Datasheet
www.ti.com
APPLICATION INFORMATION
BASIC CONNNECTIONS
4
5
1
2
3
6
8
7
10
9
DAC6574
V
OUT
A
V
OUT
B
V
DD
V
OUT
C
GND
V
OUT
D
A1
A0
SDA
SCL
SDA
SCL
I
2
C Pullup Resistors
1 kΩ to 10 kΩ (typical)
V
DD
Microcontroller or
Microprocessor With
I
2
C Port
NOTE: DAC6574 power and input/output connections are omitted for clarity, except I
C Inputs.
USING GPIO PORTS FOR I
2
C
DAC6574
SLAS408 – DECEMBER 2003
The following sections give example circuits and tips for using the DAC6574 in various applications. For more
information, contact your local TI representative, or visit the Texas Instruments website at http://www.ti.com.
For many applications, connecting the DAC6574 is extremely simple. A basic connection diagram for the
DAC6574 is shown in Figure 38 . The 0.1 µF bypass capacitors help provide the momentary bursts of extra
current needed from the supplies.
Figure 38. Typical DAC6574 Connections
The DAC6574 interfaces directly to standard mode, fast mode and high-speed mode I
2
C controllers. Any
microcontroller's I
2
C peripheral, including master-only and non-multiple-master I
2
C peripherals, work with the
DAC6574. The DAC6574 does not perform clock-stretching (i.e., it never pulls the clock line low), so it is not
necessary to provide for this unless other devices are on the same I
2
C bus.
Pullup resistors are necessary on both the SDA and SCL lines because I
2
C bus drivers are open-drain. The size
of the these resistors depend on the bus operating speed and capacitance on the bus lines. Higher-value
resistors consume less power, but increase the transition times on the bus, limiting the bus speed. Lower-value
resistors allow higher speed at the expense of higher power consumption. Long bus lines have higher
capacitance and require smaller pullup resistors to compensate. If the pullup resistors are too small the bus
drivers may not be able to pull the bus line low.
Most microcontrollers have programmable input/output pins that can be set in software to act as inputs or
outputs. If an I
2
C controller is not available, the DAC6574 can be connected to GPIO pins, and the I
2
C bus
protocol simulated, or bit-banged, in software. An example of this for a single DAC6574 is shown in Figure 39 .
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