|
|
PDF WM8721L Data sheet ( Hoja de datos )
| Número de pieza | WM8721L | |
| Descripción | portable digital audio solutions | |
| Fabricantes | Wolfson Microelectronics plc | |
| Logotipo |  |
|
Hay una vista previa y un enlace de descarga de WM8721L (archivo pdf) en la parte inferior de esta página. Total 30 Páginas | ||
|
No Preview Available !
WM8721
Internet Audio DAC with Integrated Headphone Driver
Product Preview, November 2000, Rev 1.3
DESCRIPTION
The WM8721 is a low power stereo DAC with an integrated
headphone driver. The WM8721 is designed specifically for
portable MP3 audio and speech players. The WM8721 is
also ideal for MD, CD machines and DAT players.
Stereo 24-bit multi-bit sigma delta DACs are used with
oversampling digital interpolation filters. Digital audio input
word lengths from 16-32 bits and sampling rates from 8KHz
to 96KHz are supported.
Stereo audio outputs are buffered for driving headphones
from a programmable volume control, line level outputs are
also 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
volume controls, mutes, de-emphasis and extensive power
management facilities. The device is available in a small 20-
pin SSOP package.
A USB mode is provided where all audio rates can be
derived from a simple 12MHz MCLK, saving on need for
PLL or multiple crystals.
FEATURES
• Audio Performance
− 100dB SNR (‘A’ weighted @ 48kHz) DAC
− 1.42 – 3.6V Digital Supply Operation
− 2.7 – 3.6V Analogue Supply Operation
• DAC Sampling Frequency: 8KHz – 96KHz
• 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
• Stereo Audio Outputs
• Output Volume and Mute Controls
• Highly Efficient Headphone Driver
• Playback Mode Power Consumption < 18mW
• 20-Pin SSOP Package
APPLICATIONS
• Portable MP3 Players
• CD and Minidisc Players
BLOCK DIAGRAM
DACDAT (3)
DACLRC (4)
BCLK (2)
(15) (16) (17) (14)
(11) (13) (12)
WM8721
CONTROL INTERFACE
DIGITAL
FILTERS
DAC
+6 to -73dB
1 dB Steps
VOL/
MUTE
H/P
DRIVER
CLKIN
DIVIDER
(Div x1, x2)
(18)
DAC
(19) (1) (20)
VOL/
MUTE
H/P
DRIVER
+6 to -73dB
1 dB Steps
(5) HPVDD
(8) HPGND
(7) RHPOUT
(10) ROUT
(9) LOUT
(6) LHPOUT
WOLFSON MICROELECTRONICS LTD
Lutton Court, Bernard Terrace, Edinburgh, EH8 9NX, UK
Tel: +44 (0) 131 667 9386
Fax: +44 (0) 131 667 5176
Email: [email protected]
http://www.wolfson.co.uk
Product Preview data sheets contain
specifications for products in the formative
phase of development. These products may
be changed or discontinued without notice.
2000 Wolfson Microelectronics Ltd.
1 page  
WM8721
Product Preview
Test Conditions
AVDD, HPVDD, DBVDD = 3.3V, AGND = 0V, DCVDD = 1.5V, DGND = 0V, TA = +25oC, Slave Mode, fs = 48kHz, MCLK =
256fs unless otherwise stated.
PARAMETER
SYMBOL TEST CONDITIONS
MIN
TYP MAX UNIT
SNR (Note 1,2)
A-weighted
90 97
dB
THD
1kHz, RL = 32 ohms @
PO = 10mW rms
0.1 0.1
%
60 60 dB
1kHz, RL = 32 ohms @
PO = 20mW rms
1.0 1.0
%
40 40 dB
Power Supply Rejection Ratio
PSSR
1kHz 100mVpp
50
dB
20Hz to 20kHz
100mVpp
45
dB
Programmable Gain Maximum
1kHz
6 dB
Programmable Gain Minimum
-73
Programmable Gain Step Size
1kHz
1 dB
Mute attenuation
1kHz, 0dB
80 dB
Notes:
1. 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.
2. 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.
3. 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 attenuation (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.
WOLFSON MICROELECTRONICS LTD
PP Rev 1.3 November 2000
5
5 Page 
WM8721
Product Preview
The DAC digital filter can apply digital de-emphasis under software control, as shown in Table 2. The
DAC can also perform a soft mute where the audio data is digitally brought to a mute level. This
removes any abrupt step changes in the audio that might otherwise result in audible clicks in the
audio outputs.
REGISTER
ADDRESS
0000101
Digital Audio
Path Control
BIT
2:1
LABEL
DEEMP[1:0]
DEFAULT
00
3
DACMU
1
Table 2 DAC Software Control
DESCRIPTION
De-emphasis Control
(Digital)
11 = 48KHz
10 = 44.1KHz
01 = 32KHz
00 = Disable
DAC Soft Mute Control
(Digital)
1 = Enable soft mute
0 = Disable soft mute
DAC
The WM8721 employs a multi-bit sigma delta oversampling digital to analogue converter. The
scheme for the converter is illustrated Figure 7.
FROM DAC
DIGITAL
FILTERS
TO LINE OUTPUT
Figure 7 Multi-Bit Oversampling Sigma Delta Schematic
The DAC converts the multi-level digital audio data stream from the DAC digital filters into high
quality analogue audio.
LINE OUTPUTS
The WM8721 provides two low impedance line outputs LLINEOUT and RLINEOUT, suitable for
driving typical line loads of impedance 10K and capacitance 50pF.
The LLINEOUT and RLINEOUT outputs are only available at a line output level and are not level
adjustable in the analogue domain, having a fixed gain of 0dB. The level is fixed such that at the DAC
full scale level the output level is Vrms at AVDD = 3.3 volts. Note that the DAC full scale level tracks
directly with AVDD. The scheme is shown in Figure 9. The line output includes a low order audio low
pass filter for removing out-of band components from the sigma-delta DAC. Therefore no further
external filtering is required in most applications.
WOLFSON MICROELECTRONICS LTD
PP Rev 1.3 November 2000
11
11 Page | ||
| Páginas | Total 30 Páginas | |
| PDF Descargar | [ Datasheet WM8721L.PDF ] | |
Hoja de datos destacado
| Número de pieza | Descripción | Fabricantes |
| WM8721 | Internet Audio DAC with Integrated Headphone Driver | Wolfson Microelectronics plc |
| WM8721 | portable digital audio solutions | Wolfson Microelectronics plc |
| WM8721L | portable digital audio solutions | Wolfson Microelectronics plc |
| Número de pieza | Descripción | Fabricantes |
| SLA6805M | High Voltage 3 phase Motor Driver IC. |
 Sanken |
| SDC1742 | 12- and 14-Bit Hybrid Synchro / Resolver-to-Digital Converters. |
 Analog Devices |
|
DataSheet.es es una pagina web que funciona como un repositorio de manuales o hoja de datos de muchos de los productos más populares, |
| DataSheet.es | 2020 | Privacy Policy | Contacto | Buscar |