MPSA27 Equivalent & Substitute Parts

Part Overview

The MPSA27 is an NPN Darlington bipolar junction transistor manufactured by onsemi, designed for through-hole applications in the TO-92 package. This device operates at a maximum collector voltage of 60 V with a collector current rating of 500 mA and maximum power dissipation of 625 mW. The MPSA27 is classified as obsolete, making identification of functionally equivalent alternatives necessary for ongoing design support and production continuity. Substitute parts must maintain compatibility across electrical specifications, mechanical packaging, and thermal operating ranges to ensure direct replacement capability.

Substiute Parts

MPSA27

onsemiIn Stock: 1372MPSA27 Datasheet

Current PartRFQ

BCX38C

Diodes IncorporatedIn Stock: 1524BCX38C Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the MPSA27 are identified based on strict electrical and mechanical compatibility criteria. The following parameters define acceptable substitution:

Mandatory Matching Criteria:

• Transistor topology: NPN Darlington configuration
• Package type: TO-92 through-hole form factor
• Collector-emitter breakdown voltage: 60 V (minimum requirement)
• DC current gain (hFE): 10000 or greater
• Moisture sensitivity level: 1 (Unlimited)

Allowable Parameter Variations:

• Collector current rating: Equal to or greater than 500 mA
• Maximum power dissipation: Equal to or greater than 625 mW
• Vce saturation: Lower values indicate improved performance
• Collector cutoff current: Lower values acceptable
• Operating temperature range: Extended ranges acceptable

The BCX38C meets all mandatory criteria and demonstrates enhanced electrical performance characteristics, including higher current capacity and improved thermal ratings, while maintaining identical package geometry and moisture sensitivity classification.

Parameter Comparison

Engineering Selection Recommendations

MPSA27 (onsemi) — Obsolete Status

The MPSA27 is classified as obsolete and no longer in active production. While 1300 pieces remain in current inventory, this part number is not recommended for new designs or long-term production commitments. The RoHS non-compliant status further restricts its use in regulated applications and regions with RoHS enforcement requirements.

BCX38C (Diodes Incorporated) — Active Status

The BCX38C is an active production part with superior electrical performance and compliance certifications. This device is ROHS3 compliant, meeting modern regulatory requirements for hazardous substance restrictions. The BCX38C provides enhanced specifications across all critical parameters: 60% higher collector current capacity (800 mA vs. 500 mA), 60% higher power dissipation rating (1 W vs. 625 mW), lower saturation voltage, and an extended operating temperature range to 200°C. The identical TO-92 package geometry and matching DC current gain ensure direct mechanical and functional compatibility.

For applications currently using the MPSA27, transition to the BCX38C is supported by full electrical and mechanical compatibility with the added benefit of improved performance margins and regulatory compliance.

Frequently Asked Questions (FAQ)

Q: Can the BCX38C directly replace the MPSA27 in existing circuit designs?

A: Yes. Both devices share identical package geometry (TO-92), matching collector-emitter breakdown voltage (60 V), and equivalent DC current gain specifications (10000 minimum). The BCX38C's higher current and power ratings provide additional performance margin without requiring circuit modifications.

Q: What is the primary reason for substituting the MPSA27?

A: The MPSA27 is classified as obsolete and no longer in active production. The BCX38C provides equivalent functionality with active manufacturing status, ensuring long-term availability and supply chain continuity.

Q: Are there compliance differences between these parts?

A: Yes. The MPSA27 is RoHS non-compliant, while the BCX38C is ROHS3 compliant. For applications subject to RoHS regulations or customer requirements, the BCX38C is the appropriate selection. Both parts are REACH unaffected and carry EAR99 classification.

Q: How do the thermal operating ranges compare?

A: The MPSA27 operates from -55°C to 150°C, while the BCX38C extends to -55°C to 200°C. The BCX38C's wider temperature range accommodates more demanding thermal environments without performance degradation.

Q: What is the significance of the lower Vce saturation voltage in the BCX38C?

A: Lower saturation voltage (1.25 V vs. 1.5 V) indicates reduced voltage drop across the transistor in the saturated state. This results in lower power dissipation and improved efficiency in switching applications, particularly beneficial in high-frequency or high-current scenarios.

Q: Are the moisture sensitivity levels identical?

A: Yes. Both the MPSA27 and BCX38C carry MSL 1 (Unlimited) classification, indicating no moisture sensitivity restrictions for storage, handling, or reflow processes.

Q: Can the BCX38C be used in applications requiring the exact 500 mA current specification?

A: Yes. The BCX38C's 800 mA maximum rating exceeds the 500 mA requirement, providing operational headroom. The device operates safely at 500 mA with improved thermal and performance margins.