SLAS468A June   2005  – August 2016 ADS7887 , ADS7888

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Companion Products
  6. 6 Device Comparison
  7. 7 Pin Configuration and Functions
  8. 8 Specifications
    1. 8.1 Absolute Maximum Ratings
    2. 8.2 ESD Ratings
    3. 8.3 Recommended Operating Conditions
    4. 8.4 Thermal Information
    5. 8.5 Electrical Characteristics - ADS7887
    6. 8.6 Electrical Characteristics - ADS7888
    7. 8.7 Timing Requirements
    8. 8.8 Typical Characteristics
      1. 8.8.1 ADS7887 and ADS7888
      2. 8.8.2 ADS7887 Only
      3. 8.8.3 ADS7888 Only
  9. 9 Detailed Description
    1. 9.1 Overview
      1. 9.1.1 Driving the VIN and VDD Pins of the ADS7887 and ADS7888
    2. 9.2 Functional Block Diagram
    3. 9.3 Feature Description
      1. 9.3.1 ADS7887 Operation
      2. 9.3.2 ADS7888 Operation
    4. 9.4 Device Functional Modes
      1. 9.4.1 Power-Down Mode
  10. 10Application and Implementation
    1. 10.1 Application Information
    2. 10.2 Typical Application
      1. 10.2.1 Design Requirements
      2. 10.2.2 Detailed Design Procedure
      3. 10.2.3 Application Curves
  11. 11Power Supply Recommendations
  12. 12Layout
    1. 12.1 Layout Guidelines
    2. 12.2 Layout Example
  13. 13Device and Documentation Support
    1. 13.1 Documentation Support
      1. 13.1.1 Related Documentation
    2. 13.2 Related Links
    3. 13.3 Receiving Notification of Documentation Updates
    4. 13.4 Community Resources
    5. 13.5 Trademarks
    6. 13.6 Electrostatic Discharge Caution
    7. 13.7 Glossary
  14. 14Mechanical, Packaging, and Orderable Information

Package Options

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

12 Layout

12.1 Layout Guidelines

Figure 43 shows a board layout example for the ADS7887 and ADS7888. Some of the key considerations are:

  1. Use a ground plane underneath the device and partition the PCB into analog and digital sections.
  2. Avoid crossing digital lines with the analog signal path.
  3. The power sources to the device must be clean and well-bypassed. Use 1-µF ceramic bypass capacitors in close proximity to the supply pin (VDD).
  4. Avoid placing vias between the VDD and bypass capacitors.
  5. Connect ground pin to the ground plane using short, low-impedance path.
  6. The fly-wheel RC filters are placed close to the device.

Among ceramic surface-mount capacitors, COG (NPO) ceramic capacitors provide the best capacitance precision. The type of dielectric used in COG (NPO) ceramic capacitors provides the most stable electrical properties over voltage, frequency, and temperature changes.

12.2 Layout Example

ADS7887 ADS7888 Figure43_SLAS468_crop.png Figure 43. ADS7887 and ADS7888 Example Layout