EB-2100 Datasheet, PDF (3/11 Pages) List of Unclassifed Manufacturers – DDX All-Digital, High Efficiency Evaluation Amplifier

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__ EB-2100x
adjusted using two potentiometers. The DC
voltage set by the potentiometers is read by the
microcontroller that interfaces to the volume
serial port of the DDX-2000. The DDX-2000 has
independent volume control registers that have
an adjustment range from –82.5dB to +12.0dB in
0.75dB increments. A 0dB switch setting is
included to signal the microcontroller to set the
volume level for both channels to be unity gain.
This setting is particularly useful for audio
measurements.
The EB-2100x permits three separate methods
for clocking the DDX-2000. The default is via
the 256*Fs recovered clock output from the
S/PDIF receiver IC. The second is via the
expansion header J7 used to apply an external
clock source to synchronize, for example,
multiple DDX-2000 ICs to the same clock. Zero-
ohm jumper R35 is installed to pass either of
these clock sources to the DDX-2000 master
clock input. The last method is asynchronous
from an external crystal. The DDX-2000
contains a crystal oscillator which may be used
for single sample-rate applications. Oscillator
circuit Y1, C30, C37, R24, R26 may be
populated and jumper R35 removed for
applications where a 256*Fs clock source is not
convenient. The DDX-2000 tolerates a sample
rate mismatch of +/-0.2% about the crystal
frequency without performance degradation.
The crystal footprint is a surface mount Epson
MA-506.
There are additional provisions for
demonstrating DDX-2000 functionality. The
GCEN flag is used to disable the anticlipping
function and is controlled by DIP rocker switch
SW1. Jumper R29 is provided to change the
serial port mode on the DDX-2000 from I²S to
left-justified to accommodate an external set of
signals. Jumpers R13, R14, R30 are provided
for test modes and must not be changed. A
channel reverse flag is provided which inverts
LRCLK causing left channel data to be output on
the right channel and vice versa. This function
is intended to be used for multiple amplifiers
configured as mono when used in a
multichannel audio demonstration.
POWER OUTPUT (FIG. 3C)
The DDX-2100 provides power amplification by
translating logic level PWM signals into power
level signals. These power level signals are
applied to a passive two-pole lowpass filter to
reconstruct the audio signal providing power to
the load. The output filter functions to attenuate
unwanted high frequency signals from reaching
the load. A filter design for 8Ω loads is shown in
the Fig. 3C schematic for reference.
The DDX-2100 is designed for stereo operation
as either two independent full-bridges or for
mono operation as one full-bridge with twice the
current capability, enabling higher output power.
The EB-2100x is designed to demonstrate both
configurations via component substitutions. The
schematic notes in Fig. 3C detail component
changes to convert from stereo to mono
operation. Evaluation boards configured as
either stereo or mono may be ordered with the
appropriate part number designations. Jumpers
R19, R22, R25, R33 are used to configure PWM
inputs for stereo operation. Jumpers R17, R23,
R27, R36 are used to configure PWM inputs for
mono operation. Jumpers JP1 and JP3 parallel
the output bridges enabling higher output
current. Jumpers JP2 and JP4 parallel the
output filter sections to a 4Ω load. Capacitor
C29 is the differential capacitor required for the
4Ω filter only.
In applications where only mono 100W /
4Ω operation is desired, e.g. subwoofer, the
output filter may be simplified. Two filter
sections may be employed in lieu of sections in
parallel. Inductors may be ½ the value with
twice the current rating. Capacitors are double
the value and resistors are ½ the value at twice
the power rating.
Snubbers are employed to protect the output
MOSFETs from inductive transients. Peak
voltage on the DDX-2100 output and power pins
must not exceed 40V. Output snubbers for the
stereo implementation are R15,C23 and
R31,C40 and the snubber for the mono
implementation is R21,C32.
Input protection is provided for the amplifier by
diode D1. D1 will protect from overvoltage and
reverse power applications by shunting the
power supply.
A thermal warning indicator is activated by the
DDX-2100 when its junction temperature
exceeds +130^oC. The thermal warning output is
used to force the power LED to change color
from green to red forecasting the potential of an
overtemperature shutdown.
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Details are subject to change without notice.