Datasheet

DACx311
AV
DD
V
OUT
R
10kW
2
+5V
±5V
+5.5V
OPA211
10 Fm 0.1 Fm
Three-Wire
Serial
Interface
- 5.5V
R
10kW
1
REF5050
DACx311
+5V
110 Am
V
OUT
=0Vto5V
SYNC
SCLK
D
IN
+5.5V
Three-Wire
Serial
Interface
1 Fm
V
O
+
ǒ
10 D
2
n
Ǔ
*5V
V
O
+
ƪ
AV
DD
ǒ
D
2
n
Ǔ
ǒ
R
1
) R
2
R
1
Ǔ
* AV
DD
ǒ
R
2
R
1
Ǔ
ƫ
DAC5311
DAC6311
DAC7311
SBAS442B –AUGUST 2008–REVISED MAY 2013 www.ti.com
APPLICATION INFORMATION
USING THE REF5050 AS A POWER SUPPLY BIPOLAR OPERATION USING THE DACx311
FOR THE DACx311
The DACx311 has been designed for single-supply
As a result of the extremely low supply current operation but a bipolar output range is also possible
required by the DACx311, an alternative option is to using the circuit in Figure 82. The circuit shown gives
use a REF5050 +5V precision voltage reference to an output voltage range of ±5V. Rail-to-rail operation
supply the required voltage to the part, as shown in at the amplifier output is achievable using an
Figure 81. This option is especially useful if the power OPA211, OPA340, or OPA703 as the output
supply is too noisy or if the system supply voltages amplifier. For a full list of available operational
are at some value other than 5V. The REF5050 amplifiers from TI, see the TI web site at www.ti.com
outputs a steady supply voltage for the DACx311. If
The output voltage for any input code can be
the REF5050 is used, the current needed to supply
calculated as follows:
DACx311 is typically 110μA at 5V, with no load on
the output of the DAC. When the DAC output is
loaded, the REF5050 also needs to supply the
current to the load. The total current required (with a
5kΩ load on the DAC output) is:
(1)
110μA + (5V/5kΩ) = 1.11mA
Where:
The load regulation of the REF5050 is typically
n = resolution in bits; either 8 (DAC5311), 10
0.002%/mA, which results in an error of 90μV for the
(DAC6311), or 12 (DAC7311).
1.1mA current drawn from it. This value corresponds
D = decimal equivalent of the binary code that is
to a 0.07LSB error at 12 bits (DAC7311).
loaded to the DAC register. It ranges from 0 to
255 for 8-bit DAC5311; from 0 to 1023 for the 10-
bit DAC6311; and 0 to 4095 for the 12-bit
DAC7311.
With AV
DD
= 5V, R
1
= R
2
= 10kΩ:
(2)
This is an output voltage range of ±5V with 000h (12-
bit level) corresponding to a –5V output and FFFh
(12-bit level) corresponding to a +5V output.
Figure 81. REF5050 as Power Supply to DACx311
For other power-supply voltages, alternative
references such as the REF3030 (3V), REF3033
(3.3V), or REF3220 (2.048V) are recommended. For
a full list of available voltage references from TI, see
the TI web site at www.ti.com.
Figure 82. Bipolar Operation with the DACx311
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