TDA7402 STMicroelectronics, TDA7402 Datasheet - Page 17

• Manufacturer Part Number: TDA7402
• Description: IC PROCESSOR CAR SIGNAL 44-LQFP
• Manufacturer: STMicroelectronics
• Type: Car Signal Processorr

Specifications of TDA7402

• Applications: Automotive Systems
• Mounting Type: Surface Mount
• Package / Case: 44-LQFP
• Case: QFP
• Dc: 05+
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

TDA7402
3.2.1
3.2.2
3.2.3
3.2.4
3.2.5
3.3
3.3.1
Full differential stereo input 1 (FD1)
The FD1 input is implemented as a buffered full-differential stereo stage with 100kΩ input
impedance at each input. The attenuation is programmable in 3 steps from 0 to -12dB in
order to adapt the incoming signal level. A 6dB attenuation is included in the differential
stage, the additional 6dB are done by a following resistive divider. This input is also
configurable as two single ended stereo inputs (see pin-out).
Full differential stereo input 2 (FD2)
The FD2 input has the same general structure as FD1, but with a programmable attenuation
of 0 or 6dB embedded in the differential stage.
Mono differential input 1 (MD1)
The MD1 input is designed as a basic differential stage with 56kΩ input impedance. This
input is configurable as a single ended stereo input (see pin-out).
Mono differential input 2 (MD2)
The MD2 input has the same topology as MD1, but without the possibility to configure it to
single ended.
Single ended stereo input (SE1), single ended mono input (AM) and
FM-MPX input
All single ended inputs offer an input impedance of 100kΩ. The AM pin can be connected by
software to the input of the stereo-decoder in order to use the AM noiseblanker and AM High
Cut feature.
AutoZero
The AutoZero allows a reduction of the number of pins as well as external components by
canceling any offset generated by or before the In-Gain-stage (Please notice that externally
generated offsets, e.g. generated through the leakage current of the coupling capacitors,
are not canceled).
The auto zeroing is started every time the DATA-BYTE 0 is selected and needs max. 0.3ms
for the alignment. To avoid audible clicks the Audioprocessor is muted before the loudness
stage during this time. The AutoZero feature is only present in the main signal path.
AutoZero for stereo decoder selection
A special procedure is recommended for selecting the stereo decoder at the main input-
selector to guarantee an optimum offset cancellation:
1.
2.
3.
4.
5.
Soft Mute or Mute the signal-path
Temporary deselect the stereo decoder at all input selectors
Configure the stereo decoder via IIC-Bus
Wait 1ms
Select the stereo decoder at the main input selector first
Audioprocessor part
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