Design of switched capacitor filters design example signal flow graph and differential architecture commercial switched capacitor filter in psoc. The foregoing discussion leads to the conceptual view illustrated in fig. Mf10nuniversal monolithic dual switched capacitor filter. The parameter models the amount of charge flow into the component and is normalized by the amount of output flowing charge. Switchedcapacitor ic forms notch filter application note. A cmos direct sampling mixer using switched capacitor filter technique for softwarede. A cmos direct sampling mixer using switched capacitor filter. Choi, highfrequency cmos switchedcapacitor filters, u.
Design of a lowpower switchedcapacitor bandpass filter. Opamp design project ee 5333 analog integrated circuits prof. With an external clock and 2 to 4 resistors, various secondorder and firstorder filtering functions can be realized by each filter block. Mar 05, 20 design of switched capacitor filters design example signal flow graph and differential architecture commercial switched capacitor filter in psoc. Zoh circuit file copy from the spectrerf primer module zoh pout, nout, pin, nin period. Otas used in such a filter rapidly increases when the power supply voltage is decreased to 2 v and lower. Plassche, cmos integrated analogtodigital and digitaltoanalog converters, 2nd ed.
The lmf100 is an all cmos switched capacitor filter device that consists of two filters capable of wide supply. Cmos highfrequency switched capacitor filters 2 fig. One highly successful reference point for the implementation of a switchedcapacitor circuit us ing low external voltage ic is described in l. Switched capacitor filter tuned by ring vco in cmos technology, ieice electronics express in japan, vol. In smallsignal equivalent circuit assumed that m1 and m2 were identical. Simulating switchedcapacitor filters with spectrerf. A switched capacitor sc is an electronic circuit element implementing a filter. At the input, the antialiasing filter, which usually has a lowpass transfer function. Topologies, analysis, and cmos implementation of switchedcapacitor dcdc converters 45 where a k is the charge multiplier of the kth capacitor c k. The zeros of pms are the zeros of the transfer function.
For fsl case, the equivalent output resistance of a given converter. Higher order filter functions can be obtained by cascading several mf5s or by using the mf5 in conjuction with the mf10 dual switched capacitor filter building block. The filter building block, together with an external. It uses a switched capacitor filter implementation. In addition, the switchedcapacitor resistor above has its problems it can be very sensitive to stray capacitance. First order low pass butterworth filter design procedure for the filter with 100khz cutoff using a 2 mhz clock. Topologies, analysis, and cmos implementation of switched capacitor dcdc converters 45 where a k is the charge multiplier of the kth capacitor c k. If you continue browsing the site, you agree to the use of cookies on this website. For these applications the use of switchedcapacitor filters is much more attractive.
Berkeley, department of electrical engineering, ph. Highaccuracy switchedcapacitor techniques applied to filter and. Analysis and optimization of cmos switchedcapacitor converters. Either an external clock or the onchip oscillator can be used. Tunable cmos rf filter design for new generation of mobile. Some switchedcapacitorfilter clocks scfs are selfclocking with the addition of external components, but most applications use a cmoslevel clock signal to set the scfs corner frequency. Three of these functions are simultaneously available. Simulation results for the designed rf bandpass filter show s21 19db and consuming power less than 14 mw from 1. Switched capacitor elliptic lowpass filter data sheet. Some switched capacitor filter clocks scfs are selfclocking with the addition of external components, but most applications use a cmos level clock signal to set the scfs corner frequency. Lowpower highresolution cmos switchedcapacitor delta. The basic concept behind this method is illustrated in fig. For these applications the use of switched capacitor filters is much more attractive. The adm660 can also be used in a voltage doubling mode.
Department of electrical and electronics engineering, shiraz university of. It was tested in a flipchip assembly with a 36 nh 0402 inductor to deliver up to 4. Further, switched capacitor designs have greatly benefited from the substantial developments in the field of digital signal processing. The switchedopamp technique would not violate the maximum voltage restric tions of a lowvoltage cmos process. Index termsdcdc converter, switched capacitor, resonant switched capacitor, integrated circuit s. A digitally programmable highfrequency switchedcapacitor filter for use in a switched digital video sdvvdsl link is described. The adm660adm8660 is a switched capacitor voltage con verter that can be used to invert the input supply voltage.
