ceramic surface mount amplifier rev. v3 application note C2084 ? north america tel: 800.366.2266 ? europe tel: +353.21.244.6400 ? india tel: +91.80.4155721 ? china tel: +86.21.2407.1588 1 visit www.macomtech.com for additional data sheets and product information. m/a-com technology solutions inc. and its affiliates reserve the right to make changes to the product(s) or inform ation contained herein without notice. 1. introduction m/a-com?s ceramic surface mount amplifier platform offers superior intermodulation performance for if amplifiers in a commercial lga (land grid array) package. this design approach integrates coupler feedback transformer technology into a low cost package with excellent thermal performance. the amplifiers in this family can be used individually or cascaded in pairs to achieve any gain between 10 and 30 db in 5 db steps. desired gain (db) stage 1 amplifier stage 2 amplifier prototype amplifier 10 am05-0006 n/a am05-0006-tb 15 am05-0005 n/a am05-0005-tb 20 am05-0006 am05-0006 n/a 25 am05-0005 am05-0006 n/a 30 am05-0005 am05-0005 n/a table 1. selection guide for 10 to 30 db gain 2. product selection and prototype boards for gains of 10 or 15 db an individual am05-0006 or am05-0005 amplifier would be used. for gains of 20, 25, and 30 db two amplifiers would be cascaded per table 1. note that for the 25 db gain cascade, it is desirable to put am05-0005 first, since noise figure is lower when the higher gain amplifier is the first element of the cascade. prototype boards are available for the am05-0005 and am05-0006 amplifiers. these boards are connectorized so the the customer can easier evaluate prototype quantit ies, without needing to develop prototype boards. dc voltage and return wires can be soldered or clipped to the dc connectors. the part numbers for the prototype boards are am05-0005-tb and am06-0006-tb. see figure 1 for a prototype board with the am05- 0006 amplifier mounted to it. 3. package design the base of the package is ceramic due to the power dissipated in the transistor. using a ceramic package is the best way to transfer heat out of the transistor, and still keep t he design low cost for the commercial market. a land grid array package was used so that the amplifiers can easily be soldered to the end user?s printed circuit board. there are two rf connections (rf in and rf out) and a bias connection. all of the other connections are ground. the grounds are kept small to minimize mechanical stress on the solder joints as the temperature changes, due to the thermal expansion and contraction of the ceramic. some of the grounds are actually used for thermal transfer, as opposed to just providing an rf ground. the leads are pretinned with solder to enhance soldering by the customer. see figure 2 for a top and bottom view of the package. figure 1. prototype board am05-0006-tb
ceramic surface mount amplifier rev. v3 application note C2084 ? north america tel: 800.366.2266 ? europe tel: +353.21.244.6400 ? india tel: +91.80.4155721 ? china tel: +86.21.2407.1588 2 visit www.macomtech.com for additional data sheets and product information. m/a-com technology solutions inc. and its affiliates reserve the right to make changes to the product(s) or inform ation contained herein without notice. 4. thermal design considerations the power dissipated in the amplifiers is deter- mined by the bias voltage and current. with a bias voltage of +12v and a typical current of 88 ma, the total power dissipation in an amplifier is 1.06 w. it is critical that the end user?s pc board is designed so that 1.06 w can be removed from the vicinity of the amplifier. we reco mmend using 1 oz copper on the layer of the board where the ceramic smt amplifiers are mounted. note that the amplifiers should be soldered, not epoxied to the pc board. 5. pcb design guidelines the outline drawing for the amplifier is provided in figure 3. the actual pad sizes on the lga bottom are defined here. when the amplifier is mounted to the pc board, use the ?recommended pc board mounting pattern?, which is provided in figure 4. a dotted line indicates the physical size of the bottom of the package. it shoul d be noted that the entire length of the rf traces on the ceramic should be soldered to the pc board. the rf traces on the pc board should then extend beyond the edge of the package as shown in figure 4. this keeps the solder area larger, which increases the strength. this also allows for inspection of the solder joints. the recommended solder for mounting surface mount packages is sn63 (63% sn, 37% pb) be- cause it is a eutectic compound with a melting point (183oc) high enough to exceed the standard oper- ating limit of the devices, but low enough to avoid damaging internal circuitry during proper solder reflow operations. figure 2. am05-0005 top and bottom views figure 3. am05-0005 outline drawing
ceramic surface mount amplifier rev. v3 application note C2084 ? north america tel: 800.366.2266 ? europe tel: +353.21.244.6400 ? india tel: +91.80.4155721 ? china tel: +86.21.2407.1588 3 visit www.macomtech.com for additional data sheets and product information. m/a-com technology solutions inc. and its affiliates reserve the right to make changes to the product(s) or inform ation contained herein without notice. figure 4. recommended pc board mounting pattern for am05-0005/6 amplifiers
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