Philips Semiconductors
Product specification
Hi-fi stereo audio processor; I2C-bus
TDA8425
PINNING
Fig.2 Pinning diagram.
FUNCTIONAL DESCRIPTION
Source selector
The input to channel 1 (CH1) and channel 2 (CH2) is determined by the source selector. The selection is made from the
following AF input signals:
• IN 1 L (pin 18); IN1 R (pin 20)
or
• IN2 L (pin 1); IN2 R (pin 3)
Mode selector
The mode selector selects between stereo, sound A and sound B (in the event of bilingual transmission) for OUT R and
OUT L.
Volume control and balance
The volume control consists of two stages (left and right). In each part the gain can be adjusted between +6 dB and
−64 dB in steps of 2 dB. An additional step allows an attenuation of ≥ 80 dB. Both parts can be controlled independently
over the whole range, which allows the balance to be varied by controlling the volume of left and right output channels.
Linear stereo, pseudo stereo, spatial stereo and forced mono mode(1)
It is possible to select four modes: linear stereo, pseudo stereo, spatial stereo or forced mono. The pseudo stereo mode
handles mono transmissions, the spatial stereo mode handles stereo transmissions and the forced mono can be used
in the event of stereo signals.
(1) During forced mono mode the pseudo stereo mode cannot be used.
October 1988
4
NXP [ NXP ]
