Renesas ISL23418TFRUZ-T7A

Overview

ISL23418TFRUZ-T7A from Renesas Electronics (formerly Intersil) is a volatile, single-channel, 128-tap digitally controlled potentiometer (XDCP™) with SPI interface, 100kΩ end-to-end resistance, 10-lead µTQFN package, and extended industrial temperature range (−40°C to +125°C). It functions as a programmable voltage divider or rheostat in precision biasing and gain control circuits for battery-powered instrumentation.

For engineers reviewing the ISL23418TFRUZ-T7A datasheet, ISL23418TFRUZ-T7A pinout, ISL23418TFRUZ-T7A application, or ISL23418TFRUZ-T7A equivalent, key selection criteria include its dual-supply operation (VCC = 1.7–5.5V, VLOGIC = 1.2–5.5V), mid-scale power-on default (64-tap), shutdown mode with RW–RL short, and guaranteed monotonicity in both voltage-divider and rheostat modes.

Technical Context

The ISL23418TFRUZ-T7A implements a resistor ladder with CMOS wiper switches operating in "make-before-break" mode, controlled by an 8-bit volatile Wiper Register (WR) accessible via SPI Mode 0. Its architecture supports daisy-chaining multiple units without additional chip-select lines.

It features independent logic and analog supplies enabling direct interfacing with low-voltage microcontrollers (down to 1.2V VLOGIC), while maintaining full DCP functionality across VCC = 1.7V–5.5V. Shutdown mode forces RH–RL open-circuit and internally connects RW to RL through ~2kΩ, preserving WR contents.

Key Specifications

Pinout & Package

ISL23418TFRUZ-T7A uses a 10-lead 2.1mm × 1.6mm µTQFN package (RoHS-compliant, MSL Level 3, pkg drawing L10.2.1x1.6A).

Key Features

Applications

Equivalent & Alternatives

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

Compared with AD5170BRMZ-100 and MCP41HV51-103, the ISL23418TFRUZ-T7A uniquely combines 1.2V logic compatibility, integrated shutdown, and µTQFN footprint-making it optimal for space-constrained, battery-operated systems requiring fast, low-power reconfiguration without nonvolatile overhead.

Availability

ISL23418TFRUZ-T7A is available at Aetrix Electronics and suitable for power supply margining, RF amplifier bias compensation, and portable medical equipment calibration requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for ISL23418TFRUZ-T7A 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 support for legacy XDCP™ products including the ISL23418 series.

The ISL23418 product line was designed specifically for low-power, mixed-voltage analog trimming in portable and harsh-environment electronics-emphasizing SPI flexibility, wide supply tolerance, and guaranteed monotonicity.

FAQ

What is the default wiper position of the ISL23418TFRUZ-T7A at power-up?

The ISL23418TFRUZ-T7A powers up with its wiper at mid-scale (64-tap position, WR = 40h), ensuring a defined and repeatable output voltage regardless of prior state. This behavior is hardwired and occurs every time VCC and VLOGIC rise above their minimum thresholds, providing deterministic startup for safety-critical or calibration-sensitive systems using the ISL23418TFRUZ-T7A.

Does the ISL23418TFRUZ-T7A support daisy-chaining with other DCPs?

Yes, the ISL23418TFRUZ-T7A supports SPI daisy-chaining: connect the SDO pin of one device to the SDI pin of the next, while sharing SCK and CS lines. This allows simultaneous configuration of multiple ISL23418TFRUZ-T7A units using a single SPI bus, reducing microcontroller pin count and simplifying PCB routing in multi-channel biasing applications.

What is the maximum allowable voltage on the RH, RL, or RW pins of the ISL23418TFRUZ-T7A?

The RH, RL, and RW pins of the ISL23418TFRUZ-T7A must remain within 0V to VCC at all times-including during power-up, power-down, and normal operation. Exceeding this range risks latch-up or permanent damage. The absolute maximum rating is −0.3V to 6.0V, but functional operation is strictly bounded by VCC, making proper sequencing of VCC and signal sources essential in the ISL23418TFRUZ-T7A design.

How does the shutdown mode affect the wiper terminal (RW) in the ISL23418TFRUZ-T7A?

In shutdown mode (SHDN bit = 0 in ACR), the ISL23418TFRUZ-T7A opens the RH–RL path and internally connects RW to RL through a ~2kΩ resistor. This prevents floating outputs and provides a defined low-impedance path, critical for system safety in fault conditions. Wiper register contents are preserved, and RW returns to its pre-shutdown position within 1.5µs after exit.

Can the ISL23418TFRUZ-T7A operate with VLOGIC = 1.2V while VCC = 5.5V?

Yes, the ISL23418TFRUZ-T7A fully supports independent supply rails: VLOGIC can be as low as 1.2V (enabling direct interface with 1.2V/1.8V MCUs) while VCC operates up to 5.5V (supporting higher-voltage analog signal chains). This decoupling eliminates external level shifters and ensures robust SPI communication even in mixed-supply systems using the ISL23418TFRUZ-T7A.