Transition Socket Specification SOT/DFN/QFN TRANSITION SOCKETS SOT/DFN/QFN transition sockets and associated hardware are shown below. FIGURE 7: SOT TRANSITION SOCKET WITH CABLE FIGURE 10: DFN TRANSITION SOCKET WITH CABLE Cable to Processor Module PDIP Device Adapter Gold Standoffs/ Adapters Cable to Processor Module DFN Transition Socket PDIP Device Adapter Cables Target/Application Board Gold Standoffs/ Adapters SOT Transition Socket Cables FIGURE 11: QFN TRANSITION SOCKET WITH CABLE Target/Application Board Cable to Processor Module PDIP Device Adapter FIGURE 8: DFN/QFN TWO-PART TRANSITION SOCKET Gold Standoffs/ Adapters Cable to Processor Module QFN Transition Socket PDIP Device Adapter Cables Gold Standoffs/ Adapters Target/Application Board DFN/QFN Transition Socket Target/Application Board FIGURE 9: QFN TRANSITION SOCKET Cable to Processor Module PDIP Device Adapter Gold Standoffs/ Adapters QFN Transition Socket Target/Application Board Microchip offers the following SOT/DFN/QFN transition sockets: • XLT06SOT: One 6-lead SOT transition socket with cable • XLT08DFN: One 8-lead DFN two-part transition socket • XLT08DFN2: One 8-lead DFN transition socket with cable • XLT16QFN1: One 16-lead QFN transition socket with cable • XLT28QFN3: One 28-lead QFN transition socket with cable • XLT28QFN4: One 28-lead QFN transition socket with cable • XLT44QFN2: One 44-lead QFN transition socket with cable • XLT44QFN3: One 44-lead QFN transition socket with cable The following sockets have been discontinued: • XLT28QFN: One 28-lead QFN transition socket. (Replaced by XLT28QFN4.) • XLT28QFN2: One 28-lead QFN transition socket. (Replaced by XLT28QFN3.) • XLT44QFN: One 44-lead QFN two-part transition socket. (Replaced by XLT44QFN2.) See the drawings in this section for layout dimensions. © 2006 Microchip Technology Inc. DS51194P-page 19 Transition Socket Specification RECOMMENDED INSTALLATION OF TRANSITION SOCKETS WITH CABLES 3. 4. 5. For transition sockets that use a cable, follow these instructions for installing your transition socket on the target board. Center each cable on the footprint (see below). Tape down each cable to prevent movement. Solder each lead to target pad. Remove tape and clean center cable on target footprint pin 1 PCB Layout Considerations: header pins facing down Make sure you leave enough room on the PCB to accommodate the cable, i.e., space your target pads for each device far enough apart so that the cable from one pad group will not interfere with another pad group. 6-Pin SOT Solder Instructions: 1. 2. 3. 4. Remove protective cable covering from end of cable. Position cables on target board (see below). Tape down to prevent movement. Solder each lead to target pad. Remove tape and clean. 16-Pin QFN Assembly Instructions: 1. 2. 3. 4. Start with cable associated with pin 1. Fold cable up and over, forming a radius. Header pins will now be facing upwards. Mate with the socket on the underside of the transition socket assembly, making sure pin 1 mates with the pin labeled “QFN Pin 1”. Fold over and mate the other cables. 28/44-Pin QFN Solder Instructions: 2. 8-Pin DFN Solder Instructions: 1. 2. 3. 4. Prepare leads by trimming narrowest portion to 0.10-inch maximum in length (see below). Position cables on target board (see below). Tape down to prevent movement. Solder each lead to target pad. Remove tape and clean. 3. 4. 5. Remove protective cable jacket from stripped end of cable. Lay out with long cables opposing each other and short cables opposing each other (see below). Place center lead (6th lead for 44-pin, 4th lead for 28-pin) on center target pad to center each cable on the footprint (see below). Tape down each cable to prevent movement. Solder each lead to target pad. Remove tape and clean pin 1 long 1. pin 1 use center lead to center cable on target footprint trim leads pin 1 short header pins facing down long short 8-Pin DFN Assembly Instructions: 1. 2. 3. 4. Start with cable associated with pin 1. Fold cable up and over, forming a radius. Mate with the header on the side of the transition socket assembly, making sure pin 1 mates with the pin labeled “DFN Pin 1”. Fold over and mate the other cable. 28/44-Pin QFN Assembly Instructions: 1. 2. 3. 16-Pin QFN Solder Instructions: 1. 2. Remove protective cable jacket from stripped end of cable. Lay out the four cables in a “+” pattern (see below). DS51194P-page 20 4. Start with cable associated with pin 1. Fold cable up and over, forming a radius. Header pins will now be facing upwards. Mate with the socket on the underside of the transition socket assembly, making sure pin 1 mates with the pin labeled “QFN Pin 1”. Fold over and mate the other cables. © 2006 Microchip Technology Inc. Transition Socket Specification The recommended target board footprint layout for different pin-counts is shown here. XLT06SOT 6-lead SOT-23 to 0.80-inch Adapter Socket 0.80 FIGURE 12: 6-PIN SOT, 8-PIN DFN DVA Pin 1 RECOMMENDED PCB LAYOUT 0.90 50 mils TOP VIEW 16 mils 24 mils 0.30 FIGURE 13: 16-PIN QFN 1.50 SIDE VIEW 24 mils 11 mils UNLESS OTHERWISE SPECIFIED, DIMENSIONS ARE IN INCHES. 26 mils XLT08DFN2 8/14-lead DIP to 0.025-inch Adapter Socket FIGURE 14: 28-PIN QFN DVA Pin 1: Location of 8- or 14-lead DIP pin 1 1.35 DVA Pin 1 DFN Pin 1 24 mils 11 mils 0.30 0.90 26 mils 2.37 FIGURE 15: 44-PIN QFN 0.24 TOP VIEW 0.30 16 mils 13 mils 26 mils 0.09 SIDE VIEW UNLESS OTHERWISE SPECIFIED, DIMENSIONS ARE IN INCHES. © 2006 Microchip Technology Inc. DS51194P-page 21 Transition Socket Specification XLT16QFN1, XLT28QFN3, XLT28QFN4, XLT44QFN2, XLT44QFN3 Multi-lead DIP to 0.025-inch Adapter Socket Cables 0.85 Multi-lead DIP to 0.025-inch Adapter Socket TOP VIEW XLT16QFN1 – 14-lead DIP 1.25 DVA Pin 1 QFN Pin 1 0.40 1.15 0.40 SIDE VIEW TOP VIEW BOTTOM VIEW XLT28QFN3 – 18-lead DIP (shown here) XLT28QFN4 – 28-lead DIP C 2.45 DVA Pin 1 QFN Pin 1 1.15 TOP VIEW XLT44QFN2 – 40-lead DIP (shown here) XLT44QFN3 – 44-lead DIP 2.45 cable XLT16QFN1 C 1-4 1.30 XLT28QFN3/4 1,2 1.30 3,4 2.00 XLT44QFN2/3 1,2 1.30 3,4 2.00 UNLESS OTHERWISE SPECIFIED, DIMENSIONS ARE IN INCHES. DVA Pin 1 DIP 1 Drawing shown is for 28-lead DIP. 1.15 QFN Pin 1 TOP VIEW 0.56 FRONT/BACK VIEW UNLESS OTHERWISE SPECIFIED, DIMENSIONS ARE IN INCHES. DS51194P-page 22 © 2006 Microchip Technology Inc.