3-Channel Digital Potentiometer with

Nonvolatile Memory

ADN2860

Rev. A

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: 781.329.4700

www.analog.com

Fax: 781.326.8703

© 2004 Analog Devices, Inc. All rights reserved.

FEATURES

3 channels:

Dual 512-position

Single 128-position

25 kΩ or 250 kΩ full-scale resistance

Low temperature coefficient:

Potentiometer divider 15 ppm/°C

Rheostat mode 35 ppm/

°C

Nonvolatile memory retains wiper settings

Permanent memory write protection

Linear increment/decrement

±6 dB increment/decrement

2.7 V to 5.5 V single-supply operation

±2.25 V to ±2.75 V dual-supply operation

Power-on reset time

256 bytes general-purpose user EEPROM

11 bytes RDAC user EEPROM

GBIC and SFP compliant EEPROM

APPLICATIONS

Laser diode drivers

Optical amplifiers

TIA gain setting

TEC controller temperature setpoint

FUNCTIONAL BLOCK DIAGRAM

A0

W0

B0

A1

W1

B1

A2

W2

B2

A0

W0

B0

A0

W0

B0

A1

W1

B1

A1

W1

B1

A2

W2

B2

A2

W2

B2

RDAC0

9 BITS

RDAC1

9 BITS

RDAC2

7 BITS

DATA

CONTROL

COMMAND

DECODE

LOGIC

ADDRESS

DECODE

LOGIC

DECODE

LOGIC

POWER-ON

RESET

SERIAL

INTERFACE

32 BYTES

RDAC

EEPROM

256 BYTES

USER

EEPROM

DGND

SCL

SDA

AD0

AD1

A0_EE

A1_EE

RESET

WP

Figure 1.

GENERAL DESCRIPTION

The ADN2860 provides dual 512-position and single

128-position, digitally controlled variable resistors1 (VR) in a

single 4 mm × 4 mm LFCSP package. This device performs the

same electronic adjustment function as a potentiometer,

trimmer, or variable resistor. Each VR offers a completely

programmable value of resistance between the A terminal and

the wiper, or the B terminal and the wiper. The fixed A-to-B

terminal resistance of 25 kΩ or 250 kΩ has a 1% channel-to-

channel matching tolerance and a nominal temperature

coefficient of 35 ppm/°C.

Wiper position programming, EEPROM2 reading, and EEPROM

vious default wiper position settings can be stored in memory,

and refreshed upon system power-up.

Additional features of the ADN2860 include preprogrammed

linear and logarithmic increment/decrement wiper changing.

The actual resistor tolerances are stored in EEPROM so that the

actual end-to-end resistance is known, which is valuable for

calibration in precision applications.

The ADN2860 EEPROM, channel resolution, and package size

conform to GBIC and SFP specifications. The ADN2860 is

available in a 4 mm × 4 mm, 24-lead LFCSP package. All parts

are guaranteed to operate over the extended industrial tempera-

ture range −40°C to +85°C.

potentiometer are used interchangeably.

interchangeably.