CS5521/22/23/24/28

2

DS317F8

TABLE OF CONTENTS

ANALOG CHARACTERISTICS ................................................................................................ 5

TYPICAL RMS NOISE, CS5521/23.......................................................................................... 7

TYPICAL NOISE FREE RESOLUTION (BITS), CS5521/23 .................................................... 7

TYPICAL RMS NOISE, CS5522/24/28..................................................................................... 8

TYPICAL NOISE FREE RESOLUTION (BITS), CS5522/24/28 ............................................... 8

5 V DIGITAL CHARACTERISTICS........................................................................................... 9

3 V DIGITAL CHARACTERISTICS........................................................................................... 9

DYNAMIC CHARACTERISTICS ............................................................................................ 10

RECOMMENDED OPERATING CONDITIONS ..................................................................... 10

ABSOLUTE MAXIMUM RATINGS ......................................................................................... 10

SWITCHING CHARACTERISTICS ........................................................................................ 11

1. GENERAL DESCRIPTION ..................................................................................................... 13

1.1 Analog Input ..................................................................................................................... 13

1.1.1 Instrumentation Amplifier ......................................................................................... 14

1.1.2 Coarse/Fine Charge Buffers ............................................................................... 14

1.1.3 Analog Input Span Considerations .......................................................................... 15

1.1.4 Measuring Voltages Higher than 5 V .................................................................. 15

1.1.5 Voltage Reference .............................................................................................. 16

1.2 Overview of ADC Register Structure and Operating Modes ............................................ 16

1.2.1 System Initialization ............................................................................................ 18

1.2.2 Command Register Quick Reference

............................................................... 19

1.2.3 Command Register Descriptions ........................................................................ 20

1.2.4 Serial Port Interface ............................................................................................ 25

1.2.5 Reading/Writing the Offset, Gain, and Configuration Registers .......................... 26

1.2.6 Reading/Writing the Channel-Setup Registers ................................................... 26

1.2.6.1 Latch Outputs ...................................................................................... 28

1.2.6.2 Channel Select Bits ............................................................................. 28

1.2.6.3 Output Word Rate Selection ............................................................... 28

1.2.6.4 Gain Bits .............................................................................................. 28

1.2.6.5 Unipolar/Bipolar Bit ............................................................................. 28

1.2.7 Configuration Register ........................................................................................ 28

1.2.7.1 Chop Frequency Select ....................................................................... 28

1.2.7.2 Conversion/Calibration Control Bits .................................................... 28

1.2.7.3 Power Consumption Control Bits ........................................................ 28

1.2.7.4 Charge Pump Disable ......................................................................... 29

1.2.7.5 Reset System Control Bits .................................................................. 29

1.2.7.6 Data Conversion Error Flags ............................................................... 29

1.3 Calibration ........................................................................................................................ 31

1.3.1 Self Calibration .................................................................................................... 31

1.3.2 System Calibration .............................................................................................. 32

1.3.3 Calibration Tips ................................................................................................... 34

1.3.4 Limitations in Calibration Range ......................................................................... 34

1.4 Performing Conversions and Reading the Data Conversion FIFO .................................. 34

1.4.1 Conversion Protocol ............................................................................................ 35

1.4.1.1 Single, One-Setup Conversion ............................................................ 35

1.4.1.2 Repeated One-Setup Conversions without Wait ................................. 35

1.4.1.3 Repeated One-Setup Conversions with Wait ...................................... 36

1.4.1.4 Single, Multiple-Setup Conversions .................................................... 36

1.4.1.5 Repeated Multiple-Setup Conversions without Wait ........................... 37

1.4.1.6 Repeated Multiple-Setup Conversions with Wait ................................ 37

1.4.2 Calibration Protocol ............................................................................................. 38