256-Position One-Time Programmable
Dual-Channel I2C Digital Potentiometer
Preliminary Technical Data
AD5172/AD5173
Rev. PrF 8
14/03
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FEATURES
2-Channel, 256-position
OTP(One-Time Programmable) Set-and-Forget Resistance
Setting — low cost alternative over EEMEM
Unlimited adjustments prior to OTP activation
OTP overwriting function allows temporary adjustments1
End-to-end resistance 2.5 kΩ, 10 kΩ, 50 kΩ, 100 kΩ
Compact MSOP-10 (3 mm × 4.9 mm) Package
Low tempco 5 ppm/oC in potentiometer mode
Low tempco 35 ppm/°C in rheostat mode
Fast Settling Time: tS = 5µs Typ in Power-Up
Full read/write of wiper register
Power-on preset to midscale1
Extra package address decode pins AD0 and AD1(AD5173)
Computer Software Replaces µC in Factory Programming
Applications
6 V one-time programming voltage
Single supply 2.7 V to 5.5 V
Low power, IDD = 5 µA
Wide operating temperature –40°C to +125°C
APPLICATIONS
Systems Calibrations
Mechanical Potentiometers and Trimmers® Replacements
Transducer adjustment
RF amplifier biasing
Automotive electronics adjustment
Gain control and offset adjustment
Electronics Level Settings
GENERAL OVERVIEW
The AD5172/73 are dual channel 256-position, one-time
programmable (OTP) digital potentiometers2, which employ
fuse link technology to achieve the memory retention of
resistance setting function. OTP is a cost-effective alternative
over the EEMEM approach for users who do not need to
program the digital potentiometer setting in memory for more
than once. These devices perform the same electronic
adjustment functions like most mechanical trimmers and
variable resistors do but offer enhanced resolution, solid-state
reliability, and superior low temperature coefficient
performance.
The AD5172/73 are programmed using a 2-wire I2C compatible
digital control. They allow unlimited adjustments before
permanently setting the resistance value. During the OTP
activation, a permanent fuse blown command is sent after the
final value is determined; therefore freezing the wiper position
at a given setting (analogous to placing epoxy on a mechanical
trimmer). Unlike other OTP digital potentiometers in the same
family, AD5172/73 have unique temporary OTP overwriting
feature that new adjustments if desired but the OTP setting is
restored during subsequent power up conditions. To verify the
success of permanent programming, Analog Devices patterned
the OTP validation such that the fuse status can be discerned
from two validation bits in read mode.
For applications that program AD5172/73 in the factories,
Analog Devices offers a device programming software, which
operates across Windows® 95 to XP® platforms including
Windows NT®. This software application effectively replaces the
need for external I2C controllers or host processors and
therefore significantly reduces users’ development time.
An AD5172/73 evaluation kit is available, which include the
software, connector, and cable that can be converted for the
factory programming applications.
The AD5172/73 are available in a MSOP-10 package. All parts
are guaranteed to operate over the automotive temperature
range of −40°C to +125°C. Besides their unique OTP features,
the AD5172/73 lend themselves well to other general-purpose
digital potentiometer applications due to their programmable
preset, superior temperature stability, and small form factor.
FUNCTIONAL BLOCK DIAGRAMS
RDAC
REGISTER 1
SERIAL INPUT
REGISTER
VDD
GND
SDA
SCL
FUSE
LINKS
12
RDAC
REGISTER 2
8
A1 W1 B1 A2 W2 B2
Figure 1. AD5172