AD7845ARZ Analog Devices Inc, AD7845ARZ Datasheet - Page 11

• Manufacturer Part Number: AD7845ARZ
• Description: 12-bit Parallel Vout Dac, IC
• Manufacturer: Analog Devices Inc

Specifications of AD7845ARZ

• Settling Time: 5µs
• Number Of Bits: 12
• Data Interface: Parallel
• Number Of Converters: 1
• Voltage Supply Source: Dual ±
• Power Dissipation (max): 150mW
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 24-SOIC (7.5mm Width)
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

REV. B
Figure 23 and 24 are the interface circuits for the Z80 and
MC6809 microprocessors. Again, these use the same basic
format as the 8085A interface.
Figure 23. AD7845 to Z80 Interface
Figure 24. MC6809 Interface
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DIGITAL FEEDTHROUGH
In the preceding interface configurations, most digital inputs to
the AD7845 are directly connected to the microprocessor bus.
Even when the device is not selected, these inputs will be con-
stantly changing. The high frequency logic activity on the bus
can feed through the DAC package capacitance to show up as
noise on the analog output. To minimize this digital feedthrough
isolate the DAC from the noise source. Figure 25 shows an
interface circuit which uses this technique. All data inputs are
latched from the busy by the CS signal. One may also use other
means, such as peripheral interface devices, to reduce the digital
feedthrough.
Figure 25. AD7845 Interface Circuit Using Latches to
Minimize Digital Feedthrough
AD7845