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Volume 8, Issue 3 | YOUR SEMICONDUCTOR SOLUTIONS RESOURCE |
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C o n t e n t s iCMOS Switches and Multiplexers Enable Critical Systems Functions >> Digital Potentiometers Eliminate the Need for More Costly, Less Accurate Solutions >> Flexible Clocking Scheme for Multiple Wireless Standards >> Optimizing Signal Chain Performance with Voltage References >> Protect and Optimize Communication Networks with New Quad Channel Voltage Monitors and Sequencers >> Low Power Comparators with Integrated Reference and Programmable Hysteresis >> Protect Your Valuable Communication Networks with RS-232 and RS-485 IC >> Multivoltage Supervisor ICs Monitor Low Voltage Core Supplies for Peak Performance >> Online Supervisory IC Selection Tools from ADI >>
All prices in this bulletin are in USD in quantities greater than 1000 (unless otherwise noted), recommended lowest grade resale, FOB U.S.A.
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Quad Channel, 256-Position Digital Potentiometers in 5 mm × 5 mm QFN Packaging Significantly Reduce Board Space
A digital potentiometer adjusts and trims electronic circuits in the same way that variable resistors, rheostats, and mechanical potentiometers do. These compact devices can be used to calibrate system tolerances or dynamically control system parameters, in cases where a fine tuned analog output is controlled by a digital input. The AD5204 provides 4-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 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, 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. The AD5206 is a 6-channel solution.
Packaging options help you to address your system requirement trade-offs including device cost and board area. Options for both the AD5204 and AD5206 include 24-lead SOIC, TSSOP, and PDIP packages. The AD5204 is also available in 5 mm × 5 mm LFCSP for the most popular 10 kΩ resistor value. Please click here for Digital Potentiometers selection table.
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