DAC8551-Q1 Datasheet, PDF (18/28 Pages) Texas Instruments – Automotive 16-Bit, Ultralow-Glitch, Voltage-Output DAC

DAC8551-Q1
SLASEB8A – FEBRUARY 2016 – REVISED MARCH 2016
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8.2.3 Using the REF02 As a Power Supply for the DAC8551-Q1
Due to the extremely low supply current required by the DAC8551-Q1, an alternative option is to use a precision
reference such as the REF02 device to supply the required voltage to the device, as illustrated in Figure 36.
15 V
5V
REF02
285 mA
Three-Wire
Serial
Interface
SYNC
SCLK
D_IN
DAC8551-Q1
V_OUT = 0 V to 5 V
Figure 36. REF02 As a Power Supply to the DAC8551-Q1
This configuration is especially useful if the power supply is quite noisy or if the system supply voltages are at
some value other than 5 V. The REF02 device outputs a steady supply voltage for the DAC8551-Q1. If the
REF02 device is used, the current it must supply to the DAC8551-Q1 is 200 μA. This configuration is with no
load on the output of the DAC. When a DAC output is loaded, the REF02 also must supply the current to the
load.
The total current required (with a 5 kΩ load on the DAC output) is:
200mA
)
5V
5kW
+
1.2mA
(5)
The load regulation of the REF02 is typically 0.005%/mA, resulting in an error of 299 μV for the 1.2 mA current
drawn from it. This value corresponds to a 3.9 LSB error.
18
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