Renesas X9318WS8I

Overview

X9318WS8I from Intersil is a digitally controlled potentiometer (XDCP™) implementing a 10 kΩ end-to-end resistance with 100 wiper tap points, nonvolatile wiper position storage, and 3-wire serial interface (CS/U/D/INC). It operates from 4.5–5.5 V, supports terminal voltages up to +8 V, and delivers ±1% absolute linearity over –40°C to +85°C for precision analog trim in voltage regulator feedback paths.

For engineers reviewing the X9318WS8I datasheet, X9318WS8I pinout, X9318WS8I application, or X9318WS8I equivalent, key selection criteria include its SOIC-8 package, temperature-compensated resistor array, 100-year data retention, 100,000-cycle endurance, and compatibility with LCD bias control, laser diode bias, and DC offset adjustment circuits requiring stable, reprogrammable resistance without mechanical wear.

Technical Context

The X9318WS8I integrates a 99-element resistor ladder with "make-before-break" electronic wiper switching, a 7-bit up/down counter, and nonvolatile memory for power-up recall. Its control logic responds to negative-edge-triggered INC pulses while U/D sets direction and CS enables selection or initiates nonvolatile store on CS↑ with INC HIGH.

It functions as either a three-terminal voltage divider (RH–RW–RL) or two-terminal variable resistor (RW–RL or RW–RH), with wiper resistance typ. 40 Ω and ratiometric temperature coefficient of ±20 ppm/°C - enabling stable gain/offset trimming across industrial temperature ranges without external calibration.

Key Specifications

Pinout & Package

Package: 8-lead SOIC (150 mil), RoHS-compliant Pb-free plus anneal finish, -40°C to +85°C operating range.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AD5243BRMZ10 and MCP41010-I/P, the X9318WS8I offers deterministic 3-wire control with guaranteed power-up recall, tighter RTOTAL tolerance (±20% vs. ±30%), and lower pin count - making it optimal for cost-sensitive, single-pot industrial trim where reliability and simplicity outweigh multi-channel or high-resolution needs.

Availability

X9318WS8I is available at Aetrix Electronics and suitable for LCD bias control, laser diode bias control, and voltage regulator output trim requiring stable component supply, long-term calibration retention, and industrial temperature operation.

Supply support for X9318WS8I 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 semiconductor company specializing in precision analog, power management, and interface ICs for industrial, communications, and computing markets.

The X9318WS8I belongs to Intersil's XDCP™ family of digitally controlled potentiometers, designed specifically for replacing mechanical trimmers in analog signal conditioning, power supply feedback, and display bias applications where long-term stability and programmability are essential.

FAQ

What is the operating temperature range for the X9318WS8I?

The X9318WS8I is rated for –40°C to +85°C operation, matching its "I" suffix designation. This extended industrial range ensures reliable performance in environments such as industrial control panels, outdoor instrumentation, and automotive cabin electronics where ambient temperatures fluctuate widely. The device maintains specified linearity, resistance tolerance, and nonvolatile retention across this full range.

Does the X9318WS8I require an external microcontroller to retain its wiper position after power loss?

No - the X9318WS8I stores wiper position in on-chip nonvolatile memory and automatically recalls it on power-up. No external MCU or EEPROM is needed. The store operation is triggered by raising CS while INC is HIGH; once stored, the value persists for 100 years without power. This makes the X9318WS8I ideal for "set-and-forget" analog trim applications.

Can the X9318WS8I be used as a two-terminal variable resistor?

Yes - the X9318WS8I supports both three-terminal potentiometer (RH–RW–RL) and two-terminal variable resistor (RW–RL or RW–RH) configurations. In two-terminal mode, it functions as a digitally adjustable current-limiting or gain-setting element. Wiper resistance is typically 40 Ω, and terminal voltage rating remains 0 to +8 V, enabling direct use in current-sense feedback paths.

What is the maximum allowable voltage on the RH, RL, and RW terminals of the X9318WS8I?

The absolute maximum voltage on RH, RL, and RW is +10 V with respect to VSS, but the recommended operating range is 0 to +8 V. Exceeding +8 V risks violating the specified potentiometer characteristics (e.g., linearity, noise, power rating) and may accelerate wear. The device is not designed for AC-coupled or bipolar analog signals - all terminals must remain within 0 V to +8 V during normal operation.

How does the "make-before-break" wiper switching in the X9318WS8I benefit circuit stability?

The "make-before-break" action ensures that the wiper connects to the next tap before disconnecting from the current one, preventing momentary open-circuit conditions. This avoids voltage spikes or feedback loop interruptions in sensitive applications like op-amp offset nulling or voltage regulator feedback networks. For the X9318WS8I, this behavior is intrinsic to its electronic switch design and occurs within 100–500 µs of an INC edge.