tc9404fng TOSHIBA Semiconductor CORPORATION, tc9404fng Datasheet - Page 6

• Manufacturer Part Number: tc9404fng
• Description: Modulation System Da Converter With Analog Filter
• Manufacturer: TOSHIBA Semiconductor CORPORATION

4. De-Emphasis Filter
5. DA Conversion Circuit
Figure 4 IIR Digital De-Emphasis Filter
44.1 kHz, and 48 kHz. These setting controlled in the parallel mode (
(pin 18) and SHIFT (EMP) pin (pin 19).
microcontroller setting mode for further details on serial mode settings.)
condensers and analog switches. In addition to this, the coefficients are aligned to reduce error in the
de-emphasis filter characteristics.
Transfer function:
The internal structure of this is shown in Figure 6.
The built-in digital de-emphasis circuit is available for three kind of sampling frequency, fs of 32 kHz,
This is set in the serial mode (
The digitalization of the de-emphasis filter eliminates the need for such external components as resistors,
The filter structure and characteristics are shown below.
The IC incorporates a 2’nd Σ - ∆ modulation DA converter for two channels (simultaneous output type).
Table 2 De-Emphasis Filter Setting (when in the parallel mode)
2’nd ∑-∆ converter: Y (Z) = X (Z) + (1 − Z
MODE (fs SELECT)
H
(Z)
SHIFT (EMP)
LATCH (BS)
Figure 6 Σ-∆ Modulation DA Converter
=
b (
(1
0
−
+
a
b
1
1
Z
P/ = “L”) with a microcontroller or other equipment. (refer to 9-2
Z
−
−
S
1
1
)
)
32
H
H
6
− 1
)
2
Q (Z)
Figure 5 Filter Characteristics
48
H
L
T
1
= 50 µs, T
P/ = “H”) with the LATCH (BS) pin
44.1
S
H
L
2
= 15 µs
OFF
L
L
TC9404FNG
(kHz)
2006-04-27