SBAS501D
May 2013 – May 2026
ADS1220
PRODUCTION DATA
1
1
Features
2
Applications
3
Description
4
Device Comparison Table
5
Pin Configuration and Functions
6
Specifications
6.1
Absolute Maximum Ratings
6.2
ESD Ratings
6.3
Recommended Operating Conditions
6.4
Thermal Information
6.5
Electrical Characteristics
6.6
SPI Timing Requirements
6.7
SPI Switching Characteristics
6.8
Timing Diagrams
6.9
Typical Characteristics
7
Parameter Measurement Information
7.1
Noise Performance
8
Detailed Description
8.1
Overview
8.2
Functional Block Diagram
8.3
Feature Description
8.3.1
Multiplexer
8.3.2
Low-Noise PGA
8.3.2.1
PGA Common-Mode Voltage Requirements
8.3.2.2
Bypassing the PGA
8.3.3
Voltage Reference
8.3.4
Clock Source
8.3.5
Modulator
8.3.6
Digital Filter
8.3.7
Output Data Rate
8.3.8
Excitation Current Sources
8.3.9
Low-Side Power Switch
8.3.10
Sensor Detection
8.3.11
System Monitor
8.3.12
Offset Calibration
8.3.13
Temperature Sensor
8.3.13.1
Converting From Digital Codes to Temperature
8.4
Device Functional Modes
8.4.1
Power-Up and Reset
8.4.2
Conversion Modes
8.4.2.1
Single-Shot Conversion Mode
8.4.2.2
Continuous Conversion Mode
8.4.3
Operating Modes
8.4.3.1
Normal Mode
8.4.3.2
Duty-Cycle Mode
8.4.3.3
Turbo Mode
8.4.3.4
Power-Down Mode
8.5
Programming
8.5.1
Serial Interface
8.5.1.1
Chip Select (CS)
8.5.1.2
Serial Clock (SCLK)
8.5.1.3
Data Ready ( DRDY)
8.5.1.4
Data Input (DIN)
8.5.1.5
Data Output and Data Ready (DOUT/DRDY)
8.5.1.6
SPI Timeout
8.5.2
Data Format
8.5.3
Commands
8.5.3.1
RESET (0000 011xb)
8.5.3.2
START/SYNC (0000 100xb)
8.5.3.3
POWERDOWN (0000 001xb)
8.5.3.4
RDATA (0001 xxxxb)
8.5.3.5
RREG (0010 rrnnb)
8.5.3.6
WREG (0100 rrnnb)
8.5.4
Reading Data
8.5.5
Sending Commands
8.5.6
Interfacing with Multiple Devices
8.6
Register Map
8.6.1
Configuration Registers
8.6.2
Register Descriptions
8.6.2.1
Configuration Register 0 (Address = 00h) [reset = 00h]
8.6.2.2
Configuration Register 1 (Address = 01h) [reset = 00h]
8.6.2.3
Configuration Register 2 (Address = 02h) [reset = 00h]
8.6.2.4
Configuration Register 3 (Address = 03h) [reset = 00h]
9
Application and Implementation
9.1
Application Information
9.1.1
Serial Interface Connections
9.1.2
Analog Input Filtering
9.1.3
External Reference and Ratiometric Measurements
9.1.4
Establishing a Proper Common-Mode Input Voltage
9.1.5
Unused Inputs and Outputs
9.1.6
Pseudo Code Example
9.2
Typical Applications
9.2.1
K-Type Thermocouple Measurement (–200°C to +1250°C)
9.2.1.1
Design Requirements
9.2.1.2
Detailed Design Procedure
9.2.1.3
Application Curves
9.2.2
3-Wire RTD Measurement (–200°C to +850°C)
9.2.2.1
Design Requirements
9.2.2.2
Detailed Design Procedure
9.2.2.2.1
Design Variations for 2-Wire and 4-Wire RTD Measurements
9.2.2.3
Application Curves
9.2.3
Resistive Bridge Measurement
9.2.3.1
Design Requirements
9.2.3.2
Detailed Design Procedure
9.3
Power Supply Recommendations
9.3.1
Power-Supply Sequencing
9.3.2
Power-Supply Ramp Rate
9.3.3
Power-Supply Decoupling
9.4
Layout
9.4.1
Layout Guidelines
9.4.2
Layout Example
10
Device and Documentation Support
10.1
Documentation Support
10.1.1
Related Documentation
10.2
Receiving Notification of Documentation Updates
10.3
Support Resources
10.4
Trademarks
10.5
Electrostatic Discharge Caution
10.6
Glossary
11
Revision History
12
Mechanical, Packaging, and Orderable Information
1
Features
Low current consumption:
As low as 120μA (typ) in duty-cycle mode
Wide supply range: 2.3V to 5.5V
Programmable gain: 1 to 128
Programmable data rates: Up to 2kSPS
Up to 20 Bits effective resolution
Simultaneous 50Hz and 60Hz rejection at
20SPS with single-cycle settling digital filter
Two differential or four single-ended inputs
Dual-matched programmable current sources:
10μA to 1.5mA
Internal 2.048V reference: 5ppm/°C (typ) drift
Internal 2% accurate oscillator
Internal temperature sensor:
0.5°C (typ) accuracy
SPI-compatible interface (mode 1)