popn_pico/PCB/agg-kicad/mod/ic/README.md

Names in the following format: FAMILY-PINS[-MOD][-EP][-SPECIAL]

MOD might be "W" for wide.

SPECIAL might refer to a manufacturer's specific modified footprint.

Examples: SOIC-8, SOIC-16-W, QFN48-EP

Unless otherwise noted, all pad dimensions are as per IPC-7351B nominal, while fab layer annotatons are as per IPC-7351B package maximums.

Keys (QFN/QFP/DFN/DFP)

• rows: either 2 or 4, for dual or quad packages.
• pins: total number of pins
• pins_first_row: optional when rows is 4, number of pins in row containing pin 1, for rectangular chips. Must also give row_pitch as a tuple. Defaults to pins/rows i.e. a square chip. Not applicable to 2-row chips.
• row_pitch: spacing between centres of rows of pins, or tuple of [horizontal pitch, vertical pitch] only if pins_first_row is given, where horizontal pitch is pin 1 to its opposite pin.
• pad_shape: (width, height) of a pad for a pin.
• ep_shape: (width, height) of an exposed pad underneath the chip. Leave out this parameter to skip the exposed pad.
• ep_mask_shape: (width, height, w_gap, h_gap) of mask apertures on EP. Multiple apertures will be created to fill. Leave out this parameter to cover the EP in mask aperture.
• ep_paste_shape: (width, height, w_gap, h_gap) of paste apertures on EP. Multiple apertures will be created to fill. Leave out this parameter to cover the EP in paste aperture.
• ep_vias: (drill, size, gap) of via hits to put in the EP. Leave out this parameter to not place any vias.
• pin_shape: (width, height) of the chip package pins (for Fab layer). Use negative widths for internal pins (e.g., QFNs).

Keys (BGA only)

• rows: number of rows (identified by letters)
• cols: number of columns (identified by numbers)
• pad_shape: diameter of a pad for a pin.
• mask_shape: diameter of solder mask opening for a pin.
• pin_shape: diameter of the chip package pins (for Fab layer).
• letters: Optional string of sequential letters to use naming rows, defaults to standard ABCDEFGHJKLMNPRTUVWY.

Keys (Common)

• name: Name to generate footprint under
• description: Footprint description
• skip_pins: optional, list of pin numbers to skip (leaving remaining pins in sequential order). Generates packages like SOT-23-3. Each list entry may be an exact pin to skip (eg 12 or B6) or a range of numbers or letters or both (eg 5-8 or B3-5 or A-C6 or A-C3-5)
• pin_pitch: spacing between centres of adjacent pins.
• chip_shape: (width, height) of the actual chip package (for Fab layer).
• silk: "internal" or "external" or None. Default is "internal" unless ep_shape is given in or on BGAs in which case default is "external".
• model: dictionary containing path string to 3d model, and optional offset, scale, and rotate lists of [x, y, z] values.

All lengths are in millimetres.