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参数资料
| 型号： | AD5258BRMZ1-R71 |
| 厂商： | Analog Devices, Inc. |
| 元件分类： | 数字电位计 |
| 英文描述： | Nonvolatile, I2C-Compatible 64-Position, Digital Potentiometer |
| 中文描述： | 非易失，I2C兼容的64工位，数字电位器 |
| 文件页数： | 14/24页 |
| 文件大小： | 1299K |
| 代理商： | AD5258BRMZ1-R71 |
AD5258
THEORY OF OPERATION
The AD5258 is a 64-position digitally controlled variable
resistor (VR) device. The wiper’s default value, prior to
programming the EEPROM, is midscale.
Rev. 0 | Page 14 of 24
PROGRAMMING THE VARIABLE RESISTOR
Rheostat Operation
The nominal resistance (R
AB
) of the RDAC between Terminal A
and Terminal B is available in 1 k, 10 k, 50 k, and 100 k.
The nominal resistance of the VR has 64 contact points
accessed by the wiper terminal. The 6-bit data in the RDAC
latch is decoded to select one of 64 possible settings.
A
W
B
A
W
B
A
W
B
0
Figure 37. Rheostat Mode Configuration
The general equation determining the digitally programmed
output resistance between Wiper W and Terminal B is
( )
D
W
AB
WB
R
R
D
64
R
×
+
×
=
2
(1)
where:
D
is the decimal equivalent of the binary code loaded in the
6-bit RDAC register.
R
AB
is the end-to-end resistance.
R
W
is the wiper resistance contributed by the on resistance of
each internal switch.
D5
D4
D3
D2
D1
D0
RDAC
LATCH
AND
DECODER
R
S
R
S
R
S
R
S
A
W
B
0
Figure 38. AD5258 Equivalent RDAC Circuit
Note that in the zero-scale condition, there is a relatively low
value finite wiper resistance. Care should be taken to limit the
current flow between Wiper W and Terminal B in this state to a
maximum pulse current of no more than 20 mA. Otherwise,
degradation or destruction of the internal switch contact can
occur.
Similar to the mechanical potentiometer, the resistance of the
RDAC between Wiper W and Terminal A produces a digitally
controlled complementary resistance, R
WA
. The resistance value
setting for R
WA
starts at a maximum value of resistance and
decreases as the data loaded in the latch increases in value. The
general equation for this operation is
W
AB
WA
R
R
D
D
R
×
+
×
=
2
64
64
)
(
(2)
Typical device-to-device matching is process lot dependent and
may vary by up to ±30%. For this reason, resistance tolerance is
stored in the EEPROM such that the user will know the actual
R
AB
within 0.1%.
PROGRAMMING THE POTENTIOMETER DIVIDER
Voltage Output Operation
The digital potentiometer easily generates a voltage divider at
Wiper W-to-Terminal B and Wiper W-to-Terminal A propor-
tional to the input voltage at Terminal A to Terminal B. Unlike
the polarity of V
DD
to GND, which must be positive, voltage
across Terminal A to Terminal B, Wiper W to Terminal A, and
Wiper W to Terminal B can be at either polarity.
A
V
I
W
B
V
O
0
Figure 39. Potentiometer Mode Configuration
If ignoring the effect of the wiper resistance for approximation,
connecting the A terminal to 5 V and the B terminal to ground
produces an output voltage at Wiper W-to-Terminal B starting
at 0 V up to 1 LSB less than 5 V. The general equation defining
the output voltage at V
W
with respect to ground for any valid
input voltage applied to Terminal A and Terminal B is
B
A
W
V
D
V
D
64
D
V
64
64
)
(
+
=
(3)
A more accurate calculation, which includes the effect of wiper
resistance, V
W
, is
B
AB
WA
R
A
AB
WB
R
W
V
D
R
V
D
R
D
V
)
(
)
(
)
(
+
=
(4)
Operation of the digital potentiometer in the divider mode
results in a more accurate operation over temperature. Unlike
the rheostat mode, the output voltage is dependent mainly on
the ratio of the Internal Resistors, R
WA
and R
WB
, and not the
absolute values.
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相关代理商/技术参数 |
参数描述 |
|---|---|
| AD5258BRMZ1-RL7 | 制造商:AD 制造商全称:Analog Devices 功能描述:Nonvolatile, I2C-Compatible 64-Position, Digital Potentiometer |
| AD5258BRMZ50 | 功能描述:IC POT DGTL I2C 50K 64P 10MSOP RoHS:是 类别:集成电路 (IC) >> 数据采集 - 数字电位器 系列:- 标准包装:3,300 系列:WiperLock™ 接片:257 电阻（欧姆）:100k 电路数:1 温度系数:标准值 150 ppm/°C 存储器类型:易失 接口:3 线 SPI（芯片选择） 电源电压:1.8 V ~ 5.5 V 工作温度:-40°C ~ 125°C 安装类型:表面贴装 封装/外壳:8-VDFN 裸露焊盘 供应商设备封装:8-DFN-EP（3x3） 包装:带卷 (TR) |
| AD5258BRMZ501 | 制造商:AD 制造商全称:Analog Devices 功能描述:Nonvolatile, I2C-Compatible 64-Position, Digital Potentiometer |
| AD5258BRMZ50-R7 | 功能描述:IC POT DGTL I2C 50K 64P 10MSOP RoHS:是 类别:集成电路 (IC) >> 数据采集 - 数字电位器 系列:- 标准包装:3,000 系列:DPP 接片:32 电阻（欧姆）:10k 电路数:1 温度系数:标准值 300 ppm/°C 存储器类型:非易失 接口:3 线串行（芯片选择，递增，增/减） 电源电压:2.5 V ~ 6 V 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:8-WFDFN 裸露焊盘 供应商设备封装:8-TDFN（2x3） 包装:带卷 (TR) |
| AD5258BRMZ50-R71 | 制造商:AD 制造商全称:Analog Devices 功能描述:Nonvolatile, I2C-Compatible 64-Position, Digital Potentiometer |
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