JAJSF13C March   2018  – January 2019 ADS1260 , ADS1261

PRODUCTION DATA.  

  1. 1 特長
  2. 2 アプリケーション
  3. 3 概要
    1.     Device Images
      1.      ブロック図
  4. 4 改訂履歴
  5. 5 概要（続き）
  6. 6 Device Comparison Table
  7. 7 Pin Configuration and Functions
    1.     Pin 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
    6. 8.6 Timing Requirements
    7. 8.7 Switching Characteristics
    8. 8.8 Typical Characteristics
  9. 9 Parameter Measurement Information
    1. 9.1 Noise Performance
  10. 10Detailed Description
    1. 10.1 Overview
    2. 10.2 Functional Block Diagram
    3. 10.3 Feature Description
      1. 10.3.1  Analog Inputs
        1. 10.3.1.1 ESD Diodes
        2. 10.3.1.2 Input Multiplexer
        3. 10.3.1.3 Temperature Sensor
        4. 10.3.1.4 Power-Supply Readback
        5. 10.3.1.5 Inputs Open
        6. 10.3.1.6 Internal VCOM Connection
        7. 10.3.1.7 Alternate Functions
      2. 10.3.2  PGA
        1. 10.3.2.1 PGA Bypass Mode
        2. 10.3.2.2 PGA Voltage Monitor
      3. 10.3.3  Reference Voltage
        1. 10.3.3.1 Internal Reference
        2. 10.3.3.2 External Reference
        3. 10.3.3.3 AVDD - AVSS Reference (Default)
        4. 10.3.3.4 Reference Monitor
      4. 10.3.4  Level-Shift Voltage (VBIAS)
      5. 10.3.5  Burn-Out Current Sources
      6. 10.3.6  Sensor-Excitation Current Sources (IDAC1 and IDAC2)
      7. 10.3.7  General-Purpose Input/Outputs (GPIOs)
      8. 10.3.8  Oversampling
      9. 10.3.9  Modulator
      10. 10.3.10 Digital Filter
        1. 10.3.10.1 Sinc Filter
          1. 10.3.10.1.1 Sinc Filter Frequency Response
        2. 10.3.10.2 FIR Filter
          1. 10.3.10.2.1 FIR Filter Frequency Response
        3. 10.3.10.3 Filter Bandwidth
        4. 10.3.10.4 50-Hz and 60-Hz Normal Mode Rejection
    4. 10.4 Device Functional Modes
      1. 10.4.1 Conversion Control
        1. 10.4.1.1 Continuous-Conversion Mode
        2. 10.4.1.2 Pulse-Conversion Mode
        3. 10.4.1.3 Conversion Latency
        4. 10.4.1.4 Start-Conversion Delay
      2. 10.4.2 Chop Mode
      3. 10.4.3 AC-Excitation Mode
      4. 10.4.4 ADC Clock Mode
      5. 10.4.5 Power-Down Mode
        1. 10.4.5.1 Hardware Power-Down
        2. 10.4.5.2 Software Power-Down
      6. 10.4.6 Reset
        1. 10.4.6.1 Power-on Reset
        2. 10.4.6.2 Reset by Pin
        3. 10.4.6.3 Reset by Command
      7. 10.4.7 Calibration
        1. 10.4.7.1 Offset and Full-Scale Calibration
          1. 10.4.7.1.1 Offset Calibration Registers
          2. 10.4.7.1.2 Full-Scale Calibration Registers
        2. 10.4.7.2 Offset Self-Calibration (SFOCAL)
        3. 10.4.7.3 Offset System-Calibration (SYOCAL)
        4. 10.4.7.4 Full-Scale Calibration (GANCAL)
        5. 10.4.7.5 Calibration Command Procedure
        6. 10.4.7.6 User Calibration Procedure
    5. 10.5 Programming
      1. 10.5.1 Serial Interface
        1. 10.5.1.1 Chip Select (CS)
        2. 10.5.1.2 Serial Clock (SCLK)
        3. 10.5.1.3 Data Input (DIN)
        4. 10.5.1.4 Data Output/Data Ready (DOUT/DRDY)
        5. 10.5.1.5 Serial Interface Auto-Reset
      2. 10.5.2 Data Ready (DRDY)
        1. 10.5.2.1 DRDY in Continuous-Conversion Mode
        2. 10.5.2.2 DRDY in Pulse-Conversion Mode
        3. 10.5.2.3 Data Ready by Software Polling
      3. 10.5.3 Conversion Data
        1. 10.5.3.1 Status byte (STATUS)
        2. 10.5.3.2 Conversion Data Format
      4. 10.5.4 CRC
      5. 10.5.5 Commands
