Cirrus Logic CS5460A - Manual (Page 2)

CS5460A
2 DS487F5
TABLE OF CONTENTS
1. CHARACTERISTICS & SPECIFICATIONS ............................................................................. 5
ANALOG CHARACTERISTICS ................................................................................................ 5
VREFOUT REFERENCE OUTPUT VOLTAGE........................................................................ 7
5V DIGITAL CHARACTERISTICS............................................................................................ 7
3.3 V DIGITAL CHARACTERISTICS........................................................................................ 8
ABSOLUTE MAXIMUM RATINGS ........................................................................................... 8
SWITCHING CHARACTERISTICS .......................................................................................... 9
2. OVERVIEW ............................................................................................................................. 12
2.1 Theory of Operation ......................................................................................................... 12
2.1.1 DS Modulators ................................................................................................... 12
2.1.2 High-rate Digital Low-pass Filters ....................................................................... 12
2.1.3 Digital Compensation Filters ............................................................................... 12
2.1.4 Digital High-pass Filters ...................................................................................... 12
2.1.5 Overall Filter Response ....................................................................................... 13
2.1.6 Gain and DC Offset Adjustment .......................................................................... 13
2.1.7 Real Energy and RMS Computations ................................................................. 13
2.2 Performing Measurements ............................................................................................... 13
2.2.1 CS5460A Linearity Performance ......................................................................... 15
2.2.2 Single Computation Cycle (C=0) ......................................................................... 15
2.2.3 Continuous Computation Cycles (C=1) ............................................................... 16
2.3 Basic Application Circuit Configurations .......................................................................... 16
3. FUNCTIONAL DESCRIPTION ............................................................................................... 21
3.1 Pulse-Rate Output ........................................................................................................... 21
3.2 Pulse Output for Normal Format, Stepper Motor Format and Mechanical Counter Format 22
3.2.1 Normal Format .................................................................................................... 22
3.2.2 Mechanical Counter Format ................................................................................ 23
3.2.3 Stepper Motor Format ......................................................................................... 23
3.3 Auto-boot Mode Using EEPROM ..................................................................................... 24
3.3.1 Auto-boot Configuration ...................................................................................... 24
3.3.2 Auto-boot Data for EEPROM .............................................................................. 25
3.3.3 Application Note AN225 ...................................................................................... 26
3.4 Interrupt and Watchdog Timer ......................................................................................... 26
3.4.1 Interrupt ............................................................................................................... 26
3.4.1.1 Clearing the Status Register ............................................................... 26
3.4.1.2 Typical use of the INT pin ................................................................... 26
3.4.1.3 INT Active State .................................................................................. 26
3.4.1.4 Exceptions ........................................................................................... 26
3.4.2 Watch Dog Timer ................................................................................................ 26
3.5 Oscillator Characteristics ................................................................................................. 27
3.6 Analog Inputs ................................................................................................................... 27
3.7 Voltage Reference ........................................................................................................... 27
3.8 Calibration ........................................................................................................................ 27
3.8.1 Overview of Calibration Process ......................................................................... 27
3.8.2 The Calibration Registers .................................................................................... 28
3.8.3 Calibration Sequence .......................................................................................... 28
3.8.4 Calibration Signal Input Level ............................................................................. 29
3.8.5 Calibration Signal Frequency .............................................................................. 29
3.8.6 Input Configurations for Calibrations ................................................................... 29
3.8.7 Description of Calibration Algorithms .................................................................. 30
3.8.7.1 AC Offset Calibration Sequence ......................................................... 30
3.8.7.2 DC Offset Calibration Sequence ......................................................... 31
3.8.7.3 AC Gain Calibration Sequence ........................................................... 31