AD5232BRU50-REEL7 Analog Devices Inc, AD5232BRU50-REEL7 Datasheet - Page 14
Manufacturer Part Number
IC DGTL POT DUAL 256POS 16-TSSOP
Analog Devices Inc
Specifications of AD5232BRU50-REEL7
Number Of Circuits
600 ppm/°C Typical
4-Wire SPI Serial
Voltage - Supply
2.7 V ~ 5.5 V, ±2.25 V ~ 2.75 V
-40°C ~ 85°C
Package / Case
Resistance In Ohms
Number Of Elements
# Of Taps
Power Supply Requirement
Single Supply Voltage (typ)
Dual Supply Voltage (typ)
Single Supply Voltage (min)
Single Supply Voltage (max)
Dual Supply Voltage (min)
Dual Supply Voltage (max)
Operating Temp Range
-40C to 85C
Operating Temperature Classification
For Use With
EVAL-AD5232-10EBZ - BOARD EVALUATION FOR AD5232-10
Lead Free Status / RoHS Status
THEORY OF OPERATION
The AD5232 digital potentiometer is designed to operate as a
true variable resistor replacement device for analog signals that
remain within the terminal voltage range of V
The basic voltage range is limited to a |V
digital potentiometer wiper position is determined by the RDACx
register contents. The RDACx register acts as a scratch pad register,
allowing as many value changes as necessary to place the poten-
tiometer wiper in the correct position. The scratch pad register
can be programmed with any position value using the standard
SPI serial interface mode by loading the complete representative
data-word. When a desirable position is found, this value can be
saved into a corresponding EEMEMx register. Thereafter, the wiper
position is always set at that position for any future on-off-on
power supply sequence. The EEMEM save process takes approx-
imately 25 ms. During this time, the shift register is locked,
preventing any changes from taking place. The RDY pin indicates
the completion of this EEMEM save.
SCRATCH PAD AND EEMEM PROGRAMMING
The scratch pad register (RDACx register) directly controls the
position of the digital potentiometer wiper. When the scratch
pad register is loaded with all 0s, the wiper is connected to
Terminal B of the variable resistor. When the scratch pad register
is loaded with midscale code (1/2 of full-scale position), the wiper
is connected to the middle of the variable resistor. When the
scratch pad is loaded with full-scale code, which is all 1s, the
wiper connects to Terminal A. Because the scratch pad register
is a standard logic register, there is no restriction on the number
of changes allowed. The EEMEMx registers have a program
erase/write cycle limitation that is described in the Flash/EEMEM
The basic mode of setting the variable resistor wiper position
(by programming the scratch pad register) is accomplished by
loading the serial data input register with Command Instruc-
tion 11, which includes the desired wiper position data. When
the desired wiper position is found, the user loads the serial
data input register with Command Instruction 2, which copies
the desired wiper position data into the corresponding non-
volatile EEMEMx register. After 25 ms, the wiper position is
permanently stored in the corresponding nonvolatile EEMEM
location. Table 6 provides an application programming example
listing the sequence of serial data input (SDI) words and the
corresponding serial data output appearing at the serial data
output (SDO) pin in hexadecimal format.
At system power-on, the scratch pad register is refreshed with
the last value saved in the EEMEMx register. The factory preset
EEMEM value is midscale. The scratch pad (wiper) register can
be refreshed with the current contents of the nonvolatile EEMEMx
register under hardware control by pulsing the PR pin.
| < 5.5 V. The
Rev. A | Page 14 of 24
The application programming example shown in Table 6 lists
two digital potentiometers set to independent data values. The
wiper positions are then saved in the corresponding nonvolatile
Table 6. Application Programming Example
Note that the PR pulse first sets the wiper at midscale when it is
brought to Logic 0. Then, on the positive transition to logic high,
it reloads the DAC wiper register with the contents of EEMEMx.
Many additional advanced programming commands are avail-
able to simplify the variable resistor adjustment process.
For example, the wiper position can be changed, one step at
a time, by using the software controlled increment/decrement
command instructions. The wiper position can be also be changed,
6 dB at a time, by using the shift left/right command instructions.
After an increment, decrement, or shift command instruction is
loaded into the shift register, subsequent CS strobes repeat this
command instruction. This is useful for push-button control appli-
cations (see the
is available for daisy chaining and for readout of the internal
register contents. The serial input data register uses a 16-bit
The write protect ( WP ) pin disables any changes of the scratch
pad register contents, regardless of the software commands,
except that the EEMEM setting can be refreshed using Instruction
Command 8 and PR . Therefore, the WP pin provides a hardware
EEMEM protection feature. Execute an NOP command (Com-
mand Instruction 0) before returning WP to logic high.
DIGITAL INPUT/OUTPUT CONFIGURATION
All digital inputs are ESD protected, high input impedance that
can be driven directly from most digital sources. The PR and WP
pins, which are active at logic low, must be biased to V
are not being used. No internal pull-up resistors are present on
any digital input pins.
The SDO and RDY pins are open-drain, digital outputs when pull-
up resistors are needed, but only if these functions are in use.
A resistor value in the range of 1 kΩ to 10 kΩ optimizes the power
and switching speed trade-off.
X = don’t care.
Advanced Control Modes
Loads 0x40 data into the RDAC1 register;
Wiper W1 moves to 1/4 full-scale position.
Saves a copy of the RDAC1 register contents
into the corresponding EEMEM1 register.
Loads 0x80 data into the RDAC2 register;
Wiper W2 moves to 1/2 full-scale position.
Saves a copy of the RDAC2 register contents
into the corresponding EEMEM2 register.
section). The SDO pin