AD8403ARUZ1

Overview

The AD8403ARUZ1 is a quad-channel, 8-bit digital potentiometer from Analog Devices, housed in a 24-lead TSSOP package. It provides four independent variable resistors with 256 tap positions and a nominal resistance of 1 kΩ. The device operates on a single supply voltage ranging from 2.7 V to 5.5 V. It features a 3-wire SPI-compatible serial interface for data loading at rates up to 10 MHz. Key electrical characteristics include a typical wiper resistance of 100 Ω at 5 V and a power shutdown current of less than 5 μA. The unit is qualified for automotive applications and functions within an extended industrial temperature range of −40°C to +125°C.

Feature Summary

• Quad-channel architecture with four independent 8-bit variable resistors
• 1 kΩ nominal resistance with ±1% channel-to-channel matching tolerance
• SPI-compatible 3-wire serial interface with daisy-chain capability via SDO pin
• Microwatt power shutdown mode (<5 μA) with latch retention

Applications

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

Procurement Notes

Verify the specific suffix 'U' confirms the TSSOP-24 surface-mount package variant. Confirm RoHS compliance status as manufacturing revisions may alter environmental declarations. Check for end-of-life notifications or alternative package recommendations due to potential obsolescence cycles associated with this component family.

Selection Notes

Select this part when four independent digitally controlled resistors are required in a compact surface-mount footprint. Ensure the 1 kΩ resistance value aligns with the target circuit's impedance requirements. Verify that the system logic levels are compatible with the 2.7 V to 5.5 V operating range and that the 10 MHz update rate meets the application's timing constraints.

Part Context

This component belongs to the AD8400/AD8402/AD8403 family of 1-, 2-, and 4-channel digital potentiometers. While the AD8400 offers a single channel and the AD8402 provides dual channels, the AD8403 specifically integrates four channels. The 'ARU' designation indicates the automotive-grade temperature range and the TSSOP-24 package type, distinguishing it from SOIC or PDIP variants.

Replacement Considerations

Direct functional substitutes within the same package include other AD8403 variants with different resistance values (e.g., AD8403ARZ10 for 10 kΩ). For non-automotive applications, standard commercial grade parts like AD8403ARZ1 may be considered if package compatibility is maintained.

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 SDO pin?

The Serial Data Output (SDO) pin allows for simple daisy-chaining of multiple VR devices without requiring additional external decoding logic.

What happens when the RS pin is activated?

The active-low Reset to Midscale (RS) pin forces the wiper to the center position by loading the hexadecimal code 80H into the VR latch.