ANALOG DEVICES AD5243 Service Manual

Dual 256-Position I2C Compatible

G

G

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FEATURES

2-channel, 256-position
End-to-end resistance: 2.5 kΩ, 10 kΩ, 50 kΩ, and 100 kΩ
Compact MSOP-10 (3 mm × 4.9 mm) package
Fast settling time: t
Full read/write of wiper register
Power-on preset to midscale
Extra package address decode pins AD0 and AD1 (AD5248

only)

Computer software replaces µC in factory programming

applications
Single supply: 2.7 V to 5.5 V
Low temperature coefficient: 35 ppm/°C
Low power: I
Wide operating temperature: −40°C to +125°C
Evaluation board available

APPLICATIONS

Systems calibrations
Electronics level settings
Mechanical Trimmers® replacement in new designs
Permanent factory PCB setting
Transducer adjustment of pressure, temperature, position,

chemical, and optical sensors
RF amplifier biasing
Automotive electronics adjustment
Gain control and offset adjustment

GENERAL DESCRIPTION

The AD5243 and AD5248 provide a compact 3 mm × 4.9 mm
packaged solution for dual 256-position adjustment applica­tions. These devices perform the same electronic adjustment
function as a 3-terminal mechanical potentiometer (AD5243)
or a 2-terminal variable resistor (AD5248). Available in four
different end-to-end resistance values (2.5 kΩ, 10 kΩ, 50 kΩ,
and 100 kΩ), these low temperature coefficient devices are ideal
for high accuracy and stability variable resistance adjustments.
The wiper settings are controllable through the I
digital interface. The AD5248 has extra package address decode
pins AD0 and AD1, allowing multiple parts to share the same

2

I

C 2-wire bus on a PCB. The resistance between the wiper and
either endpoint of the fixed resistor varies linearly with respect
to the digital code transferred into the RDAC latch.

= 5 µs typ on power-up

S

= 6 µA max

DD

2

C compatible

1

Digital Potentiometer

AD5243/AD5248

FUNCTIONAL BLOCK DIAGRAMS

W1

V

SDA
SCL

V

AD0
AD1

SDA

SCL

A1

DD

ND

DD

ND

REGISTER 1

REGISTER 1

ADDRESS

DECODE

B1 A2 W2

WIPER

PC INTERFACE

Figure 1. AD5243

W1

B1 W2

RDAC

/

8

SERIAL INPUT

REGISTER

Figure 2. AD5248

REGISTER 2

REGISTER 2

Operating from a 2.7 V to 5.5 V power supply and consuming
less than 6 µA allows for usage in portable battery-operated
applications.

For applications that program the AD5243/AD5258 at the
factory, Analog Devices offers device programming software
running on Windows® NT/2000/XP operating systems. This
software effectively replaces any external I
in turn enhances users’ systems time-to-market. An AD5243/
AD5248 evaluation kit and software are available. The kit
includes a cable and instruction manual.

1The terms digital potentiometer, VR, and RDAC are used interchangeably.

B2

WIPER

AD5243

04109-0-001

B2

RDAC

AD5248

04109-0-002

2

C controllers, which

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 owners.

One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: [phone] www.analog.com
Fax: [phone] © 2004 Analog Devices, Inc. All rights reserved.

AD5243/AD5248

www.BDTIC.com/ADI

TABLE OF CONTENTS

Electrical Characteristics—2.5 kΩ Version................................... 3

ESD Protection ........................................................................... 14

Electrical Characteristics—10 kΩ, 50 kΩ, 100 kΩ Versions ....... 4

Timing Characteristics—All Versions ........................................... 5

Absolute Maximum Ratings............................................................ 6

ESD Caution.................................................................................. 6

Pin Configurations and Function Descriptions ........................... 7

Typical Performance Characteristics ............................................. 8

Tes t Ci rc u it s ..................................................................................... 12

Theory of Operation ...................................................................... 13

Pro g ram m ing t he Vari a bl e Re s ist o r a n d Vo l ta g e.................... 13

