WM8940
Rev 4.4 3
TABLE OF CONTENTS
DESCRIPTION................................................................................................................ 1
FEATURES..................................................................................................................... 1
APPLICATIONS ............................................................................................................. 1
BLOCK DIAGRAM ......................................................................................................... 2
TABLE OF CONTENTS.................................................................................................. 3
PIN CONFIGURATION ................................................................................................... 6
ORDERING INFORMATION........................................................................................... 6
PIN DESCRIPTION......................................................................................................... 7
ABSOLUTE MAXIMUM RATINGS ................................................................................. 8
RECOMMENDED OPERATING CONDITIONS.............................................................. 8
ELECTRICAL CHARACTERISTICS .............................................................................. 9
TERMINOLOGY.......................................................................................................................11
AUDIO PATHS OVERVIEW ......................................................................................... 12
POWER CONSUMPTION............................................................................................. 13
SIGNAL TIMING REQUIREMENTS ............................................................................. 14
SYSTEM CLOCK TIMING........................................................................................................14
AUDIO INTERFACE TIMING –MASTER MODE ....................................................................15
AUDIO INTERFACE TIMING –SLAVE MODE........................................................................16
CONTROL INTERFACE TIMING –3-WIRE MODE.................................................................17
CONTROL INTERFACE TIMING –2-WIRE MODE.................................................................18
DEVICE DESCRIPTION ............................................................................................... 19
INTRODUCTION......................................................................................................................19
FEATURES....................................................................................................................................................................................19
MICROPHONE INPUTS................................................................................................................................................................19
PGA AND ALC OPERATION ........................................................................................................................................................19
AUX INPUT....................................................................................................................................................................................19
ADC ...............................................................................................................................................................................................19
HI-FI DAC ......................................................................................................................................................................................19
DIGITAL FILTERING.....................................................................................................................................................................19
OUTPUT MIXING AND VOLUME ADJUST ..................................................................................................................................19
AUDIO INTERFACES....................................................................................................................................................................19
CONTROL INTERFACES .............................................................................................................................................................20
CLOCKING SCHEMES .................................................................................................................................................................20
POWER CONTROL.......................................................................................................................................................................20
INPUT SIGNAL PATH..............................................................................................................20
MICROPHONE INPUTS................................................................................................................................................................20
INPUT PGA VOLUME CONTROL.................................................................................................................................................22
AUXILIARY INPUT ........................................................................................................................................................................22
INPUT BOOST...............................................................................................................................................................................23
MICROPHONE BIASING CIRCUIT...............................................................................................................................................24
ANALOGUE TO DIGITAL CONVERTER (ADC)......................................................................25
ADC DIGITAL FILTERS ................................................................................................................................................................25
SELECTABLE HIGH PASS FILTER..............................................................................................................................................26
PROGRAMMABLE NOTCH FILTERS ..........................................................................................................................................27
DIGITAL ADC VOLUME CONTROL .............................................................................................................................................29
INPUT LIMITER / AUTOMATIC LEVEL CONTROL (ALC)......................................................29
NORMAL MODE............................................................................................................................................................................32
LIMITER MODE.............................................................................................................................................................................32
ATTACK AND DECAY TIMES.......................................................................................................................................................33
NORMAL MODE............................................................................................................................................................................33
LIMITER MODE.............................................................................................................................................................................34
