EVAL-AD1940EB/AD1941EB
Rev. 0 | Page 4 of 32
SETTING UP THE EVALUATION BOARDS
POWER SUPPLY
The AD1940EB/AD1941EB are powered by a single supply
through Coax Power Jack J14. The supply should be 9 V to 12 V
dc with the ability to source at least 700 mA. The connector’s
polarity should be tip positive. This single supply is regulated to
separate 5 V analog and digital planes. The AD1940/AD1941
and AD1939 generate 2.5 V and 3.3 V, respectively, from the 5 V
supply using their on-board regulators.
DIGITAL AUDIO INPUTS AND OUTPUTS
Digital audio I/Os can be connected to the boards in two
different formats. First, the evaluation boards can input or
output a standard 2-channel S/PDIF stream. These I/Os can be
either electrical (Jack J1 and Jack J2) or optical (Fiber Optic
Modules U1 and U5). The input S/PDIF source is selected with
SW10. Both S/PDIF transmit streams are always on. The
S/PDIF I/O streams are connected to SDATA_IN0 and
SDATA_OUT0 and are active according to the specific switch
settings shown in Table 2 and Table 3.
Second, the digital audio I/O connections are in the 3-wire I
2
S
format. Input Header J11, Output Header J7, and Output
Header J8 can connect to external ADCs, DACs, and codecs
with an I
2
S left-justified or right-justified data stream. Master
clock, left/right clock, and bit clock connections are also on
these headers. Up to four stereo audio streams can be input or
output on each of these headers. These audio streams, when
selected by the rotary mode switches, interface directly to the
serial data ports of the AD1940/AD1941. These headers also
serve as the I/Os for the multichannel TDM streams.
ANALOG AUDIO INPUTS AND OUTPUTS
The evaluation boards can input six analog audio signals and
can output eight signals. The converters connected to the
AD1940/AD1941 SigmaDSP are a 4 ADC/8 DAC AD1939 and
an AD1871 stereo ADC. The full-scale I/O voltage on these
connections is 1 V rms.
RCA Jack J18 to Jack J20 are the inputs to the ADCs.
RCA Jack J3 to Jack J6 and mini Jack J12, mini Jack J15, and
mini Jack J16 are the DAC output connectors. The output is
low-pass filtered with an anti-image filter and converted from a
differential voltage output to single-ended voltage by op-amps
U28 to U31. The filters’ −3 dB cutoff frequency is 100 kHz and
has an approximate third order Bessel (linear phase) response.
CONTROL INTERFACE
PCB Connector J17 is the connection for the SPI and I
2
C
control signals. The AD1940EB/AD1941EB typically connect to
the SigmaStudio design tools with the EVAL-ADUSB1 USB
adapter board. This board connects to the PC’s USB port and
outputs either SPI or I
2
C commands to the AD1940EB/
AD1941EB. The USB adapter is provided with the evaluation
boards, or is available for standalone use in a target system. The
AD1940EB/AD1941EB can also connect directly to a PC’s
parallel port through PCB Connector J17, although this isn’t the
recommended control interface. The software connection is
further explained in the Evaluation Board Software section.
Содержание EVAL-AD1940EB
Страница 11: ...EVAL AD1940EB AD1941EB Rev 0 Page 11 of 32 SCHEMATICS 05880 002 Figure 2 S PDIF Receiver and Transmitter...
Страница 12: ...EVAL AD1940EB AD1941EB Rev 0 Page 12 of 32 05880 003 Figure 3 AD1939 Analog Input Filters...
Страница 13: ...EVAL AD1940EB AD1941EB Rev 0 Page 13 of 32 05880 004 Figure 4 AD1871 Analog Input...
Страница 14: ...EVAL AD1940EB AD1941EB Rev 0 Page 14 of 32 05880 005 Figure 5 External Digital Inputs and Microphone Input...
Страница 15: ...EVAL AD1940EB AD1941EB Rev 0 Page 15 of 32 05880 006 Figure 6 Input CPLD...
Страница 16: ...EVAL AD1940EB AD1941EB Rev 0 Page 16 of 32 05880 007 Figure 7 AD1940 AD1941 SigmaDSP...
Страница 17: ...EVAL AD1940EB AD1941EB Rev 0 Page 17 of 32 05880 008 Figure 8 Output CPLD...
Страница 18: ...EVAL AD1940EB AD1941EB Rev 0 Page 18 of 32 05880 009 Figure 9 Analog Output 0 to Analog Output 3...
Страница 19: ...EVAL AD1940EB AD1941EB Rev 0 Page 19 of 32 05880 010 Figure 10 Analog Output 4 to Analog Output 7...
Страница 20: ...EVAL AD1940EB AD1941EB Rev 0 Page 20 of 32 05880 011 Figure 11 AD1939 Codec...
Страница 21: ...EVAL AD1940EB AD1941EB Rev 0 Page 21 of 32 05880 012 Figure 12 External Digital Outputs...
Страница 22: ...EVAL AD1940EB AD1941EB Rev 0 Page 22 of 32 05880 013 Figure 13 SPI I2 C Control Interface...
Страница 23: ...EVAL AD1940EB AD1941EB Rev 0 Page 23 of 32 05880 014 Figure 14 Power Supply...
Страница 24: ...EVAL AD1940EB AD1941EB Rev 0 Page 24 of 32 PCB DIAGRAMS 05880 015 Figure 15 Top Layer Silkscreen...
Страница 28: ...EVAL AD1940EB AD1941EB Rev 0 Page 28 of 32 USB ADAPTER SCHEMATIC 05880 019 Figure 19 USB Adapter Schematic...
Страница 30: ...EVAL AD1940EB AD1941EB Rev 0 Page 30 of 32 NOTES...
Страница 31: ...EVAL AD1940EB AD1941EB Rev 0 Page 31 of 32 NOTES...
