Analog Devices AD5171 b Datasheet

64-

Position

OTP Digital Potentiometer

FEATURES

64-position
One-time programmable (OTP)

setting—low cost alternative over EEMEM
Unlimited adjustments prior to OTP activation
5 kΩ, 10 kΩ, 50 kΩ, 100 kΩ end-to-end resistance

o

Low tempco 5 ppm/

C in potentiometer mode
Low tempco 35 ppm/°C in rheostat mode
Compact standard SOT-23-8 package
Low power, I
Fast settling time, t

2

C®-compatible digital interface

I

= 10 µA max

DD

= 5 µs typ in power-up

s

Computer software replaces µC in

factory programming applications

Full read/write of wiper register

2

C device address pin

Extra I
Low operating voltage, 2.7 V to 5.5 V
OTP validation check function
Automotive temperature range −40°C to +125°C

APPLICATIONS

System calibrations
Electronics level settings
Mechanical Trimmers® and potentiometer replacements
Automotive electronics adjustments
Gain control and offset adjustments
Transducer circuit adjustments
Programmable filters up to 1.5 MHz BW

GENERAL DESCRIPTION

The AD5171 is a 64-position, one-time programmable (OTP)
digital potentiometer
the memory retention of the resistance setting function. OTP is
a cost-effective alternative over the EEMEM approach for users
who do not need to reprogram new memory settings in the
digital potentiometer. This device performs the same electronic
adjustment function as most mechanical trimmers and variable
resistors. The AD5171 is programmed using a 2-wire I
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, freezing the wiper position at a
given setting (analogous to placing epoxy on a mechanical
trimmer). When this permanent setting is achieved, the value
does not change regardless of supply variations or environmental

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.

2

that uses fuse link technology to achieve

1

set-and-forget resistance

3

2

C-

AD5171

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 the AD5171 in factories, Analog
Devices offers device programming software that operates
across Windows® 95 to XP platforms, including Windows NT.
This software application effectively replaces the need for exter-

2

C controllers or host processors and therefore significantly

nal I
reduces users’ development time.

An AD5171 evaluation kit includes the software, connector,
and cable that can be converted for 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

SDA

AD0

V

DD

GND

1

OTP allows unlimited adjustments before permanent setting.

2

The terms digital potentiometer and RDAC are used interchangeably.

3

Applies to 5 kΩ parts only.

One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: [phone]
Fax: [phone] © 2005 Analog Devices, Inc. All rights reserved.

I2C INTERFACE

AND

CONTROL LOGIC

WIPER

REGISTER

FUSE

LINK

Figure 1.

Functional Block Diagram

1

W

2

AD5171

V

DD

TOP VIEW

3

GND

(Not to Scale)

4

SCL

Figure 2. Pin Configuration

www.analog.com

8

7

6

5

AD5171

A
B
AD0
SDA

03437-0-002

A

W

B

03437-0-001

AD5171

TABLE OF CONTENTS

Electrical Characteristics ................................................................. 3

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

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

Pin Configuration and Function Descriptions............................. 7

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

Theory of Operation ...................................................................... 12

One-Time Programming (OTP).............................................. 12

Power Supply Considerations................................................... 12

ESD Protection ...........................................................................13

Terminal Voltage Operating Range.......................................... 13

Power-Up/Power-Down Sequences......................................... 14

Variable Resistance and Voltage for Rheostat Mode .............14

Variable Resistance and Voltage for Potentiometer Mode.... 15

Controlling the AD5171................................................................ 16

Software Programming.............................................................. 16

2

I

C Controller Programming.................................................... 17

2

I

C-Compatible 2-Wire Serial Bus ........................................... 18

Controlling Two Devices on One Bus..................................... 18

Applications..................................................................................... 19

DAC.............................................................................................. 19

Gain Control Compensation.................................................... 19

Programmable Voltage Source with Boosted Output ........... 19

Level Shifting for Different Voltage Operation...................... 19

Resistance Scaling ...................................................................... 19

Resolution Enhancement.......................................................... 20

RDAC Circuit Simulation Model............................................. 20

Evaluation Board............................................................................ 21

Outline Dimensions....................................................................... 22

Ordering Guide .......................................................................... 22

REVISION HISTORY

1/05—Rev. A to Rev. B

Change to Features........................................................................... 1