The cutoff frequency of the lowpass filter is selectable based on the clock frequency. Lmf100 high performance dual switched capacitor filter. An optimum switched capacitor sc decimating filter is capable of achieving a high input sampling frequency while the time period for the setting of the operational amplifiers can be maximized. Design of cmos analog integrated circuits continuous time and switched capacitor filters 86 networks. As mentioned before, many switchedcapacitor circuits available today are op amp based. Well take a look at some basic building blocks like the the op amp integrator and the simple polezero filter in future topics. Proceedings of the international symposium on low power electronics and design. Second, the use of the switched capacitor to implement lossless, lossy, and differential integrators, which are the backbone of many switched capacitor filter circuits, especially those based on national semiconductors mf10 ic 1. Switched opamp techniquethis is a fairly re cent method that suggests a way to allow a true lowvoltage operation, without the use of clock voltage boosters.
System clock accurate to few ppm c ratio accurate pdf available in ieee journal of solidstate circuits 289. Tutorial 724 generating switchedcapacitorfilter clocks. The switched opamp technique would not violate the maximum voltage restric tions of a lowvoltage cmos process. Most of these effects can only be included when using transistorlevel simulators. A zerocrossing switchedcapacitor filter design by sungah lee submitted to the department of electrical engineering and computer science on may 22, 2008, in partial fulfillment of the requirements for the degree of masters of science in electrical engineering and computer science abstract. Both paths are providing currents to the integrator in opposite polarities. A zerocrossing switched capacitor filter design by sungah lee submitted to the department of electrical engineering and computer science on may 22, 2008, in partial fulfillment of the requirements for the degree of masters of science in electrical engineering and computer science abstract. Highaccuracy switchedcapacitor techniques applied to filter. Filter specifications are met with linear networks which determine a transfer function of the form. Each of the two filter sections, together with two to four external resistors, can generate all standard 2ndorder functions. Switched capacitor filters scf passive filters components are r, l, c big, heavy, discrete inductors are limited in quality designed in sdomain active rc. Active capacitor smallsignal equivalent circuit is presented in figure 6. In the simplest case, the operation takes place in two phases. It works by moving charges into and out of capacitors when switches are opened and closed.
Switchedcapacitor filter advantage versus continuoustime filter v in v out c 1 s1 s2 1 2 c 2 v out c 2 r eq v in 3db 1 s 2 ff 1 c 2c reqc2 1 2 1 f 3db corner freq. Max293 8thorder, lowpass, elliptic, switchedcapacitor filters. Lmf100 high performance dual switched capacitor filter rev. Switched capacitor filter design a first order butterworth switched capacitor filter was designed with a plan to cascade 2 first order stages for a second order filter. Pms and q ns are polynomial of order m and n respectively. Third, example designs of active filters using the mf10 will be presented. Switchedopamp techniquethis is a fairly re cent method that suggests a way to allow a true lowvoltage operation, without the use of clock voltage boosters. Lmf100 high performance dual switched capacitor filter general description the lmf100 consists of two independent general purpose high performance switched capacitor filters. Therefore vout will be driven positive if the switchedcapacitor branch pro. The dependence of filter coefficients on capacitance ratios allows precision on the order of 0.
Ee247 lecture 10 university of california, berkeley. Switched capacitor filter sc filter resistor replaced by switch capacitor sample time but analog values 2. Later, the alter statement named enabletone1 changes the waveshape type to sine to enable the first tone. The max293max294max297 are easytouse, 8thorder, lowpass, elliptic, switched capacitor filters that can be set up with corner frequencies from 0. This work offers the use of an active inductor and capacitor to build rf bandpass filter with 0. This application note discusses the more common methods for generating a sfc. Introduction to switched capacitor filters youtube. The initial thoughts are that this sc filter would be used at the receiver end of the data link such that the discretetime output of the sc filter may be directly fed into the receiver analogtodigital ad converter. A highlyintegrated seriesparallel switched capacitor. The lowpass sc filter of figure 1, on the other hand, has features that enable a notchfilter configuration. Ee247 lecture 5 university of california, berkeley. In addition, the switched capacitor resistor above has its problems it can be very sensitive to stray capacitance. Simulating switchedcapacitor filters with spectrerf a simple track and hold 4 of 25 the designers guide community freq2 10. The max293max294max297 are easytouse, 8thorder, lowpass, elliptic, switchedcapacitor filters that can be set up with corner frequencies from 0.
