LTC kHz Continuous Time, Linear Phase Lowpass Filter FEATURES DESCRIPTION APPLICATIONS TYPICAL APPLICATION

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1 FEATURES DESCRIPTION n th Order, 0kHz Linear Phase Fiter in an SO- n Differentia Inputs and Outputs n Operates on a Singe or a ± Suppy n Low Offset: m Typica n db THD and SNR n db SNR n Shutdown Mode n Requires No Externa Components n Requires No Externa Cock Signa APPLICATIONS n CDMA Basestations n Data Communications n Antiaiasing Fiters n Smoothing or Reconstruction Fiters n Matched Fiter Pairs n Repacement for LC Fiters LTC- 0kHz Continuous Time, Linear Phase Lowpass Fiter The LTC - is a th order, continuous time, inear phase owpass fi ter. The seectivity of the LTC-, combined with its inear phase and dynamic range, make it suitabe for fi tering in data communications or data acquisition systems. The fi ter attenuation is db at f CUTOFF and at east db for frequencies above f CUTOFF. Unike comparabe LC fi ters, the LTC- achieves this seectivity with a inear phase response in the passband. With % accuracy of the cutoff frequency, the LTC- can be used in appications requiring pairs of matched fi ters, such as transceiver I and Q channes. Furthermore, the differentia inputs and outputs provide a simpe interface for these wireess systems. With a singe suppy and a P-P input, the LTC- features an impressive spurious free dynamic range of db. The maximum signa-to-noise ratio is db and it is achieved with a. P-P input signa. The LTC- features a shutdown mode where power suppy current is typicay ess than 0μA. For W-CDMA, G, CDMA 000 and other ceuar and nonceuar cutoff frequencies or singe-ended I/O, pease contact LTC Marketing for additiona information. L, LT, LTC, LTM, Linear Technoogy and the Linear ogo are registered trademarks of Linear Technoogy Corporation. A other trademarks are the property of their respective owners. TYPICAL APPLICATION Frequency Response Singe Suppy, Differentia 0kHz Lowpass Fiter 0 0 GAIN.0.9 IN IN OUT IN OUT LTC- GND SHDN OUT DELAY DELAY (μs) - TA G0 fa

2 LTC- ABSOLUTE MAXIMUM RATINGS (Note ) Tota Suppy otage... Power Dissipation... 00mW Operating Temperature Range LTC-CS... 0 C to 0 C LTC-IS... 0 C to C Storage Temperature Range... C to 0 C Lead Temperature (Sodering, 0 sec) C PIN CONFIGURATION IN IN GND TOP IEW S PACKAGE -LEAD PLASTIC SO OUT OUT SHDN T JMAX = 0 C, θ JA = 0 C/ W (NOTE ) ORDER INFORMATION LEAD FREE FINISH TAPE AND REEL PART MARKING PACKAGE DESCRIPTION TEMPERATURE RANGE LTC-CS#PBF LTC-CS#TRPBF -Lead Pastic SO 0 C to 0 C LTC-IS#PBF LTC-IS#TRPBF I -Lead Pastic SO 0 C to C Consut LTC Marketing for parts specifi ed with wider operating temperature ranges. Consut LTC Marketing for information on non-standard ead based fi nish parts. For more information on ead free part marking, go to: For more information on tape and ree specifi cations, go to: ELECTRICAL CHARACTERISTICS The denotes the specifi cations which appy over the fu operating temperature range, otherwise specifi cations are at T A = C. S =, R LOAD = 0k from each output to AC ground, and Pin open uness otherwise specifi ed. PARAMETER CONDITIONS MIN TYP MAX UNITS Operating Suppy otage. Fiter Gain = P-P, f IN = khz db f IN = 00kHz (Gain Reative to khz) db f IN = 00kHz (Gain Reative to khz) db f IN = 00kHz (Gain Reative to khz) db f IN = 0kHz (Gain Reative to khz) db f IN = 900kHz (Gain Reative to khz) db f IN =.MHz (Gain Reative to khz) db f IN =.MHz (Gain Reative to khz) db Fiter Phase = P-P, f IN = khz f IN = 00kHz f IN = 00kHz f IN = 00kHz f IN = 00kHz f IN = 0kHz f IN = 900kHz Phase Linearity Ratio of 00kHz Phase/00kHz Phase.9.0 Wideband Noise Noise BW = DC to f CUTOFF μ RMS THD f IN = 00kHz, P-P (Note ) db Fiter Differentia DC Swing Maximum Difference Between Pins and S = S = ± ±. ± ±. ±. fa

