offset Control SI GBST CLK SIC SC VDD VOUT VSS VREF SO Figure 1: Sensor Block Diagram AMI Semiconductor – Dec. 05, M-20496-004 www.amis.com 1 AMIS-721250: Contact Image Sensor 3.0 Unique Features There are six unique features incorporated into the AMIS-721250 which improve the sensor’s performance. 3.1 Pixel-to-Pixel Offset Cancellation Circuit Data Sheet The sensor employs a pixel-to-pixel offset cancellation circuit, which reduces the fix pattern noise (FPN), and amplifier offsets. In addition, this innovative circuit design greatly improves the optical linearity and low noise sensitivity. 3.2 Parallel Integrate, Transfer and Hold The sensor has a parallel integrate, transfer and hold feature, which allows the sensor to be read out while photon integration is taking place. These features are approached through the use of an integrate-and-hold cell, located at each pixel site. Each pixel’s charge is read from its storage site as the sensor’s shift register sequentially transfers each pixel’s charge onto a common video line. 3.3 Dual Scan Initiation Inputs, GBST and SI Each sensor has two scan initiation inputs, the global start pulse (GBST) and the start pulse (SI), which are compatible with standard 3.3V CMOS clocks. These clocks help to reduce the sensor-to-sensor transition FPN by initializing and preprocessing all sensors simultaneously before they start their readout scan. The internal shift register starts the scan after GBST is clocked in on the falling edge of the clock input (CLK). The start input control (SIC) selects the first sensor in a sequence of cascaded sensors to operate with 55 clock cycles of delay by connecting it to Vdd and to ground for all subsequent sensors. Then, only the first sensor clocks out 110 inactive pixels (55 clocks cycles) before accessing its first active pixel. During these 55 clock cycles, the first sensor and all of the subsequent cascaded sensors cycle through their pre-scan initialization process. After initialization, only the first sensor starts its read cycle with its first-active pixel appearing on the 56th clock cycle. The second and subsequent sensors await the entry of their SI. Furthermore, the first sensor’s SI is left unconnected, while the subsequent sensors all have their SI’s connected to the SO of their respective preceding sensor. The external scan SI is connected to all of the sensors' GBST inputs. For example in the 1200dpi mode, when the first sensor completes its scan, its end-of-scan (SO) appears on the falling edge of 389 clock cycle after the entry of GBST and 20 pixels before its last pixel, in order to have a continuous pixel readout between sensors in a module. This SO enters as the SI clock of the second and subsequent sensors; hence all subsequent sensors will start their register scan after each of the preceding sensors completes its scan. 3.4 Power Saving Each sensor incorporates a power-saving feature such that each chips amplifier is only turned on when its pixels are ready to be read out. 3.5 Common Reference Voltage between Cascaded Sensors Each sensor has an input/output bias control (VREF), which serves as an offset voltage reference. Each bias control pad is connected to an internal bias source and tied to its own amplifier’s reference bias input. In operation, these pads on every sensor are connected together. Each sensor then “shares” the same bias level to maintain a constant bias among all of the sensors. 