The AD5220 provides a single channel, 128-position digitally controlled variable resistor (VR) device. This device performs the same electronic adjustment function as a potentiometer or variable resistor. These products were optimized for instrument and test equipment push-button applications. A choice between bandwidth or power dissipation are available as a result of the wide selection of end-to-end terminal resistance values.
The AD5220 contains a fixed resistor with a wiper contact that taps the fixed resistor value at a point determined by a digitally controlled UP/DOWN counter. The resistance between the wiper and either end point of the fixed resistor provides a constant resistance step size that is equal to the end-to-end resistance divided by the number of positions (e.g., RSTEP = 10 kW/ 128 = 78 W). The variable resistor offers a true adjustable 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 kW, 50 kW, or 100 kW has a nominal temperature coefficient of 800 ppm/°C.
The chip select CS, count CLK and U/D direction control inputs set the variable resistor position. These inputs that control the internal UP/DOWN counter can be easily generated with mechanical or push button switches (or other contact closure devices). External debounce circuitry is required for the negative- edge sensitive CLK pin. This simple digital interface eliminates the need for microcontrollers in front panel interface designs.
The AD5220 is available in both surface mount (SO-8) and the 8-lead plastic DIP package. For ultracompact solutions selected models are available in the thin mSOIC package. All parts are guaranteed to operate over the extended industrial temperature range of 40°C to +85°C. For 3-wire, SPI compatible interface applications, see the AD7376/AD8400/AD8402/AD8403 products.
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·Mechanical Potentiometer Replacement·Remote Incremental Adjustment Applications·Instrumentation: Gain, Offset Adjustment·Programmable Voltage-to-Current Conversion·Programmable Filters, Delays, Time Constants·Line Impedance Matching·Power Supply Adjustment
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·128 Position·Potentiometer Replacement·10 kV, 50 kV, 100 kV·Very Low Power: 40 mA Max·Increment/Decrement Count Control
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VDD to GND . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.3 V, +7 V
VA, VB, VW to GND . . . . . . . . . . . . . . . . . . . . . . . . . . 0 V, VDD
AXBX, AXWX, BXWX . . . . . . . . . . . . . . . . . . . . . . ±20 mA
Digital Input Voltage to GND . . . . . . . . . . . 0 V, VDD + 0.3 V
Operating Temperature Range . . . . . . . . . . 40°C to +85°C
Maximum Junction Temperature (TJ MAX) . . . . . . . . +150°C
Storage Temperature . . . . . . . . . . . . . . . . .65°C to +150°C
Lead Temperature (Soldering, 10 sec) . . . . . . . . . . . .+300°C
Package Power Dissipation . . . . . . . . . . . . . .(TJ maxTA)/qJA
Thermal Resistance qJA
P-DIP (N-8) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103°C/W
SOIC (SO-8) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 158°C/W
mSOIC (RM-8) . . . . . . . . . . . . . . . . . . . . . . . . . . . 206°C/W
Post a Buying Lead
Required Field 
