EVAL-AD5245EBZ

Manufacturer Part NumberEVAL-AD5245EBZ
DescriptionEVALUATION BOARD I.C.
ManufacturerAnalog Devices Inc
EVAL-AD5245EBZ datasheets
 


Specifications of EVAL-AD5245EBZ

Lead Free Status / RoHS StatusLead free / RoHS Compliant  
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FEATURES
256-position
End-to-end resistance 5 kΩ, 10 kΩ, 50 kΩ, 100 kΩ
Compact SOT-23-8 (2.9 mm × 3 mm) package
Fast settling time: t
= 5 µs typ on power-up
S
Full read/write of wiper register
Power-on preset to midscale
Extra package address decode pin AD0
Computer software replaces µC in factory programming
applications
Single supply: 2.7 V to 5.5 V
Low temperature coefficient 45 ppm/°C
Low power: I
= 8 µA
DD
Wide operating temperature: –40°C to +125°C
Evaluation board available
APPLICATIONS
Mechanical potentiometer replacement in new designs
LCD panel V
adjustment
COM
LCD panel brightness and contrast control
Transducer adjustment of pressure, temperature, position,
chemical, and optical sensors
RF amplifier biasing
Automotive electronics adjustment
Gain control and offset adjustment
GENERAL DESCRIPTION
The AD5245 provides a compact 2.9 mm × 3 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 an I
digital interface, which can also be used to read back the wiper
register content. AD0 can be used to place up to two devices on
the same bus. Command bits are available to reset the wiper
position to midscale or to shut down the device into a state of
zero power consumption.
Rev. B
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 owners.
256-Position I
FUNCTIONAL BLOCK DIAGRAM
SCL
SDA
AD0
Operating from a 2.7 V to 5.5 V power supply and consuming
less than 8 µA allows usage in portable battery-operated
applications.
Note that the terms digital potentiometer, VR, and RDAC are
used interchangeably.
2
C-compatible
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781.329.4700
Fax: 781.461.3113
C
-Compatible
2
®
Digital Potentiometer
AD5245
V
DD
A
I
2
C
INTERFACE
W
WIPER
B
REGISTER
POR
GND
Figure 1.
PIN CONFIGURATION
W
A
1
8
AD5245
V
B
2
7
DD
TOP VIEW
GND
AD0
3
6
(Not to Scale)
SCL
4
5
SDA
Figure 2.
www.analog.com
©2006 Analog Devices, Inc. All rights reserved.

EVAL-AD5245EBZ Summary of contents

  • Page 1

    ... Single supply: 2 5.5 V Low temperature coefficient 45 ppm/°C Low power µA DD Wide operating temperature: –40°C to +125°C Evaluation board available APPLICATIONS Mechanical potentiometer replacement in new designs LCD panel V adjustment COM LCD panel brightness and contrast control Transducer adjustment of pressure, temperature, position, ...

  • Page 2

    ... Changes to Figure 40..................................................................... 14 Moved Power-Up Sequence Section to Page ............................. 14 Moved Layout and Power Supply Bypassing Section to Page . 15 Added Constant Bias to Retain Resistance Setting Section..... 15 Added Figure 42 ............................................................................ 15 Added Evaluation Board Section ................................................ 15 Added Figure 43 ............................................................................ 15 2 Moved I C Interface Section to Page........................................... 16 Changes to I2C Compatible 2-Wire Serial Bus Section ........... 16 Moved Table 5 and Table 6 to Page ...

  • Page 3

    ELECTRICAL CHARACTERISTICS 5 kΩ VERSION ± 10 ± 10 Table 1. Parameter DC CHARACTERISTICS—RHEOSTAT MODE 2 Resistor Differential Nonlinearity 2 Resistor Integral Nonlinearity 3 Nominal Resistor Tolerance ...

  • Page 4

    AD5245 10 kΩ, 50 kΩ, 100 kΩ VERSIONS ± 10 ± 10 Table 2. Parameter DC CHARACTERISTICS—RHEOSTAT MODE 2 Resistor Differential Nonlinearity 2 Resistor Integral Nonlinearity 3 ...

  • Page 5

    TIMING CHARACTERISTICS 5 KΩ, 10 KΩ, 50 KΩ, 100 KΩ VERSIONS ± 10 ± 10 Table 3. Parameter INTERFACE TIMING CHARACTERISTICS SCL Clock Frequency ...

