Renesas ISL23315TFRUZ-T7A

Overview

ISL23315TFRUZ-T7A from Renesas (formerly Intersil) is a volatile, low-voltage, I²C-controlled digital potentiometer with 256 taps, 100kΩ end-to-end resistance, ±0.15 LSB typical INL in voltage divider mode, and operation from 1.7V VCC / 1.2V VLOGIC. It serves as a precision programmable resistor in analog signal conditioning paths of power management and bias control circuits.

For engineers reviewing the ISL23315TFRUZ-T7A datasheet, ISL23315TFRUZ-T7A pinout, ISL23315TFRUZ-T7A application, or ISL23315TFRUZ-T7A equivalent, key selection criteria include its 10 Ld µTQFN package, shutdown-mode wiper-to-RL shorting, 70Ω typical wiper resistance at 3.3V, -40°C to +125°C extended temperature range, and independent VLOGIC supply enabling direct interface with 1.2V logic without level shifters.

Technical Context

The ISL23315TFRUZ-T7A integrates a monolithic CMOS resistor ladder with CMOS switch matrix and I²C interface logic, supporting both three-terminal potentiometer and two-terminal rheostat configurations. Its volatile Wiper Register (WR) is directly readable/writable via I²C, with power-on reset to mid-scale (128 decimal).

It features a dedicated VLOGIC pin decoupled from VCC, allowing bus-level compatibility across 1.2V–5.5V logic supplies while maintaining analog operation up to 5.5V. Shutdown mode forces RH–RL open-circuit and internally shorts RW to RL through ~2kΩ, preserving WR state for fast recovery.

Key Specifications

Pinout & Package

ISL23315TFRUZ-T7A uses a 10-lead 2.1mm × 1.6mm µTQFN package (Pb-free, RoHS compliant), with exposed thermal pad for enhanced thermal performance in compact layouts.

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, the ISL23315TFRUZ-T7A uniquely combines 100kΩ resistance, 1.2V VLOGIC compatibility, and µTQFN packaging-making it optimal for high-impedance, ultra-low-voltage bias control where nonvolatility is unnecessary and board space is constrained.

Availability

ISL23315TFRUZ-T7A is available at Aetrix Electronics and suitable for power supply margining, RF amplifier bias compensation, LCD panel VCOM calibration, and laser diode current regulation requiring stable component supply across automotive, industrial, and telecom design cycles.

Supply support for ISL23315TFRUZ-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 ISL23315 series was designed specifically for digitally programmable analog trimming in space-constrained, low-power systems-emphasizing I²C compatibility, wide supply flexibility, and robust thermal performance.

FAQ

What is the default wiper position of the ISL23315TFRUZ-T7A at power-on?

The ISL23315TFRUZ-T7A powers up with its volatile Wiper Register (WR) preset to 128 (0x80), placing the wiper at mid-scale-i.e., approximately 50kΩ from both RH and RL terminals in a 100kΩ device. This behavior is guaranteed across all operating conditions and eliminates undefined startup states in critical bias networks.

Can the ISL23315TFRUZ-T7A operate with a 1.2V I²C bus while VCC is at 5V?

Yes-the ISL23315TFRUZ-T7A supports independent supply rails: VLOGIC may be as low as 1.2V for I²C communication while VCC operates up to 5.5V for the analog resistor ladder. This eliminates external level shifters and allows direct interfacing with 1.2V/1.8V microcontrollers in mixed-voltage systems.

Does the ISL23315TFRUZ-T7A retain wiper position during shutdown mode?

Yes-when the SHDN bit in the Access Control Register is cleared, the ISL23315TFRUZ-T7A enters shutdown mode: RH–RL becomes an open circuit, RW is shorted to RL via ~2kΩ, and the WR register contents remain intact. Upon exit, the wiper returns to its pre-shutdown position after ≤1.5µs recall time.

What is the maximum recommended wiper current for the ISL23315TFRUZ-T7A?

The absolute maximum wiper current is ±6mA (10s duration), but the recommended operating limit is ±3mA. Exceeding ±3mA risks increased self-heating, which degrades linearity and accelerates resistance drift-particularly critical in precision bias and calibration applications using the ISL23315TFRUZ-T7A.

Is the ISL23315TFRUZ-T7A pin-compatible with other variants in the ISL23315 family?

Yes-the ISL23315TFRUZ-T7A shares identical 10 Ld µTQFN pinout and functionality with ISL23315TFRUZ-TK and all MSOP variants (e.g., ISL23315TFUZ). Resistance value (10kΩ/50kΩ/100kΩ) and package type (µTQFN vs. MSOP) are the only distinguishing factors; no PCB layout change is needed when substituting within the same package family.