BT-21751-000

Overview

The Knowles BT-21751-000 is an analog electret condenser microphone designed for voice applications. It features a side-port configuration and solder pad termination. The device operates within a voltage range of 0.9 V to 10 V, with a rated voltage of 1.3 V. Key electrical specifications include a sensitivity of -61.5 dB ±1.5 dB at 74 dB SPL and an impedance of 3.5 kOhms. The frequency response spans from 100 Hz to 4.2 kHz. Physically, the component measures 7.87 mm in length, 5.54 mm in width, and 2.29 mm in height.

Feature Summary

• Omnidirectional acoustic pickup pattern
• Analog output signal type
• Side-port design for flexible mounting orientation

Applications

• Voice communication devices
• Consumer electronics audio input
• General purpose sound detection

Procurement Notes

Verify the specific revision or suffix against the manufacturer's current documentation, as part numbers may evolve. Confirm that the required operating voltage aligns with your system's power supply rails, noting the 0.9 V minimum threshold. Ensure mechanical clearance accommodates the specified dimensions and side-port location during PCB layout.

Selection Notes

Select this component when an omnidirectional response is required for voice capture within the 100 Hz to 4.2 kHz bandwidth. The fixed 3.5 kOhm impedance must be compatible with the input stage of the connected amplifier or ADC. Consider the physical profile and side-port orientation relative to other board components and enclosure openings.

Part Context

This model belongs to Knowles' portfolio of electret condenser microphones, which are widely used in portable audio equipment. These components typically integrate a JFET impedance converter within the capsule housing, providing a low-impedance output suitable for direct connection to standard audio processing circuits without additional buffering.

Replacement Considerations

Publicly confirmed substitute part numbers are not available in the provided source data. Cross-referencing requires consulting official replacement guides or equivalent specification sheets from other manufacturers.