SNAS461G May   2010  – November 2018 LM98640QML-SP

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
    1.     Pin Functions
  6. 6 Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 ESD Ratings    
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information         
    5. 6.5 Quality Conformance Inspection
    6. 6.6 LM98640QML-SP Electrical Characteristics
    7. 6.7 AC Timing Specifications
    8. 6.8 Typical Performance Characteristics
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Input Sampling Modes
        1. 7.3.1.1 Sample & Hold Mode
          1. 7.3.1.1.1 Sample & Hold Mode CLAMP/SAMPLE Adjust
        2. 7.3.1.2 CDS Mode
          1. 7.3.1.2.1 CDS Mode Bimodal Offset
          2. 7.3.1.2.2 CDS Mode CLAMP/SAMPLE Adjust
      2. 7.3.2 Input Bias and Clamping
        1. 7.3.2.1 Sample and Hold Mode Biasing
        2. 7.3.2.2 CDS Mode Biasing
        3. 7.3.2.3 VCLP DAC
      3. 7.3.3 Programmable Gain
        1. 7.3.3.1 CDS/SH Stage Gain
        2. 7.3.3.2 PGA Gain Plots
      4. 7.3.4 Programmable Analog Offset Correction
      5. 7.3.5 Analog to Digital Converter
      6. 7.3.6 LVDS Output
        1. 7.3.6.1 LVDS Output Voltage
        2. 7.3.6.2 LVDS Output Modes
        3. 7.3.6.3 TXFRM Output
          1. 7.3.6.3.1 Output Mode 1 - Dual Lane
          2. 7.3.6.3.2 Output Mode 2 - Quad Lane
      7. 7.3.7 Clock Receiver
      8. 7.3.8 Power Trimming
    4. 7.4 Device Functional Mode
      1. 7.4.1 Powerdown Modes
      2. 7.4.2 LVDS Test Modes
        1. 7.4.2.1 Test Mode 0 - Fixed Pattern
        2. 7.4.2.2 Test Mode 1 - Horizontal Gradient
        3. 7.4.2.3 Test Mode 2 - Vertical Gradient
        4. 7.4.2.4 Test Mode 3 - Lattice Pattern
        5. 7.4.2.5 Test Mode 4 - Stripe Pattern
        6. 7.4.2.6 Test Mode 5 - LVDS Test Pattern (Synchronous)
        7. 7.4.2.7 Test Mode 6 - LVDS Test Pattern (Asynchronous)
        8. 7.4.2.8 Pseudo Random Number Mode
    5. 7.5 Programming
      1. 7.5.1 Serial Interface
      2. 7.5.2 Writing to the Serial Registers
      3. 7.5.3 Reading the Serial Registers
      4. 7.5.4 Serial Interface Timing Details
    6. 7.6 Register Maps
      1. 7.6.1 Register Definitions
  8. 8 Application and Implementation
    1. 8.1 Application Information
      1. 8.1.1 Total Ionizing Dose
      2. 8.1.2 Single Event Latch-Up and Functional Interrupt
      3. 8.1.3 Single Event Effects
    2. 8.2 Typical Application
      1. 8.2.1 Sample/Hold Mode
    3. 8.3 Initialization Set Up
  9. 9 Layout
    1. 9.1 Layout Guidelines
      1. 9.1.1 Power Planes
      2. 9.1.2 Bypass Capacitors
      3. 9.1.3 Ground Plane
      4. 9.1.4 Thermal Management
  10. 10Device and Documentation Support
    1. 10.1 Device Support
      1. 10.1.1 Development Support
        1. 10.1.1.1 Evaluation Board
        2. 10.1.1.2 Register Programming Software
    2. 10.2 Receiving Notification of Documentation Updates
    3. 10.3 Community Resources
    4. 10.4 Export Control Notice
    5. 10.5 Trademarks
    6. 10.6 Electrostatic Discharge Caution
    7. 10.7 Glossary
  11. 11Mechanical, Packaging, and Orderable Information
    1. 11.1 Engineering Samples

Package Options

Refer to the PDF data sheet for device specific package drawings

Mechanical Data (Package|Pins)
  • NBB|68
Thermal pad, mechanical data (Package|Pins)
Orderable Information

7.3.2.1 Sample and Hold Mode Biasing

Proper DC biasing of the CCD waveform in Sample and Hold mode is critical for realizing optimal operating conditions. In Sample/Hold Mode, the DC bias point of the input pin is typically set by actuating the input clamp switch (see Figure 17) during optical black pixels which connects the input pins to the VCLP pin DC voltage. The signal controlling this switch is CLPIN. CLPIN is an external signal connected on the CLPIN pin.

Actuating the input clamp will force the average value of the CCD waveform to be centered around the VCLP DC voltage. During Optical Black Pixels, the CCD output has roughly three components. The first component of the pixel is a “Reset Noise” peak followed by the Reset (or Pedestal) Level voltage, then finally the Black Level voltage signal. Taking the average of these signal components will result in a final “clamped” DC bias point that is close to the Black Level signal voltage.

To provide a more precise DC bias point (i.e. a voltage closer to the Black Level voltage), the CLPIN pulse can be “gated” by the internally generated CLAMP clock. This resulting CLPINGATED signal is the logical “AND” of the CLAMP and CLPIN signals as shown in Figure 18. By using the CLPINGATED signal, the higher Reset Noise peak will not be included in the clamping period and only the Pedestal Level components of the CCD waveform will be centered around VCLP.

LM98640QML-SP 30064710.gifFigure 19. Sample and Hold Mode Simplified Input Diagram

In Sample and Hold Mode, the impedance of the analog input pins is dominated by the switched capacitance of the CDS/Sample and Hold amplifier. The amplifier switched capacitance, shown as CS in Figure 19, and internal parasitic capacitances can be estimated by a single capacitor switched between the analog input and the VCLP reference pin for Sample and Hold mode. During each pixel cycle, the modeled capacitor, CSH, is charged to the OSX+ minus OSX– voltage then discharged. The average input current at the OSX– pin can be calculated knowing the input signal amplitude and the frequency of the pixel.

LM98640QML-SP 30064711.gifFigure 20. Equivalent Input Switched Capacitance S/H Mode