Datasheet

www.ti.com
APPLICATION INFORMATION
V
OUT
+
ǒ
D
32, 768
* 1
Ǔ
V
REF
(2)
Digitalinterfaceconnectionsomittedforclarity.
A1
OPA277
A2
OPA277
10kW
10kW
5kW
10V
V
REF
V
OUT
-10V<V
OUT
<+10V
V
REF
X
A
GND
F
A
GND
X
I
OUT
X
R
FB
X
V
DD
OneChannel
DAC8814
Cross-Reference
DAC8814
SBAS338D – JANUARY 2005 – REVISED SEPTEMBER 2006
The DAC8814, a 2-quadrant multiplying DAC, can be used to generate a unipolar output. The polarity of the
full-scale output I
OUT
is the inverse of the input reference voltage at V
REF
.
Some applications require full 4-quadrant multiplying capabilities or bipolar output swing, as shown in Figure 63 .
An additional external op amp A2 is added as a summing amp. In this circuit the first and second amps (A1 and
A2) provide a gain of 2X that widens the output span to 20 V. A 4-quadrant multiplying circuit is implemented by
using a 10-V offset of the reference voltage to bias A2. According to the following circuit transfer equation
(Equation 2 ), input data (D) from code 0 to full scale produces output voltages of V
OUT
= –10 V to V
OUT
= 10 V.
Figure 63. Four-Quadrant Multiplying Application Circuit
The DAC8814 has an industry-standard pinout. Table 4 provides the cross-reference information.
Table 4. Cross-Reference
SPECIFIED
TEMPERATURE PACKAGE PACKAGE CROSS-
PRODUCT INL (LSB) DNL (LSB) RANGE DESCRIPTION OPTION REFERENCE PART
DAC8814ICDB ± 1 ± 1 –40 ° C to +85 ° C 28-Lead MicroSOIC SSOP-28 N/A
DAC8814IBDB ± 4 ± 1.5 –40 ° C to +85 ° C 28-Lead MicroSOIC SSOP-28 AD5544RS
21
Submit Documentation Feedback