AD5061 Analog Devices, AD5061 Datasheet - Page 18

• Manufacturer Part Number: AD5061
• Manufacturer: Analog Devices

Specifications of AD5061

• Resolution (bits): 16bit
• Dac Update Rate: 1.3MSPS
• Dac Settling Time: 4µs
• Max Pos Supply (v): +5.5V
• Single-supply: Yes
• Dac Type: Voltage Out
• Dac Input Format: Ser,SPI

AD5061
APPLICATIONS
CHOOSING A REFERENCE
To achieve the optimum performance from the AD5061,
thought should be given to the choice of a precision voltage
reference. The AD5061 has just one reference input, V
voltage on the reference input is used to supply the positive
input to the DAC. Therefore, any error in the reference is
reflected in the DAC.
There are four possible sources of error when choosing a vol-
tage reference for high accuracy applications: initial accuracy,
ppm drift, long-term drift, and output voltage noise. Initial
accuracy on the output voltage of the DAC leads to a full-scale
error in the DAC. To minimize these errors, a reference with
high initial accuracy is preferred. Also, choosing a reference
with an output trim adjustment, such as the ADR43x family,
allows a system designer to trim out system errors by setting a
reference voltage to a voltage other than the nominal. The trim
adjustment can also be used at the operating temperature to
trim out any errors.
Because the supply current required by the AD5061 is
extremely low, the parts are ideal for low supply applications.
The ADR395 voltage reference is recommended. This requires
less than 100 μA of quiescent current and can, therefore, drive
multiple DACs in one system, if required. It also provides very
good noise performance at 8 μV p-p in the 0.1 Hz to 10 Hz range.
Long-term drift is a measure of how much the reference drifts
over time. A reference with a tight long-term drift specification
ensures that the overall solution remains relatively stable during
its entire lifetime. The temperature coefficient of a reference’s
output voltage affects INL, DNL, and TUE. A reference with a
tight temperature coefficient specification should be chosen to
reduce temperature dependence of the DAC output voltage on
ambient conditions.
In high accuracy applications, which have a relatively low noise
budget, reference output voltage noise needs to be considered. It
is important to choose a reference with as low an output noise
voltage as practical for the system noise resolution required.
Precision voltage references, such as the ADR435, produce low
output noise in the 0.1 Hz to 10 Hz region.
INTERFACE
SERIAL
3-WIRE
7V
Figure 46. ADR395 as Reference to the AD5061
SYNC
SCLK
DIN
ADR395
5V
AD5061
V
OUT
= 0V TO 5V
REF
. The
Rev. B | Page 18 of 20
Table 7 shows examples of recommended precision references
for use as a supply to the AD5061.
Table 7. Precision References Part List for the AD5061
Part No.
ADR435
ADR425
ADR02
ADR02
ADR395
BIPOLAR OPERATION
The AD5061 has been designed for single-supply operation, but
a bipolar output range is also possible using the circuit shown in
Figure 47. The circuit shown yields an output voltage range of
±5 V. Rail-to-rail operation at the amplifier output is achievable
using an AD8675/AD820/AD8032 or an OP196/OP295.
The output voltage for any input code can be calculated as
follows:
where D represents the input code in decimal (0 to 65536).
With V
This is an output voltage range of ±5 V with 0x0000 correspond-
ing to a −5 V output and 0xFFFF corresponding to a +5 V output.
+5V
10µF
V
V
O
O
REF
=
=
= 5 V, R1 = R2 = 10 kΩ,
⎛
⎜
⎝
⎡
⎢
⎣
Initial
Accuracy
(mV max)
±2
±2
±3
±3
±5
0.1µF
V
10
65536
Figure 47. Bipolar Operation with the AD5061
DD
×
⎛ ×
D
⎜
⎝
⎞
⎟
⎠
65536
−
INTERFACE
D
V
5
SERIAL
3-WIRE
REF
V
R1 = 10kΩ
⎞
× ⎟
⎠
Temperature Drift
(ppm/°C max)
3 (SO-8)
3 (SO-8)
3 (SO-8)
3 (SC70)
9 (TSOT-23)
AD5061
⎛
⎜
⎝
R
1
R
+
1
R
V
2
V
OUT
BF
⎞
⎟
⎠
−
V
DD
⎛ ×
⎜
⎝
AD820/
OP295
–
+
R2 = 10kΩ
R
R
2
1
0.1 Hz to
10 Hz Noise
(μV p-p typ)
8
3.4
10
10
8
⎞
⎟
⎠
+5V
–5V
⎤
⎥
⎦
±5V