SBASAE3
December 2025
ADS125H18
PRODUCTION DATA
1
1
Features
2
Applications
3
Description
4
Pin Configuration and Functions
5
Specifications
5.1
Absolute Maximum Ratings
5.2
ESD Ratings
5.3
Recommended Operating Conditions
5.4
Thermal Information
5.5
Electrical Characteristics
5.6
Timing Requirements
5.7
Switching Characteristics
5.8
Timing Diagrams
5.9
Typical Characteristics
6
Parameter Measurement Information
6.1
Offset Error Measurement
6.2
Offset Drift Measurement
6.3
Gain Error Measurement
6.4
Gain Drift Measurement
6.5
NMRR Measurement
6.6
CMRR Measurement
6.7
PSRR Measurement
6.8
SNR Measurement
6.9
INL Error Measurement
6.10
THD Measurement
6.11
SFDR Measurement
6.12
Noise Performance
6.13
TUE (Total Unadjusted Error) Measurement
7
Detailed Description
7.1
Overview
7.2
Functional Block Diagram
7.3
Feature Description
7.3.1
Voltage Divider and Input Multiplexer
7.3.2
Input Range
7.3.3
ADC Reference Voltage
7.3.4
Power Supplies
7.3.4.1
AVDD and AVSS
7.3.4.2
IOVDD
7.3.4.3
CAPA and CAPD
7.3.4.4
Power-On Reset (POR)
7.3.5
Clock Operation
7.3.5.1
Internal Oscillator
7.3.5.2
External Clock
7.3.6
Modulator
7.3.7
Digital Filter
7.3.7.1
Digital Filter Latency
7.3.7.2
Sinc3 and Sinc4 Filters
7.3.7.3
Sinc4 + Sinc1 Cascade Filter
7.3.7.4
50/60Hz Notch Filters
7.3.8
FIFO Buffer
7.3.8.1
FIFO Buffer Read and Write
7.3.8.2
FIFO Overflow and Underflow
7.3.8.3
FIFO Depth Indicator
7.3.8.4
FIFO Enable and Flush
7.3.8.5
FIFO Thresholds
7.3.9
Channel Auto-Sequencer
7.3.9.1
Auto-Sequencer: Basic Operation
7.3.9.2
Sequencer Modes
7.3.9.2.1
Single-Shot Mode
7.3.9.2.2
Single Step Continuous Conversion Mode
7.3.9.2.3
Single Sequence Mode
7.3.9.2.4
Continuous Sequence Mode
7.3.9.3
Configuring the Auto-Sequencer
7.3.9.4
Starting and Stopping the Sequencer
7.3.9.5
Auto-Sequencer and DRDY Behavior
7.3.10
Offset and Gain Calibration
7.3.11
Digital PGA
7.3.12
General Purpose IOs (GPIOs)
7.3.12.1
DRDY Output
7.3.12.2
FAULT Output
7.3.13
Open Wire Current Source (OWCS)
7.3.14
Open Wire Detection with ADC 0-code output
7.3.15
System Monitors
7.3.15.1
Internal Short (Offset Calibration)
7.3.15.2
Internal Temperature Sensor
7.3.15.3
External Reference Voltage Readback
7.3.15.4
Power-Supply Readback
7.3.15.5
Resistor Divider Supply Readback
7.3.16
Monitor Flags, Indicators and Counters
7.3.16.1
Reset (RESETn flag)
7.3.16.2
AVDD Undervoltage Monitor (AVDD_UVn flag)
7.3.16.3
Reference Undervoltage Monitor (REV_UVn flag)
7.3.16.4
Modulator Overrange Monitor (MOD_OVR_FAULTn flag)
7.3.16.5
Register Map CRC (REG_MAP_CRC_FAULTn flag)
7.3.16.6
Memory Map CRC (MEM_INTERNAL_FAULTn flag)
7.3.16.7
FIFO Overflow (FIFO_OFn flag) and FIFO Underflow (FIFO_UFn flag)
7.3.16.8
FIFO CRC Fault (FIFO_CRC_FAULTn flag)
7.3.16.9
GPIO Readback
7.3.16.10
SPI CRC Fault (SPI_CRC_FAULTn flag)
7.3.16.11
Register Write Fault (REG_WRITE_FAULTn flag)
7.3.16.12
DRDY Indicator (DRDY bit)
7.3.16.13
Sequencer Active Indicator (SEQ_ACTIVE bit)
7.3.16.14
Sequence Step Indicator (STEP_INDICATOR[4:0])
7.3.16.15
ADC Conversion Counter (CONV_COUNT[3:0])
7.3.16.16
FIFO Depth Indicator (FIFO_DEPTH[8:0])
7.3.16.17
Completed Sequence Counter (SEQ_COUNT[3:0])
