AD8403ARZ1

Overview

The AD8403ARZ1 is a quad-channel, 256-position digital potentiometer from Analog Devices. It provides four independent variable resistors in a 24-lead SOIC package. The nominal end-to-end resistance is 1 kΩ with a ±20% tolerance and a temperature coefficient of 700 ppm/°C. Each channel features an 8-bit latch for linear resistance adjustment between terminals A and B via a wiper. The device operates on a single supply voltage ranging from 2.7 V to 5.5 V and utilizes a 3-wire SPI-compatible serial interface for data input. It includes hardware reset and shutdown capabilities to minimize power consumption.

Feature Summary

• Quad-channel architecture with four independent 1 kΩ variable resistors
• 256-position resolution controlled by an 8-bit serial register
• 3-wire SPI-compatible interface supporting daisy-chaining via SDO pin
• Power shutdown mode reduces current consumption to less than 5 μA

Applications

• Mechanical potentiometer replacement in industrial systems
• Programmable filters, delays, and time constants
• Volume control and panning adjustments
• Line impedance matching circuits
• Power supply adjustment mechanisms

Procurement Notes

Verify the specific resistance value suffix when ordering, as the base model number covers multiple variants (1 kΩ, 10 kΩ, 50 kΩ, 100 kΩ). Confirm package availability, as the AD8403 is offered in PDIP, SOIC, and TSSOP formats. Check for automotive qualification requirements if the application demands AEC compliance. Ensure ESD precautions are observed during handling due to the sensitivity of the CMOS input structure.

Selection Notes

Select this component when four independent digitally controlled resistors are required in a compact surface-mount package. The 1 kΩ variant offers higher bandwidth compared to higher resistance versions but has increased nonlinearity errors. Ensure the system logic levels match the 2.7 V to 5.5 V operating range. Consider the thermal resistance of the SOIC-24 package for heat dissipation if continuous currents approach the maximum ratings.

Part Context

The AD8403 is part of the AD8400/AD8402/AD8403 family of digital potentiometers. While the AD8400 provides a single channel and the AD8402 provides dual channels, the AD8403 integrates four channels into one device. This family replaces mechanical potentiometers in applications requiring programmable resistance without moving parts. All members share similar control interfaces and electrical characteristics, differing primarily in channel count and package options.

Replacement Considerations

Direct replacements include other quad-channel digital potentiometers from Analog Devices such as the AD5204 series. When substituting, verify that the new component matches the 256-position resolution and the 1 kΩ nominal resistance. Ensure the replacement supports the same 3-wire SPI protocol and physical pinout compatibility if board space is constrained.

FAQ

How does the SHDN pin affect the resistor state?

Asserting the SHDN pin low forces Terminal A to an open-circuit condition and shorts the wiper to Terminal B, achieving a microwatt power shutdown state while retaining the previous latch settings.

What is the function of the RS pin?

The active-low RS pin forces the wiper to midscale by loading the hexadecimal value 80H into the VR latch, providing a known initial resistance state upon reset.

Can multiple AD8403 devices be connected together?

Yes, the SDO pin allows for simple daisy-chaining of multiple devices without additional external decoding logic, facilitating multi-channel expansion.