Assembly Instructions for SCA6x0 and SCA10x0 series

1 Objective


This document provides general guidelines for Printed Circuit Board (PCB) design and assembly of
VTI’s surface mountable DIL type of Pre-molded Lead-frame packages (DIL-8 for SCA6x0 series
and DIL-12 for SCA10x0 series).
It should be emphasized that this document serves only as a design guideline to help develop the
optimal assembly conditions. It is essential that users also use their own manufacturing practices
and experience to be able to fulfill the needs of varying end-use applications.
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2 VTI’S DIL-8 and DIL-12 packages


The SCA6x0 and SCA10x0 series products are SMD DIL-8 / DIL-12 components, pick-and-place
mountable, and reflow solderable. These components are completely lead-free and designed to
meet the demanding lead free soldering processes. The package consists of a pre-molded plastic
housing, with a copper based lead frame having gull-wing type of leg pins on the side of the
package to provide electrical contact to the PCB. A metal lid is attached to the top of the package.
The DIL-8 and DIL-12 packages are presented in Figure 1.
Figure 1: Three dimensional views of the DIL-8 and DIL-12 packages.

3 Package Outline and Dimensions


The outline and dimensions for the DIL-8 package are presented in Figure 2.

Figure 2: Outline and dimensions for DIL-8 package.
The outline and dimensions for the DIL-12 package are presented in Figure 3.

Figure 3: Outline and dimensions for DIL-12 package.

4 Tape and reel specifications


Packing tape dimensions are presented in figure 4. The unreeling direction and component polarity
on tape are presented in figure 5. Reel dimensions are presented in figure 6.

Figure 4: Packing tape dimensions for the DIL-8 and DIL-12 package. All dimensions in millimeters
(mm).

5.1 Recommended PCB pad layout


For optimal soldering and solder joint reliability results of VTI’s DIL component, the PCB terminal
pads should be designed larger than the package leads. Reference dimensions for the land pad
design are presented in Figure 7. Note that this is only an example and e.g. much narrower pads
can be used and also the length can be different.
Figure 7: PCB pad lay-out for the DIL-8 and DIL-12.
VTI’s DIL packages can be soldered on commonly used substrates, e.g. FR-4, ceramic etc. The
pad metallization should be solder wettable in order to assure good quality solder joints. For fine
pitch assembly, the quality of plating is important. Generally used circuit board finishes for fine pitch
SMD soldering are NiAu, OSP, Electroless-Ag and Electroless-Sn.

5.2 Solder paste and Cleaning process


The DIL package can be soldered with lead-free SAC (tin-silver-copper) solder. The SAC solder
paste composition should be near eutectic. The melting point of lead-free SAC solder can vary
between 217–221ºC, depending on the composition of solder alloy. In order to guarantee full RoHS
compatibility lead-free solder should be used for the soldering of VTI’s DIL component. Also
traditional eutectic SnPb solder can be used for soldering the DIL packages if a lead-free process
is not required. With the eutectic SnPb solder, the melting point is 183°C.
A no-clean solder paste should be used, since the cleaning process is not recommended. The
metal lid on the pre-molded package is not fully sealed and there is a risk that cleaning fluids might
penetrate inside the package. If cleaning is used, user must validate that the process does not
decrease the performance or reliability of the component. Ultrasonic agitation is strictly
prohibited for VTI’s MEMS components. Ultrasonic might destroy the MEMS structures.
The solder paste which is used must be suitable for printing it through the stencil aperture
dimensions. Type 3 paste is recommended (grain size 25-45μm).
REFERENCE