Features
| • | 48 bit color and 16 bit gray output modes |
| • | 16 bit ADC digitizes at up to 6Mpixels/s (2M RGB pixels/sec) |
| • | Digital Pixel Processing provides 1200, 800, 600, 400, 300, 200, 150, and 100dpi horizontal resolution from a 1200dpi sensor and 600, 400, 300, 200, 150, 100, 75, and 50dpi horizontal resolution from a 600dpi sensor |
| • | Provides 50-2400dpi vertical resolution in 1 dpi increments |
| • | Pixel rate error correction for gain (shading) and offset errors |
| • | Supports 4 or 16Mbit external DRAMs |
| • | Multiple CCD clocking rates allows matching of CCD clock to scan resolution and pixel depth for maximum scan speed |
| • | Stepper motor control tightly coupled with image data buffer management to maximize data transfer efficiency |
| • | PWM stepper motor current control allows microstepping for the price of fullstepping |
| • | USB interface for Plug and Play operation on USB-equipped computers |
| • | Serial EEPROM option for custom Vendor and Product IDs |
| • | Support for USB bus-powered operation |
| • | Pixel depths of 1, 2, or 4 bits are packed into bytes for faster scans of line art and low pixel depth images |
| • | Supports 3 channel CCDs and 1 channel CIS sensors |
| • | 3 (R, G, and B) 12-bit, user-programmable gamma correction tables |
| • | Compatible with a wide range of color linear CCDs and Contact Image Sensors (CIS) |
| • | Operates with 48MHz external crystal |
| • | Internal bandgap voltage reference |
| • | 100 pin TQFP package |
Description The LM9833 is a complete USB image scanner system on a single IC. The LM9833 provides all the functions (image sensor control, illumination control, analog front end, pixel processing function image data buffer/DRAM controller, microstepping motor controller, and USB interface) necessary to create a high performance color scanner. The LM9833 scans images in 48 bit color or 16 bit gray, and has output data formats for 24, 36, and 48 bit color or 8, 12, and 16 bit gray. The LM9833 supports sensors with pixel counts of up to 16384 pixels x 3 colors (1200 dpi x 13.6 inches).
The LM9833Æs low operating and suspend mode supply currents allow design of USB bus-powered scanners. The only additional active components required are an external 4Mbit or 16Mbit DRAM for data buffering and power transistors for the stepper motor.
Key Specification
| ò Analog to Digital Converter Resolution |
16 Bits |
| ò Maximum Pixel Conversion Rate |
6MHz |
| ò A4 Color 150dpi scan time |
<10 seconds |
| ò A4 Color 300dpi scan time |
<40 seconds |
| ò A4 Color 600dpi scan time |
<160 seconds |
| ò Maximum Operating Current Consumption |
136mA |
| ò Maximum Suspend Current Consumption |
175uA |
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Applications
| • | Color Flatbed Document Scanners |
| • | Color Sheetfed Document Scanners |
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