Datasheet

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DAC8822
SBAS390A – DECEMBER 2006 – REVISED MARCH 2007
PIN ASSIGNMENTS (continued)
Table 1. TERMINAL FUNCTIONS
PIN # NAME DESCRIPTION
1, 2, 24-28,
D0-D15 Digital Input Data Bits D0 to D15. Signal level must be ≤ V
DD
+0.3V. D15 is MSB.
30-38
Bipolar Offset Resistor A. Accepts up to ± 18V.
3 R
OFS
A In 2-quadrant mode, R
OFS
A ties to R
FB
A.
In 4-quadrant mode, R
OFS
A ties to R
1
A and the external reference.
4 R
FB
A Internal Matching Feedback Resistor A. Connects to the external op amp for I-V conversion.
4-Quadrant Resistor.
5 R
1
A In 2-quadrant mode, R
1
A shorts to the V
REF
A pin.
In 4-quadrant mode, R
1
A ties to R
OFS
A and the reference input.
Center Tap Point of the Two 4-Quadrant Resistors, R
1
A and R
2
A.
6 R
COM
A In 2-quadrant mode, R
COM
A shorts to the V
REF
pin.
In 4-quadrant mode, R
COM
A ties to the inverting node of the reference amplifier.
DAC A Reference Input in 2-Quadrant Mode, R
2
Terminal in 4-Quadrant Mode.
7 V
REF
A In 2-quadrant mode, V
REF
A is the reference input with constant input resistance versus code.
In 4-quadrant mode, V
REF
A is driven by the external reference amplifier.
DAC A Current Output. Connects to the inverting terminal of external precision I-V op amp for voltage
8 I
OUT
A
output.
9 AGNDA DAC A Analog Ground.
10 DGND Digital Ground.
11 AGNDB DAC B Analog Ground.
DAC B Current Output. Connects to the inverting terminal of external precision I-V op amp for voltage
12 I
OUT
B
output.
DAC B Reference Input in 2-Quadrant Mode, R
2
Terminal in 4-Quadrant Mode.
13 V
REF
B In 2-quadrant mode, V
REF
B is the reference input with constant input resistance versus code.
In 4-quadrant mode, V
REF
B is driven by the external reference amplifier.
Center Tap Point of the Two 4-Quadrant Resistors, R
1
B and R
2
B.
14 R
COM
B In 2-quadrant mode, R
COM
B shorts to the V
REF
pin.
In 4-quadrant mode, R
COM
B ties to the inverting node of the reference amplifier.
4-Quadrant Resistor.
15 R
1
B In 2-quadrant mode, R
1
B shorts to the V
REF
B pin.
In 4-quadrant mode, R
1
B ties to R
OFS
B and the reference input.
16 R
FB
B Internal Matching Feedback Resistor B. Connects to external op amp for I-V conversion.
Bipolar Offset Resistor B. Accepts up to ± 18V.
17 R
OFS
B In 2-quadrant mode, R
OFS
B ties to R
FB
B.
In 4-quadrant mode, R
OFS
B ties to R
1
B and the external reference.
Write Control Digital Input In, Active Low. WR enables input registers.
18 WR
Signal level must be ≤ V
DD
+ 0.3V.
19 A0 Address 0. Signal level must be ≤ V
DD
+ 0.3V.
20 A1 Address 1. Signal level must be ≤ V
DD
+ 0.3V.
Digital Input Load DAC Control. Signal level must be ≤ V
DD
+ 0.3V. See the Function of Control Inputs
21 LDAC
table for details.
Power-On Reset State.
RSTSEL = 0 corresponds to zero-scale reset.
22 RSTSEL
RSTSEL = 1 corresponds to midscale reset.
The signal level must be ≤ V
DD
+ 0.3V.
Reset. Active low resets both input and DAC registers.
23 RS Resets to zero-scale if RSTSEL= 0, and to midscale if RSTSEL = 1.
Signal level must be equal to or less than VDD + 0.3 V.
29 V
DD
Positive Power Supply Input. The specified range of operation is 2.7V to 5.5V.
5
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