Renesas ISL22317WFRTZ-TK

Overview

ISL22317WFRTZ-TK from Renesas (formerly Intersil) is a precision 128-tap digitally controlled potentiometer (XDCP™) with I²C interface, 10kΩ end-to-end resistance, ±10ppm/°C ratiometric temperature coefficient matched to external reference, and non-volatile EEPROM storage. It operates from 2.7V to 5.5V and delivers 99% typical resistance accuracy across temperature for high-stability analog trimming in DC margining and backlight control circuits.

For engineers reviewing the ISL22317WFRTZ-TK datasheet, ISL22317WFRTZ-TK pinout, ISL22317WFRTZ-TK application, or ISL22317WFRTZ-TK equivalent, this device supports precise rheostat or voltage-divider configurations, offers zero-compensated wiper resistance, and enables life-long retention of calibrated settings without host MCU intervention.

Technical Context

The ISL22317WFRTZ-TK implements a resistor ladder with CMOS switches in a "make-before-break" switching architecture, controlled by a volatile 7-bit Wiper Register (WR) and initialized from a non-volatile Initial Value Register (IVR). Its precision mode mirrors both resistance value and temperature coefficient of an external 0.5% 10kΩ reference resistor connected between REF_A and REF_B.

It supports two operational modes: Voltage Divider Mode (RH–RL–RW, three-terminal) and Rheostat Mode (RW–RL only, RH floating), selectable via the Mode Select Register. The I²C interface operates at up to 400kHz with open-drain SCL/SDA, pin-selectable slave address (50h or 54h), and integrated access control logic for volatile/non-volatile register access.

Key Specifications

Pinout & Package

ISL22317WFRTZ-TK uses a 10-lead 3mm × 3mm Thin DFN package (0.65mm pitch, 0.75mm max height) with exposed thermal pad internally connected to GND.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AD5170BRMZ-10 and MCP45HV51-103E/ST, the ISL22317WFRTZ-TK uniquely guarantees ±10ppm/°C ratiometric tracking to an external reference and 99% resistance accuracy-making it the only option for applications demanding drift-free analog trimming without continuous host supervision.

Availability

ISL22317WFRTZ-TK is available at Aetrix Electronics and suitable for DC margining, backlight control, and test equipment calibration requiring stable component supply, long-term calibration retention, and guaranteed temperature stability across extended industrial temperature ranges.

Supply support for ISL22317WFRTZ-TK 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

Renesas Electronics acquired Intersil in 2017 and maintains full technical and manufacturing continuity for legacy Intersil precision analog products including the ISL22317 series.

The ISL22317 family was designed specifically for high-accuracy, maintenance-free analog trimming in harsh-environment applications-emphasizing non-volatile calibration retention, ultra-low TC matching, and seamless I²C integration without external support components.

FAQ

What is the function of the REF_A and REF_B pins on the ISL22317WFRTZ-TK?

The REF_A and REF_B pins connect to an external 0.5% 10kΩ reference resistor. This resistor establishes the absolute resistance value and temperature coefficient that the ISL22317WFRTZ-TK mirrors in precision mode. REF_A must never be connected to GND, as doing so may damage the device; REF_B may be tied to GND if the RL terminal is also grounded per application requirements.

Does the ISL22317WFRTZ-TK retain its wiper setting after power cycling?

Yes. The ISL22317WFRTZ-TK automatically loads the value stored in its non-volatile Initial Value Register (IVR) into the volatile Wiper Register (WR) at power-up, provided VCC exceeds 2.6V. The IVR retains settings for 50 years at ≤+55°C or 15 years at +125°C, ensuring calibration persistence without battery backup or host intervention.

Can the ISL22317WFRTZ-TK operate as a two-terminal variable resistor?

Yes. By configuring the Mode Select Register (MSR) to Rheostat Mode (MSR<7> = 0), the ISL22317WFRTZ-TK operates as a two-terminal device between RW and RL, with RH left unconnected. In this mode, it functions as a digitally adjustable resistor ideal for current-setting and gain control applications.

What is the maximum I²C clock frequency supported by the ISL22317WFRTZ-TK?

The ISL22317WFRTZ-TK supports standard-mode I²C operation up to 400kHz. Timing parameters-including tLOW (1300ns), tHIGH (600ns), and tSU:STA (600ns)-are fully compliant with I²C specification v2.1, enabling reliable communication with common microcontrollers and FPGAs without custom timing adjustments.

How does the ISL22317WFRTZ-TK achieve 99% resistance accuracy?

The ISL22317WFRTZ-TK achieves 99% typical resistance accuracy by using an external 0.5% 10kΩ reference resistor to calibrate its internal resistor ladder. Its precision mode actively matches both the absolute resistance value and ±10ppm/°C temperature coefficient of that reference-eliminating the need for algorithmic correction or factory trimming.