Tripath Technology, Inc. - Technical Information
STATED, and will float to 1/2 of VDD. The FAULT pin can be connected directly to MUTE to
automatically recover from an overcurrent condition.
O ve r-te mp eratu r e Pr o tectio n
An over-temperature fault occurs if the junction temperature of the part exceeds approximately
155°C. The thermal hysteresis of the part is approximately 45°C, therefore the fault will
automatically clear when the junction temperature drops below 110°C.
O ve r - cu r r e n t P r o t ect i o n
An over-current fault occurs if more than approximately 7 amps of current flows from any of the
amplifier output pins. This can occur if the speaker wires are shorted together or if one side of
the speaker is shorted to ground. An over-current fault sets an internal latch that can only be
cleared if the MUTE pin is toggled or if the part is powered down. Alternately, if the MUTE pin is
connected to the FAULT pin, the HIGH output of the FAULT pin will toggle the MUTE pin and
automatically reset the fault condition.
O ve rl o ad
The OVRLDB pin is a 5V logic output. When low, it indicates that the level of the input signal has
overloaded the amplifier resulting in increased distortion at the output. The OVRLDB signal can
be used to control a distortion indicator light or LED through a simple buffer circuit, as the
OVRLDB cannot drive an LED directly.
F au l t P in
The FAULT pin is a 5V logic output that indicates various fault conditions within the device.
These conditions include: low supply voltage, low charge pump voltage, low 5V regulator voltage,
over current at any output, and junction temperature greater than approximately 155°C. All faults
except overcurrent automatically reset upon removal of the condition. The FAULT output is
capable of directly driving an LED through a series 2kΩ resistor. If the FAULT pin is connected
directly to the MUTE input an automatic reset will occur in the event of an over-current condition.
Ou tpu t Voltag e Offset
The DC offset voltages that appear at the speaker terminals of a TAA2008 amplifier are typically
small and for most applications no DC offset correction is necessary. The TAA2008 is 100% tested
to ensure that the differential output DC offset voltage is less than +/-150mV. However this DC offset
can cause a small turn on and turn off pop, depending on the offset value for that specific IC. Every
TAA2008 IC will have a different offset voltage for each channel.
If the output offset is deemed unacceptable from a turn on/off pop standpoint, there are three
recommended methods for correcting it. These methods of trimming the offset voltage are optional
and for most cases the additional circuitry is not needed.
1) A potentiometer can be used at the input of the TAA2008 as shown in the figure below. By
changing the input bias voltage the output DC offset voltage can be trimmed. Two separate
potentiometers must be used to trim both channels.
12
TAA2008 –KLi/1.0/05.06
TRIPATH [ TRIPATH TECHNOLOGY INC. ]
