AD8403AN50

The AD8403AN50 is a quad-channel, 256-position digitally controlled variable resistor from Analog Devices. It provides four independent potentiometers in a single 24-lead PDIP package, with 50 kΩ fixed end-to-end resistance and a linear taper. Each channel's wiper position is set by an 8-bit digital code loaded through a 3-wire SPI-compatible serial interface, allowing precise resistive settings without mechanical wear.

The device operates from a single 2.7 V to 5.5 V supply and is specified for -40°C to 125°C operating temperature range. It includes a power-shutdown mode drawing less than 5 µA and supports a 10 MHz data loading rate. The resistor network offers ±30% end-to-end resistance tolerance, a temperature coefficient of 500 ppm/°C, and ±1% channel-to-channel matching. Because the wiper setting is volatile, the programmed resistance is held only while power is applied and must be re-loaded after power-up.

Using a unique switching circuit, the device minimizes glitch energy and avoids make-before-break or break-before-make issues found in traditional switched-resistor designs. A serial data output pin supports daisy-chaining multiple devices without extra decode logic, and a cascade pin enables expansion in multi-device designs. Typical applications include replacing mechanical potentiometers, programmable filters, volume control, line impedance matching, and power supply adjustment.

The through-hole 24-pin DIP package (24-DIP, 0.300" lead spacing) suits breadboard prototyping and legacy designs. The AD8403 family also includes SOIC and TSSOP package options for surface-mount assembly.