SBAS943A September   2018  – August 2019 ADS1284

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Device Images
      1.      Simplified Schematic
  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 Electrical Characteristics
    6. 6.6 Timing Requirements
    7. 6.7 Switching Characteristics
    8. 6.8 Typical Characteristics
  7. 7 Parameter Measurement Information
    1. 7.1 Noise Performance
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Analog Inputs and Multiplexer
      2. 8.3.2 Programmable Gain Amplifier (PGA)
      3. 8.3.3 Analog-to-Digital Converter (ADC)
        1. 8.3.3.1 Modulator
          1. 8.3.3.1.1 Modulator Overrange
          2. 8.3.3.1.2 Modulator Input Impedance
          3. 8.3.3.1.3 Modulator Overrange Detection (MFLAG)
          4. 8.3.3.1.4 Offset
          5. 8.3.3.1.5 Voltage Reference Inputs (VREFP, VREFN)
        2. 8.3.3.2 Digital Filter
          1. 8.3.3.2.1 Sinc Filter Section (sinx / x)
          2. 8.3.3.2.2 FIR Section
          3. 8.3.3.2.3 Group Delay and Step Response
            1. 8.3.3.2.3.1 Linear Phase Response
            2. 8.3.3.2.3.2 Minimum Phase Response
          4. 8.3.3.2.4 HPF Section
    4. 8.4 Device Functional Modes
      1. 8.4.1  Synchronization (SYNC PIN and SYNC Command)
        1. 8.4.1.1 Pulse-Sync Mode
        2. 8.4.1.2 Continuous-Sync Mode
      2. 8.4.2  Reset (RESET Pin and Reset Command)
      3. 8.4.3  Master Clock Input (CLK)
      4. 8.4.4  Power-Down (PWDN Pin and STANDBY Command)
      5. 8.4.5  Power-On Sequence
      6. 8.4.6  DVDD Power Supply
      7. 8.4.7  Serial Interface
        1. 8.4.7.1 Chip Select (CS)
        2. 8.4.7.2 Serial Clock (SCLK)
        3. 8.4.7.3 Data Input (DIN)
        4. 8.4.7.4 Data Output (DOUT)
        5. 8.4.7.5 Serial Port Auto Timeout
        6. 8.4.7.6 Data Ready (DRDY)
      8. 8.4.8  Data Format
      9. 8.4.9  Reading Data
        1. 8.4.9.1 Read-Data-Continuous Mode
        2. 8.4.9.2 Read-Data-By-Command Mode
      10. 8.4.10 One-Shot Operation
      11. 8.4.11 Offset and Full-Scale Calibration Registers
        1. 8.4.11.1 OFC[2:0] Registers
        2. 8.4.11.2 FSC[2:0] Registers
      12. 8.4.12 Calibration Commands (OFSCAL and GANCAL)
        1. 8.4.12.1 OFSCAL Command
        2. 8.4.12.2 GANCAL Command
      13. 8.4.13 User Calibration
    5. 8.5 Programming
      1. 8.5.1 Commands
        1. 8.5.1.1  SDATAC Requirements
        2. 8.5.1.2  WAKEUP: Wake-Up From Standby Mode
        3. 8.5.1.3  STANDBY: Standby Mode
        4. 8.5.1.4  SYNC: Synchronize the Analog-to-Digital Conversion
        5. 8.5.1.5  RESET: Reset the Device
        6. 8.5.1.6  RDATAC: Read Data Continuous
        7. 8.5.1.7  SDATAC: Stop Read Data Continuous
        8. 8.5.1.8  RDATA: Read Data by Command
        9. 8.5.1.9  RREG: Read Register Data
        10. 8.5.1.10 WREG: Write to Register
        11. 8.5.1.11 OFSCAL: Offset Calibration
        12. 8.5.1.12 GANCAL: Gain Calibration
    6. 8.6 Register Maps
      1. 8.6.1 Register Descriptions
        1. 8.6.1.1 ID_CFG: ID_Configuration Register (address = 00h) [reset =x0h]
        2. 8.6.1.2 CONFIG0: Configuration Register 0 (address = 01h) [reset = 52h]
        3. 8.6.1.3 CONFIG1: Configuration Register 1 (address = 02h) [reset = 08h]
        4. 8.6.1.4 HPF0 and HPF1 Registers
          1. 8.6.1.4.1 HPF0: High-Pass Filter Corner Frequency, Low Byte (address = 03h) [reset = 32h]
          2. 8.6.1.4.2 HPF1: High-Pass Filter Corner Frequency, High Byte (address = 04h) [reset = 03h]
        5. 8.6.1.5 OFC0, OFC1, OFC2 Registers
          1. 8.6.1.5.1 OFC0: Offset Calibration, Low Byte (address = 05h) [reset = 00h]
          2. 8.6.1.5.2 OFC1: Offset Calibration, Mid Byte (address = 06h) [reset = 00h]
          3. 8.6.1.5.3 OFC2: Offset Calibration, High Byte (address = 07h) [reset = 00h]
        6. 8.6.1.6 FSC0, FSC1, FSC2 Registers
          1. 8.6.1.6.1 FSC0: Full-Scale Calibration, Low Byte (address = 08h) [reset = 00h]
          2. 8.6.1.6.2 FSC1: Full-Scale Calibration, Mid Byte (address = 09h) [reset = 00h]
          3. 8.6.1.6.3 FSC2: Full-Scale Calibration, High Byte (address = 0Ah) [reset = 40h]
  9. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Applications
      1. 9.2.1 Geophone Interface
      2. 9.2.2 Digital Interface
    3. 9.3 Initialization Set Up
  10. 10Device and Documentation Support
    1. 10.1 Receiving Notification of Documentation Updates
    2. 10.2 Community Resources
    3. 10.3 Trademarks
    4. 10.4 Electrostatic Discharge Caution
    5. 10.5 Glossary
  11. 11Mechanical, Packaging, and Orderable Information

