Renesas ISL23315TFUZ-TK

Overview

ISL23315TFUZ-TK from Renesas (formerly Intersil) is a volatile, low-voltage, I²C-controlled digital potentiometer with 256 taps, 100 kΩ end-to-end resistance, ±2% resistance tolerance, and operation from -40°C to +125°C. It functions as a three-terminal potentiometer or two-terminal rheostat in precision analog adjustment circuits, including power supply margining and RF amplifier bias control.

For engineers reviewing the ISL23315TFUZ-TK datasheet, ISL23315TFUZ-TK pinout, ISL23315TFUZ-TK application, or ISL23315TFUZ-TK equivalent, key selection criteria include its dual-supply architecture (VCC = 1.7–5.5 V, VLOGIC = 1.2–5.5 V), mid-scale power-on default (128), shutdown mode with RW–RL short, and MSOP-10 package compatibility with industrial temperature requirements.

Technical Context

The ISL23315TFUZ-TK implements a monolithic CMOS resistor ladder with CMOS wiper switches operating in "make-before-break" mode, ensuring glitch-free tap transitions. Its volatile Wiper Register (WR) is directly accessible via I²C, supporting read/write operations without nonvolatile storage.

It features independent VLOGIC and VCC supplies enabling direct interface with 1.2 V logic without level shifters, and integrates an Access Control Register (ACR) for shutdown control (SHDN bit) and status management - all within a single 10-pin MSOP package rated for extended industrial temperature range.

Key Specifications

Pinout & Package

ISL23315TFUZ-TK is packaged in a Pb-free, RoHS-compliant 10-lead MSOP (M10.118) with 0.5 mm pitch and thermal pad exposed on bottom.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AD5175BRMZ-100 and MCP45HV51-103E/MS, ISL23315TFUZ-TK uniquely supports dual-supply operation down to 1.2 V logic while maintaining 100 kΩ precision and industrial temperature capability - making it optimal for mixed-voltage embedded systems requiring deterministic startup behavior without nonvolatile overhead.

Availability

ISL23315TFUZ-TK is available at Aetrix Electronics and suitable for power supply margining, RF amplifier biasing, LCD panel calibration, and laser diode control requiring stable component supply across extended temperature and mixed-voltage designs.

Supply support for ISL23315TFUZ-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 its precision analog portfolio, emphasizing high-reliability, extended-temperature ICs for industrial and automotive markets.

The ISL23315TFUZ-TK belongs to Renesas' XDCP™ (eXternally Controlled Digital Potentiometer) family, designed specifically for replacing mechanical pots in harsh-environment analog trimming applications where programmability, small size, and supply flexibility are critical.

FAQ

What is the default wiper position of the ISL23315TFUZ-TK at power-on?

The ISL23315TFUZ-TK powers up with its volatile Wiper Register (WR) preset to 128 (0x80), placing the wiper at mid-scale - i.e., approximately 50 kΩ between RH and RW, and 50 kΩ between RW and RL. This behavior is guaranteed across the full -40°C to +125°C temperature range and does not require host initialization. The ISL23315TFUZ-TK maintains this deterministic startup state regardless of prior shutdown or power-cycle history.

Does the ISL23315TFUZ-TK support true 1.2 V I²C bus operation?

Yes - the ISL23315TFUZ-TK explicitly supports VLOGIC down to 1.2 V, with validated input thresholds (VIH = 0.7 × VLOGIC, VIL = 0.3 × VLOGIC) and VOL ≤ 0.2 × VLOGIC at 1.5 mA. This allows direct connection to 1.2 V GPIOs of modern ultra-low-power MCUs without external level shifters. The ISL23315TFUZ-TK's internal level shifter isolates logic signaling from the analog VCC domain, preserving signal integrity.

Can the ISL23315TFUZ-TK be used in rheostat mode, and what are the key limitations?

Yes - the ISL23315TFUZ-TK operates in rheostat mode by connecting either RH or RL to the same node and using RW and the unconnected terminal. In this configuration, resistance between RW and RL (or RW and RH) is adjustable from near-zero to 100 kΩ. Key limitations include ±0.3 LSB DNL (typical), 70 Ω wiper resistance affecting low-impedance paths, and maximum wiper current of ±3 mA - all specified in the ISL23315TFUZ-TK datasheet under rheostat test conditions.

How does shutdown mode affect the ISL23315TFUZ-TK's terminals?

In shutdown mode (activated via SHDN bit in ACR register), the ISL23315TFUZ-TK forces an open circuit between RH and RL while internally shorting RW to RL through a ~2 kΩ resistor. This provides a defined, low-impedance path for bias networks during fault or standby states. The wiper position is retained in the volatile register and restored upon exit from shutdown, with recall time specified as 1.5 µs (tShdnRec) in the ISL23315TFUZ-TK datasheet.

What is the maximum I²C clock frequency supported by the ISL23315TFUZ-TK?

The ISL23315TFUZ-TK supports standard-mode I²C operation up to 400 kHz, with timing parameters fully characterized across VLOGIC = 1.2–5.5 V and temperature (-40°C to +125°C). Key specs include tLOW ≥ 1300 ns, tHIGH ≥ 600 ns, and tSU:STA ≥ 600 ns - all compliant with I²C specification v2.1. The ISL23315TFUZ-TK does not support fast-mode plus (1 MHz) or high-speed mode.