? north america tel: 800.366.2266 / fax: 978.366.2266 ? europe tel: 44.1908.574.200 / fax: 44.1908.574.300 ? asia/pacific tel: 81.44.844.8296 / fax: 81.44.844.8298 visit www.macom.com for additi onal data sheets and pr oduct information. 1 application note on sample board operation of the masw-000834-13560t t/r switch m/a-com products rev.3 MASW-000834-000SMB sample board m/a-com inc. and its affiliates reserve the right to make changes to the product(s) or information contained herein with out notice. m/a-com makes no warr anty, representatio n or guarantee regarding the suitab ility of its products for an y particular purpose, nor does m/a-com assume any liability whatsoever arising out of the use or application of any product(s) or information. the following is an application guide for utiliza- tion of the masw-000834-13560t in conjunc- tion with a supplied sample board from m/ acom. the guide will re view the operation of the t/r using a single positive supply as well as other optional dual po larity supplies. the masw-000834-13560t is a t/r switch with two pin diodes in series in a common an- ode configuration and one pin diode in shunt on the rx path. the switch die along with select matching components are mounted in a standard 4mm mlp 16 lead package (figure 1). the switch die utilizes m/acom?s patented hmic ? process. the backsi de of the switch die is thermally grounded while electrically iso- lated. the excellent power handling of the die is achieved through specific techniques using unique thermal conductiv e epoxy embedded in the die. this allows the heat to be transferred from the series connected device to ground while maintaining electrical isolation. the large backside of the pad of the package is both thermal and electrical ground. figure 2 shows the electrical/ thermal schematic of the device. the sample board is made of rogers ro4350 material 10mils thick dielectric with added lay- ers to increase the board thickness to 62mils for handling, rigidity and connector mounting. there are on-board bias networks incorporated to accommodate biasing the device without the use of expensive external bias tees. figure 3 shows the standard board layout with compo- nent selection for optimized performance up to 6 ghz. figure 1. package outline drawing figure 2. electrical/thermal schematic
? north america tel: 800.366.2266 / fax: 978.366.2266 ? europe tel: 44.1908.574.200 / fax: 44.1908.574.300 ? asia/pacific tel: 81.44.844.8296 / fax: 81.44.844.8298 visit www.macom.com for additi onal data sheets and pr oduct information. 2 application note on sample board operation of the masw-000834-13560t t/r switch m/a-com products rev.3 MASW-000834-000SMB sample board m/a-com inc. and its affiliates reserve the right to make changes to the product(s) or information contained herein with out notice. m/a-com makes no warr anty, representatio n or guarantee regarding the suitab ility of its products for an y particular purpose, nor does m/a-com assume any liability whatsoever arising out of the use or application of any product(s) or information. the diagram in figure 4 is a schematic depiction of the figure 3 sample board drawing. there are 100 ohm resistors on the ant path and the dc2 path. this topology allows for e ither an all-positive bias scheme or a positive and negative bias scheme. figure 4. sample board schematic figure 3. sample board assembly drawing c1 c1 c1 c2 c2 l l l l r r c1: 27pf c2: 12pf l: 68nh r: 100 ohm
? north america tel: 800.366.2266 / fax: 978.366.2266 ? europe tel: 44.1908.574.200 / fax: 44.1908.574.300 ? asia/pacific tel: 81.44.844.8296 / fax: 81.44.844.8298 visit www.macom.com for additi onal data sheets and pr oduct information. 