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

7.3.4 Programmable Analog Offset Correction

The LM98640QML-SP provides two analog DACs per channel to provide flexibility in offset control. Each channel has a Coarse DAC and Fine DAC which have ±8-bit resolutions (8 bit + Sign). The two DACs can be used independently or as Coarse/Fine configuration. The Coarse DAC provides a sufficient range with moderate step sizes, while the Fine DAC is for designs which need a finely tuned offset. The correction voltage is applied to the "Video" level for both Sample & Hold and CDS input modes. Because of the DACs location in the signal path, the correction range lowers as CDS gain increases, and the output referred correction steps and ranges increase with PGA gain. Table 1 provides the range and step size of each DAC.

Table 1. Analog Offset DAC Specifications

CDS/SH GAIN RANGE(1) STEP SIZE(1) OUTPUT ADC CODES
Coarse DAC 1x ±250 mV 1 mV ±2048
2x ±125 mV 500 µV ±2048
Fine DAC 1x ±5 mV 20 µV ±41
2x ±2.5 mV 10 µV ±41
(1) Referred to Input

To use the Offset Correction DACs, the Coarse DAC and Fine DAC must be enabled using bits[6:5] of the Main Configuration Register (0x00). Then the desired correction value should be entered into the CDAC or FDAC register of the appropriate channel. The Offset Correction DACs use a signed binary format which is summarized in Table 2.

Table 2. Analog Offset Correction DAC Format

CDAC / FDAC INPUT VALUE CDAC CORRECTION (CODES) FDAC CORRECTION (CODES)
1 1111 1111 +2048 +41
1 0111 1111 +1024 +20
0 1111 1111 0 0
0 0111 1111 –1024 –20
0 0000 0000 –2048 –41