TDA7540B STMicroelectronics, TDA7540B Datasheet - Page 32

• Manufacturer Part Number: TDA7540B
• Manufacturer: STMicroelectronics

Specifications of TDA7540B

• Case: TQFP
• Dc: 06+
• Lead Free Status / Rohs Status: Compliant

DOCUMENT CD00108485
Copyright STMicroelectronics
Functional description
Figure 6.
28/75
REVISION 1.0
Stereoblend control
The stereoblend control block converts the internal LEVEL-voltage into a demodulator
compatible analog signal, which is used to control the channel separation between 0dB and
the maximum separation. Internally this control range has a fixed upper limit, which is the
internal reference voltage
V
To adjust the external LEVEL-voltage to the internal range two values must be defined: the
LEVEL gain
(VST) the LEVEL gain
the gain:
The MONO-voltage VMO (0dB channel separation) can be chosen selecting VSBL.
Relation between internal and external level-voltagees and setup of stereoblend
The stereo blend function can be switched ON/OFF using bit Addr25<d2>. Please note that
in AM it must be switched in forced mono!
Highcut control
The highcut control set-up is similar to the stereoblend control set-up: the starting point
VHCH can be set with 2 bits to be 42, 50, 58 or 66% of
to be 11, 18.3, 25.7 or 33% of VHCH (see fig. 7).
REF1
in 4% steps (see fig.6).
L
G
and VSBL. To adjust the voltage where the full channel separation is reached
L
G
has to be defined. The following equation can be used to estimate
V
REF1
. The lower limit can be programmed between 29 and 58% of
COMPANY INTERNAL
L
G
=
ACTIVE
V
REF1
/FSU@full stereo
VREF1
whereas the range can be set
Unauthorized reproduction and communication strictly prohibited
DATE 11-May-2006
TDA7540B
page: 28/75