Renesas ISL23445UFRZ-T7A

Overview

ISL23445UFRZ-T7A from Renesas Electronics (formerly Intersil) is a quad, 256-tap, volatile digitally controlled potentiometer with SPI interface, 50kΩ total resistance, 1.7V–5.5V analog supply (VCC), and independent 1.2V–5.5V logic supply (VLOGIC). It integrates four DCP cores, wiper registers, and shutdown mode for battery-powered sensor trimming and gain adjustment.

For engineers reviewing the ISL23445UFRZ-T7A datasheet, ISL23445UFRZ-T7A pinout, ISL23445UFRZ-T7A application, or ISL23445UFRZ-T7A equivalent, key selection criteria include its 50kΩ end-to-end resistance, ±0.15 LSB typical INL in voltage divider mode, 70Ω typical wiper resistance at 3.3V, -40°C to +125°C operation, and 20-lead 3×4 mm QFN package with daisy-chain SPI support.

Technical Context

The ISL23445UFRZ-T7A implements four independent resistor arrays using CMOS switches in make-before-break configuration, each controlled by an 8-bit volatile Wiper Register (WR0–WR3). Wiper position is updated via SPI Mode 0 (CPOL=0, CPHA=0), with data latched on SCK rising edge and output shifted on falling edge.

It supports dual-supply operation: VCC powers analog DCP sections (1.7V–5.5V), while VLOGIC powers digital logic and level-shifting circuitry (1.2V–5.5V), enabling direct interfacing with low-voltage microcontrollers without external level shifters. Shutdown mode disconnects DCP resistors and shorts each RW to RL through 2kΩ internal resistors.

Key Specifications

Pinout & Package

ISL23445UFRZ-T7A is housed in a 20-lead, 3mm × 4mm, 0.5mm pitch QFN package (Pb-free, RoHS compliant) with exposed thermal pad. Pin 1 is marked by dot; pin numbering follows standard QFN top-view convention.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ISL23445UFRZ-T7A, ISL23425UFRZ offers identical DCP performance but sacrifices flexible logic-level interfacing, while MCP42050-I/SL trades precision and package size for broader distributor availability and simpler PCB assembly.

Availability

ISL23445UFRZ-T7A is available at Aetrix Electronics and suitable for power supply margining, sensor circuit trimming, and RF amplifier bias compensation requiring stable component supply across automotive, industrial, and portable instrumentation markets.

Supply support for ISL23445UFRZ-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 Corporation is a global semiconductor leader delivering trusted embedded design innovation, with origins in Intersil's precision analog portfolio acquired in 2017.

The ISL23445UFRZ-T7A belongs to Renesas' XDCP™ (eXtreme Digital Controlled Potentiometer) family, engineered for high-accuracy, low-power, multi-channel analog tuning in space-constrained, thermally demanding environments.

FAQ

What is the default wiper position of the ISL23445UFRZ-T7A at power-on?

At power-on, all four wiper registers (WR0–WR3) of the ISL23445UFRZ-T7A reset to 128 (0x80 hex), positioning each wiper at mid-scale - i.e., 25kΩ from RL and 25kΩ from RH in the 50kΩ device. This behavior is guaranteed across the full -40°C to +125°C operating range and ensures a known, centered startup state without requiring initialization firmware.

Does the ISL23445UFRZ-T7A support daisy-chaining with other DCPs?

Yes, the ISL23445UFRZ-T7A supports daisy-chaining via its SPI interface: multiple devices share SDI, SCK, and CS lines, while each uses a dedicated SDO pin. The host sends sequential instruction/data bytes - the first device consumes its byte and passes remaining bytes downstream. This eliminates additional GPIOs and simplifies layout in multi-channel calibration systems using several ISL23445UFRZ-T7A units.

What is the maximum SPI clock frequency supported by the ISL23445UFRZ-T7A?

The ISL23445UFRZ-T7A supports up to 5MHz SCK frequency when VLOGIC ≥ 1.7V. At lower logic supplies (1.2V–1.6V), the maximum SCK frequency is reduced to 1MHz to ensure reliable timing margins. All SPI timing parameters - including tSU, tH, tWH, and tWL - are specified and guaranteed across this range, enabling robust communication in both high-speed and ultra-low-voltage host environments.

How does the shutdown mode affect the wiper connections in the ISL23445UFRZ-T7A?

In shutdown mode (SHDN bit = 0 in ACR), the ISL23445UFRZ-T7A forces each DCP into an end-to-end open circuit (RH–RL disconnected) and internally connects each RW terminal to its corresponding RL terminal through a 2kΩ series resistor. This isolates the potentiometer from the signal path while maintaining wiper register contents, allowing immediate resumption of prior settings upon exit - with wiper settling completed within 1.5µs after CS rising edge.

Can the ISL23445UFRZ-T7A be used in rheostat mode, and what are the key specifications in that configuration?

Yes, the ISL23445UFRZ-T7A supports rheostat mode by connecting only RW and RL (or RW and RH) while leaving the third terminal unconnected. In this mode, it delivers ±0.3 MI typical RINL and ±0.15 MI typical RDNL for the 50kΩ version at VCC ≥ 2.7V, with 2.1 MI max offset at 1.7V. Its 70Ω typical wiper resistance and 256-step resolution enable precise, low-noise current-source or gain-control applications without mechanical wear.