Gan Systems GSP665HPMB-EVBIMS2, Техническое руководство

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GSP665x-EVBIMS2
High Power IMS 2 Evaluation Platform
Technical Manual
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GSP665x-EVBIMS2 TM rev. 201021 © 2020 GaN Systems Inc. www.gansystems.com 7
Please refer to the Evaluation Board/Kit Important Notice on page 22
The IMS 2 half bridge power board is designed for users to gain hands-on experience in the following ways:
•
Evaluate the GaN E-HEMT performance in any half bridge based topology, over a range of
operating conditions. This can be done using either the accompanying power motherboard (P/N:
GSP665HPMB-EVBIMS2) or with the
users’ own board for in-system prototyping.
•
Use as a thermal and electrical design reference of the GS66516B or GS66508B GaN
PX
® package in
demanding high-power and high efficiency applications.
1.2.2 IMS Board thermal design
An IMS board assembly uses metal as the PCB core, to which a dielectric layer and copper foil layers are
bonded. The metal PCB core is often aluminum. The copper foil layers can be single or double-sided. An
IMS board offers superior thermal conductivity to standard FR4 PCB
. It’s commonly used in high power,
high current applications where most of heat is concentrated in a small footprint SMT device.
Figure 3 Cross-section view of a single layer IMS board
As high-speed Gallium Nitride power devices are adopted widely, the industry is trending away from
through-hole packaging (TH), towards surface mount packaging (SMT). Traditional TH devices, such as
the TO-220, are no longer the appropriate choice because their high parasitic inductance and capacitance
negate the performance benefits offered by GaN E-HEMTs. SMT packaging, such as PQFN, D2PAK and
GaN Systems
’ GaN
PX
®, by comparison, offer low inductance and low thermal impedance, enabling
efficient designs at high power and high switching frequency.
Thermal management of SMT power transistors must be approached differently than TH devices. TO
packages are cooled by attaching them to a heatsink, with an intermediary Thermal Interface material (TIM)
sheet for electrical high voltage insulation. The traditional cooling method for SMT power devices is to use
thermal vias tied to multiple copper layers in a PCB. The IMS board presents designers with another option
which is especially useful for high power applications. The IMS board has a much lower junction to
heatsink thermal resistance (R
thJ-HS
) than FR4 PCBs, for efficient heat transfer out of the transistor. As well,
assembly on an IMS board has lower assembly cost and risk than the TH alternative. The manual assembly
process of a TO package onto a heatsink is costly and prone to human error.
Copper Foil:
•
Typ. 1-4oz (35-140um) up to 10oz
Dielectric Layer:
•
Electrical insulation
•
Typ. 30-200um thickness
•
Thermal conductivity: 1-3W/mK
Metal Substrate/Base
•
Electrically isolated
•
Aluminum or copper
SMT Power Package