AD5245 Analog Devices, AD5245 Datasheet - Page 15

• Manufacturer Part Number: AD5245
• Description: 256-Position I2C Compatible Digital Potentiometer
• Manufacturer: Analog Devices

POWER-UP SEQUENCE
Since the ESD protection diodes limit the voltage compliance at
terminals A, B, and W (see Figure 44), it is important to power
V
otherwise, the diode will be forward biased such that V
powered unintentionally and may affect the rest of the user’s
circuit. The ideal power-up sequence is in the following order:
GND, V
powering V
long as they are powered after V
LAYOUT AND POWER SUPPLY BYPASSING
It is a good practice to employ compact, minimum lead length
layout design. The leads to the inputs should be as direct as
possible with a minimum conductor length. Ground paths
should have low resistance and low inductance.
Similarly, it is also a good practice to bypass the power supplies
with quality capacitors for optimum stability. Supply leads to the
PIN CONFIGURATION AND FUNCTION DESCRIPTIONS
PIN CONFIGURATION
DD
/GND before applying any voltage to terminals A, B, and W;
DD
, digital inputs, and then V
A
, V
B
, V
W
GND
SCL
, and the digital inputs is not important as
V
DD
W
1
2
3
4
(Not to Scale)
Figure 46.
TOP VIEW
AD5245
DD
/GND.
A/B/W
8
7
6
5
A
B
AD0
SDA
. The relative order of
DD
will be
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device should be bypassed with disc or chip ceramic capacitors
of 0.01 µF to 0.1 µF. Low ESR 1 µF to 10 µF tantalum or
electrolytic capacitors should also be applied at the supplies to
minimize any transient disturbance and low frequency ripple
(see Figure 45). Note that the digital ground should also be
joined remotely to the analog ground at one point to minimize
the ground bounce.
PIN FUNCTION DESCRIPTIONS
Table 9.
Pin
1
2
3
4
5
6
7
8
Name
W
V
GND
SCL
SDA
AD0
B
A
DD
V
DD
Description
W Terminal.
Positive Power Supply.
Digital Ground.
Serial Clock Input. Positive edge triggered.
Serial Data Input/Output.
Programmable address bit 0 for multiple
package decoding.
B Terminal.
A Terminal.
C3
Figure 45. Power Supply Bypassing
+
10 µ F
C1
0.1 µ F
V
DD
AD5245
GND
AD5245