3 ELECTRICAL CHARACTERISTICS LTC- The denotes the specifi cations which appy over the fu operating temperature range, otherwise specifi cations are at T A = C. S =, R LOAD = 0k from each output to AC ground, and Pin open uness otherwise specifi ed. PARAMETER CONDITIONS MIN TYP MAX UNITS Input Bias Current μa Input Offset Current ±0 na Input Resistance Common Mode, =. Differentia Input Capacitance pf Output DC Offset (Note ) S = ± ± m S = ± (Note ) ± ± m Output DC Offset Drift S = S = ± Ground otage (Pin ) in Singe Suppy Appications SHDN Pin Logic Threshods S =, Minimum Logica S =, Maximum Logica 0 S = ±, Minimum Logica S = ±, Maximum Logica 0 SHDN Pin Pu-Up Current Power Suppy Current Power Suppy Current in Shutdown Mode MΩ MΩ μ/ C μ/ C S =.9.. S = S = ± S = S = ± Shutdown. Incudes SHDN Pu-Up Current S = S = ± Note : Stresses beyond those isted under Absoute Maximum Ratings may cause permanent damage to the device. Exposure to any Absoute Maximum Rating condition for extended periods may affect device reiabiity and ifetime. Note : Input and output votages expressed as peak-to-peak numbers are assumed to be fuy differentia μa μa ma ma μa μa Note : Output DC offset is measured between Pin and Pin with Pin and Pin connected to Pin. Note : Therma resistance varies depending upon the amount of PC board meta attached to the device. θ JA is specifi ed for a. square inch test board covered with oz copper on both sides. Note : Output DC offset measurements are performed by automatic test equipment approximatey 0. seconds after appication of power. TYPICAL PERFORMANCE CHARACTERISTICS Frequency Response.0 GAIN.9... DELAY G0 DELAY (μs) Passband Gain and Deay vs Frequency.0 T A = C. k GAIN DELAY ± 00k G M DELAY (μs) fa

4 LTC- TYPICAL PERFORMANCE CHARACTERISTICS Passband Gain vs Frequency Over Temperature S = 0 Stopband Gain vs Frequency 0 Stopband Gain vs Frequency Over Temperature S = C 0 C C 0 0 S = 0 0 C 0 C C S = ± 0 0. k 00k G0 00k FREQUENCY (MHz) G FREQUENCY (MHz) G0 CMRR (db) Common Mode Rejection Ratio = P-P S = T A = C PSRR (db) Power Suppy Rejection Ratio = 00m P-P S = T A = C SUPPLY CURRENT (ma) Suppy Current vs Temperature S = ± S = TEMPERATURE ( C) G0 G0 G0 PIN FUNCTIONS IN, IN (Pins, ): Input Pins. Signas can be appied to either or both input pins. The typica DC gain from differentia inputs (Pin to Pin ) to the differentia outputs (Pin to Pin ) is.0/. The input range is described in the Appications Information section. GND (Pin ): Ground. The ground pin is the reference votage for the fiter and is internay biased to one-haf the tota power suppy votage of the fiter, maximizing the dynamic range of the fiter. For singe suppy operation, the ground pin shoud be bypassed with a quaity ceramic capacitor to Pin. For dua suppy operation, connect Pin to a high quaity DC ground. A ground pane shoud be used. A poor ground wi increase noise and distortion. The impedance seen at Pin is.kω in norma mode. In shutdown, the pin is internay biased to the same eves as norma mode. The impedance in shutdown mode is typicay 00kΩ but varies with suppy votage and temperature. fa

