參數(shù)資料
型號: LM4549
廠商: National Semiconductor Corporation
元件分類: Codec
英文描述: AC ’97 Rev 2.1 Codec with Sample Rate Conversion and National 3D Sound
中文描述: 交流\u0026#39;97活2.1編解碼器的采樣率轉(zhuǎn)換和國家3D聲音
文件頁數(shù): 9/18頁
文件大?。?/td> 324K
代理商: LM4549
Pin Description
(Continued)
Digital I/O and Clocking
Name
Pin
I / O
Functional Description
XTL_IN
2
I
24.576 MHz crystal input. Use a fundamental-mode type crystal. When operating from a
crystal, a 1M
resistor must be connected across pins 2 and 3.
24.576 MHz crystal output. When operating from a crystal, a 1M
resistor must be
connected across pins 2 and 3.
This data stream contains both control data and DAC audio data. This input is sampled by
the LM4549 on the falling edge of BIT_CLK.
OUTPUT when in Primary Codec Mode: This pin outputs a 12.288 MHz clock which is
derived (internally divided by two) from the 24.576MHz crystal input (XTL_IN).
INPUT when in Secondary Codec Mode (Multiple Codec configurations only): 12.288MHz
clock is to be supplied from an external source, such as from the BIT_CLK of a Primary
Codec.
This data stream contains both control data and ADC audio data. This output is clocked out
by the LM4549 on the rising edge of BIT_CLK.
48kHz sync pulse which signifies the beginning of both the SDATA_IN and SDATA_OUT
serial streams. SYNC must be synchronous to BIT_CLK.
This active low signal causes a hardware reset which returns the control registers to their
default conditions.
ID0 and ID1 set the codec address for multiple codec use where ID0 is the LSB. Connect
these pins to DVdd or GND as required. If these pins are not connected (NC), they default
to Primary codec setting (same as connecting both pins to DVdd). These pins are of inverted
polarity relative to their internal ID0, ID1 registers. If pin 45 is connected to GND, then ID0
will be set to
1
internally. Connection to DVdd corresponds to a
0
internally.
ID0 and ID1 set the codec address for multiple codec use where ID1 is the MSB. Connect
these pins to DVdd or GND as required. If these pins are not connected (NC), they default
to Primary codec setting (same as connecting both pins to DVdd). These pins are of inverted
polarity relative to their internal ID0, ID1 registers. If pin46 is connected to GND, then ID1
will be set to
1
internally. Connection to DVdd corresponds to a
0
internally.
The contents of
Powerdown Ctrl/Stat
register 26h bit 15 determines the logic level output
on this pin. This pin is to be connected to an external power amplifier’s shutdown pin. If
EAPD=0, then a logic low is output and the external amplifer is enabled. If EAPD=1, the
amplifer is shutdown. Power up default is EAPD=0.
XTL_OUT
3
O
SDATA_OUT
5
I
BIT_CLK
6
I/O
SDATA_IN
8
O
SYNC
10
I
RESET#
11
I
ID0
45
I
ID1
46
I
EAPD
47
O
Power Supplies and References
Name
AVDD
AVSS
DVDD
DVSS
Pin
25
26
1,9
4,7
I / O
I
I
I
I
Functional Description
Analog supply.
Analog ground.
Digital supply.
Digital ground.
Nominal 2.2V reference output. Not intended to sink or source current. Bypassing of this pin
should be done with short traces to maximize performance.
Nominal 2.2V reference output. Can source up to 5mA of current and can be used to bias a
microphone.
This pin is not used and should be left open (NC). However, a capacitor to ground on this
pin is permitted - it will not affect performance.
This pin is not used and should be left open (NC). However, a capacitor to ground on this
pin is permitted - it will not affect performance.
These pins are used to complete the National 3D Sound circuit. Connect a 0.022μF
capacitor between pins 3DP and 3DN. The National 3D Sound can be turned on and off via
bit D13 in control register 20h. This is a fixed-depth type stereo enhance circuit, thus writing
to register 22h has no effect. If National 3D Sound is not needed, then these pins should be
left as no connect (NC).
VREF
27
O
VREFOUT
28
O
AFILT1
29
O
AFILT2
30
O
3DP, 3DN
33,34
O
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相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
LM4549A 制造商:NSC 制造商全稱:National Semiconductor 功能描述:AC ’97 Rev 2.1 Codec with Sample Rate Conversion and National 3D Sound
LM4549AVH 制造商:Rochester Electronics LLC 功能描述:AC97 REV2.1 CODEC - Bulk 制造商:OC White Company 功能描述:Audio Codec 2ADC / 2DAC 18-Bit 48-Pin LQFP Tray
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LM4549AVH/NOPB 制造商:Texas Instruments 功能描述:Audio Codec 2ADC / 2DAC 18-Bit 48-Pin LQFP Tray
LM4549AVHX 制造商:Rochester Electronics LLC 功能描述:AC97 REV2.1 CODEC - Bulk