Package Options

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

8.4.1.2 Continuous-Sync Mode

In continuous-sync mode, either a single synchronization pulse or a continuous synchronization clock may be applied. Use the SYNC pin in this mode. When a single sync pulse is applied (rising edge), the device resynchronizes the same way as pulse-sync mode. ADC re-synchronization occurs only when the time between SYNC rising edges is not an integer multiple of the conversion period. When resynchronization occurs, DRDY continues to toggle at the period of the date rate, and the DOUT output is held low until data are ready (63 DRDY periods later). At the 63rd reading, conversion data are valid, as shown in Figure 53.

If an additional pulse is applied to the SYNC pin, the elapsed time from the previous pulse must be an integral multiple of the output data rate otherwise re-synchronization results.

If a synchronization clock is applied to the SYNC pin, the device resynchronizes only under the condition tSYNC ≠ N / fDATA, where N = 1, 2, 3, and so on. When re-synchronized, DRDY continues to strobe, but the data on DOUT is held low until new data are valid after filter reset. If the period of the synchronizing clock matches an integral multiple of the data rate, the ADC does not re-synchronize. Note that the phase of the applied clock and output data rate (DRDY) is not aligned because of the initial delay of DRDY after the SYNC clock is first applied. Figure 54 shows the timing for continuous-sync mode.

ADS1284 ai_tim_cont_sync_sbas565.gifFigure 54. Continuous-Sync Timing With SYNC Clock

Apply the synchronization clock after the continuous-sync mode is programmed. The first rising edge of SYNC then results in synchronization. Note that subsequent writes to any ADC register results in re-synchronization at the time of the register write operation. The re-synchronization leads to loss of the previous synchronization. Send the STANDBY command followed by the WAKEUP command to re-establish the previous synchronization. Re-synchronization occurs is valid as long as the time between the STANDBY and WAKEUP commands is not a multiple integer of the conversion period by at least one clock cycle.