        1. 10.5.5.1  NOP Command
        2. 10.5.5.2  RESET Command
        3. 10.5.5.3  START Command
        4. 10.5.5.4  STOP Command
        5. 10.5.5.5  RDATA Command
        6. 10.5.5.6  SYOCAL Command
        7. 10.5.5.7  GANCAL Command
        8. 10.5.5.8  SFOCAL Command
        9. 10.5.5.9  RREG Command
        10. 10.5.5.10 WREG Command
        11. 10.5.5.11 LOCK Command
        12. 10.5.5.12 UNLOCK Command
    6. 10.6 Register Map
      1. 10.6.1  Device Identification (ID) Register (address = 00h) [reset = xxh]
        1. Table 30. ID Register Field Descriptions
      2. 10.6.2  Device Status (STATUS) Register (address = 01h) [reset = 01h]
        1. Table 31. STATUS Register Field Descriptions
      3. 10.6.3  Mode 0 (MODE0) Register (address = 02h) [reset = 24h]
        1. Table 32. MODE0 Register Field Descriptions
      4. 10.6.4  Mode 1 (MODE1) Register (address = 03h) [reset = 01h]
        1. Table 33. MODE1 Register Field Descriptions
      5. 10.6.5  Mode 2 (MODE2) Register (address = 04h) [reset = 00h]
        1. Table 34. MODE2 Register Field Descriptions
      6. 10.6.6  Mode 3 (MODE3) Register (address = 05h) [reset = 00h]
        1. Table 35. MODE3 Register Field Descriptions
      7. 10.6.7  Reference Configuration (REF) Register (address = 06h) [reset = 05h]
        1. Table 36. REF Register Field Descriptions
      8. 10.6.8  Offset Calibration (OFCALx) Registers (address = 07h, 08h, 09h) [reset = 00h, 00h, 00h]
        1. Table 37. OFCAL0, OFCAL1, OFCAL2 Registers Field Description
      9. 10.6.9  Full-Scale Calibration (FSCALx) Registers (address = 0Ah, 0Bh, 0Ch) [reset = 00h, 00h, 40h]
        1. Table 38. FSCAL0, FSCAL1, FSCAL2 Registers Field Description
      10. 10.6.10 IDAC Multiplexer (IMUX) Register (address = 0Dh) [reset = FFh]
        1. Table 39. IMUX Register Field Descriptions
      11. 10.6.11 IDAC Magnitude (IMAG) Register (address = 0Eh) [reset = 00h]
        1. Table 40. IMAG Register Field Descriptions
      12. 10.6.12 Reserved (RESERVED) Register (address = 0Fh) [reset = 00h]
        1. Table 41. RESERVED Register Field Descriptions
      13. 10.6.13 PGA Configuration (PGA) Register (address = 10h) [reset = 00h]
        1. Table 42. PGA Register Field Descriptions
      14. 10.6.14 Input Multiplexer (INPMUX) Register (address = 11h) [reset = FFh]
        1. Table 43. INPMUX Register Field Descriptions
      15. 10.6.15 Input Bias (INPBIAS) Register (address = 12h) [reset = 00h]
        1. Table 44. INPBIAS Register Field Descriptions
  11. 11Application and Implementation
    1. 11.1 Application Information
      1. 11.1.1 Input Range
      2. 11.1.2 Input Overload
      3. 11.1.3 Burn-Out Current Source
      4. 11.1.4 Unused Inputs and Outputs
      5. 11.1.5 AC-Excitation
      6. 11.1.6 Serial Interface and Digital Connections
    2. 11.2 Typical Application
      1. 11.2.1 Design Requirements
      2. 11.2.2 Detailed Design Procedure
      3. 11.2.3 Application Curves
    3. 11.3 Initialization Setup
  12. 12Power Supply Recommendations
    1. 12.1 Power-Supply Decoupling
    2. 12.2 Analog Power-Supply Clamp
    3. 12.3 Power-Supply Sequencing
  13. 13Layout
    1. 13.1 Layout Guidelines
    2. 13.2 Layout Example
  14. 14デバイスおよびドキュメントのサポート
    1. 14.1 ドキュメントのサポート
      1. 14.1.1 関連資料
    2. 14.2 関連リンク
    3. 14.3 ドキュメントの更新通知を受け取る方法
    4. 14.4 コミュニティ・リソース
    5. 14.5 商標
    6. 14.6 静電気放電に関する注意事項
    7. 14.7 Glossary
  15. 15メカニカル、パッケージ、および注文情報