Changes to Electrical Characteristics ............................................ 3

Change to Table 3 ............................................................................. 6

Changes to Power Supply Considerations Section..................... 13

Changes to Level Shifting for Different Voltage Operation

Section....................................................................................... 19

Added Note to Ordering Guide.................................................... 22

11/04—Rev. 0 to Rev. A

Changes to Specifications................................................................ 3

Changes to Table 3............................................................................ 7

Changes to One-Time Programming Section ............................ 11

Changes to Power Supply Consideration Section ...................... 11

Changes to Figure 26 and Figure 27............................................. 12

1/04—Revision 0: Initial Version

Rev. B | Page 2 of 24

AD5171

ELECTRICAL CHARACTERISTICS

5 kΩ, 10 kΩ, 50 kΩ, and 100 kΩ versions; VDD = 3 V to 5 V ± 10%, VA = VDD, VB = 0 V, −40°C < TA < +125°C, unless otherwise noted.

Table 1.

Parameter Symbol Conditions Min Typ1 Max Unit

DC CHARACTERISTICS RHEOSTAT MODE

Resistor Differential Nonlinearity2 R-DNL

R
Resistor Integral Nonlinearity2 R-INL

R

, VA = no connect,

R

WB

= 10 kΩ, 50 kΩ, and 100 kΩ

R

AB

, VA = no connect, RAB = 5 kΩ –1 ±0.25 +1 LSB

WB

, VA = no connect,

R

WB

= 10 kΩ, 50 kΩ, and 100 kΩ

R

AB

, VA = no connect, RAB = 5 kΩ –1.5 ±0.5 +1.5 LSB

WB

Nominal Resistor Tolerance3 ∆RAB/RAB –30 +30 %
Resistance Temperature Coefficient (∆RAB/RAB)/∆T 35 ppm/°C
Wiper Resistance RW V

DC CHARACTERISTICS POTENTIOMETER DIVIDER

= 5 V 60 115 Ω

DD

MODE (Specifications apply to all RDACs)

Resolution N 6 Bits
Differential Nonlinearity4 DNL –0.5 ±0.1 +0.5 LSB
Integral Nonlinearity4 INL –1 ±0.2 +1 LSB
Voltage Divider Temperature Coefficient (∆VW/VW)/∆T Code = 0x20 5 ppm/°C
Full-Scale Error V

WFSE

Code = 0x3F, R

= 10 kΩ,

AB

50 kΩ, and 100 kΩ
Full-Scale Error V
Zero-Scale Error V

Code = 0x3F, RAB = 5 kΩ –1.5 0 LSB

WFSE

WZSE

Code = 0x00, R

=10 kΩ,

AB

50 kΩ, and 100 kΩ

Code = 0x00, RAB = 5 kΩ 0 2 LSB
RESISTOR TERMINALS

Voltage Range5 V
Capacitance7 A, B C

With respect to GND VDD V

A, B, W

A, B

f = 1 MHz, measured to GND,

Code = 0x20
Capacitance7 W CW

f = 1 MHz, measured to GND,

Code = 0x20
Common-Mode Leakage ICM V

= VB = VDD/2 1 nA

A

DIGITAL INPUTS

Input Logic High (SDA and SCL)6 VIH 0.7 VDD
Input Logic Low (SDA and SCL)6 VIL –0.5 0.3 VDD V
Input Logic High (AD0) VIH V
Input Logic Low (AD0) VIL V
Input Current IIL V
Input Capacitance7 C

3 pF

IL

= 3 V 3.0 VDD V

DD

= 3 V 0 1.0 V

DD

= 0 V or 5 V ±1 µA

IN

DIGITAL OUTPUTS

Output Logic Low (SDA) VOL I
Three-State Leakage Current (SDA) IOZ V
Output Capacitance7 C

3 pF

OZ

= 6 mA 0.4 V

OL

= 0 V or 5 V ±1 µA

IN

POWER SUPPLIES

Power Supply Range VDD 2.7 5.5 V
OTP Power Supply
Supply Current IDD V
OTP Supply Current
Power Dissipation10 P

