Datenblatt-pdf.com


WM8734EDS Schematic ( PDF Datasheet ) - ETC

Teilenummer WM8734EDS
Beschreibung STEREO AUDIO CODEC
Hersteller ETC
Logo ETC Logo 




Gesamt 30 Seiten
WM8734EDS Datasheet, Funktion
w
Stereo Audio CODEC
WM8734
DESCRIPTION
The WM8734 is a low power stereo CODEC ideal for MD,
CD-RW machines and DAT recording applications.
Stereo line inputs are provided, along with a mute function
and programmable line level volume control.
Stereo 24-bit multi-bit sigma delta ADCs and DACs are
used with oversampling digital interpolation and decimation
filters.
Digital audio input word lengths from 16-32 bits and
sampling rates from 8kHz to 96kHz are supported.
Stereo audio line level outputs are provided along with anti-
thump mute and power up/down circuitry.
The device is controlled via a 2 or 3 wire serial interface.
The interface provides access to all features including level
controls, mutes, de-emphasis and power management
facilities. The device is available in 20-pin SSOP or 5x5mm
QFN packages.
FEATURES
Audio Performance
90dB SNR (‘A’ weighted @ 48kHz) ADC
100dB SNR (‘A’ weighted @ 48kHz) DAC
2.7 – 3.6V Digital Supply Operation
2.7 – 3.6V Analogue Supply Operation
ADC and DAC Sampling Frequency: 8kHz – 96kHz
Selectable ADC High Pass Filter
2 or 3-Wire MPU Serial Control Interface
Programmable Audio Data Interface Modes
I2S, Left, Right Justified or DSP
16/20/24/32 bit Word Lengths
Master or Slave Clocking Mode
Stereo Audio Inputs and Outputs
20-Pin SSOP or 5x5mm QFN Package Options
APPLICATIONS
CD and Minidisc Recorder
MP3 Player / Recorder
BLOCK DIAGRAM
AVDD
VMID
AGND
RLINEIN
LLINEIN
CONTROL INTERFACE
W
WM8734
VOL
+12 to -34.5dB,
1.5dB Steps
VOL
+12 to -34.5dB,
1.5dB Steps
CLKIN
DIVIDER
(Div x1, x2)
ADC
ADC
DIGITAL
FILTERS
DAC
MUTE
DAC
MUTE
DIGTAL AUDIO INTERFACE
ROUT
LOUT
WOLFSON MICROELECTRONICS LTD
www.wolfsonmicro.com
Advanced Information, November 2001, Rev 2.2
Copyright 2001 Wolfson Microelectronics Ltd.






WM8734EDS Datasheet, Funktion
WM8734
Advanced Information
Test Conditions
AVDD, DBVDD = 3.3V, AGND = 0V, DCVDD = 3.3V, DGND = 0V, TA = +25oC, Slave Mode, fs = 48kHz, MCLK = 256fs unless
otherwise stated.
PARAMETER
SYMBOL TEST CONDITIONS
MIN
TYP
MAX
UNIT
Line Output for DAC Playback Only (Load = 47k ohms. 50pF)
0dBfs Full scale output voltage
At LINE outputs
1.0 x
Vrms
AVDD/3.3
SNR (Note 1,2,3)
A-weighted,
90
100
dB
@ fs = 48kHz
SNR (Note 1,2,3)
A-weighted
98 dB
@ fs = 96kHz
SNR (Note 1,2,3)
A-weighted, 93 dB
@ fs = 48kHz,
AVDD = 2.7V
Dynamic Range (Note 3)
DNR
A-weighted, -60dB full
scale input
85
95
dB
THD
1kHz, 0dBfs
-88 -80
dB
1kHz, -3dBfs -92 dB
Power Supply Rejection Ratio
PSSR
1kHz 100mVpp
50
dB
20Hz to 20kHz
100mVpp
45
dB
DAC channel separation
100 dB
Notes:
1. Ratio of output level with 1kHz full scale input, to the output level with the input short circuited, measured ‘A’ weighted
over a 20Hz to 20kHz bandwidth using an Audio analyser.
2. Ratio of output level with 1kHz full scale input, to the output level with all zeros into the digital input, measured ‘A’
weighted over a 20Hz to 20kHz bandwidth.
3. All performance measurements done with 20kHz low pass filter, and where noted an A-weight filter. Failure to use
such a filter will result in higher THD+N and lower SNR and Dynamic Range readings than are found in the Electrical
Characteristics. The low pass filter removes out of band noise; although it is not audible it may affect dynamic
specification values.
4. VMID decoupled with 10uF and 0.1uF capacitors (smaller values may result in reduced performance).
TERMINOLOGY
1. Signal-to-noise ratio (dB) - SNR is a measure of the difference in level between the full scale output and the output
with no signal applied. (No Auto-zero or Automute function is employed in achieving these results).
2. Dynamic range (dB) - DNR is a measure of the difference between the highest and lowest portions of a signal.
Normally a THD+N measurement at 60dB below full scale. The measured signal is then corrected by adding the 60dB
to it. (e.g. THD+N @ -60dB= -32dB, DR= 92dB).
3. THD+N (dB) - THD+N is a ratio, of the rms values, of (Noise + Distortion)/Signal.
4. Stop band attentuation (dB) – Is the degree to which the frequency spectrum is attenuated (outside audio band).
5. Channel Separation (dB) - Also known as Cross-Talk. This is a measure of the amount one channel is isolated from
the other. Normally measured by sending a full scale signal down one channel and measuring the other.
6. Pass-Band Ripple – Any variation of the frequency response in the pass-band region.
w
AI Rev 2.2 November 2001
6

