LM4937RL/NOPB National Semiconductor, LM4937RL/NOPB Datasheet - Page 20

• Manufacturer Part Number: LM4937RL/NOPB
• Description: IC AUDIO SUBSYSTM 1.25W 36USMDXT
• Manufacturer: National Semiconductor
• Series: Boomer®r
• Type: Class ABr

Specifications of LM4937RL/NOPB

• Output Type: 1-Channel (Mono) with Mono and Stereo Headphones
• Max Output Power X Channels @ Load: 1.25W x 1 @ 8 Ohm; 80mW x 2 @ 32 Ohm
• Voltage - Supply: 2.7 V ~ 5.5 V
• Features: Depop, Differential Inputs, I²C, I²S, Mute, Shutdown, SPI, Volume Control
• Mounting Type: Surface Mount
• Package / Case: 36-MicroSMDxt
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: LM4937RLTR

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Further Notes on PLL Programming
The sigma-delta PLL is designed to drive audio circuits requiring accurate clock frequencies of up to 25MHz with frequency errors
noise-shaped away from the audio band. The 5 bits of modulus control provide exact synchronization of 48kHz and 44.1kHz sample
rates from any common clock source when the oversampling rate of the audio system is 125fs. In systems where 128x oversampling
must be used (for example with an isochronous I2S data stream) a clock synchronous to the sample rate should be used as input
to the PLL (typically the I2S clock). If no isochronous source is available then the PLL can be used to obtain a clock that is accurate
to within typical crystal tolerances of the real sample rate.
Example Of PLL Settings For 48Khz Sample Rates
Example PLL Settings For 44.1Khz Sample Rates
These tables cover the most common applications, obtaining clocks for sample rates such as 22.05kHz and 192kHz should be
done by changing the P divider value or the R divider in the clock configuration diagram.
11
11.2896
12
13
14.4
16.2
16.8
19.2
19.44
19.68
19.8
f_in (MHz)
f_in (MHz)
12.288
19.44
19.68
14.4
16.2
16.8
19.2
19.8
11
12
13
44.1
44.1
44.1
44.1
44.1
44.1
44.1
44.1
44.1
44.1
44.1
fsamp (kHz)
fsamp (kHz)
48
48
48
48
48
48
48
48
48
48
48
11
8
5
13
12
9
17
16
13.5
20.5
11
20.5
16.5
11
13
27
14
13
27
M
M
5
4
9
55.125
39.0625
22.96875
55.125
45.9375
30.625
55.78125
45.9375
38.28125
45.9375
30.625
19.53125
40.625
37.5
62.5
100
100
60
25
60
50
50
N
N
5
5
5
5
5
5
5
5
5
4
5
P
5
5
5
5
5
5
5
5
6
5
5
P
21
15
9
25
23
17
33
31
26
40
21
PLL_M
PLL_M
21
25
17
53
27
25
53
40
32
20
9
7
55
39
22
55
45
30
55
45
38
45
30
PLL_N
PLL_N
100
100
60
25
19
60
37
50
40
62
50
4
2
31
4
30
20
25
30
9
30
20
PLL_N_MOD
PLL_N_MOD
17
16
20
16
0
0
0
0
0
0
0
9
9
9
9
9
9
9
9
9
7
9
PLL_P
PLL_P
20202063
11
9
9
9
9
9
9
9
9
9
9
11.025000
11.025000
11.025000
11.025000
11.025000
11.025000
11.025000
11.025000
11.025000
11.025000
11.025000
f_out (MHz)
f_out (MHz)
12
12
12
12
12
12
12
12
12
12
12