How does the silicone look like on the inside? Does it have swirls of wiring like an inductor or a processor-like thing sealed off within the silicone layer covering on the outside?
Hello, most modern power MOSFETs are “vertical” devices, meaning the current flows from the copper source clip to the copper drain tab through the silicon chip sandwiched in the middle. Within the design of the silicon chip, there are a large number of identical channels spread across the surface. Each channel is individually turned on/off through a connection to the gate. Providing many parallel paths for the current to flow allows the RDS(on) of the device to be as low as possible. Thanks for your question!
How do you manage the CTE thermal stresses between the die to bottom Cu plate, and between the die to power-clip Cu? Also, how many contact points does the power-clip make to the Emitter/Source side of the die? Thanks.
Hello! MOSFETs undergo life tests which include thermal cycles as well as reliability tests on a top of AEC-Q101 standard requirements. The MOSFETs are then specified to 175⁰C after successfully completing the life test, meaning that they are free from failures whether caused by CTE mismatch, delamination or other failure mechanism. For more details about MOSFET composition and their relevant temperature spec please see AN90016 (section 4) on nexperia.com. assets.nexperia.com/documents/application-note/AN90016.pdf
Thanks for the question. Power density is calculated based on power of device divided by its volume - we invite you to check out the datsheets to see parametrics.
Hello! How is it possible to cool that type of IC. Can you give some hints, what kind of opportinity the designer has? The copper of the PCB itself not always adequate. I myself really would like to test the device, but the missing heatsink surface for external cooler holds me back.
Hello, please refer to our Nexperia app note AN90003, LFPAK thermal design guide. In terms of testing the device to it's limit, the right cooling layout and heatsink are necessary, alternatively a copper busbar can be considered if your design allows it. assets.nexperia.com/documents/application-note/AN90003.pdf
Hybrid vehicles like the Toyota Prius use liquid cooling for the MOSFETS in the inverter/converter. My Prius has two 3-phase synchronous motors in the transaxle: a primary traction motor of 52kW, and a secondary generator for battery charging of 22kW. The inverter that provides power for these two motors has six MOSFETS mounted to a thick aluminum heatsink plate. This plate has several coolant passages running through it, and the heat produced by the MOSFETS is ultimately dumped into the atmosphere via the car's radiator. The two stators in the transaxle, where that 3-phase power is being used, are cooled by a constant spray of transmission oil. This oil is passed through a heat exchanger bolted to the outside of the transaxle housing, and the heat is passed to radiator via the same coolant circuit as the inverter. The gasoline engine has it's own separate coolant circuit to the radiator, same as any other IC engine. The 6 MOSFETS in the Prius inverter are encased in a block of resin that has an exposed surface of metal (copper or aluminum, I'm not sure which) on the bottom. I think the individual MOSFETS are soldered to this metal strip, then the block is mounted to the liquid-cooled heatsink plate with thermal conduction grease, similar to how the CPU chips in a computer are mounted to a heatsink.
Hello, thanks for your question! The difficulty of soldering SMD MOSFETs depends on what they are being soldered to. This is highly application specific, however, if a device is being soldered to a surface with low thermal resistivity and large thermal mass (for example copper cladded PCBs), you will need to apply more heat and a soldering iron alone may not be enough. In those cases hot air gun, hot plate or a reflow oven would be needed.
Hi @danielchatrie6614! There is enough cooling by providing copper surfaces next to the device or on the other side of the PCB (the heat is conducted from the Drain tab by thermal vias). If a heatsink is needed, it can be attached to the other side of the PCB. The heatsinks can be attached via pedestals to avoid it occupying the whole surface of the PCB.
Now that size I can solder by hand!
😂 you need tig welder at that stage
yeah you can even weld it.
That model is huge! I’m not sure if the model is actually working but it could handle like 10000 amps
How does the silicone look like on the inside? Does it have swirls of wiring like an inductor or a processor-like thing sealed off within the silicone layer covering on the outside?
Hello, most modern power MOSFETs are “vertical” devices, meaning the current flows from the copper source clip to the copper drain tab through the silicon chip sandwiched in the middle. Within the design of the silicon chip, there are a large number of identical channels spread across the surface. Each channel is individually turned on/off through a connection to the gate. Providing many parallel paths for the current to flow allows the RDS(on) of the device to be as low as possible. Thanks for your question!
How do you manage the CTE thermal stresses between the die to bottom Cu plate, and between the die to power-clip Cu? Also, how many contact points does the power-clip make to the Emitter/Source side of the die? Thanks.
Hello! MOSFETs undergo life tests which include thermal cycles as well as reliability tests on a top of AEC-Q101 standard requirements. The MOSFETs are then specified to 175⁰C after successfully completing the life test, meaning that they are free from failures whether caused by CTE mismatch, delamination or other failure mechanism. For more details about MOSFET composition and their relevant temperature spec please see AN90016 (section 4) on nexperia.com. assets.nexperia.com/documents/application-note/AN90016.pdf
5 times power density of a TOLL ... Please, tell me, where can I find some notes with comparation benween LFPAK88 and TOLL.
Thanks for the question. Power density is calculated based on power of device divided by its volume - we invite you to check out the datsheets to see parametrics.
Hello! How is it possible to cool that type of IC. Can you give some hints, what kind of opportinity the designer has? The copper of the PCB itself not always adequate.
I myself really would like to test the device, but the missing heatsink surface for external cooler holds me back.
Hello, please refer to our Nexperia app note AN90003, LFPAK thermal design guide. In terms of testing the device to it's limit, the right cooling layout and heatsink are necessary, alternatively a copper busbar can be considered if your design allows it.
assets.nexperia.com/documents/application-note/AN90003.pdf
Hybrid vehicles like the Toyota Prius use liquid cooling for the MOSFETS in the inverter/converter. My Prius has two 3-phase synchronous motors in the transaxle: a primary traction motor of 52kW, and a secondary generator for battery charging of 22kW. The inverter that provides power for these two motors has six MOSFETS mounted to a thick aluminum heatsink plate. This plate has several coolant passages running through it, and the heat produced by the MOSFETS is ultimately dumped into the atmosphere via the car's radiator. The two stators in the transaxle, where that 3-phase power is being used, are cooled by a constant spray of transmission oil. This oil is passed through a heat exchanger bolted to the outside of the transaxle housing, and the heat is passed to radiator via the same coolant circuit as the inverter. The gasoline engine has it's own separate coolant circuit to the radiator, same as any other IC engine. The 6 MOSFETS in the Prius inverter are encased in a block of resin that has an exposed surface of metal (copper or aluminum, I'm not sure which) on the bottom. I think the individual MOSFETS are soldered to this metal strip, then the block is mounted to the liquid-cooled heatsink plate with thermal conduction grease, similar to how the CPU chips in a computer are mounted to a heatsink.
so what watt iron do you recommend using to solder this component?.. my t12 seems to not be working.
Hello, thanks for your question! The difficulty of soldering SMD MOSFETs depends on what they are being soldered to. This is highly application specific, however, if a device is being soldered to a surface with low thermal resistivity and large thermal mass (for example copper cladded PCBs), you will need to apply more heat and a soldering iron alone may not be enough. In those cases hot air gun, hot plate or a reflow oven would be needed.
What about heatsink
Hi @danielchatrie6614! There is enough cooling by providing copper surfaces next to the device or on the other side of the PCB (the heat is conducted from the Drain tab by thermal vias). If a heatsink is needed, it can be attached to the other side of the PCB. The heatsinks can be attached via pedestals to avoid it occupying the whole surface of the PCB.