IPCB Naming Convention for Surface Mount Device 3D Models and Footprints. The 3D CAD solid electronic modes/footprint (land pattern) naming. The IPC Land Pattern Viewer is provided on CD-ROM as part of the IPC- Updates to land pattern dimensions, including patterns for new component . IPCB Naming Convention for Standard SMT Land Patterns. Surface Mount Land Patterns. Component, Category. Land Pattern Name.
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Icp is now a “Guideline” and should be used as such. In the early stages of a design, a test philosophy should be clearly deined, then a strategy for executing the tests can be implemented. Thus, some applications can be satisfied with fewer signal layers while providing additional layers for power and ground.
IPC-7351B Naming Convention for Surface Mount Device 3D Models and Footprints
If solder mask is used, it should not cover the iducial mark or the clearance area. Similar to SOT89 packages, there is no clearance between the body of the component and the packaging and interconnect structure. The requirements for a square FBGA form the mechanical and electrical connection from the package body to a mating feature such as 77351b printed board.
Some QFN packages, however, do not have thermal tabs. Each cycle shall consist of 10 to 30 seconds or 20 8.
This is done to minimize lead bending during shipping and handling. For fine-pitch components, it is good design practice to distribute approximately half of the test vias to the inside of the land pattern Test Via Grid Concepts and the other half to the outside of the land pattern as shown in 7531b Ball Grid Array BGA packages may feature land pattern names that indicate a difference in pitch between pads in the row axis vs.
Surface mount devices are furnished in tape and reel as well as tube magazine feeders to accommodate high-speed assembly systems tray carriers are most often adapted for fine-pitch components. Uniform preheating is achieved by developing a solder schedule that specifies preheat settings and conveyer speed for each type of printed board.
IPC-7351 SMD & PTH Reference Calculators
Routing conductors between lands at 1. Users are encouraged to establish the appropriate relationship ip their dimensioning system s and the profile dimensioning system and analysis concepts described herein to allow for ease of tailoring these concepts for robust process performance.
This allows the component body to settle as opposed to floating on top of solder. They may be cost-effective to avoid wave solder processes if there are only a few leaded components on the printed board.
The land pattern of the component where the ball is attached and the land pattern of the substrate mounting structure printed board should be as similar as possible. A dimensioning system with specific equations has been provided to facilitate unique land pattern development or enhance process usage. Component Cavity Parts must be capable of withstanding cleaning processes currently used IPCb by board assem bly manufacturers.
It is good design practice to locate global or panel fiducials in a three-point grid-based datum system as shown in Figure 735b B in Figure shows the converted dimensions to be considered in the overall mounting system requirements. The basic dimensions define the minimum length as measured across the two outer extremities.
IPC SMD & PTH Reference Calculators – PCB Libraries Forum – Page 1
The paste mask on thermal pads is a single square for thermal pads 4. Contact pattern is defined when viewed from the bottom. Four sided gull-wing packages are normally processed by solder reflow operations. Refer to IPC for minimum annular ring requirements for microvias. End-product drawings and speciications should specify only the minimum for conductor spacing; however, conductor widths should be deined according to minimum values, where land patterns should be deined as to their MMC.
Consult your manufacturer before placing SOICs on the wave solder side of the printed board. These small outline integrated circuits SOIC are all on 1.
Equations can be used to alter the given information to achieve a more robust solder connection, when used in particular situations where the equipment for placement or attachment are more or less precise than the assumptions made when determining the land pattern details see 3.
The results are more noticeable on fine pitch components. Similar types of components should be aligned on the printed 3.
Bulk packaging is not preferred because of lead coplanarity required for placement and soldering. Users should be aware that individual component data sheets may not meet standardized component outlines. Rounded Rectangular The first part of the padstack convention consists of a land shape.
There are ive to six main process variables that must be controlled in the wave soldering process: Solder paste is applied on the lands before component placement either by screening, stenciling, or syringe. Whether round or rectangular, once the tolerance is assigned it applies to the periphery of the lands for that particular part.
This term can be used in conjunction with other terms listed herein, e. It is faster than hand soldering but not as fast as wave, vapor, IR soldering or hot air convection.
Via-in-pad through-hole via, capped on bottom of the printed board can cause voids in a BGA solder joint, which may impact reliability. All Chip Component Body Sizes are one place to each side of the decimal point 5.