Introduction to Conversion Socket Specifications Conversion sockets are products that allow a header board (for next-generation circuit simulators or circuit debuggers) or device adapters (for MPLAB ICE 2000 circuit simulators) to interface with a socket on a target application .
Typically, a header board or device adapter has a connector that matches the development cycle device format such as DIP or PLCC. However, the target socket will match a compact production device format such as SOIC, SSOP, QFP or QFN. The solution is to convert the socket. A conversion socket is specifically designed to provide compatibility between two different types of IC package formats.
The conversion socket usually consists of two parts: the adapter socket and the adapter head. Adapter sockets are designed to plug into a header board or device adapter on one end and an adapter header on the other. Then solder the adapter header to the target application.
Why use conversion sockets in product design?
There are two very significant advantages to using an adapter socket:
1. Shorten product development cycle
2. Reduce the cost of design, layout and prototype testing A typical product design cycle has two important phases: the prototyping phase and the production design phase. Traditionally, these stages are different simply because the prototype uses microcontrollers with different package types. However, with the availability of transition sockets, the prototyping design can be identical to the production design, as the transition socket can be used to bridge differences in microcontroller packages.
What conversion sockets are currently available?
Microchip Technology currently offers the conversion sockets listed in the "Table of Contents" following this introductory section.
Use the online Development Tool Selector (DTS) to find the conversion sockets available per headboard or per device adapter. For more information on header boards or device adapters, see:
(DS51292) How does the header board specification get the most out of using a conversion socket?
Care should be taken with the placement of components to provide adequate clearance for the conversion socket interface to the printed circuit board package. This is especially true for any tall components such as connector heads, radial components or voltage regulators. See Transition Socket Mechanical Drawings for dimensions.
Transition Socket Applications - Comments and Recommendations Component placement should be considered when mating adapter sockets to SOIC/SSOP headers.
Via locations around the surface mount technology (SMT) layout area should be checked. The vias immediately adjacent to the ends of the SMT pads may inadvertently touch the header leads. Vias should be placed along the centerline of the SMT pads to reduce the possibility of pin-to-pin shorts when soldering.
Care should be taken when soldering some transition sockets to the target board.

SOIC conversion socket A SOIC conversion socket and related hardware are shown in Figure 1.

Figure 1: SOIC conversion socket
SOIC conversion socket has two components
1. Connect to the adapter socket of the DIP device adapter
2. To be soldered to the SOIC header of the target application Microchip provides the following SOIC conversion sockets:
XLT08SO-1: One 8-wire DIP adapter socket and one 8-wire SOIC header (5.28mm body size)
XLT08SN-1: An 8-wire DIP adapter socket and an 8-wire SOIC header (3.9mm body size)
XLT14SO-1: One 14-lead DIP adapter socket and one 14-lead SOIC header
XLT18SO-1: One 18-lead DIP adapter socket and one 18-lead SOIC header
XLT20SO1-1: One 20-lead DIP adapter socket and one 20-lead SOIC header
XLT28SO-1: A 28-wire DIP adapter socket and a 28-wire SOIC header layout dimensions are shown in the drawings in this section.
8-lead dipped 8-lead SOIC (narrow) 14-lead dipped 14-lead SOIC

SSOP Conversion Socket A SSOP conversion socket and associated hardware are shown in Figure 2.
Figure 2: SSOP conversion socket

SSOP conversion sockets are similar to SOIC conversion sockets. The SSOP conversion socket has two parts:
1. Connect to the adapter socket of the DIP device adapter.
2. Solder to the SSOP header of the target application.
Microchip offers the following SSOP conversion sockets:
XLT14SS-1: A 14-wire DIP adapter socket and a 14-wire SSOP header
XLT20SS-1: One 18-wire DIP adapter socket and one 20-wire SSOP header
XLT20SS1-1: A 20-wire DIP adapter socket and a 20-wire SSOP header
XLT28SS-1: A 28-wire DIP adapter socket and a 28-wire SSOP header
XLT28SS2-1: A 28-wire DIP adapter socket and a 28-wire SSOP header (pic16x55/57)
18 Lead Dip 20 Lead SSOP 20 Lead Dip 20 Lead SSOP

PLCC conversion sockets need to be used with PLCC device adapters. The DAF18-1 device adapter is equipped with eight socket strips that connect to one of two transition sockets. The DAF18-3 device adapter comes with four socket strips that connect to a conversion socket.
The PLCC adapter is designed to have a threaded insert in the center of the package so that a 4/40 screw can securely fasten the adapter to the device adapter.
The PLCC conversion socket is designed to be soldered to the target PCB PLCC surface mount mode or inserted into the PLCC socket on the target PCB.
Microchip provides the following PLCC conversion sockets:
XLT44L2: Recommended PCB Layout for a 44-Wire PLCC Conversion Socket
QFP conversion socket
qfp (mqfp, tqfp, pqfp) conversion sockets and related hardware are shown below.
QFP conversion sockets are required when used with QFP device adapters. The device adapter comes with four socket strips that connect to the conversion sockets.
Note:
To avoid solder bridging, do not place vias within 0.025" of the QFP package. Also, any vias close to the QFP should be directly on the pad centerline.
The QFP conversion socket has two parts:
1. Connect to the adapter socket of the QFP device adapter
2. Solder the QFP header to the target application
Microchip offers the following QFP conversion sockets:
XLT44PT3: One 44-wire QFP adapter socket and one 44-wire QFP header (0.8 mm)
XLT64PT5: One 64-wire QFP adapter socket and one 64-wire QFP header (0.5 mm)
XLT80PT2: One 80-wire QFP adapter socket and one 80-wire QFP header (0.65 mm)
XLT80PT3: One 80-wire QFP adapter socket and one 80-wire QFP header (0.5 mm)
The QFP transition socket solder tip uses a controlled tip with a tip temperature between 300 and 325 degrees Celsius ( 570 and 615 degrees Fahrenheit).
If possible, use a Pace Mini Wave tip or an equivalent tip design.
Plan to weld one (1/4) side first, then the other side, then the remaining two sides.
The tip should be moved towards the leads (back and forward), not across the leads; dragging the tip over the leads may damage the leads.
Use plenty of flux to help solder flow.
44 lead QFP (0.8 mm) 64/80 lead QFP (0.5 mm)

