LM9832

LM9832 42-Bit Color 1200dpi USB Image Scanner April 2000 N Image Scanner LM9832 42-Bit Color, 1200dpi USB General Description The LM9832 is a complete USB image scanner system on a single IC. The LM9832 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 LM9832 scans images in 42 bit color/14 bit gray, and has output data formats for 42 and 24 bit color/14 and 8 bit gray. The LM9832 supports sensors with pixel counts of up to 16384 pixels x 3 colors (1200 dpi x 13.6 inches). The LM9832’s 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. Features • 14 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 Applications • • • • • • • • • • Color Flatbed Document Scanners Color Sheetfed Document Scanners Key Specifications Analog to Digital Converter Resolution 14 Bits Maximum Pixel Conversion Rate 6MHz A4 Color 150dpi scan time