max509bcwpt Maxim Integrated Products, Inc., max509bcwpt Datasheet - Page 16

• Manufacturer Part Number: max509bcwpt
• Description: Max509, Max510 Quad, Serial, 8-bit Dacs With Rail-to-rail Outputs
• Manufacturer: Maxim Integrated Products, Inc.

Quad, Serial 8-Bit DACs
with Rail-to-Rail Outputs
Figure 11. MAX509 Unipolar Output Circuit
Figure 12. MAX510 Unipolar Output Circuit
16
NOT SHOWN
NOT SHOWN
INTERFACE
INTERFACE
SERIAL
SERIAL
MAX510
______________________________________________________________________________________
MAX509
REFERENCE INPUTS (V
REFERENCE INPUTS (V
REFA
5
-5V (OR GND)
REFB
4
V
-5V (OR GND)
SS
DAC D
3
DAC A
DAC B
DAC C
DAC C
DAC D
DAC A
DAC B
4
V
REFC
17
SS
REFAB
3
REFCD
REFD
SS
SS
16
TO V
TO V
13
DD
DD
AGND
AGND
6
)
)
5
18
+5V
V
+5V
V
DD
DD
14
DGND
DGND
6
8
2
1
16
15
1
20
19
2
OUTA
OUTB
OUTC
OUTD
OUTA
OUTB
OUTC
OUTD
where NB represents the digital input word. Since
AGND is common to all four DACs, all outputs will be
offset by V
more than +1V above DGND, or more than 2.5V below
DGND.
Figures 14 and 15 illustrate the generation of negative
offsets with bipolar outputs. In these circuits, AGND is
biased negatively (up to -2.5V with respect to DGND) to
provide an arbitrary negative output voltage for a 0
input code. The output voltage at OUTA is:
where NB represents the digital input word. Since
AGND is common to all four DACs, all outputs will be
offset by V
V
for Figure 14 and 15's circuits with R1 = R2. The
ICL7612 op amp is chosen because its common-mode
range extends to both supply rails.
Figure 13. MAX509/MAX510 AGND Bias Circuits (Positive
Offset)
V
REF
V
BIAS
BIAS
V
V
SERIAL INTERFACE NOT SHOWN
OUTA = -(R2/R1)(2.5V) + (NB/256)(2.5V)(R2/R1+1)
IN
IN
= 2.5V, shows the digital code vs. output voltage
BIAS
6
BIAS
5
AGND
AGND
in the same manner. Do not bias AGND
-5V (OR GND)
-5V (OR GND)
in the same manner. Table 3, with
DAC A
DAC A
V
V
SS
SS
5
REFA
3
4
REFAB
3
MAX509
MAX510
DGND
DGND
+5V
V
+5V
V
DD
DD
18
8
14
6
2
2
OUTA
OUTA