DAC8560A BURR-BROWN [Burr-Brown Corporation], DAC8560A Datasheet - Page 22

• Manufacturer Part Number: DAC8560A
• Manufacturer: BURR-BROWN [Burr-Brown Corporation]

DAC8560
SLAS464 – DECEMBER 2006
22
INTERNAL REFERENCE
The DAC8560 internal reference does not require an
external load capacitor for stability because it is
stable with any capacitive load. However, for
improved noise performance, an external load
capacitor of 150nF or larger connected to the V
output is recommended.
connections required for operation of the DAC8560
internal reference. A supply bypass capacitor at the
V
Supply Voltage
The
extremely low dropout voltage. It can be operated
with a supply of only 5mV above the reference
output voltage in an unloaded condition. For loaded
conditions, refer to the
stability of the DAC8560 internal reference with
variations in supply voltage (line regulation, DC
PSRR) is also exceptional. Within the specified
supply voltage range of 2.7V to 5.5V, the variation at
V
Characteristics.
Temperature Drift
The DAC8560 internal reference is designed to
exhibit minimal drift error, defined as the change in
reference output voltage over varying temperature.
The drift is calculated using the box method, which is
described by
Drift Error +
Where:
Figure 67. Typical Connections for Operating the
DD
REF
V
observed within temperature range T
V
within temperature range T
V
voltage.
input is also recommended.
REF_MAX
REF_MIN
REF
V
V
DAC8560
is smaller than 10 V/V; see the
REF
DD
= 2.5V, target value for reference output
DAC8560 Internal Reference
= minimum reference voltage observed
Equation
V
1 F
m
=
REF_MAX
V
internal
150nF
REF
maximum
2:
* V
Load Regulation
T
1
2
3
4
Figure 67
RANGE
REF_MIN
V
V
V
V
reference
DD
REF
FB
OUT
DAC8560
RANGE
reference
SYNC
SCLK
GND
shows the typical
D
.
IN
10
APPLICATION INFORMATION
features
6
8
7
6
5
section. The
RANGE
(ppm °C)
Submit Documentation Feedback
Typical
voltage
.
REF
an
The DAC8560 internal reference (grades C and D)
features an exceptional typical drift coefficient of
2ppm/ C from –40 C to +120 C. Characterizing a
large number of units, a maximum drift coefficient of
5ppm/ C (grades C and D) is observed. Temperature
drift
Characteristics.
Noise Performance
Typical 0.1Hz to 10Hz voltage noise can be seen in
Figure
filtering can be used to improve output noise levels,
although care should be taken to ensure the output
impedance does not degrade the AC performance.
The output noise spectrum at V
external components is depicted in
Reference Noise Density vs Frequency. Another
noise density spectrum is also shown in
which was obtained using a 4 F load capacitor at
V
impacts the DAC output noise; see the
Performance
Load Regulation
Load regulation is defined as the change in
reference output voltage as a result of changes in
load current. The load regulation of the DAC8560
internal reference is measured using force and sense
contacts as pictured in
sense lines reduce the impact of contact and trace
resistance, resulting in accurate measurement of the
load regulation contributed solely by the DAC8560
internal
summarized in the
sense lines should be used for applications requiring
improved load regulation.
REF
Sense Line
Figure 68. Accurate Load Regulation of the
results
for noise filtering. Internal reference noise
8, Internal Reference Noise. Additional
reference.
DAC8560 Internal Reference
section for more details.
are
Meter
Typical
V
OUT
summarized
Measurement
Output Pin
Figure
Characteristics. Force and
Load
68. The force and
Force Line
I
L
Figure
in
REF
Contact and
Trace Resistance
the
results
www.ti.com
without any
DAC Noise
7, Internal
Figure
Typical
are
7,