Socket Mounting Recommendations and Reflow Profile

E-tec Interconnect Ltd, Industrial Zone C, CH-1072 Forel (Lavaux), Switzerland

E-tec Socket Mounting Recommendations

PRELIMINARY

1

Purpose

This document is meant to serve as a guide for mounting E-tec surface mount device (SMD)

sockets to the printed circuit board (PCB). The recommendations described here are guidelines

only, and modifications may be needed for your particular socket, PCB, and process.

Application

The sockets this document applies to are as follows: Clam Shell, Knob Lock, Screw Lock, Twist

Lock, Quick Lock and Lever Lock in SMD style. These sockets utilize the E-tec patented spring-

pin technology. This technology allows the pins to be soldered to the PCB while still providing

compliance to the device under test (DUT) via springs located at the other end of the pin. The

pins themselves do not have solder pre-forms as a BGA would with its solder balls. However, the

sockets are designed to mount to the same PCB footprint and pads as required by the BGA, or

any other IC package the socket was designed for (except if locating pegs are used; see ‘Locating

Pegs’ section of this document). When compared to mounting a BGA, an extra volume of solder

paste is required to mount the sockets to the PCB. To effect this, a properly dimensioned stencil

is required. Once the paste has been applied, a standard reflow process is then used to solder the

socket to the PCB. After the socket is verified to have proper electrical connection to the PCB,

the system is then ready to be used.

Locating Pegs

Although designed to mount to the same footprint as the IC, with just a small amount of

additional keep-out area, E-tec sockets can also be offered with locating pegs. The sockets are

typically mounted with two locating pegs, which require two thru-holes drilled into the PCB.

These pegs help to align the socket on the PCB, and hence align the socket’s pins to the PCB’s

pads, during the soldering process. Furthermore, plating the thru-holes allows the locating pegs

to be soldered to the PCB for better mechanical stability during everyday use and handling of the

socket. If the PCB design permits, E-tec recommends the use of these locating pegs. For fine-

pitch, low pin-count sockets without locating pegs, the mechanical strength of the solder joints

may be insufficient. In these cases, it is recommended to epoxy the socket body to the PCB. 3M

Scotch-Weld 2216 B/A is a suitable epoxy. In any case, the proper volume of solder paste is

required to ensure mechanical and electrical integrity. Recommended stencil dimensions are

given in the next section of this document.