5 LTC- PIN FUNCTIONS, (Pins, ): Power Suppy Pins. For a singe suppy (Pin grounded), a quaity ceramic bypass capacitor is required from the positive suppy pin (Pin ) to the negative suppy pin (Pin ). The bypass shoud be as cose as possibe to the IC. For dua suppy appications (Pin is grounded), bypass Pin to Pin and Pin to Pin with a quaity ceramic capacitor. The maximum votage difference between the ground pin (Pin ) and the positive suppy pin (Pin ) shoud not exceed.. SHDN (Pin ): Shutdown. When the Pin votage is ow, the LTC- goes into the current saving shutdown mode. Pin has a μa pu-up current. Leaving Pin open wi pace the LTC- in its norma operating mode. OUT, OUT (Pins, ): Output Pins. Pins and are the fiter differentia output. Each pin can drive kω or 00pF oads. The common mode votage at the output pins is the same as the votage at Pin. BLOCK DIAGRAM IN R R th ORDER LINEAR PHASE FILTER NETWORK OUTPUT BUFFER OUTPUT BUFFER OUT IN INPUT BUFFERS WITH COMMON MODE TRANSLATION CIRCUIT OUT ~M SHUTDOWN SWITCH GND k k ~M SHUTDOWN SWITCH μa SHUTDOWN SHDN - BD fa

6 LTC- APPLICATIONS INFORMATION Interfacing to the LTC- The difference between the votages at Pin and Pin is the differentia input votage. The average of the votages at Pin and Pin is the common mode input votage. The difference between the votages at Pin and Pin is the differentia output votage. The average of the votages at Pin and Pin is the common mode output votage. The input and output common mode votages are independent. The input common mode votage is set by the signa source, if DC couped, or by the biasing network if AC couped (Figures and ). The output common mode votage is equa to the votage of Pin, the GND pin. The GND pin is biased to one-haf of the suppy votage by an interna resistive divider (see Bock Diagram). To ater the common mode output votage, Pin can be driven with an externa votage source or resistor network. If externa resistors are used, it is important to note that the interna k resistors can vary ±0% (their ratio ony varies ±%). The output can aso be AC couped. IN IN OUT OUT LTC- GND SHDN - F0 Input Common Mode and Differentia otage Range The range of votage each input can support whie operating in its inear region is typicay 0. to. for a singe suppy and. to. for a ± suppy. Therefore, the fiter can accept a variety of common mode input votages. Figures and show the THD of the fi ter versus common mode input votage with a P-P differentia input signa. THD (db) S = ± 0 = P-P f IN = 00kHz 90 0 INPUT COMMON MODE OLTAGE () - F0 Figure. THD vs Common Mode Input otage 0 0 S = DC COUPLED INPUT IN (COMMON MODE) = OUT OUT (COMMON MODE) = = THD (db) 0 0 Figure 0 00k IN IN OUT OUT 00k LTC- GND μf SHDN AC COUPLED INPUT (COMMON MODE) = (COMMON MODE) = Figure - F = P-P f IN = 00kHz INPUT COMMON MODE OLTAGE () - F0 Figure. THD vs Common Mode Input otage Figure shows the THD and S/N ratio versus differentia input votage eve for both a singe suppy and a ± suppy. The common mode votage of the input signa is one-haf the tota power suppy votage of the fi ter. The spurious free dynamic range, where the THD and S/N ratio are equa, is db to db when the differentia input votage eve is P-P ; that is, for a singe suppy, the. fa

