PIHR Technology : Bob Willis
'via Blog this'
Thursday, September 22, 2016
Friday, September 9, 2016
When does the 0402 Footprint become a 0503 ?
Let's look at these larger than typical 0402 size parts on an 0402 footprint.
Not a pretty sight, designers beware !
When does the 0402 Footprint become a 0503 ?
The answer depends on which supplier datasheet you are looking at and the specified capacitance.
Back in the day when the 0402 was really a 0402 size part you could design a nominal 0402 footprint and use it for all of your 0402 size parts, that's no longer the case.
Suppliers have been competing for years to provide higher capacitance values and increase working voltages in small form factors such as the 0402 (1005 metric) package.
To get more capacitance in the 0402 package suppliers have expanded the 0402 package tolerances to the point that the parts are now about 0503, vice 0402 sizes.
Conversions:
1.2mm ~ 47.2mil
0.7mm ~ 27.5mil
Let's look at some 10uF 0402 Caps:
click on images to view
Taiyo Yuden - P/N AMK105CBJ106MV-F
Kemet - P/N C0402C106M7PAC7867
Murata - P/N GRM155R60G106ME44D L=1.2 W=0.7 Max
TDK - P/N C1005X5R0G106M050BB L=1.2 W=0.7 Max
As shown in the datasheets above these 0402 10uF caps have larger than typical 0402 LxW tolerances.
Examples of typical 0402 package tolerances.
Samsung MLCC Series Typical 0402 Cap L=1.0mm +/-0.05, W= 0.5mm +/- 0.05.
PCB Design Guidelines from a Top Tier Contract Manufacturer.
Suggested Nominal footprints for an 0402 L=1.4mm, W=0.51mm
Tip: These larger than 0402 size 0402 capacitor packages are usually found when the capacitance is greater than ~ 2.2uF.
In my opinion suppliers should NOT be promoting 1.2mm x 0.7mm (47x27 mil) size parts as 0402s, they should have created a new package class called 0503.
That's It !
Not a pretty sight, designers beware !
When does the 0402 Footprint become a 0503 ?
The answer depends on which supplier datasheet you are looking at and the specified capacitance.
Back in the day when the 0402 was really a 0402 size part you could design a nominal 0402 footprint and use it for all of your 0402 size parts, that's no longer the case.
Suppliers have been competing for years to provide higher capacitance values and increase working voltages in small form factors such as the 0402 (1005 metric) package.
To get more capacitance in the 0402 package suppliers have expanded the 0402 package tolerances to the point that the parts are now about 0503, vice 0402 sizes.
Conversions:
1.2mm ~ 47.2mil
0.7mm ~ 27.5mil
Let's look at some 10uF 0402 Caps:
click on images to view
Taiyo Yuden - P/N AMK105CBJ106MV-F
Kemet - P/N C0402C106M7PAC7867
Murata - P/N GRM155R60G106ME44D L=1.2 W=0.7 Max
TDK - P/N C1005X5R0G106M050BB L=1.2 W=0.7 Max
As shown in the datasheets above these 0402 10uF caps have larger than typical 0402 LxW tolerances.
Examples of typical 0402 package tolerances.
Samsung MLCC Series Typical 0402 Cap L=1.0mm +/-0.05, W= 0.5mm +/- 0.05.
PCB Design Guidelines from a Top Tier Contract Manufacturer.
Suggested Nominal footprints for an 0402 L=1.4mm, W=0.51mm
Tip: These larger than 0402 size 0402 capacitor packages are usually found when the capacitance is greater than ~ 2.2uF.
In my opinion suppliers should NOT be promoting 1.2mm x 0.7mm (47x27 mil) size parts as 0402s, they should have created a new package class called 0503.
That's It !
Subscribe to:
Posts (Atom)