TDA7541W STMicroelectronics, TDA7541W Datasheet - Page 32

• Manufacturer Part Number: TDA7541W
• Description: IC TUNER AM/FM CAR RADIO 64-LQFP
• Manufacturer: STMicroelectronics

Specifications of TDA7541W

• 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: -
• Lead Free Status / Rohs Status: Compliant

Functional description
32/75
Deemphasis and high cut
The deemphasis low pass allows to choose between a time constant of 50 µs/75 µs
(DEEMP). The high cut control range will be in both cases T
cut control range (between VHCHT and VHCLT) the LEVEL signal is converted into a 5-bit
word, which controls the low pass time constant between T
resolution will remain 5 bits referred to the voltage range between the VHCHT- and minimum
VHCLT-values.
The high cut function can be switched off by I
Figure 3.
In AM mode (FMON = 0) the DEEMP bit together with the AM corner frequency bits (AMCF)
can be used as programmable AM frequency response. The maximum corner frequency is
defined by T
response it is need to take into account the frequency response of the AF output at
MPXOUT and the Stereo decoder demodulator too.
19 kHz PLL and pilot tone detector
The PLL has the task to lock on the 19 kHz pilot tone during a stereo-transmission to allow a
correct demodulation. The included pilot tone-detector enables the demodulation if the pilot
tone reaches the selected pilot tone threshold VPTHST. Two different thresholds are
available. The status of the detector output can be checked by reading the status byte of the
TDA7541 via I
Field strength control
The field strength input is used to control the high cut- and the stereo blend-function. In
addition the signal can be also used to control the noise blanker thresholds and as input for
the multipath detector.
Level input and gain
As level input for the stereo decoder is used the FSU voltage (pin27). Applying a capacitor at
FSTC (pin28) a desired time constant can by reached together with the internal resistor of
10k between FSU pin and FSTC pin. The second stage is a programmable gain stage to
adapt the VFSTC signal internally. The gain (LG) is widely programmable in 16 steps from
0 dB to 8.25 dB (step=0.55dB). These 4 bits are located together with the Roll-Off
Deemp
Programming of HC filter
2
High Cut Filter
Time Constant
C bus or by reading the STEREO status at MUX pin23.
3*T Deemp
, the minimum is defined by 3 x T
T Deemp
HCMax
Doc ID 13686 Rev 4
00
11
01
V
HCLT
2
C-bus.
Deemp
For the over all frequency
Deemp
HC
V
HCHT
= 2 x T
...3 x T
V
FSTC*
Deemp
Deemp
LG
. Inside the high
. Thereby the
TDA7541