64-
Position
OTP Digital Potentiometer
AD5171
Rev. 0
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FEATURES
64 positions
OTP (one-time programmable)1 set-and-forget resistance
setting—low cost alternative over EEMEM
Unlimited adjustments prior to OTP activation
5 kΩ, 10 kΩ, 50 kΩ, 100 kΩ end-to-end resistance
Low tempco 5 ppm/oC in potentiometer mode
Low tempco 35 ppm/°C in rheostat mode
Compact standard SOT-23-8 package
Low power, IDD = 10 µA max
Fast settling time, ts = 5 µs typ in power-up
I2C compatible digital interface
Computer software replaces µC in factory programming
applications
Full read/write of wiper register
Extra I2C device address pin
Power-on preset to midscale
6 V one-time programming voltage
Low operating voltage, 2.7 V to 5.5 V
OTP validation check function
Automotive temperature range −40°C to +125°C
APPLICATIONS
Systems calibrations
Electronics level settings
Mechanical potentiometers and trimmers® replacements
Automotive electronics adjustments
Gain control and offset adjustments
Transducer circuits adjustments
Programmable filters up to 1.5 MHz BW
GENERAL DESCRIPTION
The AD5171 is a 64-position, one-time programmable (OTP)
digital potentiometer2 that uses fuse link technology to achieve
the memory retention of the resistance setting function. OTP is
a cost-effective alternative over the EEMEM approach for users
who do not need to reprogram new memory settings in the
digital potentiometer. This device performs the same electronic
adjustment function as most mechanical trimmers and variable
resistors. The AD5171 is programmed using a 2-wire I2C
compatible digital control. It allows 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). When this permanent setting is achieved,
the value does not change regardless of supply variations or
environmental stresses under normal operating 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 the AD5171 in factories, Analog
Devices offers device programming software that operates
across Windows® 95 to XP® platforms including Windows NT®.
This software application effectively replaces the need for exter-
nal I2C controllers or host processors and therefore significantly
reduces users’ development time.
An AD5171 evaluation kit is available, which includes the soft-
ware, connector, and cable that can be converted for factory
programming applications.
The AD5171 is available in a compact SOT-23-8 package. All
parts are guaranteed to operate over the automotive tempera-
ture range of −40°C to +125°C. Besides its unique OTP feature,
the AD5171 lends itself well to other general-purpose digital
potentiometer applications due to its temperature performance,
small form factor, and low cost.
GND
I
2
C INTERFACE
AND
CONTROL LOGIC
A
W
B
WIPER
REGISTER
FUSE
LINK
V
DD
AD0
SDA
SCL
AD5171
03437-0-001
Figure 1. Functional Block Diagram
TOP VIEW
(Not to Scale)
8
7
6
5
1
2
3
4
W
V
DD
GND
SCL
A
B
AD0
SDA
AD5171
03437-0-002
Figure 2. Pin Configuration
1
One-time programmable (OTP)—Unlimited adjustments before
permanent setting.
2
The terms digital potentiometer and RDAC are used interchangeably.