Cmos rf switched capacitor bandpass filter tuned by ring. Ee247 lecture 8 continuoustime filter design considerations active bandpass filter design continued gmc bandpass filter using simple diff. No external components are necessary to set the filter characteristics. Initially, the waveshape is set to a fixed value by type dc.
Pdf highfrequency cmos switchedcapacitor filters for. Design of a lowpower switchedcapacitor bandpass filter in 0. Switchedcapacitor ic forms notch filter application. Ee562 minh anh nguyen slideshare uses cookies to improve functionality and performance, and to provide you with relevant advertising. Any of the classical filter configurations such as butterworth, bessel, cauer and chebyshev can be formed. Opamp design project ee 5333 analog integrated circuits. Based on the proposed structure, a prototype 1 ghz active filter designed and simulated in a 0. Mf10nuniversal monolithic dual switched capacitor filter check for samples. Second, the use of the switchedcapacitor to implement lossless, lossy, and differential integrators, which are the backbone of many switchedcapacitor filter circuits, especially those based on national semiconductors mf10 ic 1. Usually, nonoverlapping signals are used to control the switches, so. Pdf bandpass filters for communications applications are realized using an 80 mhz differential singlestage cmos operational amplifier and. Department of electrical and electronics engineering, shiraz university of technology po box 71555876, shiraz, iran. As mentioned before, many switched capacitor circuits available today are op amp based. Capacitive part of bandpass active filter created by cmos active capacitor circuit, displayed in figure 5.
Highfrequency cmos switchedcapacitor filters for communications. System clock accurate to few ppm c ratio accurate switched capacitor building blocks. Ee247 lecture 8 continuoustime filters continued various gmc filter implementations comparison of continuoustime filter topologies switchedcapacitor filters analog sampleddata filters. The switchedcapacitor path to vout is noninverting, and it is controlled by a. Max293 8thorder, lowpass, elliptic, switchedcapacitor.
Analysis and optimization of cmos switchedcapacitor. Mf5 universal monolithic switched capacitor filter february 1995 mf5 universal monolithic switched capacitor filter general description the mf5 consists of an extremely easy to use, general purpose cmos active filter building block and an uncommitted op amp. The lowpass filter has an elliptic response and is made in cmos technology. Mf10n 1features description easy to use the mf10nconsists of 2 independent and extremely easy to use, general purpose cmos active filter clock to center frequency ratio accuracy building blocks. A new rf switched capacitor bandpass filter and its command circuit made up of a ring voltage controlled oscillator with xor gates are proposed. Lmf100 dual highperformance switched capacitor filters farnell. Pdf switchedcapacitor stages are described which can function with very low typically 1 v supply voltages. Cmos rf switched capacitor bandpass filter tuned by ring vco. It is important to recognize that the choice of switched ca. Bandpass filters for communications applications are realized using an 80 mhz differential singlestage cmos operational amplifier and a fully.
Rc filter standard active filter rc and opamp with feed back resistor often implemented with mos, so called mosfet c filter 3. Ee247 lecture 8 university of california, berkeley. The voltage conversion task is achieved using a switched capacitor technique using two external charge storage capacitors. Jun 17, 2011 switched capacitor filter sc filters by student. Cmos switchedcapacitor voltage converters adm660adm8660. Recent advances in circuits, systems, telecommunications and control isbn. Pdf an optimum cmos switchedcapacitor antialiasing. An optimum cmos switchedcapacitor antialiasing decimating filter article pdf available in ieee journal of solidstate circuits 289. A cmos direct sampling mixer using switched capacitor. Highaccuracy switchedcapacitor techniques applied to.
30 244 1079 227 695 1450 1057 1208 1321 113 193 390 160 1072 1531 133 1233 287 361 615 779 1242 1194 262 791 655 1471 1432 751 806 393 731 858 911 380 706 1091 1204 923 564 1238 951 96 988 1430 7