LM4937RL/NOPB National Semiconductor, LM4937RL/NOPB Datasheet - Page 18

• 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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PLL Configuration Registers
PLL M DIVIDER CONFIGURATION REGISTER
This register is used to control the input divider of the PLL.
PLL_M (0Ah) (Set = logic 1, Clear = logic 0)
NOTES:
The M divider should be set such that the output of the divider is between 0.5 and 5MHz. See the PLL setup section for details.
The division of the M divider is derived from PLL_M as such:
M = (PLL_M+1) / 2
PLL N DIVIDER CONFIGURATION REGISTER
This register is used to control PLL N divider.
PLL_N (0Bh) (Set = logic 1, Clear = logic 0)
NOTES:
The N divider should be set such that the output of the divider is between 0.5 and 5MHz. See the PLL setup section for details. The N divider should never be
set so that (Fin/M) * N > 55MHz (or 80MHz if FAST_VCO is set in the PLL_N_MOD register).
The non-sigma-delta division of the N divider is derived from the PLL_N as such:
N = PLL_N
Fin /M is often referred to as F
PLL P DIVIDER CONFIGURATION REGISTER
This register is used to control the PLL's P divider.
Bits
6:0
Register
PLL_M
Bits
7:0
comp
(Frequency of Comparison) or F
Description
Programs the PLL input divider to select:
Register
PLL_N
PLL_M
126
ref
...
0
1
2
3
4
(Reference Frequency). In this document, F
18
PLL_N
1
248
249
Programs the PLL feedback divider:
→
11
12
...
0
10
Description
comp
is used.
Divide Ratio
Divider Off
63.5
1.5
2.5
3
1
2
→
Divide Ratio
Divider Off
248
249
10
11
12
...