Programming the Potentiometer Divider............................... 14

REVISION HISTORY

Revision 0: Initial Version

Terminal Voltage Operating Range.......................................... 14

Power-Up Sequence ................................................................... 14

Layout and Power Supply Bypassing ....................................... 14

Constant Bias to Retain Resistance Setting............................. 15

Evaluation Board ........................................................................ 15

I2C Interface .................................................................................... 16

I2C Compatible 2-Wire Serial Bus ........................................... 16

Outline Dimensions....................................................................... 19

Ordering Guide .......................................................................... 19

Rev. 0 | Page 2 of 20

AD5243/AD5248

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ELECTRICAL CHARACTERISTICS—2.5 kΩ VERSION

VDD = 5 V ± 10%, or 3 V ± 10%; VA = +VDD; VB = 0 V; −40°C < TA < +125°C; unless otherwise noted.

Table 1.

Parameter Symbol Conditions Min Typ

DC CHARACTERISTICS—RHEOSTAT MODE

Resistor Differential Nonlinearity
Resistor Integral Nonlinearity
Nominal Resistor Tolerance

2

2

3

R-DNL RWB, VA = no connect −2 ±0.1 +2 LSB
R-INL RWB, VA = no connect −6 ±0.75 +6 LSB
∆R

AB

TA = 25°C −20 +55 %
Resistance Temperature Coefficient (∆RAB/RAB )/∆T VAB = VDD, wiper = no connect 35 ppm/°C
RWB (Wiper Resistance) R

WB

Code = 0x00, VDD = 5 V 160 200 Ω

DC CHARACTERISTICS—POTENTIOMETER DIVIDER MODE (Specifications Apply to All VRs)

Differential Nonlinearity

4

DNL −1.5 ±0.1 +1.5 LSB
Integral Nonlinearity INL −2 ±0.6 +2 LSB
Voltage Divider Temperature

(∆V

)/∆T Code = 0x80 15 ppm/°C

W/VW

Coefficient
Full-Scale Error V
Zero-Scale Error V

WFSE

WZSE

Code = 0xFF −10 −2.5 0 LSB
Code = 0x00 0 2 10 LSB

RESISTOR TERMINALS

Voltage Range
Capacitance6 A, B C
Capacitance6 W C
Shutdown Supply Current
Common-Mode Leakage I

5

7

VA, VB, V

A, CB

W

I

A_SD

CM

W

GND V
f = 1 MHz, measured to GND, Code = 0x80
f = 1 MHz, measured to GND, Code = 0x80

45 pF

60 pF
VDD = 5.5 V 0.01 1 µA
VA = VB = VDD/2 1 nA

DIGITAL INPUTS AND OUTPUTS

Input Logic High V
Input Logic Low V
Input Logic High V
Input Logic Low V
Input Current I
Input Capacitance

6

IH

IL

IH

IL

IL

C

IL

VDD = 5 V 2.4 V
VDD = 5 V 0.8 V
VDD = 3 V 2.1 V
VDD = 3 V 0.6 V
VIN = 0 V or 5 V ±1 µA
5 pF

POWER SUPPLIES

Power Supply Range V
Supply Current I
Power Dissipation

8

DD RANGE

DD

P

DISS

2.7 5.5 V
VIH = 5 V or VIL = 0 V 3.5 6 µA
VIH = 5 V or VIL = 0 V, VDD = 5 V 30 µW

Power Supply Sensitivity PSS VDD = 5 V ± 10%, Code = midscale ±0.02 ±0.08 %/%

DYNAMIC CHARACTERISTICS

9

Bandwidth −3 dB BW_2.5 K Code = 0x80 4.8 MHz
Total Harmonic Distortion THD
VW Settling Time t
Resistor Noise Voltage Density e

See notes at end of section.

