4-/6-Channel
a
Digital Potentiometers
AD5204/AD5206
FEATURES
FUNCTIONAL BLOCK DIAGRAMS
256 Position
Multiple Independently Programmable Channels
AD5204—4-Channel
AD5206—6-Channel
Potentiometer Replacement
10 k⍀, 50 k⍀, 100 k⍀
3-Wire SPI-Compatible Serial Data Input
+2.7 V to +5.5 V Single Supply; ؎2.7 V Dual Supply
Operation
AD5204
V
DD
CS
A1
W1
B1
CLK
D7
D0
EN
RDAC
LATCH
#1
ADDR
DEC
A2
A1
A0
DO
SDO
R
D7
Power ON Midscale Preset
SER
REG
A4
W4
B4
APPLICATIONS
D7
D0
Mechanical Potentiometer Replacement
Instrumentation: Gain, Offset Adjustment
Programmable Voltage-to-Current Conversion
Programmable Filters, Delays, Time Constants
Line Impedance Matching
RDAC
LATCH
#4
DI
D0
SDI
SHDN
8
R
V
POWER-
ON
PRESET
SS
PR
GND
GENERAL DESCRIPTION
AD5206
V
CS
DD
The AD5204/AD5206 provides four-/six-channel, 256 position
digitally-controlled Variable Resistor (VR) devices. These de-
vices perform the same electronic adjustment function as a
potentiometer or variable resistor. Each channel of the AD5204/
AD5206 contains a fixed resistor with a wiper contact that taps
the fixed resistor value at a point determined by a digital code
loaded into the SPI-compatible serial-input register. The resis-
tance between the wiper and either endpoint of the fixed resistor
varies linearly with respect to the digital code transferred into
the VR latch. The variable resistor offers a completely program-
mable value of resistance between the A terminal and the wiper
or the B Terminal and the wiper. The fixed A-to-B terminal
resistance of 10 kΩ, 50 kΩ, or 100 kΩ has a nominal tempera-
ture coefficient of 700 ppm/°C.
A1
W1
B1
CLK
D7
EN
RDAC
LATCH
#1
ADDR
DEC
A2
A1
A0
R
D0
D7
SER
REG
A6
W6
B6
D7
D0
RDAC
LATCH
#6
DI
D0
SDI
8
R
POWER-
ON
PRESET
GND
V
SS
Each VR has its own VR latch which holds its programmed
resistance value. These VR latches are updated from an internal
serial-to-parallel shift register that is loaded from a standard
3-wire serial-input digital interface. Eleven data bits make up
the data word clocked into the serial input register. The first
three bits are decoded to determine which VR latch will be
loaded with the last eight bits of the data word when the CS
strobe is returned to logic high. A serial data output pin at
the opposite end of the serial register (AD5204 only) allows
simple daisy-chaining in multiple VR applications without
additional external decoding logic.
An optional reset (PR) pin forces all the AD5204 wipers to the
midscale position by loading 80H into the VR latch.
The AD5204/AD5206 is available in both surface mount
(SOL-24), TSSOP-24 and the 24-lead plastic DIP package. All
parts are guaranteed to operate over the extended industrial
temperature range of –40°C to +85°C. For additional single,
dual, and quad channel devices, see the AD8400/AD8402/
AD8403 products.
REV. 0
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© Analog Devices, Inc., 1999