256-Position SPI/I2C Selectable
Digital Potentiometer
AD5161
FUNCTIONAL BLOCK DIAGRAM
FEATURES
V
SDO/NC
DD
256-position
SDI/SDA
CLK/SCL
End-to-end resistance 5 kΩ, 10 kΩ, 50 kΩ, 100 kΩ
Compact MSOP-10 (3 mm × 4.9 mm) package
Pin selectable SPI/I2C compatible interface
Extra package address decode pin AD0
Full read/write of wiper register
A
2
SPI OR I C
INTERFACE
DIS
W
B
CS/AD0
Power-on preset to midscale
Single supply 2.7 V to 5.5 V
WIPER
REGISTER
Low temperature coefficient 45 ppm/°C
Low power, IDD = 8 µA
GND
Wide operating temperature –40°C to +125°C
SDO output allows multiple device daisy-chaining
Evaluation board available
Figure 1.
APPLICATIONS
Mechanical potentiometer replacement in new designs
PIN CONFIGURATION
Transducer adjustment of pressure, temperature, position,
chemical, and optical sensors
RF amplifier biasing
Automotive electronics adjustment
Gain control and offset adjustment
1
2
3
4
5
10
9
8
7
6
A
B
W
V
DIS
GND
CLK/SCL
AD5161
DD
CS/ADO
SDO/NC
SDI/SDA
TOP VIEW
(Not to Scale)
Figure 2.
GENERAL OVERVIEW
The AD5161 provides a compact 3 mm × 4.9 mm packaged
solution for 256-position adjustment applications. These devices
perform the same electronic adjustment function as mechanical
potentiometers or variable resistors, with enhanced resolution,
solid-state reliability, and superior low temperature coefficient
performance.
The wiper settings are controllable through a pin selectable SPI
or I2C compatible digital interface, which can also be used to
read back the wiper register content. When the SPI mode is
used, the device can be daisy-chained (SDO to SDI), allowing
several parts to share the same control lines. In the I2C mode,
address pin AD0 can be used to place up to two devices on the
same bus. In this same mode, command bits are available to
reset the wiper position to midscale or to shut down the device
into a state of zero power consumption.
Note:
The terms digital potentiometer, VR, and RDAC are used interchangeably.
Purchase of licensed I2C components of Analog Devices or one of its sublicensed
Associated Companies conveys a license for the purchaser under the Philips I2C
Patent Rights to use these components in an I2C system, provided that the system
conforms to the I2C Standard Specification as defined by Philips.
Operating from a 2.7 V to 5.5 V power supply and consuming
less than 5 µA allows for usage in portable battery-operated
applications.
Rev. 0
Information furnished by Analog Devices is believed to be accurate and reliable.
However, no responsibility is assumed by Analog Devices for its use, nor for any
infringements of patents or other rights of third parties that may result from its use.
Specifications subject to change without notice. No license is granted by implication
or otherwise under any patent or patent rights of Analog Devices. Trademarks and
registered trademarks are the property of their respective companies.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781.329.4700
Fax: 781.326.8703
www.analog.com
© 2003 Analog Devices, Inc. All rights reserved.