AD5231BRU10 Analog Devices Inc, AD5231BRU10 Datasheet - Page 19

• Manufacturer Part Number: AD5231BRU10
• Description: IC DGTL POT 1024POS 16-TSSOP
• Manufacturer: Analog Devices Inc

Specifications of AD5231BRU10

• Rohs Status: RoHS non-compliant
• Taps: 1024
• Resistance (ohms): 10K
• Number Of Circuits: 1
• 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: 16-TSSOP
• Resistance In Ohms: 10K
• End To End Resistance: 10kohm
• Track Taper: Logarithmic
• Resistance Tolerance: +20, -40%
• No. Of Steps: 1024
• Supply Voltage Range: 2.7V To 5.5V, ± 2.25V To ± 2.75V
• Control Interface: Serial, SPI
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

Using Additional Internal Nonvolatile EEMEM
The AD5231 contains additional user EEMEM registers for
storing any 16-bit data such as memory data for other compo-
nents, look-up tables, or system identification information.
Table 9 provides an address map of the internal storage registers
shown in the functional block diagram as EEMEM1, EEMEM2,
and 28 bytes (14 addresses × 2 bytes each) of user EEMEM.
Table 9. EEMEM Address Map
Address
0000
0001
0010
0011
…
1110
1111
1
2
3
4
RDAC STRUCTURE
The patent-pending RDAC contains multiple strings of equal
resistor segments with an array of analog switches that act as the
wiper connection. The number of positions is the resolution of
the device. The AD5231 has 1024 connection points, allowing it
to provide better than 0.1% settability resolution. Figure 43
shows an equivalent structure of the connections among the
three terminals of the RDAC. The SW
while the switches SW(0) to SW(2
depending on the resistance position decoded from the data
bits. Because the switch is not ideal, there is a 15 Ω wiper
resistance, R
and temperature. The lower the supply voltage or the higher the
temperature, the higher the resulting wiper resistance. Users
should be aware of the wiper resistance dynamics if accurate
prediction of the output resistance is needed.
RDAC data stored in EEMEM location is transferred to the RDAC register at
O1 and O2 data stored in EEMEM locations is transferred to the
power-on, or when Instruction 1, Instruction 8, or PR are executed.
Execution of Instruction 1 leaves the device in the read mode power
consumption state. After the last Instruction 1 is executed, the user should
perform a NOP, Instruction 0 to return the device to the low power idling
state.
USERx are internal nonvolatile EEMEM registers available to store 16-bit
corresponding digital register at power-on, or when Instruction 1 and
Instruction 8 are executed.
information using Instruction 3 and restore the contents using Instruction 9.
W
. Wiper resistance is a function of supply voltage
EEMEM for…
RDAC
O1 and O2
USER1
USER2
…
USER13
USER14
1, 2
4
3
N
−1) are on one at a time,
A
and SW
B
are always on,
Rev. C | Page 19 of 28
Table 10. Nominal Individual Segment Resistor (R
Device
Resolution
10-Bit
PROGRAMMING THE VARIABLE RESISTOR
Rheostat Operation
The nominal resistance of the RDAC between Terminal A and
Terminal B, R
with 1024 positions (10-bit resolution). The final digit(s) of the
part number determine the nominal resistance value, for
example, 10 kΩ = 10; 50 kΩ = 50; 100 kΩ = C.
The 10-bit data-word in the RDAC latch is decoded to select
one of the 1024 possible settings. The following discussion
describes the calculation of resistance R
10 kΩ part. For V
Terminal B for data 0x000. R
resistance, and because it is independent of the nominal
resistance. The second connection is the first tap point where
R
third connection is the next tap point representing R
19.4 Ω + 15 Ω = 34.4 Ω for data 0x002 and so on. Each LSB data
value increase moves the wiper up the resistor ladder until the
last tap point is reached at R
for a simplified diagram of the equivalent RDAC circuit. When
R
WB
WB
(1) becomes 9.7 Ω + 15 Ω = 24.7 Ω for data 0x001. The
is used, Terminal A can be left floating or tied to the wiper.
Figure 43. Equivalent RDAC Structure (Patent Pending)
AB
, is available with 10 kΩ, 50 kΩ, and 100 kΩ
R
DIGITAL
CIRCUITRY
OMITTED FOR
CLARITY
S
REGISTER
DECODER
DD
= R
WIPER
RDAC
AND
10 kΩ
Version
9.8 Ω
= 5 V, the wiper’s first connection starts at
AB
/2
N
WB
WB
R
R
R
S
S
S
(1023) = 10,005 Ω. See Figure 43
(0) is 15 Ω because of the wiper
SW(2
SW(2
SW(1)
SW(0)
SW
SW
50 kΩ
Version
48.8 Ω
N
N
A
B
–1)
–2)
WB
at different codes of a
W
A
B
100 kΩ
Version
97.6 Ω
AD5231
WB
S
)
(2) =