BT-21755-000

Overview

The Knowles BT-21755-000 is an omnidirectional electret condenser microphone designed for premium audio applications. It operates within a frequency range of 100 Hz to 4.2 kHz and supports supply voltages from 0.9 V to 10 V. The device features a sensitivity of -59.5 dBA (±3 dB) at 74 dB SPL and has an impedance of 3.5 kOhms with a current rating of 40 uA. Its compact dimensions are 7.87 mm x 5.54 mm, offering improved RFI/EMI suppression and various damping options.

Feature Summary

• Omnidirectional acoustic response for uniform sound capture
• Enhanced radio frequency and electromagnetic interference suppression
• Available in undamped, screen damped, and internally damped configurations

Applications

• Premium audio recording devices
• Voice recognition systems
• Consumer electronics requiring high-fidelity input

Procurement Notes

Verify the specific damping configuration required for your design, as the part number may denote a specific internal structure. Confirm RoHS compliance status with the supplier, as some sources indicate varying environmental certifications. Ensure voltage requirements align with the 0.9 V to 10 V operating range specified for this component.

Selection Notes

Select this component when omnidirectional pickup is necessary alongside strict size constraints. Consider the available damping variants based on the desired frequency response characteristics. Verify that the 3.5 kOhm impedance matches the preamplifier input stage requirements for optimal signal transfer.

Part Context

This microphone belongs to the Knowles BT series, which focuses on small form factor audio sensors. The series emphasizes performance in compact embedded systems where space is limited but audio quality remains critical. It serves as a specialized solution for modern portable and wearable technology designs.

Replacement Considerations

No public confirmed substitute part numbers are available in the provided documentation. Consult Knowles directly for equivalent models with similar electrical specifications and physical dimensions.