SLAS605C June   2008  – July 2018 ADS7950 , ADS7951 , ADS7952 , ADS7953 , ADS7954 , ADS7955 , ADS7956 , ADS7957 , ADS7958 , ADS7959 , ADS7960 , ADS7961

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
    1.     Detailed Block Diagram
  3. 3 Description
  4. 4 Revision History
  5. 5 Device Comparison Table
  6. 6 Pin Configuration and Functions
    1.     Pin Functions: TSSOP Packages
    2.     Pin Functions: VQFN Packages
  7. 7 Specifications
    1. 7.1  Absolute Maximum Ratings
    2. 7.2  ESD Ratings
    3. 7.3  Recommended Operating Conditions
    4. 7.4  Thermal Information: TSSOP
    5. 7.5  Thermal Information: VQFN
    6. 7.6  Electrical Characteristics: ADS7950, ADS7951, ADS7952, ADS7953
    7. 7.7  Electrical Characteristics, ADS7954, ADS7955, ADS7956, ADS7957
    8. 7.8  Electrical Characteristics, ADS7958, ADS7959, ADS7960, ADS7961
    9. 7.9  Timing Requirements
    10. 7.10 Typical Characteristics (All ADS79xx Family Devices)
    11. 7.11 Typical Characteristics (12-Bit Devices Only)
    12. 7.12 Typical Characteristics (12-Bit Devices Only)
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Reference
      2. 8.3.2 Power Saving
    4. 8.4 Device Functional Modes
      1. 8.4.1 Channel Sequencing Modes
      2. 8.4.2 Device Programming and Mode Control
        1. 8.4.2.1 Mode Control Register
        2. 8.4.2.2 Program Registers
      3. 8.4.3 Device Power-Up Sequence
      4. 8.4.4 Operating in Manual Mode
      5. 8.4.5 Operating in Auto-1 Mode
      6. 8.4.6 Operating in Auto-2 Mode
      7. 8.4.7 Continued Operation in a Selected Mode
    5. 8.5 Programming
      1. 8.5.1 Digital Output
      2. 8.5.2 GPIO Registers
      3. 8.5.3 Alarm Thresholds for GPIO Pins
  9. 9 Application and Implementation
    1. 9.1 Application Information
      1. 9.1.1 Analog Input
    2. 9.2 Typical Applications
      1. 9.2.1 Unbuffered Multiplexer Output (MXO)
        1. 9.2.1.1 Design Requirements
        2. 9.2.1.2 Detailed Design Procedure
        3. 9.2.1.3 Application Curves
      2. 9.2.2 OPA192 Buffered Multiplexer Output (MXO)
        1. 9.2.2.1 Design Requirements
        2. 9.2.2.2 Detailed Design Procedure
        3. 9.2.2.3 Application Curves
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Examples
  12. 12Device and Documentation Support
    1. 12.1 Documentation Support
      1. 12.1.1 Related Documentation
    2. 12.2 Related Links
    3. 12.3 Receiving Notification of Documentation Updates
    4. 12.4 Community Resources
    5. 12.5 Trademarks
    6. 12.6 Electrostatic Discharge Caution
    7. 12.7 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

8.4.1 Channel Sequencing Modes

There are three modes for channel sequencing, namely Manual mode, Auto-1 mode, Auto-2 mode. Mode selection is done by writing into the Mode Control Register (refer to Table 1, Table 2, and Table 5). A new multiplexer channel is selected on the second falling edge of SCLK (as shown in Figure 1) in all three modes.

Manual mode: When configured to operate in Manual mode, the next channel to be selected is programmed in each frame and the device selects the programmed channel in the next frame. On powerup or after reset the default channel is 'Channel-0' and the device is in Manual mode.

Auto-1 mode: In this mode the device scans pre-programmed channels in ascending order. A new multiplexer channel is selected every frame on the second falling edge of SCLK. There is a separate Program Register for pre-programming the channel sequence. Table 3 and Table 4 show Auto-1 ‘program register’ settings.

Once programmed the device retains ‘Program Register settings until the device is powered down, reset, or reprogrammed. It is allowed to exit and re-enter the Auto-1 mode any number of times without disturbing ‘program register’ settings.

The Auto-1 program register is reset to FFFF/FFF/FF/F hex for the 16-, 12-, 8-, 4 channel devices respectively upon device powerup or reset; implying the device scans all channels in ascending order.

Auto-2 mode: In this mode the user can configure the program register to select the last channel in the scan sequence. The device scans all channels from channel 0 up to and including the last channel in ascending order. The multiplexer channel is selected every frame on the second falling edge of SCLK. There is a separate ‘program register’ for pre-programming of the last channel in the sequence (multiplexer depth). Table 6 lists the ‘Auto-2 prog’ register settings for selection of the last channel in the sequence.

Once programmed the device retains program register settings until the device is powered down, reset, or reprogrammed. It is allowed to exit and re-enter Auto-2 mode any number of times, without disturbing the ‘program register’ settings.

On powerup or reset the bits D9-D6 of the Auto-2 program register are reset to F/B/7/3 hex for the 16/12/8/4 channel devices respectively; implying the device scans all channels in ascending order.