TDA8594 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2013. All rights reserved.
Product data sheet Rev. 5 — 11 June 2013 15 of 49
NXP Semiconductors
TDA8594
I
2
C-bus controlled 4 50 W power amplifier
7.13 Diagnostics
Diagnostic information can be read via the I
2
C-bus, and can also be available on the DIAG
pin or on the STB pin. The DIAG pin has both fixed information (power-on reset occurred,
low battery and high battery) and, via the I
2
C-bus, selectable information (temperature,
load fault and clip). This information will be seen at the DIAG pin as a logic OR. In case of
a failure, the DIAG pin remains LOW and the failure information can be read from the
microprocessor via the I
2
C-bus (the DIAG pin can be used as a microprocessor interrupt
to minimize I
2
C-bus traffic). When the failure is removed, the DIAG pin will be released.
To have full control over the clipping information, the STB pin can be programmed as a
second clip detection pin. The clip detection level can be selected for all channels at once.
It is possible to select whether the clip information is available on the DIAG pin or on the
STB pin for each channel separately. It is, for instance, possible to distinguish between
clipping of the front and the rear channels.
Diagnostic information selection possibilities are shown in Table 4
.
Fig 10. Temperature controlled amplifier gain
T
j
(°C)
145 175165155
001aad174
10
20
30
G
v
(dB)
0
Table 4. Diagnostic information availability
Diagnostic information I
2
C-bus mode Legacy mode
DIAG pin STB pin DIAG pin
POR after power-on reset, DIAG
pin will remain LOW until
amplifier has been started
no no
Low battery yes no yes
Clip detection can be enabled per channel can be enabled
per channel
yes, fixed level for all
channels on 2 %
Temperature
pre-warning
can be enabled no yes, pre-warning
level is 145 C
Short can be enabled no yes
Speaker protection
(missing current)
can be enabled no yes
