A p p l i c a t i o n N o t e , V 2. 1, F e b . 2 00 8 A p p li c a t i o n N o t e N o . 0 4 7 M a t c h i ng M e th o d s f o r V a r i ab l e C a p a c i t an c e Diodes R F & P r o t e c ti o n D e v i c e s Edition 2008-02-14 Published by Infineon Technologies AG, 81726 München, Germany © Infineon Technologies AG 2009. All Rights Reserved. Attention please! The information herein is given to describe certain components and shall not be considered as a guarantee of characteristics. Terms of delivery and rights to technical change reserved. We hereby disclaim any and all warranties, including but not limited to warranties of non-infringement, regarding circuits, descriptions and charts stated herein. Information For further information on technology, delivery terms and conditions and prices please contact your nearest Infineon Technologies Office (www.infineon.com). Warnings Due to technical requirements components may contain dangerous substances. For information on the types in question please contact your nearest Infineon Technologies Office. Infineon Technologies Components may only be used in life-support devices or systems with the express written approval of Infineon Technologies, if a failure of such components can reasonably be expected to cause the failure of that life-support device or system, or to affect the safety or effectiveness of that device or system. Life support devices or systems are intended to be implanted in the human body, or to support and/or maintain and sustain and/or protect human life. If they fail, it is reasonable to assume that the health of the user or other persons may be endangered. , Revision History: 2008-02-14, V2.1 Previous Version: V2.0, 2006-02-15 Page Subjects (major changes since last revision) 7-9 Table 2 and Table 3 update to current Infineon product range Template: a4_sd_tmplt.fm / 1 / 2005-12-01 Application Note No. 047 Matching Methods for Variable Capacitance Diodes 1 Matching Methods for Variable Capacitance Diodes This application note covers the field of the selection methods that are applied on variable capacitance diodes to reduce the effort on adjusting electronic circuits in production. Varicap or variable capacitance diodes are key semiconductors components for VCO‘s and tuner circuits. It is a semiconductor diode in which the voltage dependency of the PN junction capacitance in reverse bias node is utilized and the Q factor is optimized. These diodes are ideal tuning elements for Satellite-, TV-, VCR- and Radio - tuners and for VCO applications in mobile communication. Variable capacitance diodes for tuner applications are classified in different categories (FM, VHF, UHF, SAT) according to the application frequency and their capacitance values. Attention: Matching of diodes is usually not required for varicap diodes in VCO applications But for tuner applications there must be sufficient tracking of the input -, intermediate - and oscillator - circuits in order to get a good band pass response. The capacitances of the diodes, that are used in these stages have to be matched. For this propose capacitance diodes are sorted into matched sets of similar capacitance over the entire reverse voltage range. There are four different selections methods which can be used to provide matched diodes: • • • • • A: In line matching (SCD80, SC79) B: In line matching in groups C: Group matching (only SOD323) D: Floating matching (only SOD323) E: Unmatched (SOD323, SCD80, SC79) A: In-line matching (SCD80, SC79) Inline matching, pick and place matching, direct matching assembly are all expressions for a new tracking method. Neighboring diode chips are picked up intelligently in an orderly structure and one after another from the wafer and are placed consecutively on the leadframe. Remaining in this order the diodes are molded, punched and tested electrically. In the end the capacitance values are gliding matched within a defined ∆C/C% tolerance of n consecutive diodes on the tape. For this matching method a good wafer quality, a very small capacitance tolerance and a very good uniformity of the total capacitance curves are necessary in order to get reels with small matched capacitance tolerances. Advantage A very close matching quality of Ct and a very good Ct vs. VR characteristics of consecutive diodes. (See Figure 1) Disadvantage No capacitance selection is possible. Application Note 4 V2.1, 2008-02-14 Application Note No. 047 Matching Methods for Variable Capacitance Diodes Diode 1 Diode 2 Diode 3 ... etc 1 Figure 1 Capacitance Variation in Inline Matched Selections B: Inline matching in groups This matching method is a combination of method A: and C:. On one reel we have more than one group with group separations and the devices of the different groups are inline matched. C: Group matching (only SOD323) For this method the capacitance target range at discrete reverse voltages is split into capacitance subgroups which are allocated into capacitance tolerance categories. Figure 1 for example shows the capacitance spread range and the