SBASB74
October 2024
ADS127L21B
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 (1.65V ≤ IOVDD ≤ 2V)
5.7
Switching Characteristics (1.65V ≤ IOVDD ≤ 2V)
5.8
Timing Requirements (2V < IOVDD ≤ 5.5V)
5.9
Switching Characteristics (2V < IOVDD ≤ 5.5V)
5.10
Timing Diagrams
5.11
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
IMD Measurement
6.12
SFDR Measurement
6.13
Noise Performance
7
Detailed Description
7.1
Overview
7.2
Functional Block Diagram
7.3
Feature Description
7.3.1
Analog Input (AINP, AINN)
7.3.1.1
Input Range
7.3.2
Reference Voltage (REFP, REFN)
7.3.2.1
Reference Voltage Range
7.3.3
Clock Operation
7.3.3.1
Internal Oscillator
7.3.3.2
External Clock
7.3.4
Modulator
7.3.5
Digital Filter
7.3.5.1
Wideband Filter
7.3.5.1.1
Wideband Filter Options
7.3.5.1.2
Sinc5 Filter Stage
7.3.5.1.3
FIR1 Filter Stage
7.3.5.1.4
FIR2 Filter Stage
7.3.5.1.5
FIR3 Filter Stage
7.3.5.1.6
FIR3 Default Coefficients
7.3.5.1.7
IIR Filter Stage
7.3.5.1.7.1
IIR Filter Stability
7.3.5.2
Low-Latency Filter (Sinc)
7.3.5.2.1
Sinc3 and Sinc4 Filters
7.3.5.2.2
Sinc3 + Sinc1 and Sinc4 + Sinc1 Cascade Filter
7.3.6
Power Supplies
7.3.6.1
AVDD1 and AVSS
7.3.6.2
AVDD2
7.3.6.3
IOVDD
7.3.6.4
Power-On Reset (POR)
7.3.6.5
CAPA and CAPD
7.3.7
VCM Output Voltage
7.4
Device Functional Modes
7.4.1
Speed Modes
7.4.2
Idle Mode
7.4.3
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
7.4.6.1
Synchronized Control Mode
7.4.6.2
Start/Stop Control Mode
7.4.6.3
One-Shot Control Mode
7.4.7
Conversion-Start Delay Time
7.4.8
Calibration
7.4.8.1
OFFSET2, OFFSET1, OFFSET0 Calibration Registers (Addresses 0Ch, 0Dh, 0Eh)
7.4.8.2
GAIN2, GAIN1, GAIN0 Calibration Registers (Addresses 0Fh, 10h, 11h)
7.4.8.3
Calibration Procedure
7.5
Programming
7.5.1
Serial Interface (SPI)
7.5.1.1
Chip Select (CS)
7.5.1.2
Serial Clock (SCLK)
7.5.1.3
Serial Data Input (SDI)
7.5.1.4
Serial Data Output/Data Ready (SDO/DRDY)
7.5.1.5
SPI Frame
7.5.1.6
Full-Duplex Operation
7.5.1.7
Device Commands
7.5.1.7.1
No-Operation
7.5.1.7.2
Read Register Command
7.5.1.7.3
Write Register Command
7.5.1.8
Read Conversion Data
7.5.1.8.1
Conversion Data
7.5.1.8.2
Data Ready
7.5.1.8.2.1
DRDY
7.5.1.8.2.2
SDO/DRDY
7.5.1.8.2.3
DRDY Bit
7.5.1.8.2.4
Clock Counting
7.5.1.8.3
STATUS Byte
7.5.1.9
Daisy-Chain Operation
7.5.1.10
3-Wire SPI Mode
7.5.1.10.1
3-Wire SPI Mode Frame Reset
7.5.1.11
SPI CRC
7.5.2
Register Memory CRC
7.5.2.1
Main Program Memory CRC
7.5.2.2
FIR Filter Coefficient CRC
7.5.2.3
IIR Filter Coefficient CRC
8
Register Map
9
Application and Implementation
9.1
Application Information
9.1.1
SPI Operation
9.1.2
Input Driver
9.1.3
Antialias Filter
9.1.4
Reference Voltage
9.1.5
Simultaneous-Sampling Systems
9.2
Typical Applications
9.2.1
A-Weighting Filter Design
9.2.1.1
Design Requirements
9.2.1.2
Detailed Design Procedure
9.2.1.3
Application Curve
9.2.2
PGA855 Programmable Gain Amplifier
9.2.2.1
Design Requirements
9.2.2.2
Detailed Design Procedure
9.2.2.3
Application Curves
9.2.3
THS4551 Antialias Filter Design
9.2.3.1
Design Requirements
9.2.3.2
Detailed Design Procedure
9.2.3.3
Application Curves
9.3
Power Supply Recommendations
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
5.10
Timing Diagrams
Figure 5-1
Clock Timing Requirements
Figure 5-2
Serial Interface Timing Requirements
Figure 5-3
Serial Interface Switching Characteristics
Figure 5-4
SPI Frame Timing Requirement
Figure 5-5
RESET
Pin Timing
Figure 5-6
START Pin Timing