BU21050FS-E2

Overview

The BU21050FS-E2 is a capacitive sensor control IC featuring eight independent channels for detecting touch or proximity inputs. It operates with dual power supplies, AVDD and DVDD, both rated between 4.5V and 5.5V. The device integrates a 10-bit analog-to-digital converter (ADC) and an internal RC oscillator capable of frequencies up to 2.5 MHz. It supports two output modes: 8-channel parallel input/output (PIO) and 4-bit binary encoding. Key electrical parameters include a maximum standby current of 2 μA in shutdown mode and a typical operating current of 550 μA. The component is housed in an SSOP-A32 package.

Feature Summary

• Configurable output interface supporting either 8-channel PIO or 4-bit binary encoding modes
• Integrated 10-bit ADC for precise capacitance-to-voltage conversion
• Internal calibration mechanism that automatically adjusts sensor offsets during idle periods
• Adjustable gain levels and noise filter settings to optimize detection sensitivity

Applications

• Capacitive switch interfaces for home appliances
• Control panels for consumer electronics
• Touch-sensitive input devices requiring low software overhead

Procurement Notes

Verify the specific ordering suffix E2 corresponds to the embossed tape and reel packaging format containing 2000 pieces per reel. Confirm that the SSOP-A32 package dimensions align with the target PCB footprint. Ensure that the design accommodates the required dual power supply sequence where DVDD must be applied before or simultaneously with AVDD to prevent initialization errors.

Selection Notes

Select this component when a multi-channel capacitive sensing solution with minimal external microcontroller intervention is required. The integrated ADC and threshold comparison logic reduce the need for complex external processing. Consider the available gain stages and filter options if the application environment presents significant electrical noise or requires varying detection sensitivities across different sensor pads.

Part Context

The BU21050FS belongs to ROHM's Capacitive Sensor Control IC Series, designed to replace traditional mechanical switches. The FS suffix indicates the SSOP-A32 surface-mount package variant. This series targets applications needing reliable touch detection with reduced system complexity by handling signal conditioning and digital output generation internally.

Replacement Considerations

No direct public substitute part numbers are documented in the provided datasheet. Cross-referencing should focus on other 8-channel capacitive sensor controllers with compatible voltage ranges and package footprints.