AD7226 Analog Devices, AD7226 Datasheet - Page 11

• Manufacturer Part Number: AD7226
• Description: LC2MOS Quad 8-Bit D/A Converter
• Manufacturer: Analog Devices

AD7226
OFFSET ADJUST
Figure 21 shows how the AD7226 can be used to provide pro-
grammable input offset voltage adjustment for the AD544 op
amp. Each output of the AD7226 can be used to trim the input
offset voltage on one AD544. The 620 k resistor tied to +10 V
provides a fixed bias current to one offset node. For symmetrical
adjustment, this bias current should equal the current in the
other offset node with the half-full scale code (i.e., 10000000)
on the DAC. Changing the code on the DAC varies the bias
current and hence provides offset adjust for the AD544. For ex-
ample, the input offset voltage on the AD544J, which has a
maximum of 2 mV, can be programmably trimmed to 10 V.
Figure 21. Offset Adjust for AD544
Microprocessor Interface
Figure 22. AD7226 to 8085A Interface
Figure 24. AD7226 to 6502 Interface
Figure 25. AD7226 to Z-80 Interface
Figure 23. AD7226 to 6809 Interface
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REV. A