MAX5721 Maxim, MAX5721 Datasheet - Page 11

• Manufacturer Part Number: MAX5721
• Description: 10-Bit / Low-Power / Dual / Voltage-Output DAC with Serial Interface
• Manufacturer: Maxim

Table 2. Serial-Interface Programming Commands
The typical application circuit (Figure 3) shows the
MAX5721 configured for a unipolar output, where the
output voltages and the reference inputs have the
same polarity. Table 3 lists the unipolar output codes.
The MAX5721 can be configured for bipolar operation
using a dual supply op amp (Figure 4). The transfer
function for bipolar operation is:
X = Don’t Care
Figure 3. Typical Operating Circuit, Unipolar Output
C3
0
0
0
0
1
1
1
1
1
IN
MAX6050
GND
CONTROL
C2
0
0
1
1
0
0
1
1
1
OUT
C1
0
0
0
0
0
0
0
0
1
V
Applications Information
OUT
______________________________________________________________________________________
10-Bit, Low-Power, Dual, Voltage-Output
C0
0
1
0
1
0
1
0
1
0
DAC_
V
REF
D9–D0
REF
DATA BITS
X
X
X
X
X
X
X
X
X
GND
1024
2D
S1–S0
X
X
X
X
X
X
X
X
X
+2.7V to +5.5V
Unipolar Output
Bipolar Output
V
MAX5721
1
DD
DAC
A-B
A-B
A-B
A
B
A
B
A
B
Input register transparent, data shifted directly to DAC register, OUTA updated
Input register transparent, data shifted directly to DAC register, OUTB updated
Data shifted to input register, OUTA unchanged
Data shifted to input register, OUTB unchanged
Shift data from input register to DAC register, OUTA updated
Shift data from input register to DAC register, OUTB updated
Input registers transparent, data shifted directly to DAC registers, OUTA and
OUTB updated
Data shifted to input registers, OUTA and OUTB unchanged
Shift data from input registers to DAC registers, OUTA and OUTB updated
OUT_
DAC with Serial Interface
where DB is the decimal value of the DACs binary input
code. Table 4 shows digital codes (offset binary) and
corresponding output voltages for the circuit in Figure 4.
Careful PC board layout is important for optimal system
performance. To reduce noise injection and digital feed-
through, keep analog and digital signals separate.
Ensure that that the return path from GND to the supply
ground is short and low impedance. Use a ground
plane. Bypass V
close as possible to V
Figure 4. Bipolar Output Circuit
Power Supply and Layout Considerations
DAC_
REF
GND
FUNCTION
DD
R1
+2.7V to +5.5V
to GND with a 0.1µF capacitor as
MAX5721
DD
V
.
DD
OUT_
R1 = R2
V+
V-
R2
V
OUT
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