MCH3477-TL-H N-Channel MOSFET 20V 4.5A Equivalent & Substitute Parts

Part Overview

The MCH3477-TL-H is an N-Channel MOSFET manufactured by onsemi, rated for 20V drain-to-source voltage with 4.5A continuous drain current at 25°C. The device is packaged in a 3-SMD flat lead SC-70FL/MCPH3 surface mount configuration and dissipates 1W maximum power. This part is classified as obsolete, making identification of functionally equivalent alternatives necessary for ongoing design support and procurement continuity.

Substiute Parts

MCH3477-TL-H

onsemiIn Stock: 5919MCH3477-TL-H Datasheet

Current PartRFQ

SSM3K123TU,LF

Toshiba Semiconductor and StorageIn Stock: 33583SSM3K123TU,LF Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the MCH3477-TL-H is determined by electrical and mechanical compatibility across the following critical parameters:

Electrical Compatibility Criteria:

• FET Type: N-Channel topology must be maintained
• Drain to Source Voltage (Vdss): Minimum 20V rating required
• Continuous Drain Current (Id): Minimum 4.2A at 25°C acceptable (within 93% of original specification)
• On-State Resistance (Rds On): Maximum 38 mOhm specification must be met or improved
• Gate Charge (Qg): Lower values acceptable for improved switching performance
• Input Capacitance (Ciss): Variation acceptable within application constraints
• Maximum Gate Voltage (Vgs): ±10V minimum required
• Power Dissipation: 500 mW or greater acceptable for thermal management

Mechanical Compatibility Criteria:

• Mounting Type: Surface Mount required
• Package Configuration: 3-SMD flat lead packages acceptable
• Pin Count and Lead Configuration: Compatible with SC-70FL/MCPH3 footprint or equivalent 3-lead SMD packages

Compliance Criteria:

• RoHS3 Compliance required
• MSL Level 1 (Unlimited) required
• REACH Unaffected status required

The SSM3K123TU,LF meets all electrical and mechanical substitution criteria while maintaining full regulatory compliance.

Parameter Comparison

Engineering Selection Recommendations

The SSM3K123TU,LF is a direct substitute for the MCH3477-TL-H based on the following factors:

Product Status Alignment: The MCH3477-TL-H is classified as obsolete, while the SSM3K123TU,LF maintains active product status with 33,536 units in current inventory. This ensures long-term availability and supply chain continuity.

Electrical Specification Compliance: The substitute part meets or exceeds all critical electrical parameters. The continuous drain current of 4.2A represents 93% of the original 4.5A specification, remaining within acceptable operational margins for most applications. The on-state resistance is improved at 28 mOhm compared to 38 mOhm, providing superior conduction characteristics. Both devices share identical 20V Vdss ratings and 150°C maximum junction temperature specifications.

Regulatory and Compliance Certification: Both parts maintain ROHS3 compliance, MSL Level 1 (Unlimited) moisture sensitivity rating, and REACH Unaffected status. These certifications ensure compatibility with current manufacturing and environmental standards.

Packaging and Mechanical Compatibility: Both devices utilize 3-SMD flat lead surface mount packages suitable for identical PCB footprints. The UFM package of the substitute part is mechanically compatible with SC-70FL/MCPH3 footprint requirements.

Thermal Performance: The SSM3K123TU,LF provides improved thermal characteristics with 500 mW maximum power dissipation compared to 1W for the original part, reducing thermal management requirements in the application circuit.

Frequently Asked Questions (FAQ)

Q: Can the SSM3K123TU,LF be used as a direct replacement for the MCH3477-TL-H without PCB modifications?

A: Yes. Both devices utilize compatible 3-SMD flat lead surface mount packages. The pin configuration and electrical interface are compatible with existing PCB layouts designed for the MCH3477-TL-H.

Q: What is the significance of the 4.2A continuous drain current in the substitute part versus the 4.5A specification of the original?

A: The SSM3K123TU,LF provides 4.2A continuous drain current, representing 93% of the original specification. This reduction is acceptable for applications where the circuit design does not require the full 4.5A capacity. Circuit analysis should confirm that the 4.2A rating meets application current requirements.

Q: How do the gate charge differences affect circuit performance?

A: The SSM3K123TU,LF exhibits higher gate charge (13.6 nC versus 5.1 nC), which may increase switching time in high-frequency applications. Gate drive circuits must provide sufficient current to charge the gate within the required switching window. Applications operating at frequencies below 1 MHz typically experience negligible performance impact.

Q: What is the impact of the higher input capacitance in the substitute part?

A: The SSM3K123TU,LF has input capacitance of 1010 pF compared to 410 pF in the original part. Higher input capacitance increases gate charge time and may require adjustment of gate drive circuit impedance. This parameter is application-dependent and should be evaluated in the specific circuit context.

Q: Are there any thermal management differences between the two parts?

A: The SSM3K123TU,LF dissipates 500 mW maximum power compared to 1W for the MCH3477-TL-H. This represents improved thermal efficiency and may reduce or eliminate the need for thermal management measures such as heat sinking in the application circuit.

Q: What is the maximum gate voltage tolerance for the substitute part?

A: The SSM3K123TU,LF is rated for ±10V maximum gate voltage, compared to ±12V for the original part. Gate drive circuits must be designed to operate within the ±10V specification. Existing circuits designed for ±12V operation require verification that gate drive voltage does not exceed ±10V.

Q: How does the improved on-state resistance of the substitute part affect circuit operation?

A: The SSM3K123TU,LF provides 28 mOhm on-state resistance compared to 38 mOhm for the MCH3477-TL-H, representing a 26% improvement. Lower on-state resistance reduces conduction losses and heat generation, improving overall circuit efficiency and reducing thermal stress on the device.

Q: Is the substitute part suitable for high-frequency switching applications?

A: The SSM3K123TU,LF is suitable for switching applications up to approximately 1 MHz. Higher gate charge and input capacitance may limit performance in applications exceeding this frequency range. Circuit simulation or prototype testing is necessary to confirm suitability for specific high-frequency requirements.

Q: What inventory considerations should be evaluated when transitioning from the MCH3477-TL-H to the SSM3K123TU,LF?

A: The MCH3477-TL-H is obsolete with 5,898 units in current stock. The SSM3K123TU,LF is an active product with 33,536 units available. Long-term design transitions should prioritize the active substitute part to ensure sustained supply chain availability and support.