MJD128T4 Equivalent & Substitute Parts

Part Overview

The MJD128T4 is a PNP Darlington bipolar junction transistor manufactured by onsemi, designed for surface mount applications in the DPAK package. This component operates at maximum collector current of 8 A with a collector-emitter breakdown voltage of 120 V, suitable for switching and amplification circuits requiring moderate power dissipation up to 1.75 W.

The MJD128T4 carries an obsolete product status, which necessitates identification of functionally equivalent alternatives for new designs and ongoing production requirements. The substitute part MJD128T4G provides electrical and mechanical equivalence while maintaining active product status and improved compliance certifications.

Substiute Parts

MJD128T4

onsemiIn Stock: 856MJD128T4 Datasheet

Current PartRFQ

MJD128T4G

onsemiIn Stock: 7998MJD128T4G Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the MJD128T4 is determined by strict equivalence across the following electrical and mechanical parameters:

Electrical Parameters (Must Match):

• Transistor Type: PNP - Darlington configuration
• Maximum Collector Current (Ic): 8 A
• Collector-Emitter Breakdown Voltage: 120 V
• Saturation Voltage (Vce): 4 V @ 80 mA, 8 A
• DC Current Gain (hFE): 1000 minimum @ 4 A, 4 V
• Maximum Power Dissipation: 1.75 W
• Transition Frequency: 4 MHz
• Operating Temperature Range: -65°C to 150°C

Mechanical Parameters (Must Match):

• Package Type: TO-252-3 DPAK (2 Leads + Tab), SC-63
• Mounting Configuration: Surface Mount

The MJD128T4G meets all specified electrical and mechanical parameters, providing direct functional equivalence with identical performance characteristics and pinout compatibility.

Parameter Comparison

Engineering Selection Recommendations

Primary Selection: MJD128T4G

The MJD128T4G is the direct equivalent substitute for the obsolete MJD128T4. This part maintains complete electrical and mechanical compatibility while offering the following advantages:

• Product Status: Active product status ensures long-term availability and continued manufacturing support
• Compliance: ROHS3 compliant, meeting current environmental and regulatory requirements
• Packaging: Available in Tape & Reel format, supporting automated assembly processes and reducing component handling costs
• Inventory: Higher stock levels (7,900 units) compared to the obsolete MJD128T4 (758 units)

Both parts share identical electrical specifications, pinout configuration, and thermal characteristics. The MJD128T4G is suitable for direct replacement in all applications where the MJD128T4 was previously specified.

Frequently Asked Questions (FAQ)

Q: Can MJD128T4G be used as a direct replacement for MJD128T4 in existing designs?

A: Yes. The MJD128T4G provides complete electrical and mechanical equivalence. All electrical parameters, including collector current, breakdown voltage, saturation voltage, current gain, power rating, and frequency response are identical. The DPAK package pinout and thermal characteristics are unchanged, enabling direct substitution without circuit modification.

Q: What is the difference between MJD128T4 and MJD128T4G?

A: The primary differences are product status, compliance certification, and packaging format. The MJD128T4 is obsolete and RoHS non-compliant, while the MJD128T4G is an active product with ROHS3 compliance. The MJD128T4G is supplied in Tape & Reel packaging, whereas the MJD128T4 was supplied in bulk format. Electrical and mechanical specifications are identical.

Q: Are there any thermal or performance differences between these parts?

A: No. Both parts operate within the same temperature range (-65°C to 150°C junction temperature) and deliver identical thermal performance. Maximum power dissipation is 1.75 W for both variants. Thermal resistance and heat dissipation characteristics are equivalent.

Q: Is the DPAK package compatible with existing PCB layouts?

A: Yes. Both the MJD128T4 and MJD128T4G use the TO-252-3 DPAK package (SC-63), which is a standard surface mount package. PCB footprints, solder pad dimensions, and mounting hole specifications remain unchanged. No PCB redesign is required.

Q: What is the significance of the "G" suffix in MJD128T4G?

A: The "G" suffix indicates the part is supplied in Tape & Reel packaging format, which is standard for high-volume automated assembly. This packaging format differs from the bulk packaging of the original MJD128T4, but the component itself is electrically and mechanically identical.

Q: Can I mix MJD128T4 and MJD128T4G in the same production run?

A: Yes. Both parts are electrically and mechanically equivalent and can be used interchangeably. However, the MJD128T4 is obsolete with limited inventory (758 units), while the MJD128T4G is actively manufactured with higher availability. For new production, the MJD128T4G is the recommended choice.

Q: What compliance certifications apply to each part?

A: The MJD128T4 is RoHS non-compliant. The MJD128T4G is ROHS3 compliant and REACH unaffected. Both parts carry EAR99 ECCN classification and HTSUS code 8541.29.0095. For applications requiring RoHS compliance, the MJD128T4G is the appropriate selection.