AD5235 Datasheet, PDF (1/10 Pages) Analog Devices – Nonvolatile Memory, Dual 1024 Position Digital Potentiometers

PRELIMINARY TECHNICAL DATA
a
Nonvolatile Memory, Dual 1024
Position Digital Potentiometers
AD5235
FEATURES
Dual, 1024 Position Resolution
25K, 250K Ohm Terminal Resistance with 50ppm/°C Tempco
Nonvolatile Memory Preset
SPI Compatible Serial Data Input with Readback Function
Increment/Decrement Commands, Push Button Command
+3 to +5V Single Supply Operation
±2.5V Dual Supply Operation
30 bytes of general purpose nonvolatile memory
APPLICATIONS
Mechanical Potentiometer Replacement
Instrumentation: Gain, Offset Adjustment
Programmable Voltage to Current Conversion
Programmable Filters, Delays, Time Constants
Line Impedance Matching
Power Supply Adjustment
DIP Switch Setting
GENERAL DESCRIPTION
The AD5235 provides a dual channel, digitally controlled variable
resistor (VR) with resolutions of 1024 positions. These devices
perform the same electronic adjustment function as a potentiometer or
variable resistor. The AD5235’s versatile programming via a Micro
Controller allows multiple modes of operation and adjustment.
In the direct program mode a predetermined setting of the RDAC
register can be loaded directly from the micro controller. Another key
mode of operation allows the RDAC register to be refreshed with the
setting previously stored in the EEMEM register. When changes are
made to the RDAC register to establish a new wiper position, the
value of the setting can be saved into the EEMEM by executing an
EEMEM save operation. Once the settings are saved in the EEMEM
register, these values will be transferred automatically to the RDAC
register to set the wiper position at system power ON. Such operation
is enabled by the internal preset strobe and the preset can also be
accessed externally.
An internal scratch pad RDAC register can be programmed by the
micro controller to set the resistance between terminals W-and-B.
Once the target value is achieved, the RDAC content register can be
placed in the non-volatile memory for automatic recall during Power
Up.
The AD5235 is available in the thin TSSOP-16 package. All parts are
guaranteed to operate over the extended industrial temperature range
of -40°C to +85°C.
FUNCTIONAL BLOCK DIAGRAMS
CS
CLK
SDI
SDO
ADDRE S S
DECO DE
SER IAL
IN P U T
R E G IS TE R
RD AC1
REGIST ER
EEMEM1
RD AC1
VDD
A1
W1
B1
PR
PWR ON
PRESET
WP
R DY
EEMEM
C ON TR OL
RD AC2
REGIST ER
EEMEM2
G ND
SPARE
EEMEM
RD AC2
A2
W2
B2
VSS
G ND
REV PrD 6 Nov 2000
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