BJ-21591-000

Overview

The Knowles BJ-21591-000 is a passive magnetic microphone designed for analog audio applications. It features an omnidirectional polar pattern and operates within a frequency range of 300 Hz to 5 kHz. The component exhibits a sensitivity of -75dB ±2.5dB at 74dB SPL. Its physical dimensions include a rectangular shape with solder pads measuring 0.310 inches in length by 0.220 inches in width, and a maximum height of 0.160 inches.

Feature Summary

• Passive magnetic transduction mechanism requiring no external bias voltage
• Omnidirectional acoustic response for uniform sound capture from all angles
• Analog output signal suitable for direct interfacing with preamplifier circuits

Applications

• Voice recognition systems
• Intercom devices
• Public address microphones

Procurement Notes

Verify the specific suffix codes against official Knowles documentation to confirm exact electrical tolerances and mechanical variations. Ensure compatibility with existing PCB footprints, as pad dimensions are critical for surface mount assembly. Cross-reference RoHS compliance status with current regulatory requirements before finalizing procurement orders.

Selection Notes

Select this component when a passive, low-power solution is required for voice-band applications. The wide frequency response supports clear speech reproduction. Evaluate the need for omnidirectional pickup versus directional alternatives based on environmental noise conditions. Confirm that the analog output impedance matches the input requirements of the downstream processing circuitry.

Part Context

This model belongs to the BJ series of microphones manufactured by Knowles Acoustics. The series typically includes various variants differentiated by sensitivity, frequency response, and packaging options. These components are engineered for reliability in consumer electronics and industrial audio equipment where consistent performance is essential.

Replacement Considerations

Consult official substitution guides for compatible equivalents. Verify pinout compatibility and acoustic characteristics before replacing.