6, 8

V

6, 9

I

DD_OTP

V

DD_OTP

V

DISS

TA = 25°C 5.25 5.5 V

= 5 V or VIL = 0 V 4 10 µA

IH

= 5.5 V, TA = 25°C 100 mA

DD_OTP

= 5 V or VIL = 0 V, VDD = 5 V 0.02 0.04 mW

IH

Power Supply Sensitivity PSSR −0.025 +0.001 +0.025 %/%

–0.5 ±0.1 +0.5 LSB

–1.5 ±0.35 +1.5 LSB

–1 −0.5 0 LSB

0 0.5 1 LSB

25 pF

55 pF

VDD + 0.5

V

Rev. B | Page 3 of 24

AD5171

Parameter Symbol Conditions Min Typ1 Max Unit

DYNAMIC CHARACTERISTICS

Bandwidth –3 dB BW_5k RAB = 5 kΩ, Code = 0x20 1500 kHz
BW_10k RAB = 10 kΩ, Code = 0x20 600 kHz
BW_50k RAB = 50 kΩ, Code = 0x20 110 kHz
BW_100k RAB = 100 kΩ, Code = 0x20 60 kHz

Total Harmonic Distortion THD

Adjustment Settling Time tS1

OTP Settling Time13 t

Power-Up Settling Time—After Fuses Blown tS2

Resistor Noise Voltage e

INTERFACE TIMING CHARACTERISTICS
(Apply to all parts

7, 12

)
SCL Clock Frequency f
t

Bus Free Time between Start and Stop t1 1.3 µs

BUF

t

Hold Time (Repeated Start) t2

HD;STA

t

Low Period of SCL Clock t3 1.3 µs

LOW

t

High Period of SCL Clock t4 0.6 50 µs

HIGH

t

Setup Time for Start Condition t5 0.6 µs

SU;STA

t

Data Hold Time t6 0.9 µs

HD;DAT

t

Data Setup Time t7 0.1 µs

SU;DAT

tF Fall Time of Both SDA and SCL Signals t8 0.3 µs
tR Rise Time of Both SDA and SCL Signals t9 0.3 µs
t

Setup Time for Stop Condition t10 0.6 µs

SU;STO

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 DAC. 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

The minimum voltage requirement on the VIH is 0.7 V × VDD. For example, VIH min = 3.5 V when VDD = 5 V. It is typical for the SCL and SDA resistors to be pulled up to

V

. However, care must be taken to ensure that the minimum VIH is met when the SCL and SDA are driven directly from a low voltage logic controller without pull-up

DD

resistors.

7

Guaranteed by design; not subject to production test.

8

Different from operating power supply; power supply for OTP is used one time only.

9

Different from operating current; supply current for OTP lasts approximately 400 ms for one-time need only.

10

P

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

DISS

11

Bandwidth, noise, and settling time depend on the terminal resistance value chosen. The lowest R value results in the fastest settling time and highest

bandwidth. The highest R value results in the minimum overall power consumption.

12

All dynamic characteristics use VDD = 5 V.

13

Different from the settling time after the fuse is blown. The OTP settling time occurs only once.

7, 11, 12

0.05 %

5 µs

400 ms

5 µs

8 nV/√Hz

S_OTP

N_WB

= 1 V rms, RAB = 10 kΩ,

V

A

= 0 V DC, f = 1 kHz

V

B

= 5 V ± 1 LSB error band,

V

A

V

= 0 V, measured at VW

B

= 5 V ± 1 LSB error band,

V

A

= 0 V, measured at VW

V

B

= 5 V ±1 LSB error band,

V

A

= 0 V, measured at VW

V

B

= 5 kΩ, f = 1 kHz,

R

AB

Code = 0x20

= 10 kΩ, f = 1 kHz,

R

AB

12 nV/√Hz

Code = 0x20

400 kHz

SCL

After this period, the first clock

0.6 µs

pulse is generated.

Rev. B | Page 4 of 24

AD5171

S

t

6

5

t

7

t

10

03437-0-024

PPS

SCL

t

8

t

2

t

3

t

8

DA

t

1

t

t

9

t

t

4

9

Figure 3. Interface Timing Diagram

Rev. B | Page 5 of 24

AD5171

ABSOLUTE MAXIMUM RATINGS

Table 2.

Parameter Rating

VDD to GND –0.3, +7 V
VA, VB, VW to GND GND, VDD
Maximum Current
IWB, IWA Pulsed ±20 mA
IWB Continuous (RWB ≤ 1 kΩ, A open)
IWA Continuous (R

≤ 1 kΩ, B open)1 ±5 mA

WA

1

±5 mA

Digital Inputs and Output Voltage to GND 0 V, VDD

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.

