EVAL-ADUSB1EBZ Analog Devices Inc, EVAL-ADUSB1EBZ Datasheet - Page 3

• Manufacturer Part Number: EVAL-ADUSB1EBZ
• Description: BOARD EVAL USB TO SPI/12C
• Manufacturer: Analog Devices Inc

Specifications of EVAL-ADUSB1EBZ

• Contents: Evaluation Board
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Preliminary Technical Data
SETUP
POWER SUPPLY
The evaluation board is powered by either single supply
through connector J14 or through the USB port. The supply on
J14 should be +6 V DC, with the ability to source at least 300
mA, and must have a tip-positive polarity. This single supply is
regulated on the board to separate +5 V analog and digital
planes. Regulator U8 generates a 3.3 V supply for use by the
AD1938, which is further reduced to 2.5 V by the AD1940’s on-
chip regulator. The +5 V regulator is used to power the output
opamps and SPI signal buffer/level shifter.
ANALOG AUDIO INPUTS AND OUTPUTS
The evaluation board can input two analog audio signals and
can output six signals. The converter connected to the AD1940
SigmaDSP is a 4-ADC/8-DAC AD1938. The full-scale input
voltage can be set at either 1 V
full-scale output voltage is always set at 1 V
CONTROL INTERFACE
Header J2 is the communications connector for Serial
Peripheral Interface (SPI) control signals. Typically, the EVAL-
ADUSB1 USB adapter board will attach here and connect to a
USB port on the PC, enabling communication between the
AD1940 and SigmaStudio graphical programming software.
Communication is accomplished using the 4-wire SPI
master/slave protocol. The USB adapter is provided with the
evaluation board, or is available for standalone use in a target
system. If necessary, the EVAL-AD1940MINIB can also
connect directly to the PC’s parallel port through J2, although
this is not the recommended control interface. More
information on the software connection is available in the
SigmaStudio Software Interface section.
SWITCH FUNCTIONS
This evaluation board is primarily fixed-function. Table 1
shows the function of each switch on the board.
Table 1. Switch functions
Reference
Designator
S1
S2
Function
Board reset
Set full scale input range between 1 V
(switch to the inside) or 2 V
outside).
rms
or 2 V
rms
rms
by switch S2. The
rms
(switch to the
.
rms
Rev. PrA | Page 3 of 10
IC FUNCTIONS
Table 2 explains the function of each IC on the evaluation
board.
Table 2. IC Functions
Reference
Designator
U1
U2
U3
U4
U5
U6
U8
U9
U10
LED FUNCTIONS
The two LEDs on the evaluation board are useful components
that can indicate that the board is properly powered and set up.
D11 indicates that the +3.3 V supply is present (either through
an external supply or through USB).
The clipping LED D2 will illuminate when the input signal
reaches approximately 97% of the full-scale input range of the
ADC, based on the setting of switch S2.
RESET
The evaluation board can be reset with push-button switch S1.
This reset signal is debounced by the ADM811 (U10). The
board may also be reset by disconnecting the power. After
reset, the AD1940 is muted by default, and a control port write
will be necessary in order to pass audio again. See the Using
SigmaStudio section for more specific details about this
operation.
AD8608 Quad Opamp for analog audio input
Function
AD1940 SigmaDSP audio processor
AD1938 Codec for A/D and D/A conversion
AD8608 Quad Opamp for analog audio buffering
ADP3336 Power regulator for +5 V analog parts
AD8608 Quad Opamp for analog audio output
ADP3336 Power regulator for +3.3 V digital parts
LC541A octal buffer/driver for control signals
ADM811 for reset debounce
and filtering
buffering and input clip detection
buffering and filtering
EVAL-AD1940MINIB