Surface Mount Chip Capacitors X7R Polymer Termination - a lead free termination MLCC's are widely used in electronic circuit design for a multitude of applications. Their small package size, technical performance and suitability for automated assembly makes them the component of choice for the specifier. in ceramic devices that may not always be evident during the board assembly process. Sometimes it may be the end customer who finds out - when equipment fails! Capacitor Body and Electrodes However, despite the technical benefits, ceramic components are brittle and need careful handling on the production floor. In some circumstances they may be prone to mechanical stress damage if not used in an appropriate manner. Board flexing, depanelisation, mounting through hole components, poor storage and automatic testing may all result in cracking. Termination Solder Fillet Force Careful process control is important at all stages of circuit board assembly and transportation - from component placement to test and packaging. Any significant board flexing may result in stress fractures Crack Initiation Substrate Fig 1. Typical Mechanical Crack 3KV 2KV 1KV 630V 500V 250V 2KV 630V 1KV 500V 2KV 1KV 630V 500V 500V 250V 100V 200V 50/63V 16V 25V 250V 100V 200V 50/63V 16V 25V 250V 200V 50/63V 100V 25V 16V 250V 100V 200V 50/63V 16V 25V X7R 08 18 ce 10 12 an 06 12 cit 28 05 08 pa 03 06 Ca 10pF 12 15 18 22 27 33 39 47 56 68 82 100pF 120 150 180 220 270 330 390 470 560 680 820 1.0nF 1.2 1.5 1.8 2.2 2.7 3.3 3.9 4.7 5.6 6.8 8.2 10 12 15 18 22 27 33 39 47 56 68 82 100 120 150 180 220 270 330 390 470 560 680 820 1.0F 1.2 1.5 1.8 2.2 2.7 3.3 3.9 4.7 5.6 6.8 8.2 10 12 15 Surface Mount Chip Capacitors X7R With traditional termination materials and assembly, the chain of materials from bare PCB to soldered termination, provides no flexibility. In circumstances where excessive stress is applied - the weakest link fails. This means the ceramic itself, which may fail short circuit. Fired ceramic dielectric Syfer has the solution FlexiCapTM has been developed as a result of listening to customers' experiences of stress damage to MLCC's from many manufacturers, often caused by variations in production processes. Tin outer layer Our answer is a proprietary flexible epoxy polymer termination material, that is applied to the device under the usual nickel barrier finish. FlexiCapTM will accommodate a greater degree of board bending than conventional capacitors. FlexiCapTM termination base Intermediate nickel layer Metal electrodes Fig 2. FlexiCap MLCC cross section TM 40 36 25 22 20 22 12 18 3KV 2KV 1KV 630V 500V X7R 2KV 3KV 1KV 630V 500V 3KV 2KV 1KV 630V 500V 250V 200V 100V 50/63V 16V 25V 250V 200V 100V 50/63V 16V 25V notes 4KV 3KV 2KV 630V 1KV 500V 250V 200V 100V 50/63V 16V 25V 10pF 12 15 18 22 27 33 39 47 56 68 82 100pF 120 150 180 220 270 330 390 470 560 680 820 1.0nF 1.2 1.5 1.8 2.2 2.7 3.3 3.9 4.7 5.6 6.8 8.2 10 12 15 18 22 27 33 39 47 56 68 82 100 120 150 180 220 270 330 390 470 560 680 820 1.0F 1.2 1.5 1.8 2.2 2.7 3.3 3.9 4.7 5.6 6.8 8.2 10 12 15 Shown above are standard and high voltage ranges of X7R chip capacitors which are available with FlexiCapTM terminations. Please refer to our sales office if you require other products in our range with this new termination. For all other mechanical and electrical details please refer to the relevant sections of this catalogue. For ordering information see page 30. 29 Surface Mount Chip Capacitors Application Notes benefits Summary of PCB bend test results The benefit to the user is to facilitate a wider process window giving a greater safety margin and substantially reducing the typical root causes of mechanical stress cracking. The bend tests conducted have proved that the FlexiCapTM termination withstands a greater level of mechanical stress before mechanical cracking occurs. FlexiCapTM may be soldered using your traditional wave or reflow solder techniques and needs no adjustment to equipment or current processes. Typical examples: Syfer has delivered millions of FlexiCapTM components and during that time has collected substantial test and reliability data, working in partnership with customers world wide, to eliminate mechanical cracking. Product Mean bend (mm) Standard Term. Mean bend (mm) FlexiCapTM Improvement with FlexiCapTM 0603 X7R 1.6 6.4 + 400% 0805 X7R 3.6 6.3 + 75% 1206 X7R 3.4 6.4 + 88% 1812 X7R 3.2 6.0 + 88% 2220 X7R 3.2 6.1 + 91% Application Notes Picture taken at 1,000x magnification using a SEM to demonstrate the fibrous nature of the FlexiCapTM termination that absorbs increased levels of mechanical stress. FlexiCapTM may be handled, stored and transported in the same manner as standard terminated capacitors. The requirements for mounting and soldering FlexiCapTM are the same as for standard SMD capacitors. For customers currently using standard terminated capacitors there should be no requirement to change the assembly process when converting to FlexiCapTM. Based upon board bend tests in accordance with IEC 60384-1 the amount of board bending required to mechanically crack a polymer terminated capacitor is significantly increased compared with standard terminated capacitors. It must be stressed however, that capacitor users must not assume that the use of FlexiCapTM terminated capacitors will totally eliminate mechanical cracking. Good process controls are still required for this objective to be achieved. Ordering Information 0805 Type No Chip Size Y 100 Termination Y = FlexiCapTM Voltage 016 =16V 025 =25V 050 = 50V 063 = 63V 100 = 100V 200 = 200V 250 = 250V 500 = 500V 630 = 630V 1K0 =1kV 2K0 =2kV 3K0 =3kV 4K0 =4kV 5K0 =5kV 0101 J Capacitance First digit - 0 Second digit - First significant figure of capacitance value Third digit - Second significant figure of capacitance value Tolerance Stable class J = 5% K = 10% M = 20% X Dielectric X = X7R T Packaging T =178mm (7") reel R =330mm (13") reel B =Bulk pack tubs Fourth digit - Number of zeros following. For values that do not fit the model above, insert the capacitance code letter for the decimal point e.g. 13N6 = 13.6nF (c) Copyright/Design right, Syfer Technology Limited, 2003. FlexiCapTM is a registered trade mark of Syfer Technology Limited. notes 1. For details of the FlexiCapTM range see pages 28/29. 30 Suffix Code Used for specific customer requirements