7 APPLICATIONS INFORMATION THD, SNR (db) THD: S =, CM =. THD: S = ±, CM = 0 SNR f IN = 00kHz DIFFERENTIAL INPUT ( P-P ) - F0 Figure. Dynamic Range Diff-In, Diff-Out input votages are Pin =. DC ±0. and Pin =. DC ±0.. Aso note Figure shows a db SNR ratio for higher THD eves. As seen in Figures and, the spurious free dynamic range can be optimized by setting the input common mode votage sighty beow one-haf of the power suppy votage, i.e., for a singe suppy and 0. for a ± suppy. Figure shows the THD and SNR ratio versus differentia input votage eve for both a singe suppy and a ± suppy when the common mode input votage is and 0. respectivey. For best performance, the inputs shoud be driven differentiay. For singe-ended signas, connect the unused input to Pin or a common mode reference. LTC- Output Common Mode and Differentia otage Range The output is a fuy differentia signa with a common mode eve equa to the votage at Pin. The specifications in the Eectrica Characteristics tabe assume the inputs are driven differentiay and the output is observed differentiay. However, Pin can be used as a singe-ended output by simpy foating Pin. Pin can be used as an inverting singe-ended output by foating Pin. Using Pins or as singe-ended outputs wi decrease the performance. The common mode output votage can be adjusted by overdriving the votage present on Pin. The best performance is achieved using a common mode output votage that is equa to mid suppy (the defaut Pin votage). Figures and iustrate the THD versus output common mode votage for a P-P differentia input votage and a common mode input votage that is 0. beow mid suppy. THD (db) = P-P 00kHz S = (CM) = COMMON MODE OUTPUT OLTAGE () - F0 THD, SNR (db) THD: S =, CM = THD: S = ±, CM = 0. SNR f IN = 00kHz Figure. THD vs Common Mode Output otage THD (db) 0 IN = P-P 00kHz 0 S = ± (CM) = DIFFERENTIAL INPUT OLTAGE ( P-P ) - F0 Figure. THD vs for a Common Mode Input otage 0. Beow Mid Suppy COMMON MODE OUTPUT OLTAGE () - F0 Figure. THD vs Common Mode Output otage fa

8 LTC- APPLICATIONS INFORMATION Output Drive Pin and Pin can drive a kω or 00pF oad connected to AC ground with a ±0. signa (corresponding to a P-P differentia signa). For differentia oads (oads connected from Pin to Pin ) the outputs can produce a P-P differentia signa across kω or 0pF. For smaer signa ampitudes the outputs can drive correspondingy arger oads. Noise The wideband noise of the fiter is the RMS vaue of the device s output noise spectra density. The wideband noise data is used to determine the operating signa-to-noise at a given distortion eve. Most of the noise is concentrated in the fiter passband and cannot be removed with post fitering (Tabe ). Tabe ists the typica change in wideband noise with suppy votage. Tabe. Wideband Noise vs Bandwidth, Singe Suppy BANDWIDTH TOTAL INTEGRATED NOISE DC to f CUTOFF 0μ RMS DC to f CUTOFF μ RMS Tabe. Wideband Noise vs Suppy otage, f CUTOFF = 0kHz TOTAL INTEGRATED NOISE POWER SUPPLY DC TO f CUTOFF μ RMS ± 0μ RMS TYPICAL APPLICATIONS Test Circuit for Singe Suppy Operation.99k.99k.9k 0μF A LT 09 AMPLIFIERS A, A AND A ALLOW THE USE OF A GROUND-REFERENCED SINGLE-ENDED AC SOURCE AS THE INPUT SIGNAL AND A SEPARATE GROUND-REFERENCED DC SOURCE TO PROIDE THE INPUT DC COMMON MODE OLTAGE AMPLIFIERS A AND A ALLOW MONITORING/MEASURING THE DIFFERENTIAL OUTPUT WITH A SINGLE-ENDED, GROUND-REFERENCED INSTRUMENT.9k.99k.99k CM.9k.99k 0μF.99k.9k A LT09 A LT09.99k / CM / CM IN OUT IN OUT LTC- GND SHDN /.99k.9k.9k k A LT09 k A LT 0.0μF 9k (SINGLE ENDED) 0Ω - TA0.μF fa

9 LTC- TYPICAL APPLICATIONS Singe-Ended Input/Output Dua Suppy Fiter.99k IN IN OUT OUT.99k.9k LT09 LTC- GND R.9k SHDN NOTE: FOR SINGLE SUPPLY CONNECTION, PIN (LTC-) AND PIN (LT09) SHOULD BE GROUNDED AND RESISTOR R SHOULD BE DC BIASED AT APPROXIMATELY. (SEE TEST CIRCUIT FOR SINGLE SUPPLY OPERATION) - TA09 A Fuy Differentia Fiter with Adjustabe Output Common Mode otage * IN OUT ( )R (CM) = R R * IN OUT LTC- GND SHDN (CM) LT *. (CM). (CM) CAN BE EQUAL OR DIFFERENT FROM (CM) R NOTE: FOR SINGLE SUPPLY OPERATION, PIN (LTC-), PIN (LT) AND RESISTOR R SHOULD BE GROUNDED R 00pF - TA0 fa 9

