TDA8596_15 Datasheet, PDF (6/48 Pages) NXP Semiconductors – I2C-bus controlled 4 ´ 45 W power amplifier with symmetrical inputs

NXP Semiconductors
TDA8596
I²C-bus controlled 4 × 45 W power amplifier with symmetrical inputs
7.1 Output stage
The output stage of each amplifier channel consists of two PMOS power transistors and
two NMOS transistors in BTL configuration. The TDA8596 is manufactured in a BCDMOS
process on an isolated substrate Silicon On Insulator (SOI). Due to the absence of a
doped (bulk) substrate, this process is insensitive to latch-up induced by substrate
coupled parasitic paths.
7.2 Gain selection
The gain of the TDA8596 can be programmed at 16 dB (line driver mode) or 26 dB
(Normal operating mode). This can be done either in I²C-bus mode by means of a bus
command or in legacy mode by using the GAINSEL pin. To allow this, the device must first
be put in legacy mode by connecting the ADSEL pin to ground. In case the GAINSEL pin
is connected to ground the 26 dB mode is selected. By leaving the GAINSEL pin open the
16 dB mode is selected. The GAINSEL pin will be ignored in I²C-bus mode.
7.3 Distortion (clip-) detection
If the output of an amplifier channel starts clipping to either the supply voltage or to ground
the output signal will become distorted. When the Total Harmonic Distortion (THD) per
channel exceeds a preselected threshold (2 %, 5 % or 10 %), one of the two diagnostic
pins (DIAG or STB) will be pulled LOW. The clip information of each channel can be
directed separately to one specific diagnostic pin. This way, it is possible to distinguish
between clipping on the front or rear channels. Redirection of temperature and load
information to the diagnostic pins can be disabled to allow only the clip information to be
present on these pins. In this mode, the temperature and load information is still available
but can only be read out through the I²C-bus.
Note: during mute-to-on or on-to-mute transitions, the clip detection may be activated
even when no output clipping occurs.
7.4 Output protection and short circuit operation
When a short circuit to ground, to V_P or across the load occurs, the concerning amplifier
channel will switch off. After 16 ms of non-operation it will switch on again. If the short
circuit condition is still present the amplifier channel will again return to 16 ms of
non-operation. The 16 ms cycle will reduce the dissipation.
The other amplifier channels (without short circuit condition) will retain functionality. To
prevent audible distortion, the amplifier channel with the short circuit condition can be
disabled via the I²C-bus.
In case the diagnostic pin is selected for load fault information (IB2[D4] = 0), it will be
pulled LOW. Via the I²C-bus it can be read out which channel is shorted by what type of
short circuit (to ground, to V_P or across the load).
In order to detect a shorted load, a signal should be applied to the inputs of the amplifier.
A shorted load is only detected when the output current level on the related output
crosses the defined Safe Operating ARea (SOAR) protection threshold.
TDA8596_2
Product data sheet
Rev. 02 — 8 November 2007
© NXP B.V. 2007. All rights reserved.
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