TCM320AC36 Datasheet, PDF (17/23 Pages) Texas Instruments – VOICE-BAND AUDIO PROCESSORS VBAPE

TCM320AC36, TCM320AC37
VOICE-BAND AUDIO PROCESSORS (VBAP™)
PRINCIPLES OF OPERATION
SLWS003C – MAY 1992 – REVISED APRIL – 1998
–
+
4
EARGS
IN
_
+
2
EARA
_
VMID
+
3
EARB
NOTE A: Terminal numbers shown are for the DW and N packages.
Figure 6. Earphone Audio-Output Amplifier Configuration and Internal Gain-Setting Network
receive data format
In the companded mode, eight bits of data are received. The sign bit is the first bit received (see Table 2).
In the linear mode, 16 bits of data are received. The first 13 bits are the D/A code, and the remaining three bits
form the volume control word (see Table 2). The volume control function is actually an attenuation control in
which the first bit received is the most significant. The maximum volume occurs when all three volume control
bits are zero. Eight levels of attenuation are selectable in 3-dB steps, giving a maximum attenuation of 21 dB
when all bits are 1s. The volume control bits are not latched into the VBAP and must be present in each received
data word.
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