AD7305BN Analog Devices, AD7305BN Datasheet - Page 13

• Manufacturer Part Number: AD7305BN
• Description: +3 V/+5 V/ Rail-to-Rail Quad/ 8-Bit DAC
• Manufacturer: Analog Devices

AD7304/AD7305
APPLICATIONS
+5V
10k
10k
The AD7304/AD7305 is inherently a 2-quadrant multiplying
D/A converter. That is, it can easily be set up for unipolar out-
put operation. The full-scale output polarity is the same as the
–5V < V
< +5V
OUT
AD7304
reference input voltage polarity.
REF
In some applications it may be necessary to generate the full
Figure 34. Four-Quadrant Multiplying Application Circuit
4-quadrant multiplying capability or a bipolar output swing.
This is easily accomplished using an external true rail-to-rail op
amp, such as the OP295. Connecting the external amplifier with
two equal value resistors as shown in Figure 34 results in a full
4-quadrant multiplying circuit. In this circuit the amplifier pro-
vides a gain of two, which increases the output span magnitude
to 10 volts. The transfer equation of this circuit shows that both
negative and positive output voltages are created as the input
data (D) is incremented from code zero (V
= –5 V) to mid-
OUT
scale (V
= 0 V) to full scale (V
= +5 V).
OUT
OUT
= (D/128 –1) × V
V
(2)
OUT
REF
REV. A
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