  • Page 6

    AD5245 ABSOLUTE MAXIMUM RATINGS T = 25°C, unless otherwise noted. A Table 4. Parameter V to GND GND Terminal Current ...

  • Page 7

    PIN CONFIGURATION AND FUNCTION DESCRIPTIONS Table 5. Pin Function Descriptions Pin No. Mnemonic Description Terminal. GND ≤ Positive Power Supply GND Digital Ground. 4 SCL Serial Clock Input. Positive edge triggered. Pull-up ...

  • Page 8

    AD5245 TYPICAL PERFORMANCE CHARACTERISTICS 1.0 0.8 0.6 0.4 0.2 0 –0.2 –0.4 –0.6 –0.8 –1 128 CODE (Decimal) Figure 4. R-INL vs. Code vs. Supply Voltages 1.0 0.8 0.6 0.4 0.2 0 –0.2 –0.4 –0.6 –0.8 ...

  • Page 9

    CODE (Decimal) Figure 10. R-INL vs. Code vs. Temperature, V 1.0 0.8 0.6 0.4 0.2 0 –0.2 –0.4 –0.6 –0.8 –1.0 0 ...

  • Page 10

    AD5245 200 150 100 50 0 – 128 CODE (Decimal) Figure 16. Rheostat Mode Tempco ∆R 160 140 120 100 – 128 CODE (Decimal) Figure 17. Potentiometer ...

  • Page 11

    REF LEVEL /DIV –5.000dB 0.500dB –5.5 –6.0 –6.5 –7.0 –7.5 –8.0 –8 50kΩ –9 10kΩ 100kΩ –9.5 –10.0 –10.5 10k 100k 1M START 1 000.000Hz STOP 1 000 000.000Hz Figure 22. –3 ...

  • Page 12

    AD5245 TEST CIRCUITS Figure 28 to Figure 34 illustrate the test circuits that define the test conditions used in the product specification tables (Table 1 through Table 3). DUT Figure 28. Test Circuit for Potentiometer Divider ...

  • Page 13

    THEORY OF OPERATION The AD5245 is a 256-position digitally controlled variable resistor (VR) device. An internal power-on preset places the wiper at midscale during power-on, which simplifies the fault condition recovery at power-up. PROGRAMMING THE VARIABLE RESISTOR Rheostat Operation The ...

  • Page 14

    AD5245 PROGRAMMING THE POTENTIOMETER DIVIDER Voltage Output Operation The digital potentiometer easily generates a voltage divider at wiper-to-B and wiper-to-A proportional to the input voltage Unlike the polarity GND, which must be DD ...

  • Page 15

    ... EVALUATION BOARD An evaluation board, along with all necessary software, is available to program the AD5245 from any PC running Windows® 98/2000/XP. The graphical user interface, as shown in Figure 43, is straightforward and easy to use. More detailed information is available in the user manual, which is provided with the board ...

  • Page 16

    AD5245 I C INTERFACE C-COMPATIBLE 2-WIRE SERIAL BUS 2 The 2-wire I C serial bus protocol operates as follows: 1. The master initiates data transfer by establishing a START condition, which is when a high-to-low transition on ...

  • Page 17

    Table 8 . Write Mode AD0 Slave Address Byte Table 9. Read Mode AD0 Slave Address Byte S = START condition P ...

  • Page 18

    AD5245 Multiple Devices on One Bus Figure 47 shows two AD5245 devices on the same serial bus. Each has a different slave address because the states of their AD0 pins are different. This allows the RDAC within each device to ...

  • Page 19

    ... AD5245BRJ100-R2 –40°C to +125°C AD5245BRJ100-RL7 –40°C to +125°C 1 AD5245BRJZ100-R2 –40°C to +125°C 1 AD5245BRJZ100-RL7 –40°C to +125°C 2 AD5245EVAL Pb-free part. 2 The evaluation board is shipped with the 10 kΩ R 2.90 BSC 1.60 BSC 2.80 BSC PIN 1 0.65 BSC 1.95 1 ...

  • Page 20

    AD5245 NOTES 2 Purchase of licensed I C components of Analog Devices or one of its sublicensed Associated Companies conveys a license for the 2 purchaser under the Philips I C Patent Rights to use these components ...