Packaging — Wolfspeed Power Applications Forum

[FAQ-PACK-4] What is the creepage distance on discrete MOSFET and diode packages?

AAnders — Wed, 06 Nov 2024 17:44:58 +0000

The creepage distance along the package surface between drain and source for MOSFETs and between anode and cathode for diodes can be found in this document.

Wolfspeed Discrete Package Creepage_QA.pdf

[FAQ-PACK-3]What is the safe way of lead bending Through Hole packages?

TBhatia — Wed, 02 Nov 2022 02:05:41 +0000

In some instances, the package leads must be bent in order to properly align their pitch with that of the drilled holes in the PCB. When lead bending is necessary, these general guidelines should be followed:

- A suitable clamp on the leads between the package body and the bend is required to eliminate any

mechanical stresses from being transferred to the package body

- Clamping force should be enough to ensure no movement of the clamp on the lead during the

bending process

- Clamping force should not be excessive which can cause lead deformation or weakening

- The clamp must not contact the body of the device under any circumstances during the bending

process. This can transfer stress into the mold compound and result in damage to the part.

- Minimum recommended spacing between the body and the clamp is 0.5mm, however it is

recommended to perform the bend after the narrowing of the lead (seating plane).

- Bending the leads at the package is not allowed. A clamp must always be used on the leads.

- Bending leads laterally (parallel to the body plane) is not allowed

- Leads may be bent a maximum of 90ᵒ up or down. Do not unbend or repetitively bend the same location

[FAQ-PACK-2] What discrete packages are available from Wolfspeed?

TBhatia — Wed, 02 Nov 2022 01:53:16 +0000

For MOSFET: TO-247-3L, TO-247-4L, TO-263-7L, TO-263-7XL and TO- Leadless (TOLL). Other new packages are coming soon.

For Diode: TO-220-2, TO-220F2, TO-220 Isolated, TO-247-2, TO-247-3L, TO-252-2, TO-263-2 and QFN packages are available.

[FAQ-PACK-1] What is the benefits of the Kelvin source connection on discrete packages or modules ?

SiC_Power_Admin — Wed, 04 Aug 2021 21:22:20 +0000

The Kelvin source connection is a dedicated small signal connection directly from the source of the MOSFET and is dedicated for controlling the MOSFET. This mitigates the inductive voltage changes that can occur in the main current carrying path since the connection is decoupled from the power path. As devices like silicon carbide switch at high di/dt, these voltage changes can be significant. Use of kelvin source eliminates common source inductance that could otherwise act like a negative feedback on the gate signal. This feedback resists the action of the gate driver and results in increased switching losses and oscilltions

A comparison of a traditional package with (TO-247-4L and 7LD2PAK) and without (TO-247-3) Kelvin source are shown below . The same concept and results would apply to a power module as well.