256-Position, Two-Time Programmable,
I2C Digital Potentiometer
Rev. G
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FEATURES
256-position digital potentiometer
Two-time programmable (TTP) set-and-forget resistance
setting allows second-chance permanent programming
Unlimited adjustments prior to one-time programming
(OTP) activation
OTP overwrite allows dynamic adjustments with user-
defined preset
End-to-end resistance: 2.5 kΩ, 10 kΩ, 50 kΩ, 100 kΩ
Compact 10-lead MSOP: 3 mm × 4.9 mm package
Fast settling time: tS = 5 μs typical in power-up
Full read/write of wiper register
Power-on preset to midscale
Extra package address decode pins: AD0 and AD1
Single supply: 2.7 V to 5.5 V
Low temperature coefficient: 35 ppm/°C
Low power: IDD = 6 μA maximum
Wide operating temperature: 40°C to +125°C
Evaluation board and software are available
Software replaces MicroConverter in factory programming
applications
APPLICATIONS
Systems calibration
Electronics level setting
Mechanical trimmers replacement in new designs
Permanent factory PCB settings
Transducer adjustment of pressure, temperature, position,
chemical, and optical sensors
RF amplifier biasing
Automotive electronics adjustments
Gain control and offset adjustments
FUNCTIONAL BLOCK DIAGRAM
VDD
GND
SDA
SCL
AD0
AD1
W
RDAC
REGISTER
ADDRESS
DECODE
SERIAL INPUT
REGISTER
B
A
FUSE
LINKS
12
8
04
10
4-
0
-0
01
Figure 1.
GENERAL DESCRIPTION
The AD5170 is a 256-position, two-time programmable, digital
potentiometer1 that employs fuse link technology, giving users
two opportunities to permanently program the resistance setting.
For users who do not need to program the digital potentiometer
setting in memory more than once, the OTP feature is a cost-
effective alternative to EEMEM. The AD5170 performs the same
electronic adjustment function as mechanical potentiometers or
variable resistors with enhanced resolution, solid-state reliability,
and superior low temperature coefficient performance.
The AD5170 is programmed using a 2-wire, I2C-compatible
digital interface. Unlimited adjustments are allowed before
permanently setting the resistance value, and there are two
opportunities for permanent programming. During OTP
activation, a permanent blow fuse command freezes the wiper
position (analogous to placing epoxy on a mechanical trimmer).
Unlike traditional OTP digital potentiometers, the AD5170 has
a unique temporary OTP overwrite feature that allows for new
adjustments even after the fuse is blown. However, the OTP setting
is restored during subsequent power-up conditions. This feature
allows users to treat these digital potentiometers as volatile poten-
tiometers with a programmable preset.
For applications that program the AD5170 at the factory, Analog
Devices, Inc., offers device programming software that runs on
Windows NT, Windows 2000, and Windows XP operating
systems. This software effectively replaces any external I2C con-
trollers, thus enhancing the time-to-market of the user’s systems.
1 The terms digital potentiometer, VR, and RDAC are used interchangeably.