AD5258BRMZ100 Analog Devices Inc, AD5258BRMZ100 Datasheet - Page 18

• Manufacturer Part Number: AD5258BRMZ100
• Description: IC POT DGTL I2C 100K 64P 10MSOP
• Manufacturer: Analog Devices Inc

Specifications of AD5258BRMZ100

• Memory Type: Non-Volatile
• Temperature Coefficient: 200 ppm/°C Typical
• Taps: 64
• Resistance (ohms): 100K
• Number Of Circuits: 1
• Interface: I²C, 2-Wire Serial
• Voltage - Supply: 2.7 V ~ 5.5 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 10-MSOP, Micro10™, 10-uMAX, 10-uSOP
• Resistance In Ohms: 100K
• End To End Resistance: 100kohm
• Resistance Tolerance: ± 30%
• No. Of Steps: 64
• Supply Voltage Range: 2.7V To 5.5V
• No. Of Pots: Single
• Control Interface: I2C
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: AD5258EVAL - BOARD EVAL FOR AD5258 DGTL POT
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Lead free / RoHS Compliant

AD5258
TOLERANCE READBACK MODES
Table 15. Traditional Readback of Tolerance (Individually)
S
S
Table 16.Traditional Readback of Tolerance (Consecutively)
S
Calculating R
The AD5258 features a patented R
nonvolatile memory. The tolerance is stored in the memory
during factory production and can be read by users at any time.
The knowledge of stored tolerance allows users to accurately
calculate R
mode, and open-loop applications where knowledge of absolute
resistance is critical.
The stored tolerance resides in the read-only memory and is
expressed as a percentage. The tolerance is stored in two memory
location bytes in sign magnitude binary form (see Figure 40).
The two EEPROM address bytes are 11110 (sign + integer) and
11111 (decimal number). The two bytes can be individually
accessed with two separate commands (see Table 15). Alternatively,
readback of the first byte followed by the second byte can be
done in one command (see Table 16). In the latter case, the
memory pointer will automatically increment from the first to
7-Bit Device Address
7-Bit Device Address
7-Bit Device Address
Slave Address Byte
Slave Address Byte
Slave Address Byte
(See Table 5)
(See Table 5)
(See Table 5)
AB
. This feature is valuable for precision, rheostat
AB
Tolerance Stored in Read-Only Memory
A
SIGN
SIGN
D7
0 SA 0 0 1 1 1 1 1 0 SA S
0 SA 0 0 1 1 1 1 1 0 SA S
0 SA 0 0 1 1 1 1 1 1 SA S
D6
2
Instruction Byte
Instruction Byte
Instruction Byte
6
Figure 40. Format of Stored Tolerance in Sign Magnitude Format with Bit Position Descriptions.
7 BITS FOR INTEGER NUMBER
D5
2
AB
5
tolerance storage in the
D4
2
4
Repeat start
Repeat start
Repeat start
D3
2
3
↑
↑
↑
D2
2
(Unit is Percent. Only Data Bytes are Shown.)
7-Bit Device Address
7-Bit Device Address
2
7-Bit Device Address
Slave Address Byte
Slave Address Byte
Slave Address Byte
D1
(See Table 5)
(See Table 5)
2
(See Table 5)
1
D0
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2
0
A
1 SA D7 D6 D5 D4 D3 D2 D1 D0 NA P
1 SA D7 D6 D5 D4 D3 D2 D1 D0 NA P
1 SA D7 D6 D5 D4 D3 D2 D1 D0 MA D7 D6 D5 D4 D3 D2 D1 D0 NA P
the second EEPROM location (increments from 11110 to
11111) if read consecutively.
In the first memory location, the MSB is designated for the sign
(0 = + and 1= –) and the seven LSBs are designated for the integer
portion of the tolerance. In the second memory location, all eight
data bits are designated for the decimal portion of tolerance. Note
that the decimal portion has a limited accuracy of only 0.1%. For
example, if the rated R
Address 11110 shows 0001 1100, and Address 11111 shows
0000 1111, then the tolerance can be calculated as
MSB: 0 = +
Next 7 MSB: 001 1100 = 28
8 LSB: 0000 1111 = 15 × 2
Tolerance = +28.06%
Rounded Tolerance = +28.1% and therefore,
R
2
D7
–1
AB_ACTUAL
D6
2
–2
Sign + Integer Byte
Sign + Integer Byte
8 BITS FOR DECIMAL NUMBER
= 12.810 kΩ
Decimal Byte
2
D5
–3
2
D4
–4
2
D3
–5
AB
= 10 kΩ and the data readback from
–8
2
D2
–6
= 0.06
2
D1
–7
2
D0
–8
Decimal Byte
A