AD5722 Analog Devices, AD5722 Datasheet - Page 29

• Manufacturer Part Number: AD5722
• Description: Complete, Dual, 12-Bit, Serial Input, Unipolar/Bipolar, Voltage Output DAC
• Manufacturer: Analog Devices

Specifications of AD5722

• Resolution (bits): 12bit
• Dac Update Rate: 1MSPS
• Dac Settling Time: 10µs
• Max Pos Supply (v): +16.5V
• Single-supply: Yes
• Dac Type: Voltage Out
• Dac Input Format: Ser,SPI

•
MICROPROCESSOR INTERFACING
Microprocessor interfacing to the AD5722/AD5732/AD5752 is
via a serial bus that uses a standard protocol compatible with
microcontrollers and DSP processors. The communications
channel is a 3-wire (minimum) interface consisting of a clock
signal, a data signal, and a synchronization signal. The AD5722/
AD5732/AD5752 require a 24-bit data-word with data valid on
the falling edge of SCLK.
Table 28. Some Precision References Recommended for Use with the AD5722/AD5732/AD5752
Part No.
ADR431
ADR421
ADR03
ADR291
AD780
long-term drift specification ensures that the overall
solution remains relatively stable over its entire lifetime.
Reference output voltage noise needs to be considered in
high accuracy applications that have relatively low noise
budgets. It is important to choose a reference with as low
an output noise voltage as practical for the required system
resolution. Precision voltage references such as the
(XFET® design) produce low output noise in the 0.1 Hz to
10 Hz range. However, as the circuit bandwidth increases,
filtering the output of the reference may be required to
minimize the output noise.
Initial Accuracy (mV max)
±1
±1
±2.5
±2
±1
Long-Term Drift (ppm typ)
40
50
50
50
20
ADR431
Rev. D | Page 29 of 32
Temp Drift (ppm/°C max)
3
3
3
8
3
For all interfaces, the DAC output update can be initiated
automatically when all the data is clocked in, or it can be
performed under the control of LDAC . The contents of the
registers can be read using the readback function.
AD5722/AD5732/AD5752 to Blackfin® DSP Interface
Figure 44 shows how the AD5722/AD5732/AD5752 can be
interfaced to the Analog Devices Blackfin DSP. The Blackfin has
an integrated SPI port that can be connected directly to the SPI
pins of the AD5722/AD5732/AD5752 and the programmable I/O
pins that can be used to set the state of a digital input such as
the LDAC pin.
Figure 44. AD5722/AD5732/AD5752 to Blackfin Interface
ADSP-BF531
SPISELx
MOSI
PF10
SCK
AD5722/AD5732/AD5752
0.1 Hz to 10 Hz Noise (μV p-p typ)
3.5
1.75
6
8
4
SYNC
SCLK
SDIN
LDAC
AD5722/
AD5732/
AD5752