2-Wire Bus Dual Digitally-Controlled (XDCP) Potentiometers

Category: Converters, Electronics, Intersil Corporation

Overview of RENESAS X9268 Dual Supply/Low Power/256-Tap/2-Wire Bus Dual Digitally-Controlled Potentiometers

The X9268 by RENESAS is a sophisticated integrated circuit that features dual digitally-controlled potentiometers (XDCP). This datasheet provides detailed specifications, describing the features and functions of the X9268 device. Each potentiometer of the X9268 has 256 resistor taps, offering 0.4% resolution for precise control.

Key Features

The datasheet emphasizes the device’s dual potentiometer configuration that operates through a 2-wire serial interface enabling write, read, and transfer operations. It has a low standby current (<5uA max), and operates between a power supply voltage of ±2.7V to ±5.5V. The two potentiometers allow for multiple nonvolatile data registrations, capable of 100,000 data changes per bit per register, and offer a notable data retention period of 100 years. Wiper resistance is typically 100 ohms at a dual supply of ±5V.

Applications

Applications for the X9268 range widely, including but not limited to control mechanisms, parameter adjustments, and signal processing. It can be utilized both as a three-terminal potentiometer or as a two-terminal variable resistor, showcasing its versatility. The state-of-the-art design offers low power consumption and is presented in a 24 Ld SOIC package with Pb-Free Plus Anneal available for RoHS compliance.

Description and Functionality

The datasheet delves into the X9268’s description, explaining the digitally controlled potentiometer as an assembly of 255 resistive elements in a series array. User control is executed through a 2-wire bus interface which manipulates the wiper position across these elements. Each potentiometer comes with a volatile Wiper Counter Register (WCR) and four nonvolatile Data Registers (DR0-DR3) for adjusting and recalling wiper positions.

Power-On Recall Feature

A notable characteristic is the power-on recall, automatically loading saved wiper positions upon startup. This feature is very convenient for systems that frequently power cycle and require consistent start-up states.

Functional Diagram and Interface

The first two pages also include a functional diagram, illustrating the X9268’s internal structure, which incorporates a 2-wire bus interface for communication, along with control and interface components for handling addressing, data status, read, write, transfer, increment/decrement commands, and power-on recall operations. The diagram indicates 50kΩ or 100kΩ versions for the resistance range of the potentiometers.