Renesas ISL23315UFRUZ-T7A

Overview

ISL23315UFRUZ-T7A from Renesas (formerly Intersil) is a volatile, low-voltage, I²C-controlled digital potentiometer with 256 taps, 50kΩ end-to-end resistance, ±0.15 LSB typical INL in voltage divider mode, and operation from 1.2V VLOGIC/1.7V VCC - used for precision bias compensation in RF power amplifiers and laser diode drivers.

For engineers reviewing the ISL23315UFRUZ-T7A datasheet, ISL23315UFRUZ-T7A pinout, ISL23315UFRUZ-T7A application, or ISL23315UFRUZ-T7A equivalent, key selection factors include its dual-supply independence (VLOGIC down to 1.2V), shutdown-mode wiper-to-RL short (2kΩ), 10 Ld µTQFN package (2.1×1.6 mm), and guaranteed monotonicity across -40°C to +125°C.

Technical Context

The ISL23315UFRUZ-T7A implements a resistor ladder with CMOS "make-before-break" wiper switching controlled by an 8-bit volatile Wiper Register (WR), initialized to 128 (mid-scale) at power-on. Its I²C interface supports up to 4 devices per bus via A0/A1 address pins and requires no level shifter due to independent VLOGIC supply.

It operates in two primary modes: voltage divider (RH–RW–RL) with ratiometric tracking (4 ppm/°C TCV typical), and rheostat (RW–RL or RW–RH) with <±0.3 MI DNL. Shutdown mode forces RH–RL open-circuit while shorting RW to RL through ~2kΩ, retaining WR value for fast recall (1.5 µs).

Key Specifications

Pinout & Package

ISL23315UFRUZ-T7A uses a 10-lead µTQFN package (2.1 mm × 1.6 mm, 0.5 mm pitch, exposed pad). Pinout is identical to the MSOP variant but with different physical numbering; functional mapping is consistent.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ISL23315UFRUZ-T7A, AD5175BRMZ-50 trades volatile operation for nonvolatile memory and adds SPI-only interface, while MCP45HV51-503E/MS extends voltage range at the cost of package size and VLOGIC decoupling - making ISL23315UFRUZ-T7A optimal for compact, low-voltage, I²C-based precision bias control.

Availability

ISL23315UFRUZ-T7A is available at Aetrix Electronics and suitable for RF power amplifier bias, laser diode compensation, and power supply margining requiring stable component supply across extended temperature and low-voltage operation.

Supply support for ISL23315UFRUZ-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 high-performance analog portfolio, emphasizing precision, low-power, and automotive-grade reliability.

The ISL23315UFRUZ-T7A belongs to Renesas' XDCP™ (eXternally Digital Controlled Potentiometer) family, designed specifically for replacing mechanical trimpots in closed-loop analog control, bias tuning, and calibration-critical systems.

FAQ

What is the default wiper position of the ISL23315UFRUZ-T7A at power-on?

The ISL23315UFRUZ-T7A 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 ensures predictable startup behavior in voltage divider and rheostat configurations without host initialization.

Does the ISL23315UFRUZ-T7A support true 1.2V I²C communication?

Yes. The ISL23315UFRUZ-T7A accepts VLOGIC as low as 1.2V, and its SDA/SCL input thresholds scale with VLOGIC (VIH = 0.7×VLOGIC, VIL = 0.3×VLOGIC). With 1.2V VLOGIC, VIH is 0.84V and VIL is 0.36V - fully compatible with 1.2V logic families without level shifting.

Can the ISL23315UFRUZ-T7A be used in rheostat mode with only two terminals?

Yes. The ISL23315UFRUZ-T7A supports rheostat operation by connecting either RW–RL (with RH left unconnected) or RW–RH (with RL left unconnected). In this mode, it provides 0–50 kΩ variable resistance with ±0.3 MI DNL typical and monotonic response across all taps.

What happens to the wiper position during shutdown mode of the ISL23315UFRUZ-T7A?

In shutdown mode (SHDN bit = 0 in ACR), the ISL23315UFRUZ-T7A opens the RH–RL path and internally shorts RW to RL through ~2 kΩ. Crucially, the WR register value is retained, so the wiper returns to its exact pre-shutdown position within 1.5 µs after exit - enabling rapid resumption of calibrated settings.

Is the ISL23315UFRUZ-T7A RoHS compliant and lead-free?

Yes. The ISL23315UFRUZ-T7A carries an e4 NiPdAu termination finish and is RoHS compliant per EU Directive 2011/65/EU. It is rated MSL-1 and qualified for Pb-free reflow per IPC/JEDEC J-STD-020, with peak reflow temperature up to 260°C.