3 application note on sample board operation of the masw-000834-13560t t/r switch m/a-com products rev.3 MASW-000834-000SMB sample board m/a-com inc. and its affiliates reserve the right to make changes to the product(s) or information contained herein with out notice. m/a-com makes no warr anty, representatio n or guarantee regarding the suitab ility of its products for an y particular purpose, nor does m/a-com assume any liability whatsoever arising out of the use or application of any product(s) or information. figure 7. single positive supply biasing dc bias tx - antenna rf condition rx - antenna rf condition i dc = +20 or +50 ma [ant to tx path on] v ant = voltage in which ant resistor limits current to i dc v tx = 0v v rx = voltage in which dc2 resistor limits current to i dc must be greater than v ant [rx path off / dc2 path on] dc2 = 0 insertion loss isolation i dc = +20 or +50 ma [ant to rx path on] v ant = voltages in which resistors limit current to i dc v rx = 0v v tx = must be greater than v ant [tx path off] dc2 = equal or higher than v rx [dc2 path off] isolation insertion loss example positive bias scheme i dc = +50ma v ant = +5v v tx = 0v v rx = +25v dc2 = 0v i dc = +50ma v ant = +5v v tx = +25v v rx = +0v dc2 = +5v to accommodate biasing with a single positive suppl y, dc voltage must be applied to the antenna, rx, tx, and dc2 ports. the resistor on the antenna path will limit the current drawn when this volt- age is applied. the resistor present on the dc2 bias path limits the cu rrent when the rx shunt diode is turned on. to achieve optimum performance, 50ma of dc bias current to the diodes is necessary. m/a-com tech supplies 100 ohm resi stors on these sample boards. in order to achieve proper isolation in the ?off? ar m, the back bias (vr) on the diodes should be large enough to sustain higher power levels . the voltage levels can range from +5v to +25v, as shown in the figure. minimum back bias requirements will change depending on incident peak rf voltage and frequency of operation. please contact m/a-com technology solutions fo r additional guidance on required reverse bias voltages for specific application environments. positive voltage supply figure 5. transmit on, receive off figure 6. transmit off, receive on
? north america tel: 800.366.2266 / fax: 978.366.2266 ? europe tel: 44.1908.574.200 / fax: 44.1908.574.300 ? asia/pacific tel: 81.44.844.8296 / fax: 81.44.844.8298 visit www.macom.com for additi onal data sheets and pr oduct information. 4 application note on sample board operation of the masw-000834-13560t t/r switch m/a-com products rev.3 MASW-000834-000SMB sample board m/a-com inc. and its affiliates reserve the right to make changes to the product(s) or information contained herein with out notice. m/a-com makes no warr anty, representatio n or guarantee regarding the suitab ility of its products for an y particular purpose, nor does m/a-com assume any liability whatsoever arising out of the use or application of any product(s) or information. the sample board can accommodate dual polarity s upplies as shown in figur es 8 through 10. in this scheme, bias is applied to the rx , tx, and dc2 path. unlike the single positive polarity bias scheme, bias to the ant port is not used. a series resistor on the ant arm a nd second resistor on the dc2 path will limit the current when a negative voltage is app lied to the tx or rx port. m/a-com tech supplies 100 ohm resistors on these sample boards. in order to achieve proper isolation in the ?off? ar m, the back bias (vr) on the diodes should be large enough to sustain higher power levels . the voltage levels can range from +5v to +25v, as shown in the figure. minimum back bias requirements will change depending on incident peak rf voltage and frequency of operation. please contact m/a-com technology solutions fo r additional guidance on required reverse bias voltages for specific application environments. dual positive and negative voltage figure 10. dual positive and negati ve voltage source bias truth table dc bias tx - antenna rf condition rx - antenna rf condition v tx = negative voltage in which ant resistor limits current to i dc [ant to tx path on] v rx = positive voltage level, greater than 0v in which dc2 resistor limits current to i dc [rx path off / dc2 path on] low loss isolation v rx = negative voltage in which ant resistor limits current to i dc [ant to rx path on] v tx = positive voltage level, greater than 0v in which dc2 resistor limits current to i dc [rx path off / dc2 path on] isolation low loss example dual bias scheme v ant = 0v v tx = -5v v rx = +25v dc2 = 0v i dc = +/- 50ma v ant = 0v v rx = -5v v tx = +25v dc2 = 0v i dc = +/- 50ma figure 8. transmit on, receive off fi gure 9. transmit off, receive on
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