WM8737L w Stereo ADC with Microphone Preamplifier DESCRIPTION FEATURES SNR 97dB (A weighted 3.3V, 48kHz, normal power The WM8737L is a low power stereo audio ADC designed mode) specifically for portable applications such as minidisc and THD 84dB (at 1dB, 3.3V, normal power mode) memory audio / voice recorders. Complete Stereo / Mono Microphone Interface The device offers three sets of stereo inputs, which can be - Programmable microphone preamp configured for line-level signals, for internal or table-top - Automatic Level Control microphones, or for DC measurement (battery monitor). A - Low-noise microphone bias voltage programmable gain amplifier can be used for automatic level Configurable Power / Performance control (ALC) with user programmable hold, attack and Low Power Mode decay times. The device also has a selectable high pass - 8.5mW at AVDD = 1.8V (stereo, mic preamps off) filter to remove residual DC offsets. - 20mW at AVDD = 3.3V (stereo, mic preamps off) Low Supply Voltages If the signal source is mono, the WM8737L can run in mono - Analogue 1.8V to 3.6V mode, saving power. It can also mix two channels to mono, - Digital core: 1.42V to 3.6V either in the analogue or the digital domain. - Digital I/O: 1.8V to 3.6V Master or slave mode clocking schemes are offered. Stereo 256fs / 384fs or USB master clock rates: 12MHz, 24MHz 24-bit multi-bit sigma-delta ADCs are used with digital audio Audio sample rates: 16, 22.05, 24, 32, 44.1, 48, 88.2, 96kHz output word lengths from 16-32 bits, and sampling rates generated internally from master clock from 16kHz to 96kHz supported. 32-pin QFN package, 5 x 5 x 0.9mm The device is controlled via a 2 or 3 wire serial interface. APPLICATIONS The interface provides access to all features including gain controls, analogue or digital mono mixing, and power Memory Audio / Voice Recorders management facilities. The device is supplied in a leadless Minidisc Recorders 5x5mm QFN package. Portable Digital Music Systems BLOCK DIAGRAM Production Data, January 2012, Rev 4.4 WOLFSON MICROELECTRONICS plc To receive regular email updates, sign up at WM8737L Production Data TABLE OF CONTENTS DESCRIPTION ....................................................................................................... 1 FEATURES ............................................................................................................ 1 APPLICATIONS ..................................................................................................... 1 BLOCK DIAGRAM ................................................................................................ 1 TABLE OF CONTENTS ......................................................................................... 2 PIN CONFIGURATION .......................................................................................... 3 ORDERING INFORMATION .................................................................................. 3 PIN DESCRIPTION ................................................................................................ 4 ABSOLUTE MAXIMUM RATINGS ........................................................................ 5 RECOMMENDED OPERATING CONDITIONS ..................................................... 5 ELECTRICAL CHARACTERISTICS ..................................................................... 6 TERMINOLOGY ............................................................................................................... 8 POWER CONSUMPTION ...................................................................................... 9 SIGNAL TIMING REQUIREMENTS .................................................................... 11 DEVICE DESCRIPTION ...................................................................................... 14 INTRODUCTION ............................................................................................................ 14 INPUT SIGNAL PATH .................................................................................................... 14 ANALOGUE TO DIGITAL CONVERTER (ADC) ............................................................ 19 3D STEREO ENHANCEMENT ...................................................................................... 20 AUTOMATIC LEVEL CONTROL (ALC) ......................................................................... 21 DIGITAL AUDIO INTERFACE ........................................................................................ 24 MASTER CLOCK AND AUDIO SAMPLE RATES .......................................................... 28 CONTROL INTERFACE................................................................................................. 30 POWER SUPPLIES ....................................................................................................... 31 POWER MANAGEMENT ............................................................................................... 31 REGISTER MAP .................................................................................................. 32 DIGITAL FILTER CHARACTERISTICS .............................................................. 33 TERMINOLOGY ............................................................................................................. 33 DIGITAL FILTER RESPONSES ..................................................................................... 34 APPLICATIONS INFORMATION ........................................................................ 36 LINE INPUT CONFIGURATION ..................................................................................... 36 MICROPHONE INPUT CONFIGURATION .................................................................... 36 RECOMMENDED EXTERNAL COMPONENTS .................................................. 37 PACKAGE DIMENSIONS .................................................................................... 38 IMPORTANT NOTICE ......................................................................................... 39 ADDRESS: ..................................................................................................................... 39 REVISION HISTORY ........................................................................................... 40 PD, Rev 4.4, January 2012 w 2