Renesas X9221AUST1

Overview

X9221AUST1 from Intersil is a dual digitally controlled potentiometer (XDCP™) integrating two independent 64-tap resistor arrays with nonvolatile data registers and volatile wiper counter registers, operating from 5V ±10%, supporting 2-wire serial interface (I²C-compatible), and delivering 2kΩ end-to-end resistance in a 20-lead SOIC package for precision analog trimming applications.

For engineers reviewing the X9221AUST1 datasheet, X9221AUST1 pinout, X9221AUST1 application, or X9221AUST1 equivalent, this device enables digital calibration of gain, offset, and bias in mixed-signal systems without mechanical adjustment-critical for production repeatability, field recalibration, and embedded system parameter tuning.

Technical Context

The X9221AUST1 implements two independent 63-segment resistor arrays with FET-switched wipers controlled by 6-bit Wiper Counter Registers (WCRs), each backed by four nonvolatile Data Registers (DR0–DR3) for storing up to four wiper positions per pot. Power-up loads DR0 into the respective WCR.

It uses a standard 2-wire (I²C-compatible) serial interface with slave address 0101xxxx₂, supports instruction-based register access (Read/Write WCR, Read/Write DR, XFR between DR/WCR), and features Increment/Decrement mode for real-time fine-tuning via SCL clock pulses while holding SDA HIGH/LOW.

Key Specifications

Pinout & Package

Package: 20-lead SOIC (300-mil), RoHS-compliant Pb-free plus anneal finish, MDP0027 package drawing.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar digitally controlled potentiometer applications.

Compared with AD5242BRUZ10 and MCP42010-I/P, the X9221AUST1 uniquely combines dual-channel operation, nonvolatile register storage with auto-recall, and I²C-compatible 2-wire control-making it the only option supporting synchronized, persistent, and field-updatable analog trimming without additional memory or interface logic.

Availability

X9221AUST1 is available at Aetrix Electronics and suitable for laser diode bias control, audio channel gain trimming, power supply voltage adjustment, sensor offset calibration, and industrial analog signal conditioning requiring stable component supply and long-term calibration integrity.

Supply support for X9221AUST1 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Intersil Corporation (now part of Renesas Electronics) is a U.S.-based semiconductor company specializing in precision analog, power management, and interface ICs for industrial, communications, and computing markets.

The X9221AUST1 belongs to Intersil's XDCP™ (eXternally Digitally Controlled Potentiometer) product line, designed specifically to replace mechanical potentiometers in automated manufacturing, field-serviceable equipment, and systems requiring repeatable, drift-resistant analog parameter control.

FAQ

What is the function of the RES pins on the X9221AUST1?

The four RES (Reserved) pins on the X9221AUST1-pins 13, 14, 18, and 19-are unconnected internal nodes with no electrical function. They must remain floating and should not be tied to VCC, VSS, or any other signal. This is explicitly stated in the datasheet pin descriptions and confirmed in the pin configuration diagram. Connecting them may cause unpredictable behavior or damage. The X9221AUST1 operates correctly with these pins left unconnected.

Does the X9221AUST1 support true I²C communication?

Yes, the X9221AUST1 supports I²C-compatible 2-wire serial communication: it uses open-drain SDA with required pull-up, accepts standard START/STOP conditions, acknowledges valid slave addresses (0101xxxx₂), and conforms to I²C timing parameters including tLOW ≥4700ns and tHIGH ≥4000ns at 100kHz. However, it does not implement full I²C arbitration or clock stretching-so it functions as a basic I²C slave, not a multi-master-capable device. The X9221AUST1 datasheet confirms compatibility with standard I²C masters.

How many wiper positions can be stored nonvolatily in the X9221AUST1?

The X9221AUST1 provides four nonvolatile Data Registers (DR0–DR3) per potentiometer, allowing up to four distinct wiper positions to be stored per channel. Each register holds a 6-bit value corresponding to one of 64 possible tap positions. These values persist for 100 years and survive power cycles. DR0 is automatically loaded into the Wiper Counter Register (WCR) at power-up, making it the default startup setting for each pot. The X9221AUST1 supports both individual and global register transfers between DRs and WCRs.

What is the maximum allowable voltage across the VH and VL terminals of the X9221AUST1?

The absolute maximum voltage difference |VH/RH – VL/RL| for the X9221AUST1 is 10.3V, as specified in the Absolute Maximum Ratings table. Exceeding this risks permanent damage. For reliable operation, the recommended analog voltage range is –3.0V to +5.0V on any VH/RH, VL/RL, or VW/RW pin referenced to VSS. The device is rated for 5V ±10% supply (4.5V–5.5V), and analog signals must stay within the supply rails unless using external level-shifting circuitry. The X9221AUST1 datasheet explicitly limits terminal voltage swing to avoid junction breakdown.

Can the X9221AUST1 be used as a two-terminal variable resistor?

Yes, the X9221AUST1 can operate as a two-terminal variable resistor by connecting either VH/RH or VL/RL to the same node as VW/RW, leaving the unused terminal open. In this configuration, resistance is adjusted between the wiper and the connected terminal, ranging from near-zero (wiper at connected end) to full RTOTAL (wiper at opposite end). The datasheet confirms this usage in the DESCRIPTION section and specifies 3mA max wiper current (IW) and 40–130Ω wiper resistance (RW)-key parameters for two-terminal design. The X9221AUST1 supports this mode without derating or special configuration.