APPLICATIO S. LTC1068 Series Clock-Tunable, Quad Second Order, Filter Building Blocks FEATURES DESCRIPTIO

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1 LTC6 Series Clock-Tunable, Quad Second Order, Filter Building Blocks FEATRES Four Identical 2nd Order Filter Sections in an SSOP Package 2nd Order Section Center Frequency Error: ±.3% Typical and ±.% Maximum Low Noise per 2nd Order Section, Q : LTC6-2 µv RMS, LTC6 µv RMS LTC6- µv RMS, LTC6-2 9µV RMS Low Power Supply Current: 4.mA, Single V, LTC6- Operation with ±V Power Supply, Single V Supply or Single 3.3V Supply APPLICATIO S Lowpass or Highpass Filters: LTC6-2,.Hz to 2kHz; LTC6, Hz to khz; LTC6-, 2Hz to khz; LTC6-2, 4Hz to 2kHz Bandpass or Bandreject (Notch) Filters: LTC6-2,.Hz to khz; LTC6, Hz to 3kHz; LTC6-, 2Hz to 3kHz; LTC6-2, 4Hz to 4kHz DESCRIPTIO The LTC 6 product family consists of four monolithic clock-tunable filter building blocks. Each product contains four matched, low noise, high accuracy 2nd order switchedcapacitor filter sections. An external clock tunes the center frequency of each 2nd order filter section. The LTC6 products differ only in their clock-to-center frequency ratio. The clock-to-center frequency ratio is set to 2: (LTC6-2), : (LTC6), : (LTC6-) or 2: (LTC6-2). External resistors can modify the clock-to-center frequency ratio. High performance, quad 2nd order, dual 4th order or th order filters can be designed with an LTC6 family product. Designing filters with an LTC6 product is fully supported by FilterCAD TM filter design software for Windows. The LTC6 products are available in a 2-pin SSOP surface mount package. A customized version of an LTC6 family product can be obtained in a 6-lead SO package with internal thin-film resistors. Please contact LTC Marketing for details., LT, LTC and LTM are registered trademarks of Linear Technology Corporation. FilterCAD is a trademark of Linear Technology Corporation. All other trademarks are the property of their respective owners. TYPICAL APPLICATIO Dual, Matched, 4th Order Butterworth Lowpass Filters, Clock-Tunable p to 2kHz f 3dB = f CLK /2, 4th Order Filter Noise = 6µV RMS R 2k R2 4k R3 2k V.µF R33 2k R23 4k R3 2k 2 INV B INV C 2 HPB/NB HPC/ 3 BPB BPC 4 LPB LPC SB SC 6 LTC6-2 V 9 AGND CLK SA SD 2 LPA LPD 3 BPA BPD 4 HPA/NA HPD/ND INVA INVD R2 4k R22 2k R32 k µf R34 k R24 2k R4 4k 6 TA V OT V f CLK = (2)(f 3dB) V OT2 GAIN (db) Gain vs Frequency RELATIVE FREQEY [f IN /(f 3dB)] 6 TA2 6fb

2 LTC6 Series ABSOLTE AXI RATI GS W W W Total Supply Voltage ( to V )... 2V Power Dissipation... mw Input Voltage at Any Pin... V.3V.3V Storage Temperature Range... 6 C to C PACKAGE/ORDER I FOR TOP VIEW W ATIO (Note ) Operating Temperature Range LTC6C... C to C LTC6I... 4 C to C Lead Temperature (Soldering, sec)... 3 C INV B HPB/NB 2 BPB 3 LPB 4 SB 6 AGND 9 SA LPA BPA 2 HPA/NA 3 INV A 4 2 INV C 2 HPC/ 26 BPC 2 LPC 24 SC 23 V 22 2 CLK 2 9 SD LPD BPD 6 HPD/ND INV D G PACKAGE 2-LEAD PLASTIC SSOP T JMAX = C, θ JA = 9 C/W ORDER PART NMBER LTC6CG LTC6-2CG LTC6-CG LTC6-2CG LTC6IG LTC6-2IG LTC6-IG LTC6-2IG INV B HPB/NB 2 BPB 3 LPB 4 SB AGND 6 SA LPA 9 BPA HPA/NA INV A 2 TOP VIEW 24 INV C 23 HPC/ 22 BPC 2 LPC 2 SC 9 V CLK SD 6 LPD BPD 4 HPD/ND 3 INV D N PACKAGE 24-LEAD PDIP T JMAX = C, θ JA = 6 C/W ORDER PART NMBER LTC6CN LTC6IN Order Options Tape and Reel: Add #TR Lead Free: Add #PBF Lead Free Tape and Reel: Add #TRPBF Lead Free Part Marking: Consult LTC Marketing for parts specified with wider operating temperature ranges. ELECTRICAL CHARACTERISTICS LTC6 (Internal Op Amps). The denotes the specifications which apply over the full operating temperature range, otherwise specifications are at V S = ±V, T A = 2 V, unless otherwise noted. PARAMETER CONDITIONS MIN TYP MAX NITS Operating Supply Voltage Range 3.4 ±. V Voltage Swings V S = 3.4V, R L = k (Note 2).2.6 V P-P V S = 4.V, R L = k (Note 3) V P-P V S = ±V, R L = k ±3.4 ±4. V Output Short-Circuit Current (Source/Sink) V S = ±4.V /6 ma V S = ±V 2/ ma DC Open-Loop Gain R L = k db GBW Product V S = ±V 6 MHz Slew Rate V S = ±V V/µs Analog Ground Voltage (Note 4) V S = V, Voltage at AGND 2.V ±2% V 2 6fb

