The package of this converter is very small but it aparently can handle 24A.
Vishay SiC431 3 V to 24 V Input, 24 A microBUCK ® DC/DC Converter
It does not make sense to me with a pin width of 0.3mm. How can that be?
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\$\begingroup\$ Efficiency is one thing. Less heat to dissipate. Also good thermal contact with pcb. Besides, pins are used in groups. If only they had a built in inductor.... \$\endgroup\$– TQQQCommented Jan 17 at 12:36
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1\$\begingroup\$ Have you looked at the pinout in the datasheet? The relevant pins are Vin and SW; they are not single 0.3mm pads, but much larger. \$\endgroup\$– marcelmCommented Jan 17 at 12:41
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\$\begingroup\$ The pads are soldered to a circuit board that is much bigger. \$\endgroup\$– Stack Exchange Supports IsraelCommented Jan 17 at 12:47
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2 Answers
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It does not make sense to me with a pin width of 0.3mm
I don't know if you have checked the package but there are multiple, paralleled SW pins so not only a single 0.3-mm-wide pin carries 24 Amps, but a total of 5 bound together does.
Also the pin lengths, along with the internal bonding wires, are quite short so the contact resistance becomes really low (or at least, acceptably low) to carry at least 24 Amps (this is average, by the way, so does not include the ripple) with an acceptable dissipation and temperature rise.
One other thing that should be considered is the thermal management. if you provide large enough copper pour for the SW pins (which will also support heatsinking) then it's surely possible.
Today, you can see MOSFETs in DFN5x6 that can handle hundreds of Amps from only 4(D)+3(S)=7 pins. So it's not an impossible thing to achieve.
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Figure 1. Large solder pads on Vin, GND and SW.
Figure 2. From page 18 of the datasheet.
It looks to me that the whole of the exposed pads on the bottom of the package can be soldered to the PCB.
Page 21 shows the surface area of the square part of the VIN terminal to be about 1 mm2 which is much more reasonable.
