TDA8933 Datasheet, PDF (12/47 Pages) NXP Semiconductors – Class-D audio amplifier

NXP Semiconductors
TDA8933
Class-D audio amplifier
8.5 Diagnostic input and output
Whenever one of the protections is triggered, except for TF, pin DIAG is activated to LOW
level (see Table 6). An internal reference supply will pull up the open-drain DIAG output to
approximately 2.4 V. This internal reference supply can deliver approximately 50 µA. The
DIAG pin refers to pin CGND.The diagnostic output signal during different short circuit
conditions is illustrated in Figure 5. Using pin DIAG as input, a voltage < 0.8 V will put the
device into Fault mode.
V_o
2.4 V
V_o
2.4 V
amplifier
restart
0V
0V
≈ 50 ms ≈ 50 ms
shorted load
no restart
short to
supply line
001aad759
Fig 5. Diagnostic output for different kinds of short circuit conditions
8.6 Differential inputs
For a high common-mode rejection ratio and for maximum flexibility in the application, the
audio inputs are fully differential. By connecting the inputs anti-parallel, the phase of one
of the two channels can be inverted, so that the amplifier can operate as a mono BTL
amplifier. The input configuration for a mono BTL application is illustrated in Figure 6.
In the single-ended configuration it is also recommended to connect the two differential
inputs in anti-phase. This has advantages for the current handling of the power supply at
low signal frequencies and minimizes supply pumping (see also Section 14.8).
audio
input
IN1P
IN1N
OUT1
IN2P
IN2N
OUT2
001aad760
Fig 6. Input configuration for a mono BTL application
TDA8933_1
Preliminary data sheet
Rev. 01 — 15 May 2007
© NXP B.V. 2007. All rights reserved.
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