EVAL-AD5110SDZ Analog Devices, EVAL-AD5110SDZ Datasheet - Page 24

• Manufacturer Part Number: EVAL-AD5110SDZ
• Description: Digital Potentiometer Development Tools Evaluation board
• Manufacturer: Analog Devices
• Series: AD5110r

Specifications of EVAL-AD5110SDZ

• Rohs: yes
• Product: Evaluation Boards
• Tool Is For Evaluation Of: AD5110
• Resistance: 10 kOhms
• Operating Supply Voltage: 5.5 V
• Interface Type: I2C
• Maximum Operating Temperature: + 125 C
• Factory Pack Quantity: 1

AD5110/AD5112/AD5114
RDAC ARCHITECTURE
To achieve optimum performance, Analog Devices, Inc., has
patented the RDAC segmentation architecture for all the digital
potentiometers. In particular, the
employ a two-stage segmentation approach as shown in
Figure 46. The
designed with the transmission gate CMOS topology and with
the gate voltage derived from V
Top Scale/Bottom Scale Architecture
In addition, the
feature to reduce the resistance between terminals. These extra
steps are called bottom scale and top scale. At bottom scale, the
typical wiper resistance decreases from 70 Ω to 45 Ω. At top
scale, the resistance between Terminal A and Terminal W is
decreased by 1 LSB, and the total resistance is reduced to 70 Ω.
The extra steps are not equal to 1 LSB and are not included in
the INL, DNL, R-INL, and R-DNL specifications.
6-BIT/7-BIT/8-BIT
ADDRESS
DECODER
Figure 46.
AD5110/AD5112/AD5114
AD5110/AD5112/AD5114
AD5110/AD5112/AD5114
R
R
R
R
L
L
L
L
A
B
DD
AD5110/AD5112/AD5114
.
TS
BS
Simplified RDAC Circuit
R
R
wiper switch is
include a new
S
S
W
Rev. B | Page 24 of 28
PROGRAMMING THE VARIABLE RESISTOR
Rheostat Operation—±8% Resistor Tolerance
The
only two terminals are used as a variable resistor. The unused
terminal can be floating or tied to the Terminal W as shown in
Figure 47.
The nominal resistance between Terminal A and Terminal B,
R
tap points accessed by the wiper terminal. The 5-/6-/7-bit data
in the RDAC latch is decoded to select one of the 32/64/128
possible wiper settings. The general equations for determining
the digitally programmed output resistance between the W
terminal and B terminal are
AD5110:
AD5112:
AD5114:
where:
D is the decimal equivalent of the binary code in the 5-/6-/7-bit
RDAC register.
R
R
R
AB
AB
W
BS
is the wiper resistance.
, is available in 5 kΩ, 10 kΩ, and 80 kΩ and has 32/64/128
is the wiper resistance at bottom scale
is the end-to-end resistance.
AD5110/AD5112/AD5114
R
R
R
R
R
R
WB
WB
WB
WB
WB
WB
A
B
(
(
(
=
=
D
D
=
D
R
R
)
)
R
)
BS
BS
=
=
=
BS
128
64
D
W
Figure 47. Rheostat Mode Configuration
D
32
D
×
×
×
R
R
R
AB
AB
AB
+
+
+
R
A
B
R
W
R
W
W
W
operate in rheostat mode when
Bottom scale (0xFF) (1)
Bottom scale (0xFF) (3)
Bottom scale (0xFF) (5)
From 0x00 to 0x80 (2)
From 0x00 to 0x40 (4)
From 0x00 to 0x20 (6)
A
B
Data Sheet
W