MD9745APZ-F Equivalent & Substitute Parts

Part Overview

The MD9745APZ-F is an electret condenser microphone manufactured by Knowles, designed for analog audio capture applications requiring omnidirectional pickup patterns. This component operates across a 100 Hz to 10 kHz frequency range with a sensitivity of -44dB ±2dB at 94dB SPL, suitable for embedded audio systems and consumer electronics.

The MD9745APZ-F is classified as obsolete. Identifying equivalent substitute parts is necessary to maintain design continuity, ensure supply chain availability, and support ongoing production or maintenance requirements for systems utilizing this microphone.

Substiute Parts

MD9745APZ-F

KnowlesIn Stock: 821MD9745APZ-F Datasheet

Current PartRFQ

AOM-4544P-2-R

PUI Audio, Inc.In Stock: 102635AOM-4544P-2-R Datasheet

MFR RecommendedRFQ

CMA-4544PF-W

CUI DevicesIn Stock: 18648CMA-4544PF-W Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the MD9745APZ-F are qualified based on the following core electrical and mechanical parameters:

Critical Matching Parameters:

• Microphone type: Electret Condenser
• Output type: Analog
• Directional pattern: Omnidirectional
• Termination: PC Pins
• Physical form factor: Circular, 0.382" diameter (9.70mm)
• Impedance: 2.2 kOhms
• Supply current: 500 µA
• Sensitivity class: -44dB ±2dB

Allowable Variation Parameters:

• Frequency range: Extended ranges are acceptable if they encompass or exceed the original 100 Hz ~ 10 kHz specification
• Voltage range: Substitute parts must support operation within the original 2 V ~ 10 V range; lower minimum voltages or higher maximum voltages do not disqualify a part
• S/N ratio: Improvements over the original 55dB specification are acceptable
• Height: Minor dimensional variations within manufacturing tolerance are acceptable

Two substitute parts meet these criteria: the AOM-4544P-2-R from PUI Audio, Inc. and the CMA-4544PF-W from CUI Devices.

Parameter Comparison

Engineering Selection Recommendations

Both substitute parts are qualified replacements for the MD9745APZ-F based on electrical and mechanical parameter alignment.

AOM-4544P-2-R (PUI Audio, Inc.) is an active product with ROHS3 compliance and extended frequency response (50 Hz ~ 16 kHz). This part supports a lower minimum operating voltage (1.5 V) compared to the original specification (2 V minimum), providing greater flexibility in low-power applications. The S/N ratio is improved to 60dB. Height tolerance is within acceptable manufacturing variation at 0.185" (4.70mm).

CMA-4544PF-W (CUI Devices) is an active product with ROHS3 compliance and the widest frequency response (20 Hz ~ 20 kHz). This part requires a minimum operating voltage of 3 V, which is higher than the original 2 V minimum but remains within the upper operating range. The S/N ratio is improved to 60dB. Height tolerance is within acceptable manufacturing variation at 0.183" (4.65mm).

Both parts maintain identical impedance (2.2 kOhms), supply current (500 µA), sensitivity (-44dB ±2dB), and physical diameter (0.382" / 9.70mm) as the original component. Selection between these two substitutes depends on specific application requirements regarding minimum operating voltage and frequency response bandwidth.

Frequently Asked Questions (FAQ)

Q: Can the AOM-4544P-2-R or CMA-4544PF-W be used as direct replacements for the MD9745APZ-F?

A: Both parts are electrically and mechanically compatible substitutes. They share identical microphone type, output configuration, directional pattern, impedance, supply current, sensitivity class, and physical form factor. Both are qualified for direct substitution in PC pin-based designs.

Q: What is the difference in voltage requirements between the three parts?

A: The MD9745APZ-F operates from 2 V to 10 V. The AOM-4544P-2-R operates from 1.5 V to 10 V, supporting lower-voltage applications. The CMA-4544PF-W operates from 3 V to 10 V, requiring higher minimum voltage. Verify that your power supply meets the minimum voltage requirement of your selected substitute.

Q: How do the frequency ranges differ?

A: The MD9745APZ-F covers 100 Hz to 10 kHz. The AOM-4544P-2-R extends this to 50 Hz to 16 kHz. The CMA-4544PF-W provides the widest range at 20 Hz to 20 kHz. All three parts cover the original frequency band; the substitutes offer extended bandwidth.

Q: Are there height differences that could affect PCB layout?

A: The MD9745APZ-F has a maximum height of 0.177" (4.50mm). The AOM-4544P-2-R is 0.185" (4.70mm), and the CMA-4544PF-W is 0.183" (4.65mm). These variations are within typical manufacturing tolerances for circular microphone components. Verify clearance in your mechanical design if height is constrained.

Q: What is the significance of the improved S/N ratio in the substitute parts?

A: Both substitute parts offer a 60dB S/N ratio compared to the original 55dB specification. This represents improved signal-to-noise performance and is a beneficial characteristic that does not affect compatibility or substitution eligibility.

Q: Are the substitute parts RoHS compliant?

A: Both the AOM-4544P-2-R and CMA-4544PF-W are ROHS3 compliant. The original MD9745APZ-F does not specify RoHS status. If RoHS compliance is required for your application, both substitutes meet this requirement.

Q: What packaging is available for each substitute?

A: The AOM-4544P-2-R is supplied in Bulk packaging. The CMA-4544PF-W is supplied in Box packaging. Confirm packaging requirements with your procurement process.