AD5273 Analog Devices, AD5273 Datasheet - Page 13

• Manufacturer Part Number: AD5273
• Description: 64-Position OTP Digital Potentiometer
• Manufacturer: Analog Devices

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bypass capacitor should be applied at V
disturbances during the programming as shown in Figure 6a. Once
the programming is completed, the supply voltage can be reduced
to 2.7 V with supply current of less than 1 µA.
For users who have an on-board 3 V supply for portable appli-
cations, a separate 5 V supply must be applied one time in the
factories for programming and a low VF Schoktty Diode should
be designed with the AD5273 to isolate the supply voltages.
Once the programming is done, the 5 V supply can be removed
with V
shows one such implementation.
REV. 0
Figure 6b. External Power Supply Applied for Programming
DD
Figure 6a. OTP Power Supply Requirement
maintained at 2.7 V for minimum operation. Figure 6b
5V
100mA
3V
5%
10 F
(REMOVED AFTER OTP PROGRAMMING)
10 F
C
5V
100mA
C
5%
AD5273
SCL
SDA
V
DD
AD5273
SDA
SCL
V
DD
DD
to minimize the transient
Figure 7. Computer Software
–13–
CONTROLLING THE AD5273
There are two ways of controlling the AD5273. Users can either
program the device with computer software or with external I
controllers.
Software Programming
Due to the advantage of the one-time-programmable feature, most
systems using the AD5273 will program the devices in the facto-
ries before shipping to the end users. As a result, ADI offers device
programming software that can be implemented in the factory on
computers running Windows NT, 2000, and XP platforms. The
software can be downloaded from the AD5273 product folder at
www.analog.com
any programming languages or user programming skills. Figure 7
shows the software interface.
Write
The AD5273 starts at midscale after power up prior to any OTP
programming. To increment or decrement the resistance, the user
may simply move the scrollbar on the left. Once the desired set-
ting is found, the user may press the Program Permanent button
to lock the setting permanently. To write any specifi c values, the
user should use the bit pattern control in the upper screen and
press the Run button. The format of writing data to the device
is shown in Table I. Once the desired setting is found, the user
may turn the T bit to 1 and press the Run button to program the
setting permanently.
Read
To read the validation bits and data out from the device, the user
may simply press the Read button. The user may also set the bit
pattern in the upper screen and press the Run button. The format
of reading data out from the device is shown in Table II.
and is an executable fi le that does not require
AD5273
2
C