LM49350RLX/NOPB National Semiconductor, LM49350RLX/NOPB Datasheet - Page 44

• Manufacturer Part Number: LM49350RLX/NOPB
• Description: IC AUDIO SUBSYSTM .8W D 36USMDXT
• Manufacturer: National Semiconductor
• Series: Boomer®r
• Type: Class Dr

Specifications of LM49350RLX/NOPB

• Output Type: 1-Channel (Mono) with Mono and Stereo Headphones
• Max Output Power X Channels @ Load: 2W x 1 @ 4 Ohm; 69mW x 2 @ 32 Ohm
• Voltage - Supply: 2.7 V ~ 5.5 V
• Features: 3D, DAC, Depop, I²C, I²S, Mute, Short-Circuit and Thermal Protection, Shutdown, Volume Control
• Mounting Type: Surface Mount
• Package / Case: 36-MicroSMDxt
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: LM49350RLX

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power requirements. Please refer to the demonstration board
schematic shown in Figure 23.
20.8 AUXILIARY OUTPUT AMPLIFIER
The LM49350’s auxiliary output (AUXOUT) amplifier provides
differential drive capability to loads that are connected across
its outputs. This results in output signals at the AUX_OUT+
and AUX_OUT- pins that are 180 degrees out of phase with
respect to each other. This effectively doubles the maximum
possible output swing for a specific supply voltage when com-
pared to single-ended output configurations. The differential
output configuration also allows the load to be isolated from
ground since both the AUX_OUT+ and AUX_OUT- pins are
biased at the same DC potential. This eliminates the need for
any large and expensive DC blocking capacitors at the AUX-
OUT amplifier outputs. The load can then be directly con-
nected to the positive and negative outputs of the AUXOUT
Bits
Bits
Bits
0
1
2
3
4
5
0
1
2
3
4
0
1
2
3
4
5
AUX_NEG_6dB
HP_NEG_6dB
LS_NEG_6dB
DACR_ADCR
AUXR_ADCR
DACL_ADCL
MICR_ADCR
AUXL_ADCL
MICL_ADCL
DACR_AUX
CP_FORCE
AUXR_AUX
DACL_AUX
MICR_AUX
AUXL_AUX
MICL_AUX
EPMODE
Field
Field
Field
The right DAC output is added to the AUX output.
The left DAC output is added to the AUX output.
The right MIC input is added to the AUX output. Setting this bit enables the MIC BIAS output.
The left MIC input is added to the AUX output. Setting this bit enables the MIC BIAS output.
The right AUX input is added to the AUX output.
The left AUX input is added to the AUX output.
If set the HPR output is driven with the negative input of the HPL output stage.
If set, both HPL and HPR are attenuated by 6dB. This is useful when adding stereo signals
that need more headroom due to being highly correlated.
If set the class D output is attenuated by 6dB. This is useful when adding stereo signals that
need more headroom due to being highly correlated.
If set the AUX output is attenuated by 6dB. This is useful when adding stereo signals that
need more headroom due to being highly correlated.
If set, a -LS_VDD rail will be created on HP_VSS, even if the HP output stage is not required.
The right DAC output is added to the ADC right input.
The left DAC output is added to the ADC left input.
The right MIC input is added to the ADC right input. Setting this bit enables MIC BIAS.
The left MIC input is added to the ADC left input. Setting this bit enables MIC BIAS.
The right AUX input is added to the ADC right input.
The left AUX input is added to the ADC left input.
TABLE 22. OUTPUT_OPTIONS (0x14h)
TABLE 21. AUX_OUTPUT (0x13h)
TABLE 23. ADC_INPUT (0x15h)
44
amplifier which then isolates it from any ground noise, thereby
improving signal to noise ratio (SNR) and power supply re-
jection ratio (PSRR).
The AUXOUT amplifier has two modes of operation. The pri-
mary mode of operation is high current drive mode (Earpiece
Mode) where the AUXOUT amplifier can be used to differen-
tially drive a mono earpiece speaker. The secondary mode of
operation is low current drive mode where the AUXOUT am-
plifier operates in a power saving mode (AUX_LINE_OUT
Mode) to provide a differential output that is used as a mono
differential line level input to a standalone mono differential
input class D amplifier (LM4675) for stereo loudspeaker ap-
plications.
Description
Description
Description