DEM-DAI1602 Datasheet, PDF (2/11 Pages) Texas Instruments – EVALUATION FIXTURE

GENERAL DISCUSSION
POWER SUPPLIES
The DEM-DAI1602 requires three external supplies: a +5V
supply (V_CC) is required for the PCM1602; a digital audio
receiver (U3); and associated logic circuitry (U3, U4). An
onboard regulator (the REG1117-3.3) is used to generate
+3.3V from V_CC, which is required by the PCM1602 and
associated buffers (U5, U6). The output of the regulator can
be disabled by a jumper (JP3) and an external +3.3V supply
may then be provided at connector CN4.
The op amps used for the low-pass active filters (U50
through U52 ) require positive and negative power supplies.
The +V_S supply is typically +15V, with a maximum value of
+18V and a minimum value of +5V. The –V_S supply is
typically –15V, with a minimum value of –18V and a
maximum value of –5V.
The power supplies used for V_CC, +V_S, and –V_S should be
well regulated and filtered. Switching power supplies may
be used, but linear regulated supplies are recommended for
optimal performance. All supplies should be rated for a
minimum of 500mA of output current.
DIGITAL AUDIO INTERFACE
The digital audio interface is provided by a Crystal CS8414
digital audio receiver (U3). The interface is used to receive
a stereo, linear PCM, S/PDIF data stream from either an
electrical or optical source. The electrical input is furnished
by an RCA connector (PJ1), while the optical input is
provided by a Toshiba TOSLINK optical receiver (OPT).
S/PDIF streams are available from industry standard audio
test systems (Audio Precision, Rhode & Schwarz), as well as
commercial audio equipment (DVD, CD, and DAT players).
The CS8414 outputs a stereo data stream at its SDATA pin.
This may be used by any or all of the PCM1602’s three data
inputs, DIN1 through DIN3. Jumper block JP2 is used to
connect the CS8414 data output to the desired PCM1602
data input pins.
PCM1602 DAUGHTER CARD
The PCM1602 package is soldered directly to a small
printed circuit board, referred to as the “daughter card.”
The daughter card includes four male connectors that plug
into four corresponding female connectors on the DEM-
DAI1602 board. The daughter card arrangement is used to
provide the best possible dynamic performance, while al-
lowing the PCM1602 to be easily interchanged with future
multichannel DAC products.
DAC OUTPUT FILTERS
Three dual op amps (the OPA2134 ) are included to provide
second-order Butterworth low-pass filters for the DAC out-
puts. These filters are required to attenuate the out-of-band
noise generated by the PCM1602’s delta-sigma
DACs.
PC PRINTER PORT INTERFACE
A Centronics connector is included so that the DEM-DAI1602
may be connected to a PC printer port. The demonstration
software included with the DEM-DAI1602 uses this connec-
tion to write and read the PCM1602’s internal registers
through the MDO, MDI, MC, and ML pins.
CONNECTORS
CN1 is the main power-supply connector. Connections for
V_CC, +V_S, –V_S, and power-supply grounds are provided.
CN2 is the zero-flag connector. Connector pins ZFLGA and
ZFLG1 through ZFLG6 correspond directly to the zero-flag
output pins of the PCM1602. Alternatively, the zero-flag
outputs may be used as general-purpose logic outputs.
CN3 is a Centronics connector used to interface the DEM-
DAI1602 to a PC printer port. The +5V logic signals from
the printer port are buffered by U6.
CN4 is used to connect an optional external +3.3V power
supply to the DEM-DAI1602. Typically, this connector is
not used since an onboard regulator IC (U8) is used to
generate the +3.3V supply. If an external +3.3V supply is
used, remove the jumper at JP3.
CN10 through CN13 provide the connection to the PCM1602
daughter board. Figure 1 shows the electrical connections
for CN10 through CN13. Figure 4 shows the daughter card
schematic. The mapping between the daughter card connec-
tors and CN10 through CN13 is shown in Table I.
DEM-DAI1602 CONNECTOR
CN10
CN11
CN12
CN13
DAUGHTER-CARD CONNECTOR
CN001
CN002
CN003
CN004
TABLE I. Daughter-Card Connector Mapping.
OPT is the optical receiver input to the CS8414 digital audio
receiver.
PJ1 is the RCA connector used for shielded cable input to the
CS8414 digital audio receiver.
PJ2 is the audio output connector corresponding to the
PCM1602’s V_OUT1 output.
PJ3 is the audio output connector corresponding to the
PCM1602’s V_OUT2 output.
PJ4 is the audio output connector corresponding to the
PCM1602’s V_OUT3 output.
PJ5 is the audio output connector corresponding to the
PCM1602’s V_OUT4 output.
PJ6 is the audio output connector corresponding to the
PCM1602’s V_OUT5 output.
PJ7 is the audio output connector corresponding to the
PCM1602’s V_OUT6 output.
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DEM-DAI1602
SBAU035