SNAS474H April   2009  – March 2015 LM98725

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
  6. 6 Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 Handling Ratings
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Electrical Characteristics
    5. 6.5 AC Timing Specifications
    6. 6.6 Serial Interface Timing Details
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagrams
      1. 7.2.1 LM98725 Overall Chip Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1  Modes of Operation Introduction
      2. 7.3.2  Mode 3 - Three Channel Input/Synchronous Pixel Sampling
      3. 7.3.3  Mode 2 - Two Channel Input/Synchronous Pixel Sampling
      4. 7.3.4  Mode 1 - One Channel Input
      5. 7.3.5  CIS Lamp and Coefficient Modes
      6. 7.3.6  Clock Sources
        1. 7.3.6.1 User Provided Clock Signal
        2. 7.3.6.2 Crystal Oscillator Driver On-Chip
        3. 7.3.6.3 Clock Multiplication - Basic
        4. 7.3.6.4 Clock Multiplication - Flexible
      7. 7.3.7  Clock Sources - Additional Settings and Flexibility
      8. 7.3.8  Spread Spectrum Clock Generation (SSCG)
      9. 7.3.9  Typical EMI Cases and Recommended SSCG Settings
      10. 7.3.10 Recommended Master/Slave, Clock Source and SSCG Combinations and Settings
        1. 7.3.10.1 Master Mode Operation (LM98725 Controls Line Timing)
        2. 7.3.10.2 Slave Mode Operation (Host FPGA or ASIC Controls Line Timing)
        3. 7.3.10.3 SSCG Configuration/Usage Flow
        4. 7.3.10.4 Changing SSCG Settings
    4. 7.4 Device Functional Modes
      1. 7.4.1  Mode 3 - Three Channel Input/Synchronous Pixel Sampling
      2. 7.4.2  Mode 2 - Two Channel Input/Synchronous Pixel Sampling
      3. 7.4.3  Mode 1 - One Channel Input
      4. 7.4.4  Input Bias and Clamping
        1. 7.4.4.1 Input Bias and Clamping - AC Coupled Applications
      5. 7.4.5  Sample/Hold Mode
      6. 7.4.6  DC Coupled Applications
      7. 7.4.7  Input Source Follower Buffers
      8. 7.4.8  CDS Mode
      9. 7.4.9  VCLP DAC
      10. 7.4.10 Gain and Offset Correction
        1. 7.4.10.1 Analog Offset
        2. 7.4.10.2 Digital Offset
        3. 7.4.10.3 Even/Odd Offset Coefficients
      11. 7.4.11 LM98725 Typical Line Timing and Pixel Gain Regions
      12. 7.4.12 Automatic Black and White Level Calibration Loops
        1. 7.4.12.1 Calibration Overview
        2. 7.4.12.2 Different Modes for Different Needs
        3. 7.4.12.3 Calibration Initiation
        4. 7.4.12.4 Key Calibration Settings
        5. 7.4.12.5 General Black Loop Operation
        6. 7.4.12.6 ADAC/DDAC Convergence
        7. 7.4.12.7 General White Loop Operation
        8. 7.4.12.8 White Loop Modes
        9. 7.4.12.9 Bimodal (Automatic) Correction
      13. 7.4.13 Coarse Pixel Phase Alignment
      14. 7.4.14 Internal Sample Timing
        1. 7.4.14.1 CCD Timing Generation
          1. 7.4.14.1.1 CCD Timing Generation
        2. 7.4.14.2 SH Interval Details - Multiple States Defined within SH Interval
        3. 7.4.14.3 SH Outputs - Low Speed Line Timing Usage
        4. 7.4.14.4 Controlled Inversion
      15. 7.4.15 CCD Timing Generator Master/Slave Modes
        1. 7.4.15.1 Master Timing Generator Mode
        2. 7.4.15.2 Slave Timing Generator Mode
        3. 7.4.15.3 Multiple SH Intervals
        4. 7.4.15.4 Support for CIS Sensors
        5. 7.4.15.5 LVDS Output Format - LM98714 Mode
      16. 7.4.16 LVDS Control Bit Coding - LM98714 Mode
        1. 7.4.16.1 Latency Compensation of CB Bits
      17. 7.4.17 Flexible LVDS Formatting Mode: Mapping
        1. 7.4.17.1 TXOUT0 Disable
        2. 7.4.17.2 Parity
        3. 7.4.17.3 Latency Compensation of CB Bits
      18. 7.4.18 LVDS Data Randomization for EMI Reduction
        1. 7.4.18.1 Mode 00: Scrambler Disabled
        2. 7.4.18.2 Mode 01: Full Scrambler Using the full 21-bit Pseudo Random Sequence
        3. 7.4.18.3 Mode 10: One Bit Scrambler Using the PRS Shift Bit Only, Sending This Bit Out on a CB Bit
        4. 7.4.18.4 Mode 11: “LSB” Scrambler
        5. 7.4.18.5 Scrambler Inhibit Bit Select
      19. 7.4.19 LVDS Drive Strength Adjust
      20. 7.4.20 LVDS Output Timing Details
        1. 7.4.20.1 Optional TXCLK Delay
      21. 7.4.21 LVDS Data Latency Diagrams
      22. 7.4.22 Data Test Patterns
        1. 7.4.22.1 LVDS Output Pattern Modes
          1. 7.4.22.1.1 Worst Case Transitions (Alternating 0x2A/0x55 on Each LVDS Pair)
          2. 7.4.22.1.2 Fixed Output Data
        2. 7.4.22.2 AFE Output Pattern Modes
          1. 7.4.22.2.1 Up-Counter Data
          2. 7.4.22.2.2 Fixed AFE Pattern
      23. 7.4.23 CMOS Output Format
      24. 7.4.24 CMOS Output Data Latency Diagrams
      25. 7.4.25 Serial Interface
        1. 7.4.25.1 Serial Interface Operating Modes
        2. 7.4.25.2 Serial Interface in Absence of MCLK
        3. 7.4.25.3 Writing to the Serial Registers
        4. 7.4.25.4 Reading the Serial Registers
        5. 7.4.25.5 LM98714 Compatible 3 Wire Serial Signaling
    5. 7.5 Register Maps
      1. 7.5.1 Configuration Registers
        1. 7.5.1.1 Register Summary Table
  8. 8 Layout
    1. 8.1 Layout Example
  9. 9 Device and Documentation Support
    1. 9.1 Trademarks
    2. 9.2 Device Support
    3. 9.3 Electrostatic Discharge Caution
    4. 9.4 Glossary
  10. 10Mechanical, Packaging, and Orderable Information