6 Page









WM8734EDS pdf, datenblatt
WM8734
Advanced Information
DEVICE DESCRIPTION
The WM8734 is a high performance audio CODEC designed specifically for audio applications that
require recording and playback features.
The CODEC includes line inputs to the on-board ADC, line outputs from the on-board DAC, a
configurable digital audio interface and a choice of 2 or 3 wire MPU control interface. It is fully
compatible and an ideal partner for a range of industry standard microprocessors, controllers and
DSPs.
The CODEC includes a stereo low noise input. Line inputs have +12dB to -34dB logarithmic volume
level adjustments and mute. All the required input filtering is contained within the device.
The on-board stereo analogue to digital converter (ADC) is of a high quality using a multi-bit high-
order oversampling architecture delivering optimum performance with low power consumption. The
output from the ADC is available on the digital audio interface. The ADC includes an optional digital
high pass filter to remove unwanted dc components from the audio signal.
The on-board digital to analogue converter (DAC) accepts digital audio from the digital audio
interface. Digital filter de-emphasis at 32kHz, 44.1kHz and 48kHz can be applied to the digital data
under software control. The DAC employs a high quality multi-bit high-order oversampling
architecture to again deliver optimum performance with low power consumption.
Special techniques allow the audio to be muted and the device safely placed into standby, sections
of the device powered off and volume levels adjusted without any audible clicks, pops or zipper
noises. Therefore standby and power off modes may be used dynamically under software control,
whenever recording or playback is not required.
The device caters for a number of different sampling rates including industry standard 8kHz, 32kHz,
44.1kHz, 48kHz, 88.2kHz and 96kHz. The digital filters used for both record and playback are
optimised for each sampling rate used.
The digitised output is available in a number of audio data formats I2S, DSP Mode (a burst mode in
which frame sync plus 2 data packed words are transmitted), MSB-First, left justified and MSB-First,
right justified. The digital audio interface can operate in both master or slave modes.
The software control uses either a 2 or 3-wire MPU interface.
AUDIO SIGNAL PATH
LINE INPUTS
The WM8734 provides Left and Right channel line inputs (RLINEIN and LLINEIN). The inputs are
high impedance and low capacitance, thus ideally suited to receiving line level signals from external
hi-fi or audio equipment.
Both line inputs include independent programmable volume level adjustments and input mute. The
scheme is illustrated in Figure 8. Passive RF and active Anti-Alias filters are also incorporated within
the line inputs. These prevent high frequencies aliasing into the audio band or otherwise degrading
performance.
w
AI Rev 2.2 November 2001
12

12 Page





SeitenGesamt 30 Seiten
PDF Download[ WM8734EDS Schematic.PDF ]

Link teilen




Besondere Datenblatt

TeilenummerBeschreibungHersteller
WM8734EDSSTEREO AUDIO CODECETC
ETC

TeilenummerBeschreibungHersteller
CD40175BC

Hex D-Type Flip-Flop / Quad D-Type Flip-Flop.

Fairchild Semiconductor
Fairchild Semiconductor
KTD1146

EPITAXIAL PLANAR NPN TRANSISTOR.

KEC
KEC


www.Datenblatt-PDF.com       |      2020       |      Kontakt     |      Suche