VISTA, CA -- A handful of errors have been uncovered in the industry printed circuit board design standard.

Table 9-1 of IPC-2221, Generic Standard on Printed Board Design, shows an incorrect conversion from millimeters to inches. Notes 1 and 2 of the table read, "Add 0.05 mm [0.0197 in.]." The SI number likely should be 0.00197 in., which is roughly 2 mils, not the 20 mils referenced in the notes.

Also, Section 1.6.3, Note 3, characterizes the three standard producibility levels as

• Level A General Design Producibility - Preferred
• Level B Moderate Producibility - Standard
• Level C High Producibility - Reduced

As noted by designer Bill Brooks on the IPC TechNet listserv, " 'High' producibility implies that the board is very producible, when in fact it should be referencing the 'least' producible condition … or most difficult to produce."

Typos are not unusual in standards, which typically are developed by industry volunteers and proofed by IPC staff. The A revision of IPC-2221 was published in 2003.