DAC8812 Datasheet, PDF (15/18 Pages) Texas Instruments – Dual, Serial Input 16-Bit Multiplying Digital-to-Analog Converter

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DAC8812
SBAS349A – AUGUST 2005 – REVISED DECEMBER 2005
APPLICATION INFORMATION
The DAC8812, 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 35.
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.
ǒ Ǔ V_OUT +
D
32, 768
*
1
V_REF
(2)
10 V
V_REF
10 kW
5 kW
10 kW
OPA277
V_OUT
-10 V < V_OUT < +10 V
V_DD
V_REFX R_FBX
One Channel
DAC8812
I_OUTX
A_GNDX
OPA277
Digital interface connections omitted for clarity.
Figure 35. Four-Quadrant Multiplying Application Circuit
Cross-Reference
The DAC8812 has an industry-standard pinout. Table 4 provides the cross-reference information.
PRODUCT
DAC8812ICPW
DAC8812IBPW
INL
(LSB)
±1
±2
DNL
(LSB)
±1
±1
Table 4. Cross-Reference
SPECIFIED
TEMPERATURE
RANGE
–40°C to +85°C
–40°C to +85°C
PACKAGE
DESCRIPTION
16-Lead Thin Shrink
Small-Outline Package
16-Lead Thin Shrink
Small-Outline Package
PACKAGE
OPTION
TSSOP-16
TSSOP-16
CROSS-REFERENCE
PART NUMBER
N/A
AD5545BRU
15