TDA8595 NXP Semiconductors, TDA8595 Datasheet - Page 7

• Manufacturer Part Number: TDA8595
• Description: The TDA8595 is a complementary quad Bridge Tied Load (BTL) audio power amplifiermade in BCDMOS technology
• Manufacturer: NXP Semiconductors

NXP Semiconductors
TDA8595_2
Product data sheet
7.1 Input stage
7.2 Output stage
7.3 Distortion (clip-) detection
7.4 Output protection and short-circuit operation
7.5 SOAR protection
The input stage is a high-impedance pseudo-differential input stage. The negative inputs
of the four channels are combined on the ACGND pin. For the best performance on
supply voltage ripple rejection and pop noise, the capacitor connected to the ACGND pin
must be four times the value of the input capacitor (or as close to the value as possible).
The output stage of each amplifier channel consists of two PMOS power transistors and
two NMOS transistors in BTL configuration. The process used is the BCDMOS process
with an isolated substrate, SOI process, which has almost no parasitic components and
therefore prevents latch-up.
If the output of the amplifier starts clipping to the supply voltage or to ground, the output
will become distorted. If the distortion per channel exceeds a selectable threshold (2 %,
5 % or 10 %), one of the two diagnostic pins (DIAG pin or STB pin) will be activated. To be
able to detect if, for instance, the front channels (channel 1 and channel 3) or rear
channels (channel 2 and channel 4) are clipping, the clip information can be directed per
channel to the DIAG pin or the STB pin. It is possible to have only the clip information on
the diagnostic pins by disabling the temperature and load information on the diagnostic
pin. In this mode the temperature and load protection are still functional but can only be
read via the I
When a short-circuit to ground, V
amplifier, only the amplifier with the short-circuit is switched off. The channel that has a
short-circuit and the type of short-circuit can be read-back via the I
diagnostic pin is enabled for load fault information (IB2[D4] = 0) the DIAG pin will be pulled
LOW. After 16 ms the amplifier will be switched on again and, if the short-circuit conditions
still occur, the amplifier will be switched off.
The 16 ms cycle will reduce the dissipation. To prevent audible distortion, the amplifier
channel with the short-circuit can be disabled via the I
The output transistors are protected by Safe Operating ARea (SOAR) protection. The
TDA8595 has a two-stage SOAR protection:
•
•
If the differential output voltage across the load is less than 1 V, and the current
through the load is more than 4 A, the amplifier channel will be switched off during
16 ms. To prevent incorrect switch-off with an inductive load or very high input signals,
the condition (V
If the differential output voltage across the load is more than 1 V, and the current
through the load is more than 8 A, the amplifier channel will be switched off during
16 ms.
2
C-bus.
o
Rev. 02 — 21 November 2007
< 1 V and I
L
P
> 4 A) must exist for more than 300 s.
or across the load occurs on one or more outputs of an
I
2
C-bus controlled 4
2
C-bus.
2
45 W power amplifier
C-bus. If the
TDA8595
© NXP B.V. 2007. All rights reserved.
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