Operating Temperature Range –40°C to +125°C
Maximum Junction Temperature (TJ max) 150°C
Storage Temperature –65°C to +150°C
Lead Temperature (Soldering, 10 sec) 300°C
Vapor Phase (60 sec) 215°C
Infrared (15 sec) 220°C
Thermal Resistance2 θJA 230°C/W

1

Maximum terminal current is bounded by the maximum applied voltage

across any two of the A, B, and W terminals at a given resistance; the
maximum current handling of the switches, and the maximum power
dissipation of the package. V

2

Package power dissipation = (TJ max – TA)/θJA.

DD

= 5 V.

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. B | Page 6 of 24

AD5171

PIN CONFIGURATION AND FUNCTION DESCRIPTIONS

8

A

7

B

6

AD0

5

SDA

03437-0-003

V

DD

GND

SCL

W

1

2

AD5171

TOP VIEW

3

(Not to Scale)

4

Figure 4. Pin Configuration

Table 3. Pin Function Descriptions

Pin No. Mnemonic Description

1 W Wiper Terminal W. GND ≤ VW ≤ VDD.
2 VDD

Positive Power Supply. Specified for operation from 2.7 V to 5.5 V. For OTP programming, V

minimum of 5.25 V and have a100 mA driving capability.
3 GND Common Ground.
4 SCL

5 SDA

Serial Clock Input. Requires a pull-up resistor. If it is driven direct from a logic controller without the pull-up

resistor, ensure that V

min is 0.7 V × VDD.

IH

Serial Data Input/Output. Requires a pull-up resistor. If it is driven direct from a logic controller without a pull-up

resistor, ensure that V

min is 0.7 V × VDD.

IH

6 AD0 I2C Device Address Bit. Allows a maximum of two AD5171s to be addressed.
7 B Resistor Terminal B. GND ≤ VB ≤ VDD.
8 A Resistor Terminal A. GND ≤ VA ≤ VDD.

needs to be a

DD

Rev. B | Page 7 of 24

AD5171

TYPICAL PERFORMANCE CHARACTERISTICS

0.10
VDD = 5V

0.08

0.06

0.04

0.02

0

–0.02

–0.04

RHEOSTAT MODE INL (LSB)

–0.06

–0.08

–0.10

–40°C

+25°C

32248160 40485664

CODE (DECIMAL)

Figure 5. R-INL vs. Code vs. Temperature

+125°C

03437-0-004

–0.02

–0.04

–0.06

POTENTIOMETER MODE DNL (LSB)

–0.08

–0.10

0.10

0.08

0.06

0.04

0.02

0

VDD = 5V

–40°C

32248160 40485664

CODE (DECIMAL)

Figure 8. DNL vs. Code vs. Temperature

+25°C

+125°C

03437-0-007

–0.02

–0.04

RHEOSTAT MODE DNL (LSB)

–0.06

–0.08

–0.10

–0.02

–0.04

–0.06

POTENTIOMETER MODE INL (LSB)

–0.08

–0.10

0.10

0.08

0.06

0.04

0.02

0.10

0.08

0.06

0.04

0.02

0

0

VDD = 5V

+25°C

–40°C

32248160 40485664

CODE (DECIMAL)

Figure 6. R-DNL vs. Code vs. Temperature

VDD = 5V

+25°C

–40°C

32248160 40485664

CODE (DECIMAL)

Figure 7. INL vs. Code vs. Temperature

+125°C

+125°C

03437-0-005

03437-0-006

0

–0.1

–0.2

–0.3

–0.4

FSE (LSB)

–0.5

–0.6

–0.7

–40 –20 0 20 40 60 80 100 120 140

VDD = 5V

VDD = 3V

TEMPERATURE (°C)

Figure 9. Full-Scale Error

0.6

0.5

0.4

0.3

ZSE (LSB)

0.2

0.1

0

–40 –20 0 20 40 60 80 100 120 140

VDD = 3V

VDD = 5V

TEMPERATURE (°C)

Figure 10. Zero-Scale Error

03437-0-008

03437-0-009

Rev. B | Page 8 of 24