3-Channel Digital Potentiometer with
Nonvolatile Memory
ADN2860
32 BYTES
RDAC
EEPROM
DGND
SCL
SDA
AD0
AD1
I2C
SERIAL
INTERFACE
DATA
CONTROL
A0_EE
COMMAND
DECODE
LOGIC
A1_EE
RESET
WP
POWER-ON
RESET
ADDRESS
DECODE
LOGIC
RDAC0
A0
W0
9 BITS
RDAC1
B0
A1
W1
9 BITS
RDAC2
B1
A2
W2
7 BITS
DECODE
LOGIC
B2
03615-001
VSS
RDAC0
REGISTER
256 BYTES
USER
EEPROM
VDD
RDAC1
REGISTER
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
I2C-compatible serial interface
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
100-year typical data retention at TA = 55°C
FUNCTIONAL BLOCK DIAGRAM
RDAC2
REGISTER
FEATURES
Figure 1.
APPLICATIONS
Laser diode drivers
Optical amplifiers
TIA gain setting
TEC controller temperature setpoint
GENERAL DESCRIPTION
The ADN2860 provides dual 512-position and single
128-position, digitally controlled variable resistors 1 (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-tochannel matching tolerance and a nominal temperature
coefficient of 35 ppm/°C.
Wiper position programming, EEPROM 2 reading, and EEPROM
writing are conducted via the standard 2-wire I2C 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.
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 temperature range −40°C to +85°C.
1
2
The terms programmable resistor, variable resistor, RDAC, and digital
potentiometer are used interchangeably.
The terms nonvolatile memory, EEMEM, and EEPROM are used
interchangeably.
Rev. B
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