RB-TK2019 データシートの表示（PDF） - Unspecified
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RB-TK2019 Datasheet PDF : 11 Pages
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Tripath Technology, Inc. - Technical Information
JUMPER SETTINGS
J1 is a 2-pin header for the MUTE control. With the jumper shorting the header pins the part is un-muted. When
the jumper is removed the mute pin is pulled high (5V) and the amplifier is muted. Please refer to the Board
Connection Diagram for location of J1.
INDICATOR LED’S
The RB-TK2019 Revision 2.0 has one red LED labeled H-MUTE. The HMUTE LED will glow red and both
outputs are muted when a fault occurs or the MUTE header (J1) is opened. Please refer to the TK2019 Data
Sheet for a complete description of HMUTE. Please refer to the Board Connection Diagram for the LED
location.
OUTPUT OFFSET NULL
There are two potentiometers, R16 (Channel 1) and R24 (Channel 2) that are used to manually trim the output
offset to half of the supply rail voltage (VCC). Because this board uses an output DC blocking capacitor the
offset measurement must be made at or before C62 and C63 and not at the output header. Please refer to the
Board Connection Diagram for the potentiometer locations. The offset should be trimmed to VCC/2 or +12V for
a 24V supply. Although the idle current is not affected by the offset, the output power will be reduced if the
output offset is not properly trimmed. The Evaluation board is shipped with the offset nulled within +/-10mV for a
24V supply.
GAIN SETTING
The gain of the RB-TK2019 Rev 2.0 is set to 10V/V. The gain of the TK2019 is the product of the TC2001
(control stage) gain and the TPS1035 (power stage) gain. The control stage gain is set to unity. Before
changing the gain of the RB-TK2019 Rev 2.0, please refer to the Amplifier Gain section of the TK2019 Data
Sheet.
PERFORMING MEASUREMENTS ON THE RB-TK2019 REV 2.1:
The RB-TK2019 Rev 2.1 operates by generating a high frequency switching signal based on the audio input.
This signal is sent through a low-pass filter that recovers an amplified version of the audio input. The frequency
of the switching pattern is spread spectrum in nature and typically varies between 100kHz and 1MHz, 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.
The measurements of certain performance parameters, particularly noise related specifications such as
THD+N, are significantly affected by the design of the low-pass filter used on the output as well as the
bandwidth setting of the measurement instrument used. Unless the filter has a very sharp roll-off just beyond
the audio band or the bandwidth of the measurement instrument is limited, some of the inaudible noise
components introduced by the TK2019 amplifier switching pattern will degrade the measurement by including
out of band (audio) energy.
One feature of the TK2019 is that it does not require large multi-pole filters to achieve excellent performance in
listening tests, usually a more critical factor than performance measurements. Though using a multi-pole filter
may remove high-frequency noise and improve THD+N type measurements (when they are made with wide-
bandwidth measuring equipment), these same filters degrade frequency response. The RB-TK2019 Rev 2.1
has a simple two-pole output filter with excellent performance in listening tests.
(See Application Note 4 for additional information on bench testing)
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RB-TK2019 – MC/1.0/12-03
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