TDA7541B STMicroelectronics, TDA7541B Datasheet - Page 30

• Manufacturer Part Number: TDA7541B
• Description: IC TUNER AM/FM CAR RADIO 64-LQFP
• Manufacturer: STMicroelectronics

Specifications of TDA7541B

• Modulation Or Protocol: AM, FM
• Applications: Automotive Audio
• Current - Receiving: 48mA
• Data Interface: PCB, Surface Mount
• Antenna Connector: PCB, Surface Mount
• Voltage - Supply: 7.7 V ~ 9 V
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 64-LQFP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Features: -
• Frequency: -
• Sensitivity: -
• Memory Size: -
• Data Rate - Maximum: -

Functional description
4.1.5
Note:
4.1.6
30/77
Table 12.
Strong adjacent channel correction
Under strong adjacent channel it is possible to have disturbance of the audio signal created
by interference between ISS filter control (deviation detection) and adjacent channel mute.
The control bits SACCE and SACCT can be used to avoid this disturbance. If the function is
activated (SACCE = “1”) the IF counter together with the internal field strength is used to
suppress a malfunction of deviation detection. The bit SACCT is changing the sensitivity of
the SACC block (SACCT = “1” means higher sensitivity).
Figure 10
The IF counter must be switched ON if this function is used (Addr25D4 = “1”)
Weak signal mute
The filtered field strength signal (FSWO) is the reference for soft slope mute control in weak
signal condition to eliminate audible effects. The start point and mute depth are
programmable (WMTH, WMD) in a wide range. These settings together with FSWO bits are
influencing the weak signal mute behavior. The time constant is defined by external
capacitance at PIN 42. Additional adjacent channel mute function is supported. A high pass
filter with -3 dB threshold frequency of 100 kHz, amplifier and peak rectifier generates an
adjacent noise signal from Demodulator output. This value is compared with adjustable
threshold (ACMTH). For present strong adjacent channel the MPX signal is additional
attenuated (ACMD) and has the same time constant as weak signal mute.
ac
0
0
0
0
0
0
1
1
1
1
ac+
shows the ISS block diagram including the SACC function.
0
0
0
0
0
0
0
1
0
1
ISS control modes
Input signals
sm
0
0
0
1
1
1
0
0
0
0
dev
0
1
1
0
1
1
0
0
1
1
Doc ID 16048 Rev 1
dev+
0
0
1
0
0
1
0
0
0
1
inton
0
0
0
1
0
0
1
1
1
1
int80
Mode1
0
0
0
1
0
0
1
1
0
0
Function
narrow
narrow
narrow
wide
wide
wide
wide
wide
mid
mid
inton
0
0
0
1
1
0
1
1
1
1
Mode2
int80
0
0
0
1
0
0
0
1
0
1
TDA7541B
Function
narrow
narrow
narrow
wide
wide
wide
wide
mid
mid
mid