DAC7631 - dreamm

+V
+V
+2.5V
OPA2350
2200pF
100Ω
1000pF
1
2
3
4
V REF H DAC7631
V REF H Sense
V REF L
V REF L Sense
FIGURE 10. Single-supply Buffered V REF H.
LE (LSB)
DLE (LSB)
2.5
2.0
1.5
1.0
0.5
0
–0.5
–1.0
–1.5
LINEARITY ERROR AND
DIFFERENTIAL LINEARITY ERROR vs CODE
(DAC A, +25°C)
2.0
1.5
1.0
0.5
0
–0.5
–1.0
–1.5
–2.0
0000 H 2000 H 4000 H 6000 H 8000 H
Digital Input Code
FIGURE 11. Linearity and Differential Error Curves for
Figure 10.
LE (LSB)
DLE (LSB)
2.5
2.0
1.5
1.0
0.5
0
–0.5
–1.0
–1.5
–2.0
–2.5
LINEARITY ERROR AND
DIFFERENTIAL LINEARITY ERROR vs CODE
(DAC A, +25°C)
2.0
1.5
1.0
0.5
0
–0.5
–1.0
–1.5
–2.0
0000 H 2000 H 4000 H 6000 H 8000 H
Digital Input Code
A000 H C000 H E000 H FFFF H
FIGURE 13. Linearity and Differential Error Curves for
Figure 12.
1
V REF H
V CC
20
+
0.1µF 1µF
2
V REF H Sense
AGND
19
3
V REF L
V SS
18
4
V REF L Sense
V OUT Sense
17
Serial Data Out
5
6
7
DGND
V CC
SDO
A000 H C000 H E000 H FFFF H
Reset DAC Registers
+5V
+V
+2.5V
DAC7631
V OUT
NC
RSTSEL
16
15
14
V OUT
Serial Data In
Clock
Chip Select
8
9
10
SDI
CLK
CS
RST
LOAD
LDAC
13
12
11
Load
Load DAC Registers
FIGURE 12. Low cost Single-supply Configuration.
Data is shifted into the device through the SDI and CLK pins
and arrives in a shift register. Once all 16 bits have been
transferred, the LOAD pin, which is level-sensitive, should
be brought low to latch the data into a buffer register called
the DAC input register. To latch the new data into the DAC
itself, the LDAC pin, which is edge-sensitive, must be
brought high. When this is done, the DAC will assume the
new value and the output voltage will change (provided that
the new value is different from the old one). Note that
settling time is measured from the time that the LDAC pin
is brought high, since the device’s output does not begin to
change until then.
The DAC7631’s double-buffering scheme allows the device
to be updated through the serial interface without disturbing
the voltage on the output pin. It also allows the user to use
separate logic for driving the serial input and triggering
15
DAC7631
®