a
3-Channel Digital
Potentiometer with
Nonvolatile Memory
Preliminary Technical Data ADN2860


REV. PrD Page 1 of 15
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FEATURES
3 Channels: Dual 512-Position
Single 128-Position
25KΩ or 150KΩ Full-Scale Resistance
Low Temperature Coefficient: 35ppm/°C
Nonvolatile Memory Retains Wiper Settings
Permanent Memory Write-Protection
Linear Increment/Decrement
Log taper Increment/Decrement
I
2
C Compatible Serial Interface
3V to 5V Single Supply Operation
±2.5V Dual Supply Operation
256 Bytes General Purpose User EEPROM
11 Bytes RDAC user EEPROM
GBIC and SFP Compliant EEPROM
100-year Typical Data Retention at TA=55°C


APPLICATIONS
Laser Diode Drivers
Optical Amplifiers
TIA Gain Setting
TEC Controller Temperature Set Points
FUNCTIONAL BLOCK DIAGRAM
DATA
CONTROL
256 bytes
USER EEPROM
32 bytes
RDAC EEPROM
COMMAND DECODE LOGIC
ADDRESS DECODE LOGIC
CONTROL LOGIC
RDAC0
REGISTER
A0
W0
B0
RDAC0
9 bit
RDAC1
REGISTER
A1
W1
B1
RDAC1
9 bit
RDAC2
REGISTER
A2
W2
B2
RDAC2
7 bit
SCL
SDA
I2C
SERIAL
INTERFACE
A0_R
A1_R
A0_E
A1_E
8
VDD
VSS
GND
POWER
ON RESET
PRB
WPB









GENERAL DESCRIPTION
The ADN2860 provides dual 512-position and a single 128-
position digitally controlled variable resistor
1
(VR) in a single
4x4mm 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 25kΩ or 250kΩ has a 1% channel-to-channel matching
tolerance and a nominal temperature coefficient of 35ppm/°C.

Wiper position programming, EEPROM reading, and EEPROM
writing is conducted via the standard 2-wire I
2
C interface.
Previous/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, and
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
conforms to GBIC and SFP specifications. The ADN2860 is
available in a 4x4mm 24-lead LFCSP package. All parts are
guaranteed to operate over the extended industrial temperature
range of –40C to 85°C.

1. The term nonvolatile memory, EEMEM, and EEPROM are used
interchangeably
2. The term programmable resistor, variable resistor, RDAC, and digital
potentiometer are used interchangeably.