7.3.17
Test DAC (TDAC)
7.3.18
Parallel Post Filters
7.3.18.1
Configuring the Parallel Post Filters
7.3.18.2
Frequency Response of the Parallel Post Filters
7.3.18.3
Settling Times and DRDY Behavior When Using the Post Filters
7.3.18.4
Examples of Recommended Post Filter Settings
7.3.19
Chip Select Forwarding
7.3.19.1
Configuring the CS forward feature
7.3.19.2
CS Forward Timeout
7.3.19.3
CS Forward Header, Frame, and State Diagram
7.3.19.4
Disabling the CS-FWD mode
7.4
Device Functional Modes
7.4.1
Power-Scalable Speed Modes
7.4.2
Sequencer Functional Modes
7.4.3
Idle Mode and Standby Mode
7.4.4
Power-Down Mode
7.4.5
Reset
7.4.5.1
RESET Pin
7.4.5.2
Reset by SPI Register Write
7.4.5.3
Reset by SPI Input Pattern
7.4.6
Synchronization
7.4.7
Conversion-Start Delay Time
7.5
Programming
7.5.1
Serial Interface (SPI)
7.5.2
Serial Interface Signals
7.5.2.1
Chip Select (CS)
7.5.2.2
Serial Clock (SCLK)
7.5.2.3
Serial Data Input (SDI)
7.5.2.4
Serial Data Output/Data Ready (SDO/DRDY)
7.5.2.5
Data Ready (DRDY) Pin
7.5.3
Serial Interface Communication Structure
7.5.3.1
SPI Frame
7.5.3.2
STATUS Header
7.5.3.3
SPI CRC
7.5.4
Device Commands
7.5.4.1
No-Operation
7.5.4.2
Read Conversion Data
7.5.4.3
Read Register Command
7.5.4.4
Write Register Command
7.5.4.5
Read FIFO Buffer Command
7.5.5
Continuous Read Mode
7.5.5.1
Read Conversion Data in Continuous Read Mode
7.5.5.2
Read Registers in Continuous Read Mode
7.5.5.3
Read FIFO Buffer in Continuous Read Mode
7.5.6
SPI communication after POR or Reset
7.5.7
DRDY Pin Behavior
7.5.8
Daisy-Chain Operation
7.5.9
3-Wire SPI Mode
7.5.9.1
3-Wire SPI Mode Frame Re-Align
7.5.10
Conversion Data
7.5.11
Data Ready
7.5.11.1
DRDY Pin and SDO/DRDY Pin
7.5.11.2
DRDY Bit
7.5.11.3
Clock Counting
7.6
Register Map
7.6.1
ADS125H18 Status and General Configuration Page
7.6.2
ADS125H18 Step Configuration Page
8
Application and Implementation
8.1
Application Information
8.1.1
Serial Interface Connections
8.1.2
Interfacing with Multiple Devices
8.1.3
Unused Inputs and Outputs
8.1.4
Device Initialization
8.2
Typical Applications
8.2.1
2-Terminal V/I PLC Analog Input Module
8.2.1.1
Design Requirements
8.2.1.2
Detailed Design Procedure
8.2.1.3
Application Performance Plots - Crosstalk
8.2.2
3-Terminal V/I PLC Analog Input Module
8.2.3
2 -Terminal V/I PLC Analog Input Module With Solid State Switch
8.2.4
2-Terminal, single ended V/I PLC Analog Input Module
8.2.5
2-Terminal, I-Input PLC Analog Input Module
8.3
Power Supply Recommendations
8.3.1
Power Supplies
8.3.2
Power-Supply Sequencing
8.3.3
Power-Supply Decoupling
8.4
Layout
8.4.1
Layout Guidelines
8.4.2
Layout Example
9
Device and Documentation Support
9.1
Documentation Support
9.1.1
Related Documentation
9.2
Receiving Notification of Documentation Updates
9.3
Support Resources
9.4
Trademarks
9.5
Electrostatic Discharge Caution
9.6
Glossary
10
Revision History
11
Mechanical, Packaging, and Orderable Information
Package Options
Mechanical Data (Package|Pins)
RHB|36
MPQF772
Thermal pad, mechanical data (Package|Pins)
Orderable Information
sbasae3_oa
sbasae3_pm
Data Sheet
ADS125H18
8/16-Channel,
1MSPS
,
24
-Bit, Delta-Sigma ADC