LM4550BVH/NOPB National Semiconductor, LM4550BVH/NOPB Datasheet - Page 20

• Manufacturer Part Number: LM4550BVH/NOPB
• Description: IC AC '97 AUDIO CODEC 48-LQFP
• Manufacturer: National Semiconductor
• Type: Audio Codec '97r

Specifications of LM4550BVH/NOPB

• Data Interface: Serial
• Resolution (bits): 18 b
• Number Of Adcs / Dacs: 2 / 2
• Sigma Delta: Yes
• Dynamic Range, Adcs / Dacs (db) Typ: 90 / 89
• Voltage - Supply, Analog: 4.2 V ~ 5.5 V
• Voltage - Supply, Digital: 3 V ~ 5.5 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 48-LQFP
• Audio Codec Type: Stereo
• No. Of Adcs: 2
• No. Of Dacs: 2
• No. Of Input Channels: 8
• No. Of Output Channels: 3
• Adc / Dac Resolution: 18bit
• Sampling Rate: 48kSPS
• Interface Type: Serial
• Supply Voltage Range: 3V To 5.5V, 4.2V
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: *LM4550BVH; *LM4550BVH/NOPB; LM4550BVH

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AC Link Serial Interface Protocol
SDATA_OUT: Slots 3 & 4 – PCM Playback Left/Right
Channels
Slots 3 and 4 are 20-bit fields used to transmit PCM data to
the left and right channels of the stereo DAC when the codec
is in Primary mode or Secondary mode 1. Any unused bits
should be stuffed with zeros. The LM4550B DACs have
18-bit resolution and will therefore use the 18 MSBs of the
20-bit PCM data (MSB justified). The AC ’97 Rev 2.1 speci-
fication allocates the Left channel of 5.1 Audio to slot 3 and
the Right channel to slot 4.
SDATA_OUT: Slots 7 & 8 – PCM Playback Left/Right
Surround
Slots 7 and 8 are 20-bit fields used to transmit PCM data to
the left and right channels of the stereo DAC when the codec
is in Secondary mode 2. Any unused bits should be stuffed
with zeros. The LM4550B DACs have 18-bit resolution and
AC LINK INPUT FRAME:
SDATA_IN, CONTROLLER INPUT FROM LM4550B OUTPUT
The AC Link Input Frame contains status and PCM data from
the LM4550B control registers and stereo ADC. Input
(Continued)
Bits
19:4
Bits
19:0
3:0
Register Write
Description
Description
PCM Audio
(Left /Right
Channels)
Reserved
Control
SLOTS 3 & 4, OUTPUT FRAME
Data
Data
SLOT 2, OUTPUT FRAME
Controller should stuff with
zeros if operation is “read”
Set to "0"
Slots used to stream data to
DAC when codec is in Primary
or Secondary 1 modes.
Set unused bits to "0"
Comment
Comment
FIGURE 6. AC Link Input Frame
20
will therefore use the 18 MSBs of the 20-bit PCM data (MSB
justified). The AC ’97 Rev 2.1 specification allocates the Left
Surround channel of 5.1 Audio to slot 7 and the Right Sur-
round channel to slot 8.
SDATA_OUT: Slots 6 & 9 – PCM Playback (Center/LFE)
Slots 6 and 9 are 20-bit fields used to transmit PCM data to
the left and right channels of the stereo DAC when the codec
is in Secondary mode 3. Any unused bits should be stuffed
with zeros. The LM4550B DACs have 18-bit resolution and
will therefore use the 18 MSBs of the 20-bit PCM data (MSB
justified). The AC ’97 Rev 2.1 specification allocates the
Center channel of 5.1 Audio to slot 6 and the LFE (Low
Frequency Enhancement) channel to slot 9.
SDATA_OUT: Slots 5, 10, 11, 12 – Reserved
These slots are not used by the LM4550B and should all be
stuffed with zeros by the AC ’97 Controller.
Frames are carried on the SDATA_IN signal which is an
input to the AC ’97 Digital Audio Controller and an output
Bits
19:0
Bits
19:0
(Center/ LFE
Description
Description
PCM Audio
PCM Audio
(Left/Right
Surround)
Surround)
SLOTS 7 & 8, OUTPUT FRAME
SLOTS 6 & 9, OUTPUT FRAME
Data
Data
Slots used to stream data to
DAC when codec is in
Secondary 2 mode.
Set unused bits to "0"
Slots used to stream data to
DAC when codec is in
Secondary 3 mode.
Set unused bits to "0"
Comment
Comment
20123708