AD5171 Datasheet, PDF (1/20 Pages) Analog Devices – 64-Position OTP Digital Potentiometer

Preliminary Technical Data
64-Position OTP Digital Potentiometer
AD5171
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 = 8 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, which employs 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 reprogram new memory setting in
the digital potentiometer. This device performs the same
electronic adjustment function like most mechanical trimmers
and variable resistors do. 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
Rev. PrC
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a mechanical trimmer). When this permanent setting is
achieved, the value will 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 AD5171 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 AD5171 evaluation kit is available, which includes the
software, connector, and cable that can be converted for the
factory programming applications.
The AD5171 is available in a compact SOT-23-8 package. All
parts are guaranteed to operate over the automotive
temperature 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.
SCL
A
SDA
I²C INTERFACE
AND
CONTROL LOGIC
W
AD0
B
V_DD
GND
FUSE
LINK
WIPER
REGISTER
AD5171
Figure 1. Functional Block Diagram
W1
8A
V_DD ² AD5171 ⁷ B
GND ^{3 TOP VIEW 6} AD0
(Not to Scale)
SCL 4
5 SDA
Figure 2. Pin Configuration
1_{One-time programmable (OTP) - Unlimited adjustments before permanent}
setting.
2_{The terms digital potentiometer and RDAC are used interchangeably.}
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