Renesas ISL23418TFUZ-TK

Overview

ISL23418TFUZ-TK from Renesas Electronics (formerly Intersil) is a volatile, single-channel, 128-tap digitally controlled potentiometer (XDCP™) with SPI interface, 100kΩ end-to-end resistance, 70Ω typical wiper resistance at 3.3V, and operation from 1.7V to 5.5V VCC and 1.2V to 5.5V VLOGIC. It serves as a programmable voltage divider or rheostat in precision biasing and gain control circuits.

For engineers reviewing the ISL23418TFUZ-TK datasheet, ISL23418TFUZ-TK pinout, ISL23418TFUZ-TK application, or ISL23418TFUZ-TK equivalent, this page delivers verified electrical specs, µTQFN-10 package layout, shutdown behavior, temperature coefficient data, and real-world use cases in RF amplifier biasing and LCD voltage adjustment - all confirmed against FN7901 Rev 1.00.

Technical Context

The ISL23418TFUZ-TK implements a monolithic CMOS resistor ladder with CMOS switch matrix and volatile 8-bit Wiper Register (WR), enabling precise digital control of wiper position via SPI Mode 0 (rising-edge clock-in, falling-edge clock-out). Its "make-before-break" switching ensures glitch-free transitions between taps.

It features independent VLOGIC and VCC supplies, allowing direct interfacing with 1.2V logic without level shifters, and integrates shutdown mode that forces RH–RL open-circuit while shorting RW to RL through ~2kΩ. Power-on defaults WR to 64 (mid-scale), and wiper settling time is 300ns for large-signal transitions.

Key Specifications

Pinout & Package

ISL23418TFUZ-TK is housed in a 10-lead 2.1mm × 1.6mm µTQFN package (RoHS-compliant, MSL Level 3, pkg drawing L10.2.1x1.6A), with wettable flanks and exposed 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 MCP41HV51-104E/MS, the ISL23418TFUZ-TK delivers lowest wiper resistance (70Ω), fastest settling (300ns), and widest VLOGIC range (1.2V–5.5V), making it optimal for low-noise, battery-constrained, and mixed-voltage embedded systems where volatility is acceptable.

Availability

ISL23418TFUZ-TK is available at Aetrix Electronics and suitable for power supply margining, RF amplifier bias compensation, LCD bias adjustment, and portable medical equipment calibration requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for ISL23418TFUZ-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 XDCP™ digitally controlled potentiometers, with focus on high-reliability industrial and automotive applications.

The ISL23418TFUZ-TK belongs to Renesas' XDCP™ family, designed specifically for replacing mechanical potentiometers in automated calibration, adaptive biasing, and programmable gain control systems where digital configurability, small footprint, and extended temperature operation are critical.

FAQ

What is the default wiper position of the ISL23418TFUZ-TK at power-on?

The ISL23418TFUZ-TK powers up with its volatile Wiper Register (WR) preset to 64 (0x40 hexadecimal), placing the wiper at mid-scale - exactly halfway between RL and RH terminals. This guarantees a known, repeatable startup voltage in voltage divider configurations and avoids undefined output states during system initialization. The ISL23418TFUZ-TK does not retain wiper position across power cycles due to its volatile register architecture.

Can the ISL23418TFUZ-TK operate with a 1.2V microcontroller SPI interface?

Yes - the ISL23418TFUZ-TK supports VLOGIC down to 1.2V, allowing direct connection to low-voltage microcontrollers without level-shifting circuitry. Its input thresholds scale with VLOGIC (VIH = 0.7×VLOGIC, VIL = 0.3×VLOGIC), and it accepts SCK frequencies up to 1MHz at 1.2V. This capability is explicitly validated in FN7901 Rev 1.00 Section "Serial Interface Specification" and makes the ISL23418TFUZ-TK ideal for energy-efficient portable designs.

What happens to the ISL23418TFUZ-TK wiper during shutdown mode?

In shutdown mode (activated by setting SHDN bit in ACR), the ISL23418TFUZ-TK disconnects RH from RL (open-circuit end-to-end) and internally shorts RW to RL through a ~2kΩ resistor. This provides a defined, low-impedance path for the wiper while isolating the high-side terminal - a safety feature useful during firmware updates or fault recovery. The WR value remains intact, and the wiper returns to its prior position within 1.5µs after shutdown exit.

Does the ISL23418TFUZ-TK support daisy-chaining with other DCPs?

Yes - the ISL23418TFUZ-TK supports SPI daisy-chaining: connect the SDO of one device to the SDI of the next, while sharing SCK and CS lines. This allows simultaneous configuration of multiple ISL23418 units using a single SPI bus, reducing MCU pin count and PCB routing complexity. Daisy-chain operation is documented in FN7901 Rev 1.00 Section "Daisy Chain Configuration" and requires no additional hardware or protocol modifications.

What is the maximum allowable voltage on the RH, RL, or RW pins of the ISL23418TFUZ-TK?

The absolute maximum voltage on any DCP terminal (RH, RL, or RW) is limited to the VCC supply voltage - not to exceed VCC at any time, including during power-up sequencing. Exceeding VCC risks latch-up or permanent damage. The ISL23418TFUZ-TK's DCP terminal voltage range is strictly 0V to VCC, as specified in FN7901 Rev 1.00 "Recommended Operating Conditions" and "Absolute Maximum Ratings". This constraint applies regardless of VLOGIC level.