ltp: tft035 version 1.0 8.8.2000 vi telefilter application note tfs 210e - 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 4784-52 / 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 reserves 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 driven single ended. 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) to get the best agreement between the pcb measurement and the measurement in a reference test fixture. 2. theoretical matching the balanced driven source and load impedances of the filter are: source impedance: 630 ? || -9.2 pf load impedance: 915 ? || -.5,7 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. 2.1. single ended matching c2 output 50 ohm l2 input 50 ohm l1 c1 saw 1,2,3,5,6,7, 4 10 8,9,11,12 l1 = 77 nh (82nh) l2 = 117 nh (120nh) c1 = 29 pf (27pf) c2 = 19 pf (18pf) 2.2. ballanced matching 3 4 10 9 1,2,5,6,7,8,11,12 lb-in lb-out c1 l1 c2 l4 l3 l2 input 50 ohm output 50 ohm saw l1=38 nh (39 nh) l3=58 nh (56 nh) l2=38 nh (39 nh) l4=58 nh (56 nh) c1=27 pf c2=18 pf
ltp: tft035 version 1.0 8.8.2000 vi telefilter application note tfs 210e - 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 4784-52 / 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 reserves 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 3.1. single ended matching c2 output 50 ohm l3 input 50 ohm l1 c1 saw 1,2,3,5,6,7, 4 10 8,9,11,12 l4 l2 l1 = 8,2 nh l3 = 68 nh l2 = 47 nh l4 = 12 nh c1 = 33 pf c2 = 27 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 parasitics, additional parasitics of active parts) are different to this pcb the matching elements have to be slightly adjusted. 3.2. balanced ended matching 3 4 10 9 1,2,5,6,7,8,11,12 lb-in lb-out c1 l1 c2 l4 l3 l2 input 50 ohm output 50 ohm saw l1 =39 nh l3 = 27 nh l2 =22 nh l4 = 68 nh c1 =33 pf c2 = 27 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 parasitics, additional parasitics of active parts) are different to this pcb the matching elements have to be slightly adjusted.
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