TAS5424C-Q1_15 Datasheet, PDF (21/51 Pages) Texas Instruments – TAS54x4C-Q1 Four-Channel Automotive Digital Amplifiers

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TAS5414C-Q1, TAS5424C-Q1
SLOS795E – SEPTEMBER 2013 – REVISED JANUARY 2015
7.3.9 Hardware Control Pins
There are four discrete hardware pins for real-time control and indication of device status.
1. FAULT pin: This active-low open-drain output pin indicates the presence of a fault condition that requires the
device to go into the Hi-Z mode or standby mode. On assertion of this pin, the device has protected itself and
the system from potential damage. One can read the exact nature of the fault via I²C with the exception of
PVDD undervoltage faults below POR, in which case the I²C bus is no longer operational. However, the fault
is still indicated due to FAULT pin assertion.
2. CLIP_OTW pin: Configured via I²C, this active-low open-drain pin\ indicates one of the following conditions:
overtemperature warning, the detection of clipping, or the logical OR of both of these conditions. During
tweeter detect diagnostics, assertion of this pin also occurs when a tweeter is present. If overtemperature
warning is set, the device can also indicate thermal foldback on this pin.
3. MUTE pin: This active-low pin is used for hardware control of the mute-unmute function for all four channels.
Capacitor C_MUTE controls the time constant for the gain ramp needed to produce a pop- and click-free mute
function. For pop- and click-free operation, implementation of the mute function should be through I²C
commands. The use of a hard mute with an external transistor does not ensure pop- and click-free operation,
and TI does not recommended it except as an emergency hard mute function in case of a loss of I²C control.
Sharing the C_MUTE capacitor between multiple devices is disallowed.
4. STANDBY pin: On assertion of this active-low pin, the device goes into a complete shutdown, and the typical
current-draw limit is 2 μA, typical. STANDBY can be used to shut down the device rapidly. If all channels are
in Hi-Z, the device enters standby in approximately 1 ms. All I²C register content is lost and the I²C bus goes
into the high-impedance state on assertion of the STANDBY pin.
7.3.10 AM Radio Avoidance
To reduce interference in the AM radio band, the device has the ability to change the switching frequency via I²C
commands. Table 2 lists the recommended frequencies. The fundamental frequency and its second harmonic
straddle the AM radio band listed. This eliminates the tones that can be present due to demodulation of the
switching frequency by the AM radio.
Table 2. Recommended Switching Frequencies for AM Mode Operation
US
AM FREQUENCY
(kHz)
540–670
680–980
990–1180
1190–1420
1430–1580
1590–1700
SWITCHING
FREQUENCY
(kHz)
417
500
417
500
417
500
EUROPEAN
AM FREQUENCY
(kHz)
SWITCHING
FREQUENCY
(kHz)
522–675
417
676–945
500
946–1188
417
1189–1422
500
1423–1584
417
1585–1701
500
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