TDA7438 STMicroelectronics, TDA7438 Datasheet - Page 6
TDA7438
Manufacturer Part Number
TDA7438
Description
IC PROCESSOR AUDIO DGTL 28-PDIP
Manufacturer
STMicroelectronics
Type
Audio Processorr
Datasheet
1.TDA7438D.pdf
(19 pages)
Specifications of TDA7438
Applications
Automotive Systems
Mounting Type
Through Hole
Package / Case
28-DIP (0.600", 15.24mm)
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
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TDA7438
The fig.5 refers to basic T Type Bandpass Filter starting from the filter component values (R1 internal and
R2,C1,C2 external) the centre frequency Fc, the gain Av at max. boost and the filter Q factor are computed
as follows:
Viceversa, once Fc, Av, and Ri internal value are fixed, the external components values will be:
3.2 Treble Stage
The treble stage is a high pass filter whose time constant is fixed by an internal resistor (25K typical) and
an external capacitor connected between treble pins and ground Typical responses are reported in Figg.
14 to 17.
3.3 CREF
The suggested 10mF reference capacitor (CREF) value can be reduced to 4.7mF if the application re-
quires faster power ON.
Figure 6. THD vs. frequency
6/19
C1
=
----------------------------- -
2
A
R2
V
A
F
–
R
V
c
1
i
=
Q
=
=
Q
---------------------------------------------------------------------
2
R2C2
------------------------------------------------------------
---------------------------------------------------------- -
2
=
------------------------------------------ -
R2C1
R1C1
Ri R2 C1 C2
C1 F
A
+
Ri R2 C1 C2
V
R2C1
–
+
1
c
+
1
Figure 7. THD vs. RLOAD
C2
R2C2
R2C2
–
A
Q
=
+
V
2
RiC1
----------------------- -
A
–
Q
V
1
2
–
1Q
C1
Q
2