capacitance Ct at fixed reverse voltages VR. Every capacitance range at the discrete reverse voltage will be assigned to fixed capacitance categories Cc (Cc=1,2,3...n) with a capacitance tolerance ∆C/C%= (Cmax.n - Cmin.n)/Cmin.n). Diodes with the same group address from a matched group. For example: Table 1 Group matching (only SOD323) Reverse Voltage 1V 6V 15 V 25 V 28 V Group no. 1 address 4 3 3 2 2 Group no. 2 address 4 4 5 3 3 Group no. 2 address 2 2 3 2 2 Application Note 5 V2.1, 2008-02-14 Application Note No. 047 Matching Methods for Variable Capacitance Diodes Group 1 Group 2 Group 3 Figure 2 Capacitance Spread and Group Addresses Diodes from these matched groups (or preselected capacitance groups) are randomly distributed in quality. To get a reel with 3 000 or 10 000 devices, possible two or more matched groups must be on one reel. Matched groups on the reel ate separated by empty pockets. Advantage In this matching method any number of devices in a group are matched and any selection of capacitance ratio is directly possible. Disadvantage In this matching method more than one matched group is on the reel and the diode capacitance curves might cross each other (see Figure 3) D: Floating matching (only SOD323) The continuos processing of a complete tape is made possible by what we call floating matching. Continuos matching on the tape is accomplished by successive placing of “related” preselected matched groups (according method A) on the tape. In this case a random section of the tape of a specified number of consecutive taped diodes (typically 7) are always matched with a capacitance tolerance ∆C/C%. Advantage No group separation on the tape by empty pockets, which means easier handling by the customers and tight matching quality Disadvantage No total capacitance ratio- selection possible. Application Note 6 V2.1, 2008-02-14 Application Note No. 047 Available matching methods per package and the corresponding E-numbers Diode 1 Diode 2 Diode 3 ... etc 1 -1 Figure 3 Capacitance Variations in group or floating matched selection E: Unmatched (SOD323, SCD80, SC79) Unmatched diodes are sufficient for all applications where it is not necessary to track several resonant circuit to the same resonant frequency (e.g. VCO‘s in mobile communication). 2 Available matching methods per package and the corresponding E-numbers One tables for every package: SOD323, SCD80 and SC79. Table 2 SOD323 overview of matching methods Matching Type 3k Group matched BB439 E6327 Floating matched BB439 Unmatched BB439 E7263 Group matched BB545 E7904 Floating matched BB545 E7906 Unmatched BB545 E7908 Group matched BB535 E7904 Floating matched BB535 E7906 Unmatched BB535 E7908 Group matched BB639 E7904 Floating matched BB639 E7906 Unmatched BB639 E7908 Group matched BB639C E7904 Floating matched BB639C E7906 Unmatched BB639C E7908 Group matched BB640 E6327 Application Note 7 V2.1, 2008-02-14 Application Note No. 047 Available matching methods per package and the corresponding E-numbers Table 2 SOD323 overview of matching methods (cont’d) Matching Type 3k Floating matched BB640 E7786 Unmatched BB640 E7263 Group matched BB644 E7904 Floating matched BB644 Unmatched BB644 E7908 Group matched BB669 E7904 Floating matched BB669 E7906 Unmatched BB669 E7908 Group matched BB831 E7904 Floating matched BB831 E7906 Unmatched BB831 E7908 Group matched BB833 E6327 Floating matched BB833 Unmatched BB833 Group matched BB837 Floating matched BB837 E6327 Unmatched BB837 E7263 E7263 Note: All E7xxx E-numbers are discontinued Table 3 SCD80 overview of matching methods Matching Type 3k 8k1) In-line matched BB555 E7902 E7912 Unmatched BB555 E7908 In-line matched BB565 E7902 Unmatched BB565 E7908 In-line matched BB659 E7902 Unmatched BB659 E7908 In-line matched BB659C E7902 Unmatched BB659C E7908 In-line matched BB664 E7902 Unmatched BB664 E7908 In-line matched BB689 E7902 Unmatched BB689 E7908 In-line matched BB857 E7902 Unmatched BB857 E7908 Unmatched BBY51-02W E6327 Unmatched BBY52-02W E6327 Unmatched BBY53-02W E6327 Unmatched BBY55-02W E6327 In-line matched BBY56-02W E7902 Unmatched BBY56-02W E6327 Application Note 8 E7912 E7912 E7912 E7912 E6127 E6127 V2.1, 2008-02-14 Application Note No. 047 Available matching methods per package and the corresponding E-numbers Table 3 SCD80 overview of matching methods (cont’d) Matching Type 3k 8k1) Unmatched BBY57-02W E6327 E6127 Unmatched BBY58-02W E6327 E6127 1) With 2 mm reel pitch, detailed information available on data sheet Table 4 SC79 overview of matching methods Matching Type 3k 8k1) In-line matched BB555-02V E7902 E7912 In-line matched BB565-02V E7902 E7912 In-line matched BB659C-02V E7902 E7912 In-line matched BB664-02V E7902 E7912 E7912 In-line matched BB689-02V E7902 Unmatched BBY53-02V E6327 Unmatched BBY55-02V E6327 Unmatched BBY56-02V E6327 Unmatched BBY57-02V E6327 Unmatched BBY58-02V E6327 Unmatched BBY59-02V E6327 Unmatched BBY65-02V E6327 Unmatched BBY66-02V E6327 1) With 2 mm reel pitch, detailed information available on data sheets Application Note 9 V2.1, 2008-02-14