BU21025GUL-E2

Overview

The BU21025GUL-E2 is a low-power 4-wire resistive touch screen controller manufactured by ROHM Semiconductor. It integrates a 12-bit SAR A/D converter to measure coordinates and touch pressure, featuring a built-in digital filter for noise reduction. The device operates on a single supply voltage ranging from 1.65V to 3.60V, with a typical operating current of 120µA and a maximum standby current of 0.8µA. Communication is handled via a 2-wire serial interface (I²C compatible) supporting clock frequencies up to 400kHz. The component is housed in a VCSP50L2 package measuring 2.00mm x 1.50mm x 0.55mm.

Feature Summary

• Integrated 12-bit Successive Approximation Resistor (SAR) Analog-to-Digital Converter for high-resolution coordinate measurement.
• Built-in Median Average Filter (MAF) to reduce noise and improve signal stability during touch detection.
• Low power consumption with 0.8µA maximum standby current and auto power-down control capabilities.
• Supports 2-wire serial interface with SCL/SDA pins and programmable slave address bits via AD0 and AD1.

Applications

• Smartphones and tablets utilizing 4-wire resistive touch screens.
• Personal Digital Assistants (PDAs) and portable media players.
• Digital still cameras and digital video cameras.
• Portable TVs and PC peripherals such as laptop PCs and touch screen monitors.

Procurement Notes

Verify the specific suffix E2 against the manufacturer's current documentation to confirm compliance with RoHS directives and lead-free manufacturing standards. Confirm availability status as older revisions may be marked Not Recommended for New Designs (NRND). Ensure the ordering quantity aligns with the standard tape and reel packaging quantity of 3000 pieces.

Selection Notes

Select this component for designs requiring a compact footprint and low standby current in battery-operated devices. Ensure the system microcontroller supports the required 2-wire serial protocol and can handle the active low interrupt output. Verify that the supply voltage range of 1.65V to 3.60V matches the target system's power rail. Consider the internal clock frequency tolerance if precise timing is critical for the application.

Part Context

The BU21025GUL series belongs to ROHM's portfolio of touch screen controllers designed for portable electronics. The BU21025GUL specifically targets 4-wire resistive interfaces, distinguishing it from capacitive or other resistive variants in the family. The E2 suffix typically denotes environmental compliance features such as halogen-free materials and RoHS adherence, consistent with ROHM's product naming conventions.

Replacement Considerations

Consult the official ROHM replacement guide for direct pin-compatible alternatives. The BU21021GUL is a related model but supports different interface configurations; verify functional equivalence before substitution. No public substitute part numbers are explicitly listed in the provided datasheet text.