Nonvolatile Memory,
Dual 256-Position Digital Potentiometer
Data Sheet
AD5232
FEATURES
FUNCTIONAL BLOCK DIAGRAM
V
DD
Dual-channel, 256-position resolution
10 kΩ, 50 kΩ, and 100 kΩ nominal terminal resistance
Nonvolatile memory maintenance of wiper settings
Predefined linear increment/decrement instructions
Predefined 6 dB step log taper increment/decrement
instructions
AD5232
ADDR
DECODE
CS
CLK
SDI
RDAC1
REGISTER
A1
SERIAL
INTERFACE
W1
B1
SDO
EEMEM1
RDAC1
SPI-compatible serial interface
Wiper settings and EEMEM readback
3 V to 5 V single-supply operation
RDAC2
REGISTER
POWER-ON
RESET
PR
A2
2.5 V dual-supply operation
W2
WP
14 bytes of general-purpose user EEMEM
Permanent memory write protection
100-year typical data retention (TA = 55°C)
B2
EEMEM
CONTROL
EEMEM2
RDAC2
RDY
14 BYTES
USER
EEMEM
APPLICATIONS
Mechanical potentiometer replacement
Instrumentation: gain and offset adjustment
Programmable voltage-to-current conversion
Programmable filters, delays, and time constants
Programmable power supply
GND
V
SS
Figure 1.
Low resolution DAC replacement
Sensor calibration
GENERAL DESCRIPTION
The AD5232 device provides a nonvolatile, dual-channel,
digitally controlled variable resistor (VR) with 256-position
resolution. This device performs the same electronic adjustment
function as a mechanical potentiometer with enhanced resolution,
solid state reliability, and superior low temperature coefficient
performance. The versatile programming of the AD5232, per-
ormed via a microcontroller, allows multiple modes of operation
and adjustment.
All internal register contents can be read via the serial data
output (SDO). This includes the RDAC1 and RDAC2 registers,
the corresponding nonvolatile EEMEM1 and EEMEM2 registers,
and the 14 spare USER EEMEM registers that are available for
constant storage.
The basic mode of adjustment is the increment and decrement
command instructions that control the wiper position setting
register (RDACx). An internal scratch pad RDACx register can
be moved up or down one step of the nominal resistance between
Terminal A and Terminal B. This step adjustment linearly changes
the wiper to Terminal B resistance (RWB) by one position segment
of the device’s end-to-end resistance (RAB). For exponential/
logarithmic changes in wiper setting, a left/right shift command
instruction adjusts the levels in 6 dB steps, which can be useful
for audio and light alarm applications.
In the direct program mode, a predetermined setting of the RDAC
registers (RDAC1 and RDAC2) can be loaded directly from the
microcontroller. Another important mode of operation allows
the RDACx register to be refreshed with the setting previously
stored in the corresponding EEMEM register (EEMEM1 and
EEMEM2). When changes are made to the RDACx register to
establish a new wiper position, the value of the setting can be
saved into the EEMEMx register by executing an EEMEM save
operation. After the settings are saved in the EEMEMx register,
these values are automatically transferred to the RDACx register
to set the wiper position at system power-on. Such operation is
enabled by the internal preset strobe. The preset strobe can also
be accessed externally.
The AD5232 is available in a thin, 16-lead TSSOP package.
All parts are guaranteed to operate over the extended industrial
temperature range of −40°C to +85°C. An evaluation board, the
EVAL-AD5232-10EBZ, is available.
Rev. C
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