DEM-PCM1704 Datasheet, PDF (2/5 Pages) Burr-Brown (TI) – EVALUATION FIXTURE

BLOCK DIAGRAM
CND1
Control
+5V V_CC
CN1
±5V V_CC
CN2
±V_A
DEM-DIR1700
CND2
Socket
Header
DF1704
Digital
Filter
UD2
DEM-PCM1704
Digital Section
PCM1704
DAC
OPA627
I/V
OPA2134
LPF
Header CN3
PCM1704
DAC
OPA627
I/V
OPA2134
LPF
DAC Section
PJ2
Right
PJ1
Left
HARDWARE DESCRIPTION
This section describes the hardware components of the
DEM-PCM1704 demonstration board.
DAC SECTION
The DAC section of the demonstration board includes two
PCM1704Us, two OPA627s used as current-to-voltage (I/V)
converters, and a OPA2134 dual op amp used to provide
second-order lowpass filters for the right and left audio
channels. Connectors are provided for power supplies and
interfacing to the digital section or an external digital host.
Connectors
Connector CN1 is used to provide power to the PCM1704
DACs. +V_CC should be set for +5V_DC, and –V_CC should be
set for –5V_DC.
Connector CN2 is used to provide power to the OPA627 and
OPA2134 op amps. +V_A is typically set for +15V_DC (maxi-
mum is +18V_DC), while –V_CC is typically set to –15V_DC
(maximum is –18V_DC).
The GND pins on connectors CN1 and CN2 are connected
to the analog ground plane of the DAC section.
CN3 is used to connect the audio interface of the digital
section to the PCM1704 DACs. Normally, jumpers should
be installed for BCK, WDCK, DOL, DOR, and GND.
However, if the user desires to bypass the circuitry of the
digital section and drive the DACs directly from another
signal source, this can be accomplished through this connec-
tor.
RCA jacks PJ1 and PJ2 provide the left and right audio
channel outputs. They provide straight forward connection
to measurement and commercial audio equipment.
Switches
DIP switch SW0 is used to set up the data format for the two
PCM1704 DACs. Table I shows the function of the DIP
switch settings.
SW0
20-BIT
INVL
INVR
FUNCTION
Selects Data Word Length
Selects Phase for Left Channel DAC
Selects Phase for Right Channel DAC
SETTINGS
H = 24 Bits, L = 20 Bits
H = Normal, L = Inverted
H = Normal, L = Inverted
TABLE I. DAC Data Format Configuration.
DIGITAL SECTION
The digital section of the DEM-PCM1704 demonstration
board includes the DF1704 digital filter, DIP switches for
configuring the filter, a connector for the PC interface cable
and digital power supply, and a header for the input data
interface. A socket is provided for the DEM-DIR1700
digital audio receiver adaptor board so that clocks and data
can be derived from a standard S/PDIF input source.
Connectors
Connector CND1 is used to provide the +5V digital power
supply and ground connections. It is also used to provide
connection with an external host when using the DF1704
digital filter in Software control mode. The PC interface
cable which accompanies the DEM-PCM1704 kit can be
used to provide the connection with a PC parallel (or printer)
port to control the MC, MD, ML, and RST signals. The
cable also includes two banana plugs for connection to an
external +5V supply.
Connector CND2 is used to provide the audio input data
interface. CND2 can be connected to an external source, or
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DEM-PCM1704
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