MD9745APA-1 Equivalent & Substitute Parts

Part Overview

The MD9745APA-1 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 -41dB ±3dB at 94dB SPL, utilizing PC pin termination in a 0.382" diameter circular package.

The MD9745APA-1 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 incorporating this microphone.

Substiute Parts

MD9745APA-1

KnowlesIn Stock: 1166MD9745APA-1 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 MD9745APA-1 are qualified based on the following critical parameters that determine functional compatibility:

• Microphone Type: Electret Condenser (required match)
• Output Type: Analog (required match)
• Direction: Omnidirectional (required match)
• Termination: PC Pins (required match)
• Physical Dimensions: 0.382" diameter circular package (required match)
• Impedance: 2.2 kOhms (required match)
• Supply Current: 500 µA (required match)
• Voltage Compatibility: Overlap within operating ranges (2 V ~ 10 V minimum requirement)

The two substitute parts identified—AOM-4544P-2-R and CMA-4544PF-W—satisfy all mandatory mechanical and electrical compatibility criteria. Both are active-status electret condenser microphones with identical physical form factors, impedance, and termination methods. Variations in frequency response, sensitivity, and S/N ratio represent performance enhancements relative to the obsolete MD9745APA-1.

Parameter Comparison

Engineering Selection Recommendations

Both substitute parts are active-status components with current manufacturing support, addressing the obsolescence of the MD9745APA-1.

AOM-4544P-2-R (PUI Audio, Inc.) offers the lowest minimum operating voltage at 1.5 V, providing flexibility for battery-powered or low-voltage applications. This part maintains full compatibility with the original design voltage range and delivers improved S/N ratio (60dB vs. 55dB) and extended frequency response (50 Hz ~ 16 kHz). RoHS3 compliance and MSL 1 rating support modern manufacturing and storage requirements.

CMA-4544PF-W (CUI Devices) provides the widest frequency response (20 Hz ~ 20 kHz), supporting applications requiring extended low-frequency and high-frequency capture. This part requires a minimum operating voltage of 3 V, which remains within the original design specification. RoHS3 compliance and MSL 1 rating are provided. The base product number CMA-4544 indicates established product lineage and supply continuity.

Both parts are REACH Unaffected and classified under ECCN EAR99, maintaining regulatory alignment with the original component.

Frequently Asked Questions (FAQ)

Q: Can AOM-4544P-2-R or CMA-4544PF-W be used as direct replacements for MD9745APA-1?

A: Both parts are mechanically and electrically compatible substitutes. They share identical physical dimensions (0.382" diameter), impedance (2.2 kOhms), termination method (PC Pins), and supply current (500 µA). Voltage ranges overlap with the original specification. The primary design consideration is frequency response: the original MD9745APA-1 operates 100 Hz ~ 10 kHz, while substitutes extend this range. Applications sensitive to frequency response characteristics should verify compatibility with system requirements.

Q: What are the voltage compatibility considerations?

A: The MD9745APA-1 operates 2 V ~ 10 V. The AOM-4544P-2-R operates 1.5 V ~ 10 V, providing lower-voltage flexibility. The CMA-4544PF-W operates 3 V ~ 10 V, requiring minimum 3 V supply. Both substitutes maintain full compatibility within the original 2 V ~ 10 V operating window.

Q: How do sensitivity and S/N ratio differences affect system performance?

A: The MD9745APA-1 provides -41dB ±3dB sensitivity with 55dB S/N ratio. Both substitutes provide -44dB ±2dB sensitivity with 60dB S/N ratio. The 3dB sensitivity difference represents a minor output level reduction; the improved S/N ratio (5dB gain) indicates lower noise floor. System gain structures should be evaluated to confirm adequate signal levels.

Q: Are there packaging or supply chain differences?

A: The AOM-4544P-2-R is supplied in Bulk packaging with 102,573 units in stock. The CMA-4544PF-W is supplied in Box packaging with 18,609 units in stock. Both are active products with established supply chains, contrasting with the obsolete MD9745APA-1 status.

Q: Do the substitute parts meet current compliance requirements?

A: Both AOM-4544P-2-R and CMA-4544PF-W are RoHS3 Compliant with MSL 1 (Unlimited) moisture sensitivity rating, supporting modern manufacturing and storage protocols. Both are REACH Unaffected and EAR99 classified, maintaining regulatory alignment.