LM4934WL National Semiconductor, LM4934WL Datasheet - Page 24

• Manufacturer Part Number: LM4934WL
• Manufacturer: National Semiconductor

Specifications of LM4934WL

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Common Clock Settings for the DAC
Methods for producing these clock frequencies are described in the PLL section.
The R divider can be used when the master clock is exactly 12.00 MHz in order to generate different sample rates. The Table
below shows different sample rates supported from 12.00MHz by using only the R divider and disabling the PLL. In this way we
can save power and the clock jitter will be low.
The R divider can also be used along with the P divider in order to create the clock needed to support low sample rates.
DAC Setup Register
This register is used to configure the basic operation of the stereo DAC.
DAC_SETUP (0Eh)
R_DIV
11
9
7
5
4
3
2
0
Fs (kHz)
176.4
44.1
44.1
88.2
192
Bits
48
48
96
1:0
2
3
4
5
6
Divide Value
2.5
1.5
6
5
4
3
2
1
DITHER_OFF
ALWAYS_ON
CUST_COMP
DAC_MODE
DAC Oversampling Ratio
MUTE_R
Register
MUTE_L
DITHER
DAC Clock Generator Input Frequency
(Set = logic 1, Clear = logic 0)
125
128
125
128
64
64
32
32
If set the DAC frequency response can be programmed manually via a 5 tap FIR
DAC_MODE
“compensation” filter. This can be used to enhance the frequency response of
The DAC used in the LM4934 can operate in one of 4 oversampling modes.
small loudspeakers or provide a crude tone control. The compensation
00
01
10
11
Mutes the right DAC channel on the next zero crossing.
Mutes the left DAC channel on the next zero crossing.
2.4
4.8
Coefficients can be set by using registers 10h to 15h.
12
2
3
4
6
8
If set the dither in DAC is enabled all the time.
Oversampling
Rate
125
128
64
32
24
Required CLock at DAC Clock Generator Input (MHz)
(Continued)
The modes are described as follows:
If set the dither in DAC is disabled.
<
MHz
Description
Typical FS
48KHz
44.1KHz
48KHz
96KHz
192KHz
>
22.5792
11.2896
11.2896
12.288
12.288
24.576
11.025
Sample Rate Supported
12
Clock Required
12.000MHz (USB
Mode)
11.2896MHz
12.288MHz
12.288MHz
24.576MHz
19.2
9.6
12
16
24
32
48
8
<
KHz
>