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LM98714
Three Channel, 16-Bit, 45 MSPS Digital Copier Analog
Front End with Integrated CCD/CIS Sensor Timing
Generator and LVDS Output
General Description
The LM98714 is a fully integrated, high performance 16-Bit,
45 MSPS signal processing solution for digital color copiers,
scanners, and other image processing applications. Highspeed signal throughput is achieved with an innovative architecture utilizing Correlated Double Sampling (CDS), typically employed with CCD arrays, or Sample and Hold (S/H)
inputs (for Contact Image Sensors and CMOS image sensors). The signal paths utilize 8 bit Programmable Gain
Amplifiers (PGA), a +/-9-Bit offset correction DAC and independently controlled Digital Black Level correction loops for
each input. The PGA and offset DAC are programmed independently allowing unique values of gain and offset for each
of the three inputs. The signals are then routed to a 45MHz
high performance analog-to-digital converter (ADC). The
fully differential processing channel shows exceptional noise
immunity, having a very low noise floor of -74dB. The 16-bit
ADC has excellent dynamic performance making the
LM98714 transparent in the image reproduction chain.
Applications
n Multi-Function Peripherals
n Facsimile Equipment
n Flatbed or Handheld Color Scanners
n High-speed Document Scanner
Features
n LVDS/CMOS Outputs
n LVDS/CMOS Pixel Rate Input Clock or ADC Input Clock
n CDS or S/H Processing for CCD or CIS sensors
n Independent Gain/Offset Correction for Each Channel
n Digital Black Level Correction Loop for Each Channel
n Programmable Input Clamp Voltage
n Flexible CCD/CIS Sensor Timing Generator
Key Specifications
n Maximum Input Level 1.2 or 2.4 Volt Modes
n (both with + or - polarity option)
n ADC Resolution 16-Bit
n ADC Sampling Rate 45 MSPS
n INL +/- 23 LSB (typ)
n Channel Sampling Rate 15/22.5/30 MSPS
n PGA Gain Steps 256 Steps
n PGA Gain Range 0.7 to 7.84x
n Analog DAC Resolution +/-9 Bits
n Analog DAC Range +/-300mV or +/-600mV
n Digital DAC Resolution +/-6 Bits
n Digital DAC Range -1024 LSB to + 1008 LSB
n SNR -74dB (
@
0dB PGA Gain)
n Power Dissipation 505mW (LVDS) 610mW (CMOS)
n Operating Temp 0 to 70˚C
n Supply Voltage 3.3V Nominal (3.0V to 3.6V range)
System Block Diagram
20105370
October 2006
LM98714 - Three Channel, 16-Bit, 45 MSPS Digital Copier Analog Front End with Integrated
CCD/CIS Sensor Timing Generator and LVDS Output
© 2006 National Semiconductor Corporation DS201053 www.national.com
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LM98714 Overall Chip Block Diagram
20105301
FIGURE 1. Chip Block Diagram
LM98714
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LM98714 Pin Out Diagram
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FIGURE 2. LM98714 Pin Out Diagram
LM98714
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Typical Application Diagram
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FIGURE 3. Typical Application Diagram
LM98714
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