パッケージ・オプション

デバイスごとのパッケージ図は、PDF版データシートをご参照ください。

メカニカル・データ（パッケージ｜ピン）
  • RHB|32
サーマルパッド・メカニカル・データ
発注情報

10.1 Overview

The ADS1260 and ADS1261 are 5-channel and 10-channel, precision 24-bit, delta-sigma (ΔΣ) ADCs with an integrated analog front end (AFE) and voltage reference. The low-noise and low-drift architecture make the ADCs suitable for precision measurement of low signal level sensors, such as strain-gauge bridges, pressure transducers and temperature sensors.

Key features of the ADC are:

  • Very low noise, 1-GΩ input impedance PGA
  • High-precision, 24-bit ΔΣ ADC
  • Internal oscillator
  • 2.5-V voltage reference
  • Signal and voltage reference monitors
  • Excitation current sources
  • Input level-shift voltage
  • Sensor burn-out current sources
  • Temperature sensor
  • Cyclic redundancy check (CRC) communication error detection
  • Two voltage reference inputs ( ADS1261)
  • Four GPIO with AC-excitation ( ADS1261)

The analog inputs (AINx) connect to the input multiplexer (MUX). The ADC supports three (five) differential or five (ten) single-ended input configurations for the ADS1260 and ADS1261, respectively.

The programmable gain amplifier (PGA) follows the input multiplexer. The PGA is suitable for direct connection to low-level sensors. The gain is programmable from 1 to 128. The PGA bypass option connects the analog inputs directly to the precharge buffered modulator, extending the input voltage range to the power supplies. The PGA output connects to pins CAPP and CAPN. The ADC antialias filter is provided at the PGA output with an external capacitor.

The PGA is monitored to verify linear operation. Alarm bits in the status register set if the linear range of the PGA is exceeded.

A delta-sigma modulator measures the input voltage relative to the reference voltage to produce the 24-bit conversion result. The differential input range of the ADC is ±VREF / Gain.

The digital filter averages and decimates the modulator output data to yield the final, down-sampled conversion result. The sinc filter is programmable (sinc1 through sinc5) allowing optimization of conversion time, conversion noise and line-cycle rejection. The finite impulse response (FIR) filter mode provides single-cycle settled data with simultaneous rejection of 50-Hz and 60-Hz at data rates of 20 SPS or less.

The ADC reference is either 2.5-V internal, external or the 5-V analog power supply. The REFOUT pin provides the buffered reference voltage output. The external reference is monitored for low or missing voltage. The ADS1261 provides two voltage reference inputs, multiplexed with the analog inputs.

The ADC includes two current sources that provide excitation to resistive sensors (RTD). Additionally, the ADS1261 provides four GPIO control lines. The GPIOs are used for input and output of general-purpose logic signals, as well as providing drive signals for AC-excited bridges. The GPIOs are multiplexed to the analog inputs.

The temperature sensor and the power supply voltages are read through the multiplexer. The programmable burn-out test currents connect to the multiplexer output. The currents detect failed sensors or faults in the sensor connection. The level-shift voltage on AINCOM provides the bias for floating sensors.

The SPI-compatible serial interface is used to read the conversion data and also to configure and control the ADC. Data communication errors are detected by CRC. The serial interface consists of four signals: CS, SCLK, DIN and DOUT/DRDY. The dual function DOUT/DRDY provides data output and also the data ready signal. The ADC serial interface can be implemented with as little as three pins by tying CS low.

The ADC clock is either internal or external. The ADC detects the external clock automatically. The nominal clock frequency is 7.3728 MHz (10.24 MHz for 40-kSPS operation).

ADC conversions are controlled by the START pin or by the START command. The ADC is programmable for continuous or one-shot conversions. The DRDY or DOUT/DRDY pin provides the conversion data ready signal. When taken low, the RESET pin resets the ADC. The ADC is powered down by the PWDN pin or is powered down in software mode.

The ADC operates in either bipolar analog supply configuration (±2.5 V), or in a single 5-V supply configuration. The digital power supply range is 2.7 V to 5 V. The BYPASS pin is the internal subregulator output used for the ADC digital core.