ir3092 International Rectifier Corp., ir3092 Datasheet - Page 33

• Manufacturer Part Number: ir3092
• Description: 2 Phase Opteron, Athlon, Or Vr10.x Control Ic
• Manufacturer: International Rectifier Corp.

PCB AND STENCIL DESIGN METHODOLOGY
See Figures 14-16.
PCB Metal Design (0.5mm Pitch Leads)
PCB Solder Resist Design (0.5mm Pitch Leads)
Stencil Design (0.5mm Pitch Leads)
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1. Lead land width should be equal to nominal part lead width. The minimum lead to lead spacing
2. Lead land length should be equal to maximum part lead length + 0.2 mm outboard extension +
3. Center pad land length and width should be = maximum part pad length and width. However, the
4. Sixteen 0.30mm diameter vias shall be placed in the pad land spaced at 1.2mm, and connected
1. Lead lands. The solder resist should be pulled away from the metal lead lands by a minimum of
2. The minimum solder resist width is 0.13mm, therefore it is recommended that the solder resist is
3. At the inside corner of the solder resist where the lead land groups meet, it is recommended to
4. Land Pad. The land pad should be SMD, with a minimum overlap of the solder resist onto the
5. Ensure that the solder resist in-between the lead lands and the pad land is
6. The single via in the land pad should be tented with solder resist 0.4mm diameter, or 0.1mm
1. The stencil apertures for the lead lands should be approximately 80% of the area of the lead
2. The stencil lead land apertures should therefore be shortened in length by 80% and centered on
3. The center land pad aperture should be striped with 0.25mm wide openings and spaces to
4. The maximum length and width of the center land pad stencil aperture should be equal to the
7x7
48 Lead
0.5mm pitch MLPQ
should be
0.05mm inboard extension. The outboard extension ensures a large and inspectable toe fillet,
and the inboard extension will accommodate any part misalignment and ensure a fillet.
minimum metal to metal spacing should be
and
to ground to minimize the noise effect on the IC, and to transfer heat to the PCB.
0.060mm. The solder resist mis-alignment is a maximum of 0.050mm and it is recommended
that the lead lands are all NSMD. Therefore pulling the S/R 0.060mm will always ensure NSMD
pads.
completely removed from between the lead lands forming a single opening for each “group” of
lead lands.
provide a fillet so a solder resist width of
copper of 0.060mm to accommodate solder resist mis-alignment. In 0.5mm pitch cases it is
allowable to have the solder resist opening for the land pad to be smaller than the part pad.
high aspect ratio of the solder resist strip separating the lead lands from the pad land.
larger than the diameter of the via.
lands. Reducing the amount of solder deposited will minimize the occurrence of lead shorts.
Since for 0.5mm pitch devices the leads are only 0.25mm wide, the stencil apertures should not
be made narrower; openings in stencils < 0.25mm wide are difficult to maintain repeatable solder
release.
the lead land.
deposit approximately 50% area of solder on the center pad. If too much solder is deposited on
the center land pad the part will float and the lead lands will be open.
solder resist opening minus an annular 0.2mm pull back to decrease the incidence of shorting
the center land to the lead lands when the part is pushed into the solder paste.
06/25/04
IR3092