AD5442ABCPZ-1-RL7 View Datasheet(PDF) - Analog Devices
Part Name
Description
MFG CO.
'AD5442ABCPZ-1-RL7' PDF : 24 Pages View PDF
AD5512A/AD5542A
Data Sheet
Assuming a perfect reference, the unipolar worst-case output
voltage can be calculated from the following equation:
( ) VOUT−UNI
=
D
2N
×
VREF
+ VGE
+ VZSE + INL
where:
VOUT−UNI is the unipolar mode worst-case output.
D is the code loaded to DAC.
N is the resolution of the DAC.
VREF is the reference voltage applied to the part.
VGE is the gain error in volts.
VZSE is the zero-scale error in volts.
INL is the integral nonlinearity in volts.
BIPOLAR OUTPUT OPERATION
With the aid of an external op amp, the AD5512A/AD5542A
can be configured to provide a bipolar voltage output. A typical
circuit is shown in Figure 32. The matched bipolar offset resistors,
RFB and RINV, are connected to an external op amp to achieve
this bipolar output swing, typically RFB = RINV = 28 kΩ. Table 10
shows the transfer function for this output operating mode.
Also provided on the AD5542A are a set of Kelvin connections
to the analog ground inputs. The example includes the ADR421
+5V +2.5V
10µF
0.1µF
0.1µF
2.5 V reference and the AD8628 low offset and zero-drift
reference buffer.
Table 10. AD5542A Bipolar Code Table
DAC Latch Contents
MSB
LSB
Analog Output
1111 1111 1111 1111
+VREF × (32,767/32,768)
1000 0000 0000 0001
+VREF × (1/32,768)
1000 0000 0000 0000
0V
0111 1111 1111 1111
−VREF × (1/32,768)
0000 0000 0000 0000
−VREF × (32,768/32,768) = −VREF
Assuming a perfect reference, the worst-case bipolar output
voltage can be calculated from the following equation:
V OUT −BIP
= [(VOUT −UNI
+ VOS )(2 + RD) − VREF (1 + RD)]
1 + (2 + RD)
A
where:
VOUT−BIP is the bipolar mode worst-case output
VOUT−UNI is the unipolar mode worst-case output.
VOS is the external op amp input offset voltage.
RD is the RFB and RINV resistor matching error.
A is the op amp open-loop gain.
SERIAL
INTERFACE
VDD
CS
RFB
REFF REFS
RFB INV
DIN
SCLK
AD5512A/
RINV
AD5542A
LDAC
VOUT
DGND AGNDF AGNDS
+5V
BIPOLAR
OUTPUT
–5V
EXTERNAL
OP AMP
Figure 32. Bipolar Output
Rev. B | Page 16 of 24
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