Datasheet
V
FB
V
REF
V
REF
+6V
±5V
-6V
OPA703
DAC8560
10 Fm 0.1 Fm
R
1
10kW
R
2
10kW
Three-Wire
SerialInterface
V
OUT
GND
V
DD
V
DD
V
HYST
+
ǒ
Ť
V
REF_PRE
* V
REF_POST
Ť
V
REF_NOM
Ǔ
10
6
(ppm)
V
FB
+6V
±2.5V
-6V
OPA703
DAC8560
150nF
R
1
10kW
R
2
10kW
Three-Wire
SerialInterface
V
OUT
GND
V
DD
V
DD
V
REF
V
O
+ ƪV
REF
ǒ
D
65536
Ǔ
ǒ
R
1
) R
2
R
1
Ǔ
* V
REF
ǒ
R
2
R
1
Ǔ
ƫ
V
O
+
ǒ
10 D
65536
Ǔ
* 5V
DAC8560
www.ti.com
SLAS464B –DECEMBER 2006– REVISED NOVEMBER 2011
Long-Term Stability
Long-term stability/aging refers to the change of the
output voltage of a reference over a period of months
or years. This effect lessens as time progresses, as
shown in Figure 6, the typical long-term stability
curve. The typical drift value for the DAC8560 internal
reference is 50ppm from 0 hours to 1900 hours. This
parameter is characterized by powering-up and
measuring 20 units at regular intervals for a period of
1900 hours.
Thermal Hysteresis
Thermal hysteresis for a reference is defined as the
Figure 69. Bipolar Output Range Using External
change in output voltage after operating the device at
Reference at 5V
+25°C, cycling the device through the specified
temperature range, and returning to +25°C. It is
expressed in Equation 3:
(3)
Where:
V
HYST
= thermal hysteresis.
V
REF_PRE
= output voltage measured at +25°C
pre-temperature cycling.
V
REF_POST
= output voltage measured after the
device has been cycled through the temperature
range of –40°C to +120°C, and returned to
+25°C.
DAC NOISE PERFORMANCE
Figure 70. Bipolar Output Range Using Internal
Typical noise performance for the DAC8560 with the
Reference
internal reference enabled is shown in Figure 39 to
Figure 41. Output noise spectral density at pin V
OUT
The output voltage for any input code can be
versus frequency is depicted in Figure 39 for
calculated as using Equation 4:
full-scale, midscale, and zero scale input codes. The
typical noise density for midscale code is 170nV/√Hz
at 1kHz and 100nV/√Hz at 1MHz. High-frequency
noise can be improved by filtering the reference noise
as shown in Figure 40, where a 4μF load capacitor is
(4)
connected to the V
REF
pin and compared to the
where D represents the input code in decimal
no-load condition. Integrated output noise between
(0–65535).
0.1Hz and 10Hz is close to 50μV
PP
(midscale), as
shown in Figure 41.
With V
REF
= 5V, R
1
= R
2
= 10kΩ.
BIPOLAR OPERATION USING THE DAC8560
(5)
The DAC8560 has been designed for single-supply
This result has an output voltage range of ±5V with
operation, but a bipolar output range is also possible
0000h corresponding to a –5V output and FFFFh
using the circuit in either Figure 69 or Figure 70. The
corresponding to a 5V output, as shown in Figure 69.
circuit shown gives an output voltage range of ±V
REF
.
Similarly, using the internal reference, a ±2.5V output
Rail-to-rail operation at the amplifier output is
voltage range can be achieved, as shown in
achievable using an OPA703 as the output amplifier.
Figure 70.
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