AD5293BRUZ-20 Analog Devices Inc, AD5293BRUZ-20 Datasheet - Page 20

• Manufacturer Part Number: AD5293BRUZ-20
• Description: IC DGTL POT 1024POS 20K 14TSSOP
• Manufacturer: Analog Devices Inc

Specifications of AD5293BRUZ-20

• Temperature Coefficient: 35 ppm/°C Typical
• Taps: 1024
• Resistance (ohms): 20K
• Number Of Circuits: 1
• Interface: SPI Serial
• Voltage - Supply: 9 V ~ 33 V, ±9 V ~ 16.5 V
• Operating Temperature: -40°C ~ 105°C
• Mounting Type: Surface Mount
• Package / Case: 14-TSSOP
• Resistance In Ohms: 20K
• End To End Resistance: 20kohm
• Track Taper: Linear
• No. Of Steps: 256
• Resistance Tolerance: ± 1%
• Control Interface: Serial, SPI
• No. Of Pots: Single
• Potentiometer Ic: RoHS Compliant
• Supply Voltage Range: ± 9V To ± 16.5V
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Memory Type: -
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: AD5293BRUZ-20-U1; AD5293BRUZ-20-U1

AD5293
Table 13. Control Register Function
Register Name
Control
RDAC ARCHITECTURE
To achieve optimum performance, Analog Devices, Inc., has
patented the RDAC segmentation architecture for all the digital
potentiometers. In particular, the AD5293 employs a 3-stage
segmentation approach, as shown in Figure 46. The AD5293
wiper switch is designed with transmission gate CMOS topology
and with the gate voltage derived from V
PROGRAMMING THE VARIABLE RESISTOR
Rheostat Operation—1% Resistor Tolerance
The AD5293 operates in rheostat mode when only two terminals
are used as a variable resistor. The unused terminal can be left
floating or it can be tied to the W terminal, as shown in Figure 47.
DECODER
ADDRESS
10-BIT
A
B
Figure 47. Rheostat Mode Configuration
Figure 46. Simplified RDAC Circuit
W
Bit Name
C1
C2
A
B
A
B
R
R
R
R
L
L
L
L
W
DD
R
R
R
R
A
B
Description
Calibration enable.
0 = resistor performance mode (default).
1 = normal mode.
RDAC register write protect.
0 = locks the wiper position through the digital interface (default).
1 = allows update of wiper position through digital interface.
M
M
M
M
.
R
R
W
W
W
S
W
W
Rev. D | Page 20 of 24
The nominal resistance between Terminal A and Terminal B,
R
points that are accessed by the wiper terminal. The 10-bit data
in the RDAC latch is decoded to select one of the 1024 possible
wiper settings. The AD5293 contains an internal ±1% resistor
tolerance calibration feature that can be enabled or disabled,
enabled by default by programming Bit C2 of the control
register (see Table 12 and Table 13).
The digitally programmed output resistance between the
W terminal and the A terminal, R
and B terminal, R
absolute resistance error over both the full supply and temperature
ranges. As a result, the general equation for determining the
digitally programmed output resistance between the W terminal
and B terminal is
where:
D is the decimal equivalent of the binary code loaded in the
10-bit RDAC register.
R
Similar to the mechanical potentiometer, the resistance of the RDAC
between the W terminal and the A terminal also produces a digitally
controlled complementary resistance, R
to give a maximum of 1% absolute resistance error. R
the maximum resistance value and decreases as the data loaded
into the latch increases. The general equation for this operation is
where:
D is the decimal equivalent of the binary code loaded in the
10-bit RDAC register.
R
In the zero-scale condition, a finite total wiper resistance of 120 Ω
is present. Regardless of the setting in which the part is operating,
care should be taken to limit the current between the A terminal to
B terminal, the W terminal to the A terminal, and the W terminal
to the B terminal to the maximum continuous current of ±3 mA or
to the pulse current specified in Table 6. Otherwise, degradation,
or possible destruction of the internal switch contact, can occur.
AB
AB
AB
, is available in 20 kΩ, 50 kΩ, and 100 kΩ and has 1024 tap
is the end-to-end resistance.
is the end-to-end resistance.
R
R
WB
WA
(
(
D
D
)
)
=
=
1024
1024
D
WB
1024
, is calibrated to give a maximum of ±1%
×
−
R
D
AB
×
R
AB
WA
, and the W terminal
WA
. R
WA
is also calibrated
WA
starts at
(1)
(2)