Tripath Technology, Inc. - Technical Information
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 all 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.
P ow er D i ssi p at i o n Der at i n g
For operating at ambient temperatures above 25°C the device must be derated based on a
150°C maximum junction temperature, TJMAX as given by the following equation:
(T
=
− T )
A
JMAX
P
DISS
θ
JA
where…
PDISS = maximum power dissipation
TJMAX = maximum junction temperature of TA2024B
TA = operating ambient temperature
θJA = junction-to-ambient thermal resistance
Where θJA of the package is determined from the following graph:
JA vs Copper Area
Θ
50
40
Pdiss - 1.35W
30
20
10
Pdiss - 2W
Pdiss - 3.4W
0
1
2
3
4
5
6
Copper Area (square inches)
In the above graph Copper Area is the size of the copper pad on the PC board to which the heat
slug of the TA2024B is soldered. The heat slug must be soldered to the PC Board to increase
the maximum power dissipation capability of the TA2024B package. Soldering will minimize the
likelihood of an over-temperature fault occurring during continuous heavy load conditions. The
vias used for connecting the heatslug to the copper area on the PCB should be 0.013” diameter.
Perfo rm an ce Mea su r emen ts o f th e T A20 2 4B
The TA2024B operates by generating a high frequency switching signal based on the audio input.
This signal is sent through a low-pass filter (external to the Tripath amplifier) that recovers an
amplified version of the audio input. The frequency of the switching pattern is spread spectrum
and typically varies between 100kHz and 1.0MHz, which is well above the 20Hz – 20kHz audio
band. The pattern itself does not alter or distort the audio input signal but it does introduce some
inaudible components.
10
TA2024B –KL/1.2/01.06
TRIPATH [ TRIPATH TECHNOLOGY INC. ]
