Renesas ISL23315UFUZ-TK

Overview

ISL23315UFUZ-TK from Renesas (formerly Intersil) is a volatile, single-channel, 256-tap digitally controlled potentiometer (DCP) with I²C interface, 50 kΩ end-to-end resistance, 10-lead MSOP package, and operation from 1.7V VCC / 1.2V VLOGIC - used for precision bias compensation in RF power amplifiers and laser diode drivers.

For engineers reviewing the ISL23315UFUZ-TK datasheet, ISL23315UFUZ-TK pinout, ISL23315UFUZ-TK application, or ISL23315UFUZ-TK equivalent, key selection criteria include wiper settling time (1.5 µs), shutdown mode behavior (RW shorted to RL via ~2 kΩ), ratiometric tempco (4 ppm/°C), low-power standby current (<1 µA at 1.2V/1.7V), and dual-supply independence between analog and logic domains.

Technical Context

The ISL23315UFUZ-TK implements a monolithic CMOS resistor ladder with CMOS wiper switches operating in "make-before-break" mode, controlled by an 8-bit volatile Wiper Register (WR) accessible via standard I²C protocol. Its dual-supply architecture isolates VLOGIC (1.2–5.5 V) from VCC (1.7–5.5 V), enabling direct interfacing with low-voltage microcontrollers without level shifters.

It supports four device addresses via A0/A1 pins, features power-on reset to mid-scale (WR = 128), and includes a dedicated Access Control Register (ACR) for shutdown control (SHDN bit). Shutdown forces RH–RL open-circuit while internally connecting RW to RL through a ~2 kΩ path - preserving WR state and enabling fast recall (1.5 µs).

Key Specifications

Pinout & Package

ISL23315UFUZ-TK uses a 10-lead MSOP package (M10.118, 3.0 × 3.0 mm, 0.5 mm pitch) with exposed pad for thermal enhancement. Pin numbering follows standard top-view orientation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ISL23315UFUZ-TK, the ISL23315TFUZ-TK offers higher resistance and lower tempco for precision high-Z biasing, while the MCP45HV51-502E/P trades dual-supply operation for nonvolatile wiper storage - making it suitable for fail-safe systems but incompatible with 1.2 V I²C buses.

Availability

ISL23315UFUZ-TK is available at Aetrix Electronics and suitable for RF amplifier calibration, laser diode biasing, LCD panel tuning, and power supply margining requiring stable component supply across extended temperature and low-voltage logic environments.

Supply support for ISL23315UFUZ-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, including digitally controlled potentiometers optimized for industrial and communications infrastructure.

The ISL23315 series was designed specifically for high-accuracy, low-power, multi-supply analog trimming in battery-powered and thermally demanding systems - emphasizing I²C compatibility, wide voltage operation, and robust parametric stability.

FAQ

What is the default wiper position after power-on for the ISL23315UFUZ-TK?

The ISL23315UFUZ-TK powers up with its volatile Wiper Register (WR) preset to 128 (0x80), placing the wiper at mid-scale - i.e., approximately 25 kΩ between RL and RW, and 25 kΩ between RW and RH. This behavior is guaranteed across all operating conditions and ensures deterministic startup in voltage divider or rheostat configurations.

Does the ISL23315UFUZ-TK support true 1.2 V I²C communication?

Yes - the ISL23315UFUZ-TK accepts VLOGIC down to 1.2 V, with verified VIH ≥ 0.7×VLOGIC and VOL ≤ 0.2×VLOGIC at 1.5 mA sink. Its internal level shifter eliminates need for external translation when interfacing with 1.2 V microcontrollers or FPGAs, unlike legacy DCPs requiring ≥1.8 V logic.

How does shutdown mode affect the RW terminal in the ISL23315UFUZ-TK?

In shutdown mode (SHDN bit = 0 in ACR), the ISL23315UFUZ-TK opens the RH–RL path and internally connects RW to RL through a ~2 kΩ resistor. The wiper register value is retained, and RW returns to its prior position within 1.5 µs after exiting shutdown - enabling rapid reactivation without host reconfiguration.

What is the maximum recommended capacitive load on the SDA/SCL lines for reliable I²C operation with the ISL23315UFUZ-TK?

The ISL23315UFUZ-TK specifies a maximum total bus capacitance (Cb) of 400 pF for SDA and SCL. With typical pin capacitance of 10 pF per line, this allows up to ~390 pF of external trace + stub + device loading. Rise/fall times remain within spec (≤250 ns) if RC time constant stays below 100 ns, supporting robust 400 kHz operation in dense PCB layouts.

Can the ISL23315UFUZ-TK be used in rheostat mode, and what are the key specifications in that configuration?

Yes - the ISL23315UFUZ-TK supports rheostat mode (RW–RL or RW–RH). In this mode, it delivers ±0.3 MI differential nonlinearity, 2.1 MI offset error at 1.7 V, and 100 ppm/°C resistance tempco. These specs ensure stable, monotonic resistance adjustment for current-setting and gain-control applications without requiring RH or RL termination.