2N6427G Equivalent & Substitute Parts

Part Overview

The 2N6427G 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 current of 500 mA with a collector-emitter breakdown voltage of 40 V and a maximum power dissipation of 625 mW. The 2N6427G is classified as an obsolete product, making identification of functionally equivalent alternatives necessary for ongoing design support, maintenance, and production continuity in legacy systems.

Substiute Parts

2N6427G

onsemiIn Stock: 9652N6427G Datasheet

Current PartRFQ

MMBT6427LT1G

onsemiIn Stock: 33195MMBT6427LT1G Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution of the 2N6427G is determined by electrical and mechanical parameter equivalence across the NPN Darlington transistor category. The critical parameters that define substitution eligibility are:

Electrical Parameters:

• Transistor Type: NPN - Darlington configuration
• Maximum Collector Current (Ic): 500 mA
• Collector-Emitter Breakdown Voltage: 40 V
• Vce Saturation characteristics: 1.5V @ 500µA, 500mA
• Collector Cutoff Current: 1 µA
• DC Current Gain (hFE): 20000 @ 100mA, 5V
• Operating Temperature Range: -55°C to 150°C

Mechanical Parameters:

• Package compatibility (through-hole or surface-mount variants of equivalent form factor)
• Mounting type and lead configuration

The MMBT6427LT1G qualifies as a functional substitute because it maintains identical electrical specifications across all critical parameters while offering a surface-mount SOT-23-3 package alternative. This substitution is valid for applications where package form factor can be accommodated through board redesign or adapter solutions.

Parameter Comparison

Engineering Selection Recommendations

For Direct Through-Hole Replacement: The 2N6427G remains the appropriate choice for existing through-hole PCB designs. However, due to its obsolete product status, long-term availability cannot be assured. Current inventory of 925 pieces is available from the specified supplier.

For New Designs or PCB Redesign Scenarios: The MMBT6427LT1G is the recommended substitute when board-level modifications are feasible. This part maintains complete electrical equivalence while offering the advantage of active product status from onsemi. The MMBT6427LT1G is RoHS3 compliant, providing enhanced environmental and regulatory compliance compared to the 2N6427G. Significantly higher inventory availability (33,100 pieces) ensures supply chain continuity. The surface-mount SOT-23-3 package reduces board space requirements and improves manufacturing efficiency through automated assembly processes.

Compliance Considerations: Both parts carry REACH Unaffected status and EAR99 ECCN classification. The MMBT6427LT1G provides superior long-term compliance positioning through active product status and RoHS3 certification.

Frequently Asked Questions (FAQ)

Q: Can the MMBT6427LT1G be used as a direct pin-for-pin replacement for the 2N6427G?

A: No. The MMBT6427LT1G uses a surface-mount SOT-23-3 package, while the 2N6427G uses a through-hole TO-92 package. Pin-for-pin replacement is not possible without PCB redesign or the use of adapter solutions. However, the electrical characteristics are fully equivalent.

Q: What are the key electrical differences between these two parts?

A: There are no electrical differences. Both parts are NPN Darlington transistors with identical maximum ratings: 500 mA collector current, 40 V breakdown voltage, 1.5V saturation voltage at rated conditions, 20,000 minimum DC current gain, and -55°C to 150°C operating temperature range.

Q: Why is the 2N6427G classified as obsolete?

A: The 2N6427G is an older through-hole component. onsemi has transitioned this product line to surface-mount technology, represented by the MMBT6427LT1G. Obsolete status indicates that onsemi no longer manufactures this part, though existing inventory may remain available through authorized distributors.

Q: Is the MMBT6427LT1G suitable for high-temperature applications?

A: Yes. The MMBT6427LT1G operates across the same temperature range as the 2N6427G: -55°C to 150°C junction temperature. Both parts are suitable for applications requiring extended temperature operation.

Q: What is the power dissipation difference between these parts?

A: The 2N6427G has a maximum power rating of 625 mW in the TO-92 package. The MMBT6427LT1G has a maximum power rating of 225 mW in the SOT-23-3 package. This difference reflects the thermal characteristics of the respective packages, not the transistor die itself. Circuit design must account for the lower power dissipation capability of the surface-mount package.

Q: Are there moisture sensitivity concerns with either part?

A: Both parts carry MSL 1 (Unlimited) classification, indicating no moisture sensitivity restrictions. Standard handling and storage procedures apply.

Q: Which part should be selected for new production designs?

A: The MMBT6427LT1G is the appropriate choice for new designs. It provides active product status, RoHS3 compliance, superior supply chain availability, and manufacturing advantages through surface-mount technology. The 2N6427G should be reserved for legacy system maintenance only.