W

S

N_WB

VA = 1 V rms, VB = 0 V, f = 1 kHz 0.1 %
VA = 5 V, VB = 0 V, ±1 LSB error band 1 µs
RWB = 1.25 kΩ, RS = 0 3.2

1

Max Unit

DD

V

nV/√Hz

Rev. 0 | Page 3 of 20

AD5243/AD5248

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ELECTRICAL CHARACTERISTICS—10 kΩ, 50 kΩ, 100 kΩ VERSIONS

VDD = 5 V ± 10%, or 3 V ± 10%; VA = VDD; VB = 0 V; −40°C < TA < 125°C; unless otherwise noted.

Table 2.

Parameter Symbol Conditions Min Typ

DC CHARACTERISTICS—RHEOSTAT MODE

Resistor Differential Nonlinearity
Resistor Integral Nonlinearity
Nominal Resistor Tolerance

2

2

3

R-DNL RWB, VA = no connect −1 ±0.1 +1 LSB
R-INL RWB, VA = no connect −2.5 ±0.25 +2.5 LSB
∆R

AB

TA = 25°C −20 +20 %
Resistance Temperature Coefficient (∆RAB/RAB )/∆T VAB = VDD, wiper = no connect 35 ppm/°C
RWB (Wiper Resistance) R

WB

Code = 0x00, VDD =5 V 160 200 Ω

DC CHARACTERISTICS—POTENTIOMETER DIVIDER MODE (Specifications Apply to All VRs)

Differential Nonlinearity
Integral Nonlinearity
Voltage Divider Temperature

4

4

DNL −1 ±0.1 +1 LSB
INL −1 ±0.3 +1 LSB
(∆V

)/∆T Code = 0x80 15 ppm/°C

W/VW

Coefficient
Full-Scale Error V
Zero-Scale Error V

WFSE

WZSE

Code = 0xFF −2.5 −1 0 LSB
Code = 0x00 0 1 2.5 LSB

RESISTOR TERMINALS

Voltage Range
Capacitance6 A, B C
Capacitance6 W C
Shutdown Supply Current
Common-Mode Leakage I

5

7

VA, VB, V

A, CB

W

I

A_SD

CM

W

GND V
f = 1 MHz, measured to GND, Code = 0x80
f = 1 MHz, measured to GND, Code = 0x80

45 pF

60 pF
VDD = 5.5 V 0.01 1 µA
VA = VB = VDD/2 1 nA

DIGITAL INPUTS AND OUTPUTS

Input Logic High V
Input Logic Low V
Input Logic High V
Input Logic Low V
Input Current I
Input Capacitance C

IH

IL

IH

IL

IL

IL

VDD = 5 V 2.4 V
VDD = 5 V 0.8 V
VDD = 3 V 2.1 V
VDD = 3 V 0.6 V
VIN = 0 V or 5 V ±1 µA
5 pF

POWER SUPPLIES

Power Supply Range V
Supply Current I
Power Dissipation P

DD RANGE

DD

DISS

2.7 5.5 V
VIH = 5 V or VIL = 0 V 3.5 6 µA
VIH = 5 V or VIL = 0 V, VDD = 5 V 30 µW

Power Supply Sensitivity PSS VDD = 5 V ± 10%, Code = midscale ±0.02

DYNAMIC CHARACTERISTICS

Bandwidth −3 dB BW

Total Harmonic Distortion THD
VW Settling Time (10 kΩ/50 kΩ/100

t

S

W

RAB = 10 kΩ/50 kΩ/100 kΩ, Code = 0x80

VA = 1 V rms, VB = 0 V, f = 1 kHz, RAB = 10 kΩ

0.1 %

VA = 5 V, VB = 0 V, ±1 LSB error band 2 µs

kΩ)
Resistor Noise Voltage Density e

See notes at end of section.

N_WB

RWB = 5 kΩ, RS = 0 9

1

600/100/4
0

Max Unit

V

DD

±0.0

%/%

8

kHz

nV/√Hz

Rev. 0 | Page 4 of 20

AD5243/AD5248

www.BDTIC.com/ADI

TIMING CHARACTERISTICS—ALL VERSIONS

VDD = 5V ± 10%, or 3V ± 10%; VA = VDD; VB = 0 V; −40°C < TA < +125°C; unless otherwise noted.

