BU21023MUV-E2

Overview

The BU21023MUV-E2 is a silicon monolithic integrated circuit resistive touch screen controller manufactured by Rohm Semiconductor. It supports 4-wire resistive touch screens with dual-touch detection and gesture recognition capabilities, including pinch, spread, and rotation. The device operates on a single 3V power supply within a voltage range of 2.7V to 3.6V. It features a 10-bit ADC for coordinate resolution and offers selectable 4-wire SPI or 2-wire serial host interfaces. The component is housed in a VQFN028V5050 package measuring 5.00 mm x 5.00 mm x 1.00 mm and functions within an operating temperature range of -20°C to +85°C.

Feature Summary

• Enables dual-touch detection and gesture recognition (pinch, spread, rotate) on standard 4-wire resistive screens.
• Supports firmware download from a HOST processor or external EEPROM via dedicated interface pins.
• Includes programmable interrupt polarity and adjustable touch detection thresholds for pressure sensitivity tuning.
• Integrates internal filtering options to eliminate false coordinates and intelligent calibration support.

Applications

• Smartphones and tablet PCs requiring pan and zoom operations.
• Digital cameras, video cameras, and GPS receivers.
• Automotive navigation screens and touch kiosks.
• Notebook PCs and LCD displays with USB interfaces.

Procurement Notes

Verify the specific ordering suffix E2, which denotes embossed tape and reel packaging. Confirm that the design accommodates the discontinued status often associated with this model series. Ensure compatibility with the VQFN028V5050 footprint and thermal pad grounding requirements specified in the datasheet application notes.

Selection Notes

Select this controller when using 4-wire resistive touch panels instead of capacitive ones to reduce development costs. Choose the SPI interface if higher speed data transfer is required, or the 2-wire serial interface for simpler pin counts. Ensure the host system can provide the necessary 2.7V to 3.6V supply voltage and supports the 10-bit ADC resolution requirements.

Part Context

This component belongs to the BU21023 series of resistive touch screen controllers. It shares functional similarities with the BU21023GUL but differs in package type, utilizing the VQFN028V5050 form factor. The series is designed to bridge the functionality gap between basic resistive controllers and complex capacitive systems by adding multi-touch logic to resistive hardware.

Replacement Considerations

Publicly confirmed substitute part numbers are not available in the provided documentation. Designers should consult Rohm Semiconductor for current active replacements or evaluate the BU21024FV-M for similar resistive touch functionalities with potential package differences.

FAQ

How is the communication interface selected?

The interface is selected via the IFSEL pin. Tying IFSEL to logic low selects the 4-wire SPI mode, while tying it to logic high selects the 2-wire serial mode.

Can the firmware be updated after manufacturing?

Yes, the firmware for the internal CPU can be downloaded from a HOST processor or from an external EEPROM connected to the ECL and EDA pins.

What is the maximum operating supply voltage?

The maximum recommended operating supply voltage (VDD) is 3.6V, with a typical operating voltage of 3.0V.