64-Position Up/Down
Control Digital Potentiometer
AD5227
Rev. B
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FEATURES
64-position digital potentiometer
10 kΩ, 50 kΩ, 100 kΩ end-to-end terminal resistance
Simple up/down digital or manual configurable control
Midscale preset
Low potentiometer mode tempco = 10 ppm/°C
Low rheostat mode tempco = 35 ppm/°C
Ultralow power, I
DD
= 0.4 μA typ and 3 μA max
Fast adjustment time, ts = 1 μs
Chip select enable multiple device operation
Low operating voltage, 2.7 V to 5.5 V
Automotive temperature range, −40°C to +105°C
Compact thin SOT-23-8 (2.9 mm × 3 mm) Pb-free package
APPLICATIONS
Mechanical potentiometer and trimmer replacements
LCD backlight, contrast, and brightness controls
Portable electronics level adjustment
Programmable power supply
Digital trimmer replacements
Automatic closed-loop control
FUNCTIONAL BLOCK DIAGRAM
04419-0-001
CS
U/D
CLK
GND
V
DD
6-BIT UP/DOWN
CONTROL
LOGIC
POR
MIDSCALE
WIPER
REGISTER
A
W
B
AD5227
Figure 1.
GENERAL DESCRIPTION
The AD5227 is Analog Devices’ latest 64-step up/down control
digital potentiometer
1
. This device performs the same electronic
adjustment function as a 5 V potentiometer or variable resistor.
Its simple 3-wire up/down interface allows manual switching or
high speed digital control. The AD5227 presets to midscale at
power-up. When
CS
is enabled, the devices changes step at
every clock pulse. The direction is determined by the state of
the U/
D
pin (see ). The interface is simple to activate by
any host controller, discrete logic, or manually with a rotary
encoder or pushbuttons. The AD5227’s 64-step resolution, small
footprint, and simple interface enable it to replace mechanical
potentiometers and trimmers with typically 6× improved
resolution, solid-state reliability, and design layout flexibility,
resulting in a considerable cost savings in end users’ systems.
Table 1
1
The terms digital potentiometer and RDAC are used interchangeably.
The AD5227 is available in a compact thin SOT-23-8 (TSOT-8)
Pb-free package. The part is guaranteed to operate over the
automotive temperature range of −40°C to +105°C.
Users who consider EEMEM potentiometers should refer to
some recommendations in the Applications section.
Table 1. Truth Table
CS
CLK
U/
D
Operation
1
0
↓
0 R
WB
Decrement
0
↓
1 R
WB
Increment
1 X X No Operation
1
R
WA
increments if R
WB
decrements and vice versa.
