TO38-31018-B20

Overview

The TO38-31018-B20 is a subminiature electret condenser microphone manufactured by Knowles. It features an omnidirectional polar pattern and operates within a frequency range of 80 Hz to 10 kHz. The device requires a supply voltage between 0.9 V and 1.6 V, drawing a current rating of 29 uA. Its sensitivity is specified at -64.5 dBA ±3dB @ 74dB SPL, with an impedance of 4.4 kOhms. This analog microphone is designed for high-performance audio capture in space-constrained environments.

Feature Summary

• Compact subminiature form factor suitable for rugged and space-limited applications
• Omnidirectional acoustic response for uniform sound capture from all directions
• Low power consumption design compatible with portable battery-operated systems

Applications

• Portable consumer electronics requiring compact audio input
• Medical devices needing reliable acoustic sensing in small enclosures
• Industrial equipment utilizing space-constrained monitoring systems

Procurement Notes

Verify the specific suffix B20 against official Knowles documentation to confirm exact sensitivity tolerance and packaging configuration. Ensure compatibility with existing biasing circuits given the 0.9 V to 1.6 V operating range. Cross-reference impedance specifications with pre-amplifier inputs to maintain signal integrity. Confirm lead-free compliance if required by target assembly standards.

Selection Notes

Select this component when a low-profile omnidirectional microphone is required for analog audio signals. The fixed sensitivity of -64.5 dBA suits applications not requiring extreme gain stages. Consider the 4.4 kOhm impedance when designing input matching networks. Evaluate the 80 Hz lower frequency limit against bass requirements of the target application.

Part Context

This model belongs to the TO38 series of subminiature electret microphones produced by Knowles Precision Devices. The series is engineered for durability and consistent performance in demanding environments. These components utilize standard electroacoustic transducer principles with a diaphragm and backplate structure.

Replacement Considerations

Direct substitutes must match the TO38 package outline and electrical characteristics. Verify equivalent sensitivity and impedance values to ensure circuit compatibility without redesign.