AD5206_15 Datasheet, PDF (1/20 Pages) Analog Devices – 4-/6-Channel Digital Potentiometers

FEATURES
256 positions
Multiple independently programmable channels
AD5204—4-channel
AD5206—6-channel
Potentiometer replacement
Terminal resistance of 10 kΩ, 50 kΩ, 100 kΩ
3-wire SPI-compatible serial data input
+2.7 V to +5.5 V single-supply operation; ±2.7 V dual-supply
operation
Power-on midscale preset
APPLICATIONS
Mechanical potentiometer replacement
Instrumentation: gain, offset adjustment
Programmable voltage-to-current conversion
Programmable filters, delays, time constants
Line impedance matching
GENERAL DESCRIPTION
The AD5204/AD5206 provide 4-/6-channel, 256-position
digitally controlled variable resistor (VR) devices. These
devices 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
resistance 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
programmable 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
temperature coefficient of 700 ppm/°C.
Each VR has its own VR latch that 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 is 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 requiring
additional external decoding logic.
4-/6-Channel
Digital Potentiometers
AD5204/AD5206
FUNCTIONAL BLOCK DIAGRAMS
CS
AD5204
V_DD
CLK
A1
D7
EN
W1
A2
A1
ADDR
DEC
RDAC
LATCH
1
B1
SDO
DO A0
D7
D0 _R
SER
REG
SDI
DI D0
GND
8
POWER-ON
PRESET
D7
RDAC
LATCH
4
D0
R
A4
W4
B4
SHDN
V_SS
PR
Figure 1.
CS
AD5206
V_DD
CLK
A1
D7
EN
W1
RDAC
A2
A1
ADDR
DEC
LATCH
1
B1
A0
D0 R
D7
SER
REG
D7
A6
W6
SDI
DI D0
RDAC
LATCH
B6
6
8
D0 R
POWER-ON
GND
PRESET
V_SS
Figure 2.
An optional reset (PR) pin forces all the AD5204 wipers to the
midscale position by loading 0x80 into the VR latch.
The AD5204/AD5206 are available in the 24-lead surface-
mount SOIC, TSSOP, and PDIP packages. The AD5204 is also
available in a 32-lead, 5 mm × 5 mm LFCSP 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 data sheets.
Rev. C
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