AD5764R Analog Devices, AD5764R Datasheet - Page 30

• Manufacturer Part Number: AD5764R
• Description: Complete Quad, 16-Bit, High Accuracy, Serial Input, Bipolar Voltage Output DAC
• Manufacturer: Analog Devices

Specifications of AD5764R

• Resolution (bits): 16bit
• Dac Update Rate: 1MSPS
• Dac Settling Time: 8µs
• Max Pos Supply (v): +16.5V
• Single-supply: No
• Dac Type: Voltage Out
• Dac Input Format: Ser,SPI

AD5764R
LAYOUT GUIDELINES
In any circuit where accuracy is important, careful considera-
tion of the power supply and ground return layout helps to
ensure the rated performance. Design the PCB on which the
AD5764R
are separated and confined to certain areas of the board. If the
AD5764R
AGNDx-to-DGND connection, establish the connection at one
point only. Establish the star ground point as close as possible to
the device. The
10 µF in parallel with 0.1 µF on each supply located as close to
the package as possible, ideally right up against the device. The
10 µF capacitors are of the tantalum bead type. The 0.1 µF
capacitor should have low effective series resistance (ESR) and low
effective series inductance (ESI), such as the common ceramic
types that provide a low impedance path to ground at high
frequencies to handle transient currents due to internal logic
switching.
The power supply lines of the
as possible to provide low impedance paths and reduce the effects
of glitches on the power supply line. Shield fast-switching signals,
such as clocks, with digital ground to avoid radiating noise to other
parts of the board; they should never be run near the reference
inputs. A ground line routed between the SDIN and SCLK lines
helps reduce cross talk between them. (A ground line is not
required on a multilayer board because it has a separate ground
plane; however, it is helpful to separate the lines.) It is essential to
minimize noise on the reference inputs because it couples
through to the DAC output. Avoid crossover of digital and
analog signals. Run traces on opposite sides of the board at right
is mounted such that the analog and digital sections
is in a system where multiple devices require an
AD5764R
should have ample supply bypassing of
AD5764R
*ADDITIONAL PINS OMITTED FOR CLARITY.
MICROCONTROLLER
SERIAL CLOCK OUT
SERIAL DATA OUT
CONTROL OUT
SYNC OUT
should use as large a trace
V
V
V
V
IA
IB
IC
ID
ADuM1400*
Figure 44. Isolated Interface
Rev. D | Page 30 of 32
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angles to each other to reduce the effects of feedthrough on the
board. A microstrip technique is recommended but not always
possible with a double-sided board. In this technique, the com-
ponent side of the board is dedicated to the ground plane, and
the signal traces are placed on the solder side.
GALVANICALLY ISOLATED INTERFACE
In many process control applications, it is necessary to provide
an isolation barrier between the controller and the unit being
controlled to protect and isolate the controlling circuitry from
any hazardous common-mode voltages that may occur. Iso-
couplers provide voltage isolation in excess of 2.5 kV. The serial
loading structure of the
interfaces because the number of interface lines is kept to a mini-
mum. Figure 44 shows a 4-channel isolated interface to the
AD5764R
information on iCoupler products, refer to www.analog.com.
MICROPROCESSOR INTERFACING
Microprocessor interfacing to the
a serial bus that uses standard protocol that is compatible with
microcontrollers and DSP processors. The communication
channel is a 3-wire (minimum) interface consisting of a clock
signal, a data signal, and a synchronization signal. The
requires a 24-bit data-word with data valid on the falling edge
of SCLK.
For all the interfaces, a DAC output update can be performed
automatically when all the data is clocked in, or it can be done
under the control of LDAC. The contents of the DAC register
can be read using the readback function.
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using an
V
V
V
V
ADuM1400
OA
OB
OC
OD
AD5764R
TO SCLK
TO SDIN
TO SYNC
TO LDAC
iCoupler® product. For more
AD5764R
makes it ideal for isolated
is accomplished via
Data Sheet
AD5764R