TC9470FN Datasheet, PDF (13/19 Pages) Toshiba Semiconductor – Modulation DA Converter with Built-in 8-Times Oversampling Digital Filter/Dynamic Digital Bass Boost/Analog Filter

TC9470FN
10.2.1 Setting Mode 1
Serial setting mode 1 is enabled when D12 = “L”.
(1) Digital attenuator
The digital attenuation command is enabled when D12 = L. The attenuation data can be set in
4096 different ways (coefficient: 12 bit, maximum attenuation: −72.245dB). The relationship with
the command’s output is shown below.
Table 9 Attenuation Data/Audio Data Output
Attenuation Data
AT [11:00]
FFFH
FFEH
FFBH
···
C80H
···
640H
···
002H
001H
000H
Audio Output
−0.000dB
−0.002dB
−0.004dB
···
−2.142dB
···
−8.163dB
···
−66.224dB
−72.245dB
−∞
001 (HEX) to FFE (HEX): The attenuation value is obtained with the following equation.
ATT = 20 ℓog (input data/4095) dB
Example: When the attenuation data is EA0H
ATT = 20 ℓog (4000/4095) dB = −0.204dB
If an input level is set to −48dB or less when it is set as the amount (−72.245dB) of the maximum
attenuation, the target effective attenuation data of digital attenuator of TC9470FN will be lost. The
output data is set to “0” when an input level is set to −48dB or less. An effective input level is
decided by the following formula.
Effective input data = −[120dB + Attenuation level (dB)]
10.2.2 Setting Mode 2
Serial setting mode 2 is enabled when D12 = “H” and D11 = “L”.
(1) Digital de-emphasis filter
Controlled with EMP.
Table 10 Digital De-Emphasis Filter Setting
EMP
L
H
De-emphasis filter
OFF
ON
13
2002-02-27