3.6 Selectable Resolutions of 600dpi or 1200dpi The switch control input (SC) is connected to ground or to Vdd to set the sensor to operate in the 600dpi or 1200dpi mode, respectively. In the 1200dpi mode, all 688 pixels are clocked out, whereas in the 600dpi mode, pixels one and two are combined, three and four are combined and so on up to pixels 687 and 688 being combined. One half of the pixel amplifiers and one half of the scanning register are then disabled. As a result, sensitivity in the 600dpi mode will be twice that of the 1200dpi mode. The 600dpi readout time will be approximately half of the 1200dpi readout time. Unlike a CCD array, both the 600dpi and 1200dpi arrays can operate with the same clock frequency. th AMI Semiconductor – Dec. 05, M-20496-004 www.amis.com 2 AMIS-721250: Contact Image Sensor 4.0 Functional Description 4.1 Input/Output Terminals Data Sheet The AMIS-721250 image sensor has ten input and output (I/O) pads. Their symbols and function descriptions are listed in Table 1. Table 1: Input and Output Terminals Signal I/O Description Start pulse: SI I Input to start a line scan (see discussion of the sensors unique features for further details) Global start pulse: GBST I Globally initializes the start inputs of all sensors and starts the scanning process of the first sensor (see discussion of the sensors unique features for further details) Clock: CLK I Clock input for the shift register Start input control: SIC I Input to control the Start Pulse to the first sensor (see discussion of the sensors unique features for further details) Switch control: SC I Selects the 600 or 1200dpi mode (see discussion of the sensors unique features for further details) VDD I Power supply Video output voltage: VOUT O Output video signal from the amplifier VSS I Ground Reference voltage: VREF I/O Reference input voltage for the amplifier output. Sets the output’s reset (dark) level. End of scan pulse: SO O Output from the shift register at the end of a scan AMI Semiconductor – Dec. 05, M-20496-004 www.amis.com 3 AMIS-721250: Contact Image Sensor 4.2 Bonding Pad Layout Diagram Figure 2 shows the bonding pad locations for the AMIS-721250 sensor. 14560µm Data Sheet 425µm Y SI GBST CLK SIC SC VDD VOUT VSS VR SO X X Pad Location Table Pad SI GBST CLK SIC SC VDD VOUT VSS VREF SO Location Start Pulse Global Start Pulse Clock Start Input Control Switch Control Power Supply Video Output Voltage Ground Reference Voltage End of Scan Pulse Y 30 30 30 30 30 34 30 34 30 30 X 1000 3442 4199 4590 4945 5414 5820 10549 10909 13259 Notes: 1. The drawing is not to scale. 2. The die length and width are given in the above sensor die figure 3. Pad locations are listed in the Pad Location Table eg. Y X X SI GBST 4. Each pad is 120 x 80um 5. All dimensions are in um 6. Die size does not include the scribe line Figure 2: AMIS-721250 Bonding Pad Layout AMI Semiconductor – Dec. 05, M-20496-004 www.amis.com 4 AMIS-721250: Contact Image Sensor 4.3 Wafer Scribe Line Figure 3 outlines the scribe line dimensions surrounding the sensor die on a wafer. Data Sheet 60µm 15µm 425µm 55µm 14560µm 55µm 60µm Figure 3: Wafer Scribe Line 5.0 Electro-Optical Specifications Table 2 lists the electro-optical specifications of the AMIS-721250 sensor at 25°C and Vdd = 5.0V. Table 2: Electro-Optical Specifications Parameter (1) Number of pixels (1) Pixel-to-pixel spacing (2) Sensitivity @ 600dpi Sensitivity @ 1200dpi (3) Saturation voltage (4) Photo-response non-uniformity (5) Adjacent photo-response non-uniformity (6) Dark output voltage level (7) Dark output non-uniformity (8) Random thermal noise (rms) (9) Sensor-to-sensor photo-response non-uniformity (10) Photo response linearity Analog output drive current Symbol Min. 344 or 688 42.3 / 21.15 Typ. Max. 344 or 688 42.3 / 21.15 Units µm V / uJ / cm 15 15 1.7 100 3.0 10 2 >1.0 Volts % % V mV mV % % mA 2 Sv VSat Up Upn Vd Ud Vno Usensor PRL Iout 1220 610 1.65 Notes for Table 2 are listed on the next page under “Definitions of Electro-Optical Specifications”. AMI Semiconductor – Dec. 05, M-20496-004 www.amis.com 5 AMIS-721250: Contact Image Sensor 5.1 Definitions of Electro-optical Specifications Data Sheet ° All electrical specifications are measured at a pixel rate of 2.5MHz, a temperature of 25 C, Vdd=5.0V, Vref=1.7V and at an integration time of 2.2ms for 600dpi and 4.4ms for 1200dpi. The average output voltage (Vpavg) is adjusted to approximately 1.0V, unless stated otherwise. The modules’ internal Green LED (525 ± 20nm) was used as the light source for measurements requiring illumination. As a guideline, the recommended load on the output should be 1KΩ