Datasheet – What Does BSC SQ Mean?


I'm reading this DAC datasheet. The last page (p. 32) gives certain of the chip's dimensions, some in units of "BSC SQ".

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What does BSC SQ mean? Is it standard to express sizes in BSC SQ?

Best Answer

BSC means "Basic Spacing Between Centers". This is often used if the reference lines don't refer to a physical point or edge, like in the case of the pins: the reference is in the middle of the pin, instead of one of the edges.

BSC SQ = BSC square, i.e. in both X and Y dimensions.

The abbreviation BSC is misused in the case of the package outline, and overall dimensions, as they are specified by physical edges which can be measured.

Usually a mechanical drawing of a package will show minimum and maximum values. BSC SQ must be regarded as nominal, so may deviate, but it doesn't say by how much.