Renesas X9279UV14IZ

Overview

X9279UV14IZ from Intersil is a single-channel, 256-tap, digitally controlled potentiometer (XDCP™) with 50kΩ end-to-end resistance, 2-wire serial interface, and -40°C to +85°C industrial temperature range. It operates from 2.7V to 5.5V, features non-volatile data registers, power-up recall of DR0 to WCR, and wiper resistance of 150Ω typical at 5V. It serves as a programmable resistor or three-terminal potentiometer in precision analog trimming applications.

For engineers reviewing the X9279UV14IZ datasheet, X9279UV14IZ pinout, X9279UV14IZ application, or X9279UV14IZ equivalent, this page delivers verified specifications, validated pin functions, confirmed industrial-grade operation, and two documented alternative parts for gain control, offset calibration, and sensor signal conditioning circuits requiring stable digital resistance adjustment.

Technical Context

The X9279UV14IZ implements a monolithic CMOS resistor ladder with 255 discrete segments and 256 tap points, controlled by an 8-bit volatile Wiper Counter Register (WCR). Its 2-wire bus interface supports read/write/transfer operations to four non-volatile Data Registers (DR0–DR3), with hardware write protection via the WP pin.

Power-on behavior loads DR0 into the WCR, enabling deterministic startup wiper position. The device supports increment/decrement mode for fine-grained wiper adjustment via SCL clocking while holding SDA high (increment) or low (decrement), with no external components required for basic operation.

Key Specifications

Pinout & Package

Package: 14-lead TSSOP (4.4mm width), Pb-free (RoHS compliant), moisture sensitivity level (MSL) rated per IPC/JEDEC J-STD-020.

Key Features

Applications

Equivalent & Alternatives

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

Compared with X9279UV14IZ, ISL95810 offers lower resistance for current-sensitive trimming, while ISL95811 provides higher resistance for ultra-low-quiescent-current biasing-both retain identical interface, packaging, and industrial temperature rating but differ in fundamental resistance scaling for circuit-specific optimization.

Availability

X9279UV14IZ is available at Aetrix Electronics and suitable for industrial sensor calibration, programmable power supplies, and embedded audio systems requiring stable component supply with guaranteed long-term availability and RoHS-compliant sourcing.

Supply support for X9279UV14IZ 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 (now part of Renesas Electronics) is a semiconductor company specializing in precision analog, power management, and interface ICs for industrial, computing, and communications markets.

The X9279 family was designed as digitally controlled potentiometers for replacing mechanical trimmers in high-reliability analog signal conditioning, offering non-volatile storage, industrial temperature operation, and I²C-compatible control.

FAQ

What is the end-to-end resistance of the X9279UV14IZ and how is it specified?

The X9279UV14IZ has a nominal end-to-end resistance of 50kΩ, confirmed in the Ordering Information table and Analog Characteristics section of the datasheet. This value is fixed for the "U" version (X9279U-series) and applies across the full -40°C to +85°C operating range with ±20% tolerance. The 50kΩ value is optimized for low-noise, medium-impedance analog applications such as sensor biasing and audio gain control, and is distinct from the 100kΩ "T" version.

Does the X9279UV14IZ support true I²C communication, and what are its bus timing requirements?

Yes, the X9279UV14IZ supports standard I²C-compatible 2-wire communication with SDA (open-drain) and SCL inputs. It operates at up to 400kHz clock frequency, with defined start/stop conditions, acknowledge polling, and 3-byte instruction sequences. The device requires external pull-up resistors on both lines, and adheres to I²C voltage thresholds (VIH ≥ 0.7×VCC, VIL ≤ 0.3×VCC), making it interoperable with standard MCU I²C peripherals without protocol translation.

How does the power-up recall function work in the X9279UV14IZ?

On power-up, the X9279UV14IZ automatically loads the contents of Data Register 0 (DR0) into the volatile Wiper Counter Register (WCR), establishing a known wiper position without host intervention. This behavior is guaranteed provided VCC ramp rate stays within 0.2–50 V/ms and VCC rises before any RH/RL/VW signals. DR0 must be pre-programmed during manufacturing or field calibration to ensure deterministic startup behavior for the X9279UV14IZ.

Can the X9279UV14IZ be used as a two-terminal variable resistor, and what are the design implications?

Yes, the X9279UV14IZ can be configured as a two-terminal variable resistor by connecting either RH or RL to the wiper (RW) pin, effectively using only one half of the resistor array. In this mode, total resistance ranges from 0Ω (wiper at shorted terminal) to 50kΩ (wiper at opposite terminal). Designers must observe ±3mA absolute maximum wiper current and ensure voltage across the active segment remains within VCC–VSS limits to avoid latch-up or parametric shift in the X9279UV14IZ.

What is the purpose of the WP (Write Protect) pin on the X9279UV14IZ, and how should it be used?

When pulled LOW, the WP pin disables all non-volatile writes to the four Data Registers (DR0–DR3) in the X9279UV14IZ, preventing accidental overwrites of calibrated values during system operation or reset sequences. It does not affect volatile WCR writes or read operations. For robust field operation, WP should be tied to GND via a pull-down resistor or controlled by a system supervisor IC to enforce write protection after initial calibration is complete.