10 LTC- TYPICAL APPLICATIONS Simpe Puse Shaping Circuit for Singe Operation,.Mbps Leve Data.Mbps DATA.99k.99k.99k IN OUT IN OUT LTC- GND SHDN 00m/DI - TA0 0ns/DI - TA0 Simpe Puse Shaping Circuit for Singe Operation, Mbps (Msps) Leve Data D Msps DATA D0.99k 0k.99k.99k IN OUT IN OUT LTC- GND SHDN 00m/DI - TA0 00ns/DI - TA0 0 fa

11 TYPICAL APPLICATIONS Narrowband Ceuar Basestation Receiver LTC- RF/IF SECTION 90 0 LTC- LPF LO ADC I Q DSP 90 LTC- LPF ADC - TA0 PACKAGE DESCRIPTION S Package -Lead Pastic Sma Outine (Narrow.0 Inch) (Reference LTC DWG # 0-0-0).00 BSC.0 ± (.0.00) NOTE. MIN.0 ±.00.. (.9.9).0. (.0.9) NOTE.00 ±.00 TYP RECOMMENDED SOLDER PAD LAYOUT (0.0 0.) (0. 0.0) 0 TYP.0.09 (..) (0.0 0.).0.00 (0.0.0) NOTE: INCHES. DIMENSIONS IN (MILLIMETERS).0.09 (0. 0.) TYP. DRAWING NOT TO SCALE. THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS. MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED.00" (0.mm).00 (.0) BSC SO 00 Information furnished by Linear Technoogy Corporation is beieved to be accurate and reiabe. However, no responsibiity is assumed for its use. Linear Technoogy Corporation makes no representation that the interconnection of its circuits as described herein wi not infringe on existing patent rights. fa

12 LTC- TYPICAL APPLICATION Seective 0kHz CDMA Fiter R Ω C 0pF R Ω R Ω C 000pF R Ω R.k R.k R9.k R0.k C pf U LT C pf C R k R k C 0pF R k R k C FGND IN OUT IN OUT U LTC- GND SHDN C - TA Frequency Response k M TA RELATED PARTS PART NUMBER DESCRIPTION COMMENTS LTC0- MHz/00kHz Continuous Time, Low Noise, Lowpass Eiptic Fiter f CUTOFF = 00kHz or MHz LTC/LTC- Universa th Order Active RC Fiters f CUTOFF(MAX) = 0kHz (LTC), f CUTOFF(MAX) = 00kHz (LTC-) LTC-/LTC- th Order Active RC Lowpass Fiters f CUTOFF(MAX) = khz LTC9-/LTC9- Sef Cocked, 0th Order Linear Phase Lowpass Fiters f CLK /f CUTOFF = /, f CUTOFF(MAX) = khz (LTC9-) f CLK /f CUTOFF = /, f CUTOFF(MAX) = 00kHz (LTC9-) fa LT 009 RE A PRINTED IN USA Linear Technoogy Corporation 0 McCarthy Bvd., Mipitas, CA 90- (0) -900 FAX: (0) LINEAR TECHNOLOGY CORPORATION 000

LTC Linear Phase 8th Order Lowpass Filter FEATURES APPLICATIONS DESCRIPTION TYPICAL APPLICATION

LTC Linear Phase 8th Order Lowpass Filter FEATURES APPLICATIONS DESCRIPTION TYPICAL APPLICATION LTC69-7 Linear Phase 8th Order Lowpass Fiter FEATURES n 8th Order, Linear Phase Fiter in SO-8 Package n Raised Cosine Ampitude Response n 43 Attenuation at 2 f CUTOFF n Wideband Noise: 4μV RMS n Operates