ltp:tft031 version 1.0 18.12.08 ______________________________________________________________________________________________________ vi telefilter application note tfs 210c - 1/2 ______________________________________________________________________________________________________ vi telefilter vectron international, inc. potsdamer stra?e 18 267 lowell road d 14 513 teltow / germany hudson, nh 03051 / usa tel: (+49) 3328 4784-0 / fax: (+49) 3328 4784-30 tel: (603) 598-0070 fax: (603) 598-0075 e-mail: tft@telefilter.com e-mail: vti@vtinh.com vi telefilter rese rves the right to make changes to the product(s) and/or information contained herein without notice. no liab ility is assumed as a result of their use or application. no rights under any patent accompany the sale of any such product(s) or infor mation. 1. general the filter is single ended driven. it is matched to 50 ? the matching element values given below are valid on the test pcb. if the parasitics on the customer pcb and on this pcb are different, the matching elements have to be optimised regarding the circuit and pcb design. the matching elements have been chosen from the e12- series (european standard series with fixed tolerances). 2. theoretical matching the termination impedances of the filter are: source impedance: 295 ? || 1,15 pf load impedance: 295 ? || 1,15 pf the values of the matching elements which are given below are calculated from the source and load impedance. if the values of the matching elements are not equal to standard values the best standard values are given in brackets. 50 ? test circuit 1 7 2,3,4,5,6,8,9,10,11,12 saw c1 l1 1 c2 l2 l1 = 84 nh l2 = 84 nh c1 = 6.8 pf c2 = 6.8 pf 50 ? test circuit 2 7 2,3,4,5,6,8,9,10,11,12 saw l1 c1 1 l2 c2 c1 = 6.8 pf c2 = 6.8 pf l1 =126 nh l2 =126 nh
ltp:tft031 version 1.0 18.12.08 ______________________________________________________________________________________________________ vi telefilter application note tfs 210c - 2/2 ______________________________________________________________________________________________________ vi telefilter vectron international, inc. potsdamer stra?e 18 267 lowell road d 14 513 teltow / germany hudson, nh 03051 / usa tel: (+49) 3328 4784-0 / fax: (+49) 3328 4784-30 tel: (603) 598-0070 fax: (603) 598-0075 e-mail: tft@telefilter.com e-mail: vti@vtinh.com vi telefilter rese rves the right to make changes to the product(s) and/or information contained herein without notice. no liab ility is assumed as a result of their use or application. no rights under any patent accompany the sale of any such product(s) or infor mation. 3. matching on the pcb for example: pcb with 50 ? test circuit 1 7 2,3,4,5,6,8,9,10,11,12 saw c1 l1 1 c2 l2 l1 = 68 nh l2 = 68 nh c1 = 4.7 pf c2 = 4.7 pf the matching on the pcb does slightly differ from the theoretical matching. the reason for that are parasitics of the pcb. if the parasitics on the customer board (mentioned pa rasitics, additional parasitics of active parts) are different to this pcb the matching elements have to be slightly adjusted. in case of questions please contact us to
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