MET-42 Audio Transformer Equivalent & Substitute Parts

Part Overview

The MET-42 is a 150:12 ohm audio transformer manufactured by Tamura, designed for data/voice coupling applications. This through-hole mounted component operates across the 300Hz to 100kHz frequency range with a 3.54:1 turns ratio and 50mW power level rating. The part is currently in active production status with 924 units available in inventory. Equivalent and substitute parts are identified to support procurement flexibility, inventory management, and supply chain continuity when the primary MET-42 becomes unavailable or when design requirements permit alternative sourcing.

Substiute Parts

MET-42

TamuraIn Stock: 1019MET-42 Datasheet

Current PartRFQ

SP-42

Triad MagneticsIn Stock: 1699SP-42 Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the MET-42 audio transformer is determined by strict equivalence across the following critical parameters:

Primary Substitution Criteria:

• Turns Ratio: 3.54:1 (exact match required)
• Impedance Primary: 150 Ohms (exact match required)
• Impedance Secondary: 12 Ohms (exact match required)
• Frequency Range: 300Hz ~ 100kHz (exact match required)
• Frequency Response: ±2dB (exact match required)
• Power Level: 50mW (exact match required)
• Mounting Type: Through Hole (exact match required)
• Termination Style: PC Pin (exact match required)

Secondary Compatibility Parameters:

• DC Resistance values within acceptable tolerance
• Voltage isolation rating equal to or exceeding specification
• Operating temperature range equal to or exceeding specification
• Physical dimensions compatible with PCB footprint
• RoHS and environmental compliance status

The SP-42 manufactured by Triad Magnetics meets all primary substitution criteria and qualifies as a direct equivalent for the MET-42.

Parameter Comparison

Engineering Selection Recommendations

MET-42 (Tamura) Selection Criteria:

• Primary choice when Tamura sourcing is preferred or contractually specified
• Active production status with 924 units in current inventory
• RoHS Compliant certification
• MSL 1 rating provides unlimited shelf life storage capability

SP-42 (Triad Magnetics) Selection Criteria:

• Direct functional equivalent with identical electrical performance across all critical parameters
• Active production status with higher inventory availability (1645 units)
• ROHS3 Compliant certification (enhanced environmental compliance)
• Extended operating temperature range (-40°C to 85°C) provides broader thermal margin
• Higher voltage isolation rating (1000VRMS) offers additional safety margin
• Not Applicable MSL status indicates no moisture sensitivity constraints
• Physically compatible with MET-42 PCB footprint (dimensions within 0.01" tolerance)

Both parts are suitable for direct substitution in audio coupling and data/voice coupling applications operating within the specified 300Hz to 100kHz frequency band at 50mW power levels.

Frequently Asked Questions (FAQ)

Q: Can SP-42 be used as a direct replacement for MET-42 in existing designs?

A: Yes. The SP-42 meets all critical electrical parameters including turns ratio (3.54:1), impedance values (150 ohms primary, 12 ohms secondary), frequency range (300Hz ~ 100kHz), and frequency response (±2dB). Physical dimensions are compatible with MET-42 PCB footprints. Both use identical through-hole PC pin termination.

Q: What are the differences in DC resistance between MET-42 and SP-42?

A: MET-42 primary DCR is 20 ohms versus SP-42 at 18 ohms. MET-42 secondary DCR is 2.5 ohms versus SP-42 at 2.7 ohms. These variations are within acceptable tolerance for audio coupling applications and do not affect functional compatibility.

Q: Does SP-42 provide better isolation performance than MET-42?

A: SP-42 specifies 1000VRMS isolation at 1 second, while MET-42 specifies 500VRMS at 30 seconds. SP-42 provides higher isolation voltage rating, offering additional safety margin in applications requiring enhanced dielectric strength.

Q: Are there temperature range differences between these parts?

A: MET-42 operates from -20°C to 85°C. SP-42 operates from -40°C to 85°C. SP-42 provides extended low-temperature capability, suitable for applications requiring operation in colder environments.

Q: What is the significance of MSL ratings for these transformers?

A: MET-42 carries MSL 1 (Unlimited), indicating no moisture sensitivity constraints and unlimited shelf life storage. SP-42 is listed as Not Applicable for MSL, indicating no moisture sensitivity concerns. Both parts are suitable for standard storage and handling without special moisture control requirements.

Q: Are both parts RoHS compliant?

A: Yes. MET-42 is RoHS Compliant. SP-42 is ROHS3 Compliant. Both meet environmental compliance requirements. ROHS3 represents enhanced compliance standards.

Q: What packaging formats are available?

A: MET-42 is supplied in Tube packaging. SP-42 is supplied in Bulk packaging. Packaging format selection depends on assembly process requirements and inventory management preferences.

Q: Are physical dimensions identical between MET-42 and SP-42?

A: Dimensions are compatible but not identical. MET-42: 0.409" L x 0.310" W (10.40mm x 7.87mm). SP-42: 0.410" L x 0.310" W (10.41mm x 7.87mm). The 0.01" length difference is within standard PCB footprint tolerance. Height is identical at 0.465" (11.80mm) for both parts.

Q: Which part should be selected for new designs?

A: Both MET-42 and SP-42 are suitable for new designs. Selection depends on supplier preference, inventory availability, and specific application requirements. SP-42 offers extended temperature range and higher isolation voltage. MET-42 provides established Tamura sourcing. Both are active production parts with adequate inventory.