SBAS565C January   2014  – August 2019 ADS1283

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
    1.     Simplified Schematic
  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 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 Stage (sinx / x)
          2. 8.3.3.2.2 FIR Stage
          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 Stage
      4. 8.3.4 Master Clock Input (CLK)
    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  Power-Down (PWDN Pin and STANDBY Command)
      4. 8.4.4  Power-On Sequence
      5. 8.4.5  DVDD Power Supply
      6. 8.4.6  Serial Interface
        1. 8.4.6.1 Chip Select (CS)
        2. 8.4.6.2 Serial Clock (SCLK)
        3. 8.4.6.3 Data Input (DIN)
        4. 8.4.6.4 Data Output (DOUT)
        5. 8.4.6.5 Serial Port Auto Timeout
        6. 8.4.6.6 Data Ready (DRDY)
      7. 8.4.7  Data Format
      8. 8.4.8  Reading Data
        1. 8.4.8.1 Read-Data-Continuous Mode
        2. 8.4.8.2 Read-Data-By-Command Mode
      9. 8.4.9  One-Shot Operation
      10. 8.4.10 Offset and Full-Scale Calibration Registers
        1. 8.4.10.1 OFC[2:0] Registers
        2. 8.4.10.2 FSC[2:0] Registers
      11. 8.4.11 Calibration Commands (OFSCAL and GANCAL)
        1. 8.4.11.1 OFSCAL Command
        2. 8.4.11.2 GANCAL Command
      12. 8.4.12 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

8.3.1 Analog Inputs and Multiplexer

A diagram of the input multiplexer is shown in Figure 25.

ADS1283 ai_ana_in_mux_bas418.gifFigure 25. Analog Inputs and Multiplexer

ESD diodes protect the multiplexer inputs. If either input is taken below AVSS – 0.3 V, or above AVDD + 0.3 V, the ESD protection diodes can turn on. If these conditions are possible, use external clamp diodes, series resistors, or both to limit the input current to safe values (see the Absolute Maximum Ratings table).

Also, overdriving one unused input can affect the conversions of the other input. If an overdriven input interacts with the measured input, clamp the overdriven signal with external Schottky diodes.

The specified input operating range of the PGA is shown in Equation 2:

Equation 2. ADS1283 q_avss-0p1v_bas418.gif

For best operation, maintain absolute input levels (input signal level and common-mode level) within these limits.

The multiplexer connects one of the two external differential inputs to the preamplifier inputs, in addition to internal connections for various self-test modes. Table 3 summarizes the multiplexer configurations for Figure 25.

Table 3. Multiplexer Modes

MUX[2:0] SWITCHES DESCRIPTION
000 S1, S5 AINP1 and AINN1 connected to preamplifier
001 S2, S6 AINP2 and AINN2 connected to preamplifier
010 S3, S4 Preamplifier inputs shorted together through 400-Ω internal resistors
011 S1, S5, S2, S6 AINP1, AINN1 and AINP2, AINN2 connected together and to the preamplifier
100 S6, S7 External short, preamplifier inputs shorted to AINN2 (common-mode test)

The typical on-resistance (RON) of the multiplexer is 30 Ω (each switch). When the multiplexer is used to drive an external load on one input by a signal generator on the other input, on-resistance and on-resistance amplitude dependency can lead to measurement errors. Figure 26 shows THD versus load resistance and amplitude. THD improves with high-impedance loads and with lower-amplitude drive signals. The data are measured with the circuit from Figure 27 with MUX[2:0] = 011.

ADS1283 ai_thd-ch_load_bas418.gifFigure 26. THD vs External Load and Signal Magnitude (PGA); See Figure 27
ADS1283 ai_input1-2_bas565.gifFigure 27. Driving an External Load Through the Multiplexer