パッケージ・オプション

メカニカル・データ（パッケージ｜ピン）
サーマルパッド・メカニカル・データ
発注情報

1 Features

  • LVDS/CMOS Outputs
  • LVDS/CMOS/Crystal Clock Source with PLL Multiplication
  • Integrated Flexible Spread Spectrum Clock Generation
  • CDS or S/H Processing for CCD or CIS Sensors
  • Independent Gain/Offset Correction for Each Channel
  • Automatic per-Channel Gain and Offset Calibration
  • Programmable Input Clamp Voltage
  • Flexible CCD/CIS Sensor Timing Generator

2 Applications

  • Multi-Function Peripherals
  • High-speed Currency/Check Scanners
  • Flatbed or Handheld Color Scanners
  • High-speed Document Scanners
  • Key Specifications:
    • Maximum Input Level
      • 1.2 or 2.4 Volt Modes
      • (Both with + or - Polarity Option)
    • ADC Resolution: 16-Bit
    • ADC Sampling Rate: 81 MSPS
    • INL: +17/- 28 LSB (typ)
    • Channel Sampling Rate: 30/30/27 MSPS
    • PGA Gain Steps: 256 Steps
    • PGA Gain Range: 0.62 to 8.3x
    • Analog DAC Resolution: ±9 Bits
    • Analog DAC Range: ±307 mV or ±614 mV
    • Digital DAC Resolution: ±6 Bits
    • Digital DAC Range: -2048 LSB to + 2016 LSB
    • SNR: –74dB (@0 dB PGA Gain)
    • Power Dissipation: 755 mW (LVDS)
    • Operating Temp: 0 to 70°C
    • Supply Voltage: 3.3 V Nominal (3.0-V to 3.6-V Range)

3 Description

The LM98725 is a fully integrated, high performance 16-Bit, 81 MSPS signal processing solution for digital color copiers, scanners, and other image processing applications. The LM98725 achieves high-speed signal throughput with an innovative architecture utilizing Correlated Double Sampling (CDS), typically employed with CCD arrays, or Sample and Hold (S/H) inputs (for higher speed CCD or 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 independently programmed PGA and offset DAC allow unique values of gain and offset for each of the three analog inputs. The signals are then routed to a 81 MHz high performance analog-to-digital converter (ADC). The fully differential processing channel shows exceptional noise immunity with a very low noise floor of –74 dB. The 16-bit ADC has excellent dynamic performance making the LM98725 transparent in the image reproduction chain.

A very flexible integrated Spread Spectrum Clock Generation (SSCG) modulator is included to assist with EM compliance and reduce system costs.

Device Information(1)

PART NUMBER PACKAGE BODY SIZE (NOM)
LM98725 TSSOP (56) 14.0 mm × 6.10 mm
  1. For all available packages, see the orderable addendum at the end of the datasheet.

System Block Diagram

LM98725 30085370.gif

4 Revision History

Changes from G Revision (October 2014) to H Revision

Changes from F Revision (January 2014) to G Revision

  • Added, updated, or renamed the following sections: Device Information Table, Pin Configuration and Functions; Layout; Device and Documentation Support; Mechanical, Packaging, and Ordering Information Go
  • Added "Note" in Serial InterfaceGo

Changes from E Revision (April 2013) to F Revision

  • Added content from System Overview section to end of document. Go

Changes from D Revision (April 2009) to E Revision

  • Changed layout of National Data Sheet to TI formatGo