 |
Electronic Components Datasheet Search |
|
|
Electronic Components Datasheet Search |
|
LTC1067 Datasheet(PDF) 9 Page - Linear Technology |
|
||||||||||||||||||||||||||||||
LTC1067 Datasheet(HTML) 9 Page - Linear Technology |
|
|
9 / 20 page  9 LTC1067/LTC1067-50 ODES OF OPERATIO Mode 1 In Mode 1, the ratio of the external clock frequency to the center frequency of each 2nd order section is internally fixed at the part’s nominal ratio. Figure 3 illustrates Mode 1 providing 2nd order notch, lowpass and bandpass outputs. Mode 1 can be used to make high order Butter- worth lowpass filters; it can also be used to make low Q notches and for cascading 2nd order bandpass functions tuned at the same center frequency. Mode 1 is faster than Mode 3. Please refer to the Operating Limits paragraph under Appli- cations Information for a guide to the use of capacitor CC. Linear Technology’s universal switched-capacitor filters are designed with a fixed internal, nominal fCLK/fO ratio. The LTC1067 has a 100:1 fCLK/fO ratio and the LTC1067-50 has a 50:1 fCLK/fO ratio. Filter designs often require the fCLK/fO ratio of each section to be different from the nominal ratio and in most cases different from each other. Ratios other than the nominal value are possible with external resistors. Operating modes use external resistors, connected in different arrangements to realize different fCLK/fO ratios. By choosing the proper mode, the fCLK/fO ratio can be increased or decreased from the part’s nominal ratio. The choice of operating mode also effects the transfer function at the HP/N pins. The LP and BP pins always give the lowpass and bandpass transfer functions respectively, regardless of the mode utilized. The HP/N pins have a different transfer function depending on the mode used. Mode 1 yields a notch transfer function. Mode 3 yields a highpass transfer function. Mode 2 yields a highpass- notch transfer function (i.e., a highpass with a stopband notch). More complex transfer functions, such as low- pass-notch, allpass or complex zeros, are achieved by summing two or more of the LP, BP or HP/N outputs. This is illustrated in sections Mode 2n and Mode 3a. Choosing the proper mode(s) for a particular application is not trivial and involves much more than just adjusting the fCLK/fO ratio. Listed here are six of the nearly twenty modes available. To make the design process simpler and quicker, Linear Technology has developed the FilterCAD TM for Windows ® design software. FilterCAD is an easy-to- use, powerful and interactive filter design program. The designer can enter a few filter specifications and the program produces a full schematic. FilterCAD allows the designer to concentrate on the filter’s transfer function and not get bogged down in the details of the design. Alternatively, those who have experience with the Linear Technology family of parts can control all of the details themselves. For a complete listing of all the operating modes, consult the appendices of the FilterCAD manual or the Help files in FilterCAD. FilterCAD can be obtained free of charge on the Linear Technology web site (http:// www.linear-tech.com) or you can order the FilterCAD CD-ROM by contacting Linear Technology’s marketing department. FilterCAD is a trademark of Linear Technology Corporation. Windows is a registered trademark of Microsoft Corporation. Mode 1b Mode 1b is derived from Mode 1. In Mode 1b (Figure 4) two additional resistors R5 and R6 are added to lower the amount of voltage fed back from the lowpass output into the input of the SA (or SB) switched-capacitor summer. This allows the filter’s clock-to-center frequency ratio to be adjusted beyond the part’s nominal ratio. Mode 1b maintains the speed advantages of Mode 1 and should be considered an optimum mode for high Q designs with fCLK to fCUTOFF (or fCENTER) ratios greater than the part’s nominal ratio. Figure 3. Mode 1, 2nd Order Filter Providing Notch, Bandpass and Lowpass Outputs – + Σ ∫ ∫ AGND NOTE: RATIO = 100 FOR LTC1067 = 50 FOR LTC1067-50 R1 N BP LP VIN 1067 F03 + – S R2 R3 CC fO = ; fn = fO Q = ; HON = – ; HOBP = – HOLP = HON R2 R1 R3 R1 R3 R2 fCLK RATIO |
Similar Part No. - LTC1067_15 |
|
Similar Description - LTC1067_15 |
|
|
|
Link URL |
| Privacy Policy |
| ALLDATASHEET.COM |
| Does ALLDATASHEET help your business so far? [ DONATE ] |
About Alldatasheet | Advertisement | Datasheet Upload | Contact us | Privacy Policy | Link Exchange | Manufacturer List All Rights Reserved©Alldatasheet.com |
| Russian : Alldatasheetru.com | Korean : Alldatasheet.co.kr | Spanish : Alldatasheet.es | French : Alldatasheet.fr | Italian : Alldatasheetit.com Portuguese : Alldatasheetpt.com | Polish : Alldatasheet.pl | Vietnamese : Alldatasheet.vn Indian : Alldatasheet.in | Mexican : Alldatasheet.com.mx | British : Alldatasheet.co.uk | New Zealand : Alldatasheet.co.nz |
|
Family Site : ic2ic.com |
icmetro.com |
English ▼
English
Chinese
German
Japanese
Russian
Korean
Spanish
French
Italian
Portuguese
Polish
Vietnamese
Indian
Mexican
British
New Zealand
