MB9750USB-4 Equivalent & Substitute Parts

Part Overview

The MB9750USB-4 is an electret condenser microphone manufactured by Knowles, designed for analog audio capture applications requiring unidirectional pickup patterns. This component operates across a 1.5 V to 10 V supply range with a sensitivity of -47dB ±3dB @ 94dB SPL and covers a frequency range of 100 Hz to 10 kHz. The product is currently obsolete, making identification of compatible substitute components essential for ongoing system support and new design implementations.

Substiute Parts

MB9750USB-4

KnowlesIn Stock: 918MB9750USB-4 Datasheet

Current PartRFQ

CMI-5247TF-K

CUI DevicesIn Stock: 4118CMI-5247TF-K Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the MB9750USB-4 is determined by strict alignment across the following critical parameters:

• Microphone Type: Electret condenser technology
• Output Configuration: Analog signal output
• Directional Pattern: Unidirectional pickup
• Sensitivity Level: -47dB ±3dB @ 94dB SPL
• Voltage Compatibility: 1.5 V ~ 10 V operating range
• Supply Current: 500 µA
• Physical Form Factor: 0.382" diameter (9.70mm) circular package
• Termination Method: Solder pads
• Port Location: Top-mounted

The CMI-5247TF-K from CUI Devices meets all mandatory substitution criteria while maintaining electrical and mechanical compatibility with the original MB9750USB-4 specification.

Parameter Comparison

Engineering Selection Recommendations

The CMI-5247TF-K is the qualified substitute for the obsolete MB9750USB-4 based on the following engineering criteria:

Electrical Compatibility: Both components operate within identical voltage ranges (1.5 V ~ 10 V) and draw equivalent supply current (500 µA). Sensitivity specifications are identical at -47dB ±3dB @ 94dB SPL, ensuring consistent audio capture performance in equivalent circuit designs.

Mechanical Compatibility: Physical dimensions are matched at 0.382" diameter (9.70mm) with negligible height variation (0.205" vs. 0.213"). Both components feature top-mounted solder pad termination, enabling direct PCB integration without redesign.

Functional Compatibility: Both microphones employ electret condenser technology with unidirectional pickup patterns and analog output. The CMI-5247TF-K provides an extended frequency range (70 Hz ~ 20 kHz versus 100 Hz ~ 10 kHz) and improved signal-to-noise ratio (60dB versus 55dB), representing performance enhancement over the original specification.

Product Status: The CMI-5247TF-K maintains active production status with RoHS3 compliance and REACH unaffected designation, ensuring long-term availability and regulatory alignment.

Impedance Consideration: The CMI-5247TF-K operates at 680 Ohms impedance compared to the MB9750USB-4 at 2.2 kOhms. Circuit impedance matching and signal conditioning requirements must be evaluated during integration to ensure optimal performance in the target application.

Frequently Asked Questions (FAQ)

Q: Can the CMI-5247TF-K directly replace the MB9750USB-4 without circuit modifications?

A: Direct mechanical and electrical substitution is possible due to matched voltage ranges, supply current, sensitivity, and physical form factor. However, the impedance difference (680 Ohms vs. 2.2 kOhms) may require signal conditioning circuit adjustments depending on the original design's input impedance specifications.

Q: What is the significance of the frequency range difference between these components?

A: The MB9750USB-4 operates from 100 Hz to 10 kHz, while the CMI-5247TF-K extends from 70 Hz to 20 kHz. The substitute provides broader frequency coverage, which is compatible with applications designed for the original narrower range. Applications requiring the specific 100 Hz lower cutoff should evaluate whether the 70 Hz specification introduces undesired low-frequency content.

Q: Why is the impedance different between these two microphones?

A: Impedance is determined by internal transducer design and does not affect substitution eligibility when both components meet the voltage, current, and sensitivity requirements. The lower impedance of the CMI-5247TF-K (680 Ohms) may provide improved signal-to-noise performance in certain circuit topologies but requires verification against the original circuit's input impedance specifications.

Q: Are both components suitable for the same packaging and assembly processes?

A: Yes. Both the MB9750USB-4 and CMI-5247TF-K feature identical 0.382" diameter circular packages with solder pad termination and top-mounted port location. Height variation is minimal (0.205" vs. 0.213"), presenting no assembly or clearance concerns in standard PCB designs.

Q: What compliance certifications apply to the substitute component?

A: The CMI-5247TF-K is RoHS3 compliant and REACH unaffected. Both components carry EAR99 ECCN classification and identical HTSUS codes (8518.10.8030), confirming regulatory and trade alignment.

Q: Is the improved signal-to-noise ratio of the CMI-5247TF-K a performance advantage?

A: The CMI-5247TF-K provides a 60dB signal-to-noise ratio compared to the MB9750USB-4 at 55dB. This 5dB improvement represents enhanced noise floor performance and may provide measurable audio quality benefits in noise-sensitive applications, though the original design specifications should be reviewed to determine if this enhancement is required or beneficial for the intended use case.