Datasheet

V =
HYST
´ 10 (ppm/ C)°
6
|V V |-
REF_PRE REF_POST
V
REF_NOM
OutputPin
Meter
Load
ForceLine
SenseLine
Contactand
TraceResistance
I
L
V
OUT
DAC8565
www.ti.com SBAS411C –JUNE 2007–REVISED MARCH 2011
Load Regulation Thermal Hysteresis
Load regulation is defined as the change in reference Thermal hysteresis for a reference is defined as the
output voltage as a result of changes in load current. change in output voltage after operating the device at
The load regulation of the internal reference is +25°C, cycling the device through the operating
measured using force and sense contacts as shown temperature range, and returning to +25°C.
in Figure 98. The force and sense lines reduce the Hysteresis is expressed by Equation 3:
impact of contact and trace resistance, resulting in
accurate measurement of the load regulation
contributed solely by the internal reference.
Measurement results are summarized in the Typical
(3)
Characteristics. Force and sense lines should be
Where:
used for applications that require improved load
V
HYST
= thermal hysteresis.
regulation.
V
REF_PRE
= output voltage measured at +25°C
pre-temperature cycling.
V
REF_POST
= output voltage measured after the
device cycles through the temperature range
of –40°C to +120°C, and returns to +25°C.
DAC NOISE PERFORMANCE
Typical noise performance for the DAC8565 with the
internal reference enabled is shown in Figure 54 to
Figure 56. Output noise spectral density at the V
OUT
pin versus frequency is depicted in Figure 54 for
full-scale, midscale, and zero-scale input codes. The
Figure 98. Accurate Load Regulation of the
typical noise density for midscale code is 120nV/√Hz
DAC8565 Internal Reference
at 1kHz and 100nV/√Hz at 1MHz. High-frequency
noise can be improved by filtering the reference noise
as shown in Figure 55, where a 4.8μF load capacitor
Long-Term Stability
is connected to the V
REF
H/V
REF
OUT pin and
Long-term stability/aging refers to the change of the
compared to the no-load condition. Integrated output
output voltage of a reference over a period of months
noise between 0.1Hz and 10Hz is close to 6μV
PP
or years. This effect lessens as time progresses (see
(midscale), as shown in Figure 56.
Figure 6, the typical long-term stability curve). The
typical drift value for the 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.
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