Table 3.

Parameter Symbol Conditions Min Typ1 Max Unit

I2C INTERFACE TIMING CHARACTERISTICS

SCL Clock Frequency f
t

Bus Free Time between STOP and START t

BUF

t

Hold Time (Repeated START) t

HD;STA

t

Low Period of SCL Clock t

LOW

t

High Period of SCL Clock t

HIGH

t

Setup Time for Repeated START Condition t

SU;STA

t

Data Hold Time

HD;DAT

t

Data Setup Time t

SU;DAT

11

tF Fall Time of Both SDA and SCL Signals t
tR Rise Time of Both SDA and SCL Signals t
t

Setup Time for STOP Condition t

SU;STO

See notes at end of section.

NOTES

1

Typical specifications represent average readings at 25°C and VDD = 5 V.

2

Resistor position nonlinearity error R-INL is the deviation from an ideal value measured between the maximum resistance and the minimum resistance wiper

positions. R-DNL measures the relative step change from ideal between successive tap positions. Parts are guaranteed monotonic.

3

VAB = VDD, wiper (VW) = no connect.

4

INL and DNL are measured at VW with the RDAC configured as a potentiometer divider similar to a voltage output D/A converter. VA = VDD and VB = 0 V.

DNL specification limits of ±1 LSB maximum are guaranteed monotonic operating conditions.

5

Resistor terminals A, B, W have no limitations on polarity with respect to each other.

6

Guaranteed by design and not subject to production test.

7

Measured at the A terminal. The A terminal is open circuited in shutdown mode.

8

P

is calculated from (IDD × VDD). CMOS logic level inputs result in minimum power dissipation.

DISS

9

All dynamic characteristics use VDD = 5 V.

10

See timing diagrams for locations of measured values.

11

The maximum t

must be met only if the device does not stretch the low period (t

HD:DAT

10

(Specifications Apply to All Parts)

SCL

1

2

0 400 kHz

1.3 µs
After this period, the first clock pulse is

generated.

3

4

5

t

6

7

8

9

10

1.3 µs

0.6 µs

0.6 µs

0.9 µs
100 ns
300 ns
300 ns

0.6 µs

) of the SCL signal.

LOW

0.6 µs

Rev. 0 | Page 5 of 20

AD5243/AD5248

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ABSOLUTE MAXIMUM RATINGS

TA = 25°C, unless otherwise noted.

Table 4.

Parameter Value

VDD to GND –0.3 V to +7 V
VA, VB, VW to GND V
Terminal Current, Ax to Bx, Ax to Wx, Bx to Wx1

Pulsed ±20 mA

Continuous ±5 mA
Digital Inputs and Output Voltage to GND 0 V to 7 V
Operating Temperature Range –40°C to +125°C
Maximum Junction Temperature (T
Storage Temperature –65°C to +150°C
Lead Temperature (Soldering, 10 sec) 300°C
Thermal Resistance2 θJA: MSOP-10

1

Maximum terminal current is bounded by the maximum current handling of

the switches, maximum power dissipation of the package, and maximum
applied voltage across any two of the A, B, and W terminals at a given
resistance.

2

Package power dissipation = (T

− TA)/θJA.

JMAX

) 150°C

JMAX

DD

230°C/W

Stresses above those listed under Absolute Maximum Ratings
may cause permanent damage to the device. This is a stress
rating only; functional operation of the device at these or any
other conditions above those indicated in the operational
section of this specification is not implied. Exposure to absolute
maximum rating conditions for extended periods may affect
device reliability.

ESD CAUTION

ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily accumulate on
the human body and test equipment and can discharge without detection. Although this product features
proprietary ESD protection circuitry, permanent damage may occur on devices subjected to high energy
electrostatic discharges. Therefore, proper ESD precautions are recommended to avoid performance
degradation or loss of functionality.

Rev. 0 | Page 6 of 20