Two-part transition receptacles include:
1. Connect to the adapter socket of the DIP device adapter
2. The QFN header microchip to be soldered to the target application provides the following SOT/DFN/QFN conversion sockets:
XLT06SOT: A 14-lead plug into a 6-lead SOT-23 conversion socket with cable
xlt08dfn2: A 14-wire DIP to 8-wire DFN conversion socket with cable
xlt16qfn1: A 14-wire DIP to 16-wire QFN conversion socket with cable
XLT20QFN-1: A 20-wire DIP adapter socket and a 20-wire QFN header
xlt28qfn3: An 18-wire DIP to 28-wire QFN conversion socket with cable
XLT28QFN4: A 28-lead DIP to 28-lead QFN conversion socket with cable
xlt44qfn2: One 40-lead DIP to 44-lead qfn conversion socket with cable
xlt44qfn3: A 28-wire DIP to 44-wire QFN conversion socket with cable
XLT44QFN4: One 28-lead DIP to 44-lead QFN conversion socket with cable
XLT44QFN5: An 18-Lead DIP to 44-Lead QFN Transition Socket, with Cable Recommended Installation of Transition Socket with Cable For transition sockets using cables, follow the instructions below to install the transition socket on the target board.
Printed circuit board layout considerations:
Make sure you leave enough room on the PCB for the cables, that is, space the target pads of each device far enough apart so that the cables from one pad group don't interfere with the other.
6-pin SOT soldering instructions:
1. Remove the protective cable cover from the cable end.
2. Place the cable on the target board (see below). Tape to prevent movement.
3. Solder each lead to the target pad.
4. Remove tape and clean.

8-pin DFN soldering instructions:
1. By trimming the narrowest part to a maximum length of 0.10 inches (see below).
2. Place the cable on the target board (see below). Tape to prevent movement.
3. Solder each lead to the target pad.
4. Remove tape and clean.
8-pin DFN assembly instructions:
1. Start with the cable associated with pin 1.
2. Fold the cable up to form a radius.
3. Mate with the header on the side of the transition socket assembly, making sure that pin 1 mates with the pin labeled "DFN pin 1".
4. Fold the other cable and pair it.
16-pin QFN soldering instructions:
1. Remove the protective cable jacket from the stripped end of the cable.
2. Route the four cables in "+" mode (see below).
3. Place each cable in the center of the footprint (see below). Tape each cable to prevent movement.
4. Solder each lead to the target pad. 5. Remove tape and clean
16-pin QFN assembly instructions:
1. Start with the cable associated with pin 1.
2. Fold the cable up to form a radius. The header pins will now be facing up.
3. Match the socket on the underside of the transition socket assembly, making sure that pin 1 mates with the pin labeled "QFN Pin 1".
4. Fold and pair the other cables.
28/44 pin QFN soldering instructions:
1. Remove the protective cable jacket from the stripped end of the cable.
2. Arrange with long cables facing each other and short cables facing each other.
3. Place the center wire (6th wire on 44-pin, 4th wire on 28-pin) on the center target pad to center each cable on the schematic. Tape each cable to prevent movement.
4. Solder each lead to the target pad. 5. Remove tape and clean
28/44 Pin QFN Assembly Instructions:
1. Start with the cable associated with pin 1.
2. Fold the cable up to form a radius. The header pins will now be facing up.
3. Match the socket on the underside of the transition socket assembly, making sure that pin 1 mates with the pin labeled "QFN Pin 1".
4. Fold and pair the other cables.
Recommended PCB Layout XLT06SOT
14 lead dip 6 lead SOT-23
Recommended target board schematic layouts for different pin counts are shown here.
xlt16qfn1, xlt28qfn3, xlt28qfn4, xlt44qfn2, xlt44qfn3, xlt44qfn4, xlt44qfn5

XLT20QFN-1 Soldering suggests that this socket is difficult to solder because the pins of the device are not exposed, but embedded in the socket's surface feet (SF).
1. First, add viscous flux to the target landing pattern.
2. Visually align the QFN SF with the target landing pattern. Then solder the two opposite SF pins to the target soldering station so the SF doesn't move.
3. Complete the soldering of the remaining SF pins.
4. If the SF has an intermediate ground pin, pass the solder through the bottom of the target board through the hole. This will connect the center QFN SF pin to the target board.
5. Check each solder connection on the QFN SF pins.
disconnected socket