AD5233BRUZ50-R7 Analog Devices Inc, AD5233BRUZ50-R7 Datasheet - Page 15

• Manufacturer Part Number: AD5233BRUZ50-R7
• Description: IC DGTL POT QUAD 64POS 24-TSSOP
• Manufacturer: Analog Devices Inc

Specifications of AD5233BRUZ50-R7

• Taps: 64
• Resistance (ohms): 50K
• Number Of Circuits: 4
• Temperature Coefficient: 600 ppm/°C Typical
• Memory Type: Non-Volatile
• Interface: 4-Wire SPI Serial
• Voltage - Supply: 2.7 V ~ 5.5 V, ±2.25 V ~ 2.75 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 24-TSSOP
• Resistance In Ohms: 50K
• Number Of Elements: 4
• # Of Taps: 64
• Resistance (max): 50KOhm
• Power Supply Requirement: Single/Dual
• Interface Type: Serial (4-Wire/SPI)
• Single Supply Voltage (typ): 3/5V
• Dual Supply Voltage (typ): ±2.5V
• Single Supply Voltage (min): 2.7V
• Single Supply Voltage (max): 5.5V
• Dual Supply Voltage (min): ±2.25V
• Dual Supply Voltage (max): ±2.75V
• Operating Temp Range: -40C to 85C
• Operating Temperature Classification: Industrial
• Mounting: Surface Mount
• Pin Count: 24
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

THEORY OF OPERATION
The AD5233 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 V
digital potentiometer wiper position is determined by the
RDAC register contents.
The RDAC register acts as a scratchpad register, allowing as
many value changes as necessary to place the potentiometer
wiper in the correct position. The scratchpad register can be
programmed with any position value using the standard SPI
serial interface mode by loading the complete representative
data-word. Once a desirable position is found, this value can be
stored in an EEMEM register. Thereafter, the wiper position is
always restored to that position for subsequent power-up.
The EEMEM data storing process takes approximately 25 ms;
during this time, the shift register is locked, preventing any
changes from taking place. The RDY pin pulses low to indicate
the completion of this EEMEM storage.
The following instructions facilitate the user’s programming
needs (see Table 7 for details):
0 = Do nothing.
1 = Restore EEMEM contents to RDAC.
2 = Store RDAC setting to EEMEM.
3 = Store RDAC setting or user data to EEMEM.
4 = Decrement 6 dB.
5 = Decrement all 6 dB.
6 = Decrement one step.
7 = Decrement all one step.
8 = Reset EEMEM contents to RDACs.
9 = Read EEMEM contents from SDO.
10 = Read RDAC wiper setting from SDO.
11 = Write data to RDAC.
12 = Increment 6 dB.
13 = Increment all 6 dB.
14 = Increment one step.
15 = Increment all one step.
DD
− V
SS
SS
< 5.5 V. The
< V
TERM
< V
DD
Rev. B | Page 15 of 32
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SCRATCHPAD AND EEMEM PROGRAMMING
The scratchpad RDAC register directly controls the position of
the digital potentiometer wiper. For example, when the scratchpad
register is loaded with all 0, the wiper is connected to Terminal
B of the variable resistor. The scratchpad register is a standard
logic register with no restriction on the number of changes
allowed, but the EEMEM registers have a program erase/write
cycle limitation (see the Flash/EEMEM Reliability section).
BASIC OPERATION
The basic mode of setting the variable resistor wiper position
(programming the scratchpad register) is accomplished by
loading the serial data input register with Instruction 11,
Address A1, Address A0, and the desired wiper position
data. When the proper wiper position is determined, the
user can load the serial data input register with Instruction 2,
which stores the wiper position data in the EEMEM register.
After 25 ms, the wiper position is permanently stored in the
nonvolatile memory location. Table 5 provides a programming
example listing the sequence of serial data input (SDI) words
with the serial data output appearing at the SDO pin in
hexadecimal format.
Table 5. Set and Store RDAC Data to EEMEM Register
SDI
0xB010
0x20XX
At system power-on, the scratchpad register is automatically
refreshed with the value previously stored in the EEMEM
register. The factory-preset EEMEM value is midscale, but it
can be changed by the user thereafter.
During operation, the scratchpad (RDAC) register can be
refreshed with the EEMEM register data with Instruction 1 or
Instruction 8. The RDAC register can also be refreshed with the
EEMEM register data under hardware control by pulsing the PR
pin. The PR pulse first sets the wiper at midscale when brought
to Logic 0, and then, on the positive transition to Logic 1, it
reloads the RDAC wiper register with the contents of EEMEM.
Many additional advanced programming commands are
available to simplify the variable resistor adjustment process
(see Table 7). For example, the wiper position can be changed
one step at a time using the increment/decrement instruction or
by 6 dB with the shift left/right instruction. Once an increment,
decrement, or shift instruction has been loaded into the shift
register, subsequent CS strobes can repeat this command.
A serial data output SDO pin is available for daisy-chaining and
for readout of the internal register contents.
SDO
0xXXXX
0xB010
Action
Writes Data 0x10 to the RDAC1 register,
Wiper W1 moves to ¼ full-scale position.
Stores RDAC1 register content into the
EEMEM1 register.
AD5233