DAC8574 Datasheet, PDF (31/40 Pages) Texas Instruments – QUAD, 16-BIT, LOW-POWER, VOLTAGE OUTPUT, I2C INTERFACE DIGITAL-TO-ANALOG CONVERTER

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DAC8574
SLAS377A – JANUARY 2003 – REVISED JUNE 2003
APPLICATION INFORMATION (continued)
USING REF02 AS A POWER SUPPLY FOR DAC8574
Due to the extremely low supply current required by the DAC8574, a possible configuration is to use a REF02 +5
V precision voltage reference to supply the required voltage to the DAC8574’s supply input as well as the
reference input, as shown in Figure 58. This 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 outputs a steady supply voltage for the DAC8574.
If the REF02 is used, the current it needs to supply to the DAC8574 is 950 µA typical and 1600 µA max for V_DD =
5 V. When a DAC output is loaded, the REF02 also needs to supply the current to the load. The total typical
current required (with a 5 kΩ load on a single DAC output) is:
950 µA + (5 V / 5 kΩ) = 1.950 mA
The load regulation of the REF02 is typically 0.005%/mA, which results in an error of 488µV for 1.950-mA of
current drawn from it. This corresponds to a 6.4 LSB error for a 0 V to 5 V output range.
15 V
5V
REF02
950 mA
I²C
Interface
SCL
SDA
V_DD, V_ref
DAC8574
V_OUT = 0 V to 5 V
Figure 58. REF02 Power Supply
REF3040 can also be used to generate a 4.096-V reference from a 5-V supply.
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