Renesas ISL22424TFR16Z

Overview

ISL22424TFR16Z from Renesas (formerly Intersil) is a dual digitally controlled potentiometer (XDCP™) with 256-tap resolution, SPI interface, non-volatile wiper storage, and dual-supply operation (VCC = 2.25–5.5V, V− = −2.25 to −5.5V). It integrates two independent 100kΩ DCPs, 13 general-purpose non-volatile registers, and shutdown mode - used for precision gain/offset trimming in bipolar signal chains and programmable biasing in industrial sensor interfaces.

For engineers reviewing the ISL22424TFR16Z datasheet, ISL22424TFR16Z pinout, ISL22424TFR16Z application, or ISL22424TFR16Z equivalent, key selection criteria include dual-rail voltage support, ±45 ppm/°C end-to-end tempco, 70Ω typical wiper resistance, 1.5µs wiper response time, and QFN-16 package compatibility with high-density PCB layouts.

Technical Context

The ISL22424TFR16Z implements two independent resistor arrays using CMOS-switched ladder networks, each controlled by an 8-bit volatile Wiper Register (WRi) and backed by a non-volatile Initial Value Register (IVRi). At power-up, IVRi contents are automatically loaded into WRi, ensuring repeatable startup positions without host intervention.

Its SPI interface operates in Mode 0 (CPOL = 0, CPHA = 0), supporting daisy-chain configuration and full read/write access to all registers including 13 GP NV registers. Shutdown mode (SHDN bit in ACR) forces open-circuit DCP terminals and shorts RWi to RLi, reducing current to <4µA while preserving wiper state.

Key Specifications

Pinout & Package

ISL22424TFR16Z uses a 16-lead QFN package (4mm × 4mm, L16.4x4A) with exposed die pad internally connected to V−. Thermal land for EPAD should be connected to V− plane or left floating per TB389.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AD5242BRUZ100 and MCP42100-E/ST, the ISL22424TFR16Z uniquely supports true dual-supply operation enabling direct connection to ±V rails, includes 13 GP NV registers for system-level calibration storage, and offers QFN-16 packaging with thermal EPAD for improved power dissipation in high-density layouts.

Availability

ISL22424TFR16Z is available at Aetrix Electronics and suitable for industrial sensor conditioning, programmable gain amplifier calibration, and bipolar power supply trim requiring stable component supply across extended temperature ranges and long product lifecycles.

Supply support for ISL22424TFR16Z 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 industrial and automotive-grade components with robust process technology and long-term support.

The ISL22424TFR16Z belongs to Renesas' XDCP™ family of digitally controlled potentiometers, designed specifically for replacing mechanical trimpots in harsh-environment applications demanding non-volatile settings, wide temperature operation, and bipolar signal handling.

FAQ

What is the power-up behavior of the ISL22424TFR16Z?

At power-up, the ISL22424TFR16Z first resets both Wiper Registers (WR0/WR1) to 0x80 (mid-scale), then loads the stored values from the non-volatile Initial Value Registers (IVR0/IVR1) into WR0/WR1. This recall occurs within 5ms after VCC exceeds 1.9V, ensuring deterministic wiper positioning without host intervention. The ISL22424TFR16Z does not require external initialization to restore calibrated settings.

Does the ISL22424TFR16Z support daisy-chaining multiple devices on one SPI bus?

Yes, the ISL22424TFR16Z supports daisy-chain configuration via its SPI interface. Multiple ISL22424TFR16Z devices can share SCK, SDI, and CS lines, with SDO of one device connected to SDI of the next. The protocol allows sequential read/write operations across the chain using standard instruction bytes - no additional hardware or address decoding is needed for expansion.

How does shutdown mode affect the DCP terminals in the ISL22424TFR16Z?

In shutdown mode (activated by setting SHDN bit in ACR), each DCP is forced into an open-circuit state between RH and RL, while the wiper (RW) is internally shorted to RL. This eliminates current flow through the resistor array and prevents unintended signal coupling. The ISL22424TFR16Z draws <4µA in this state, and wiper position is retained for immediate restoration upon exit.

What is the maximum SPI clock frequency supported by the ISL22424TFR16Z?

The ISL22424TFR16Z supports SPI clock frequencies up to 5MHz under recommended operating conditions. Timing parameters including tCYC (200ns), tWH/tWL (100ns min), and tSU/tH (50ns min) are fully characterized at this rate. For reliable operation, ensure SCK rise/fall times ≤10ns and bus capacitance ≤30pF when using the SDO open-drain mode with external pull-up.

Can the ISL22424TFR16Z be used in rheostat mode, and what are the key specs in that configuration?

Yes, each DCP in the ISL22424TFR16Z can operate as a two-terminal variable resistor (rheostat) by connecting either RH or RL to the same node. In rheostat mode, it maintains ±0.4 LSB differential non-linearity (DNL) and ±1.5 MI integral non-linearity (INL) for the 100kΩ option. Wiper resistance remains 70Ω typical, and ratiometric tempco is ±4 ppm/°C - ideal for precision current-setting applications.