Renesas ISL23318TFRUZ-T7A

Overview

ISL23318TFRUZ-T7A from Renesas (formerly Intersil) is a volatile, single-channel, 128-tap digitally controlled potentiometer (DCP) with I²C interface, 100kΩ end-to-end resistance, ±0.15 LSB differential nonlinearity, and operation from -40°C to +125°C. It functions as a precision voltage divider or rheostat in gain control, sensor trimming, and power supply margining circuits.

For engineers reviewing the ISL23318TFRUZ-T7A datasheet, ISL23318TFRUZ-T7A pinout, ISL23318TFRUZ-T7A application, or ISL23318TFRUZ-T7A equivalent, key selection criteria include its 1.2V–5.5V VLOGIC independence, 70Ω typical wiper resistance at 3.3V, shutdown mode with internal RW–RL short, 10-lead UTQFN package (2.1×1.6mm), and guaranteed monotonicity across temperature.

Technical Context

The ISL23318TFRUZ-T7A implements a resistor ladder with CMOS switch matrix controlled by a volatile 7-bit Wiper Register (WR), initialized to 64 (mid-scale) on power-up. Its I²C interface supports up to four devices per bus via A0/A1 address pins and operates without level shifters down to 1.2V logic.

It features make-before-break switching, ratiometric temperature coefficient as low as 2.3 ppm/°C (T-option), and dual-supply architecture: VCC (1.7–5.5V) powers analog circuitry while VLOGIC (1.2–5.5V) independently supplies the I²C interface-enabling direct interfacing with low-voltage microcontrollers.

Key Specifications

Pinout & Package

ISL23318TFRUZ-T7A uses a 10-lead UTQFN package (Pb-free, RoHS compliant, MSL3). Pinout is identical to the MSOP variant but arranged in a 2.1×1.6mm body with bottom thermal pad.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AD5170BRMZ-100 and MCP45HV51-103E/MS, the ISL23318TFRUZ-T7A uniquely combines 1.2V I²C compatibility, 100kΩ resistance, and 2.1×1.6mm UTQFN packaging-making it optimal for space-constrained, multi-rail embedded systems requiring deterministic startup behavior and minimal BOM overhead.

Availability

ISL23318TFRUZ-T7A is available at Aetrix Electronics and suitable for battery-powered instrumentation, sensor signal conditioning, and power supply margining requiring stable component supply across extended temperature and long product lifecycles.

Supply support for ISL23318TFRUZ-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 its precision analog portfolio, emphasizing high-reliability, extended-temperature ICs for industrial and automotive markets.

The ISL23318TFRUZ-T7A belongs to Renesas' XDCP™ (eXternally Digitally Controlled Potentiometer) family, designed specifically for replacing mechanical pots in automated calibration, adaptive biasing, and programmable analog front-ends where repeatability, longevity, and digital control are essential.

FAQ

What is the default wiper position of the ISL23318TFRUZ-T7A at power-on?

The ISL23318TFRUZ-T7A initializes its volatile Wiper Register (WR) to 64 (hex 40) on every power-up, placing the wiper at mid-scale (64th tap) between RH and RL terminals. This behavior is guaranteed across the full -40°C to +125°C operating range and ensures a known, repeatable starting point for system calibration sequences without requiring host initialization.

Does the ISL23318TFRUZ-T7A support true 1.2V I²C communication?

Yes, the ISL23318TFRUZ-T7A supports full I²C functionality-including START/STOP detection, ACK generation, and data transfer-at VLOGIC = 1.2V. Its input thresholds scale with VLOGIC (VIH = 0.7×VLOGIC, VIL = 0.3×VLOGIC), and VOL remains ≤0.2×VLOGIC at 1.5mA sink, enabling direct interface with 1.2V microcontrollers without level shifters.

How does the shutdown mode affect the ISL23318TFRUZ-T7A's terminals?

In shutdown mode (SHDN bit = 0 in Access Control Register), the ISL23318TFRUZ-T7A opens the RH–RL path and internally connects RW to RL through a ~2kΩ resistor. This creates a defined low-impedance path at RW while isolating RH, preventing floating nodes and ensuring safe default behavior during system sleep or fault conditions.

Can the ISL23318TFRUZ-T7A be used in rheostat mode with only two terminals?

Yes, the ISL23318TFRUZ-T7A supports rheostat operation by connecting either RH or RL to the same node as RW and leaving the unused terminal open. In this configuration, resistance between RW and the connected terminal is digitally adjustable from near-zero to 100kΩ, with guaranteed monotonicity and ±0.15 LSB DNL across temperature.

What is the maximum recommended wiper current for the ISL23318TFRUZ-T7A?

The absolute maximum wiper current for the ISL23318TFRUZ-T7A is ±6mA (per JESD78 latch-up test conditions), but the recommended operating limit is ±3mA. Exceeding ±3mA risks increased wiper resistance drift, reduced long-term reliability, and potential violation of the device's specified 70Ω typical wiper resistance at 3.3V.