Datasheet
www.ti.com
APPLICATION INFORMATION
BASIC CONNNECTIONS
8
6
4
9
5
7
1
2
3
12
14
11
10
13
16
15
DAC7573
V
OUTA
V
OUTB
V
REFH
V
DD
V
REFL
GND
V
OUTC
V
OUTD
A3
A2
A1
A0
IOV
DD
SDA
SCL
L
DAC
SDA
SCL
I
2
C Pullup Resistors
1 kΩ to 10 kΩ (typical)
IOV
DD
Microcontroller or
Microprocessor With
I
2
C Port
NOTE: DAC7573 power and input/output connections are omitted for clarity, except I
C Inputs.
USING GPIO PORTS FOR I
2
C
DAC7573
SLAS398 – SEPTEMBER 2003
The following sections give example circuits and tips for using the DAC7573 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 DAC7573 is extremely simple. A basic connection diagram for the
DAC7573 is shown in Figure 40 . The 0.1 µF bypass capacitors provide the momentary bursts of extra current
needed from the supplies.
Figure 40. Typical DAC7573 Connections
The DAC7573 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
DAC7573. The DAC7573 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 DAC7573 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 DAC7573 is shown in Figure 41 .
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