3 ELECTRICAL CHARACTERISTICS LTC6 Series LTC6 (Complete Filter). The denotes the specifications which apply over the full operating temperature range, otherwise specifications are at V S = ±V, T A = 2 V, unless otherwise noted. PARAMETER CONDITIONS MIN TYP MAX NITS Clock-to-Center Frequency Ratio (Note ) V S = 4.V, f CLK = MHz, Mode (Note 3), ±.3 ±. % f O = khz, Q =, =.V RMS, ±.9 % R = R3 = 49.9k, R2 = k V S = ±V, f CLK = MHz, Mode, ±.3 ±. % f O = khz, Q =, = V RMS, ±.9 % R = R3 = 49.9k, R2 = K Clock-to-Center Frequency Ratio, V S = 4.V, f CLK = MHz, Q = (Note 3) ±.2 ±.9 % Side-to-Side Matching (Note ) V S = ±V, f CLK = MHz, Q = ±.2 ±.9 % Q Accuracy (Note ) V S = 4.V, f CLK = MHz, Q = (Note 3) ± ±3 % V S = ±V, f CLK = MHz, Q = ± ±3 % f O Temperature Coefficient ± ppm/ C Q Temperature Coefficient ± ppm/ C DC Offset Voltage (Note ) V S = ±V, f CLK = MHz, V OS ± mv (See Table ) (DC Offset of Input Inverter) V S = ±V, f CLK = MHz, V OS2 ±2 ±2 mv (DC Offset of First Integrator) V S = ±V, f CLK = MHz, V OS3 ± ±4 mv (DC Offset of Second Integrator) Clock Feedthrough V S = ±V, f CLK = MHz. mv RMS Max Clock Frequency (Note 6) V S = ±V, Q 2., Mode.6 MHz Power Supply Current V S = 3.4V, f CLK = MHz (Note 2) 3. ma V S = 4.V, f CLK = MHz (Note 3) 6. ma V S = ±V, f CLK = MHz 9. ma LTC6-2 (Internal Op Amps) V S = ±V, T A = 2 V, unless otherwise noted. PARAMETER CONDITIONS MIN TYP MAX NITS Operating Supply Voltage Range 3.4 ±. V Voltage Swings V S = 3.4V, R L = k (Note 2).2.6 V P-P V S = 4.V, R L = k (Note 3) V P-P V S = ±V, R L = k ±3.4 ±4. V Output Short-Circuit Current (Source/Sink) V S = ±4.V /6 ma V S = ±V 2/ ma DC Open-Loop Gain R L = k db GBW Product V S = ±V 6 MHz Slew Rate V S = ±V V/µs Analog Ground Voltage (Note 4) V S = V, Voltage at AGND 2.V ±2% V LTC6-2 (Complete Filter) V S = ±V, T A = 2 V, unless otherwise noted. PARAMETER CONDITIONS MIN TYP MAX NITS Clock-to-Center Frequency Ratio (Note ) V S = 4.V, f CLK = MHz, Mode (Note 3), 2 ±.3 2 ±. % f O = khz, Q =, =.V RMS, 2 ±.9 % R = R3 = 49.9k, R2 = k V S = ±V, f CLK = MHz, Mode, 2 ±.3 2 ±. % f O = Hz, Q =, = V RMS, 2 ±.9 % R = R3 = 49.9k, R2 = K 6fb 3

4 LTC6 Series ELECTRICAL CHARACTERISTICS LTC6-2 (Complete Filter). The denotes the specifications which apply over the full operating temperature range, otherwise specifications are at V S = ±V, T A = 2 V, unless otherwise noted. PARAMETER CONDITIONS MIN TYP MAX NITS Clock-to-Center Frequency Ratio, V S = 4.V, f CLK = MHz, Q = (Note 3) ±.2 ±.9 % Side-to-Side Matching (Note ) V S = ±V, f CLK = MHz, Q = ±.2 ±.9 % Q Accuracy (Note ) V S = 4.V, f CLK = MHz, Q = (Note 3) ± ±3 % V S = ±V, f CLK = MHz, Q = ± ±3 % f O Temperature Coefficient ± ppm/ C Q Temperature Coefficient ± ppm/ C DC Offset Voltage (Note ) V S = ±V, f CLK = MHz, V OS ± mv (See Table ) (DC Offset of Input Inverter) V S = ±V, f CLK = MHz, V OS2 ±2 ±2 mv (DC Offset of First Integrator) V S = ±V, f CLK = MHz, V OS3 ± ±4 mv (DC Offset of Second Integrator) Clock Feedthrough V S = ±V, f CLK = MHz. mv RMS Max Clock Frequency (Note 6) V S = ±V, Q 2., Mode.6 MHz Power Supply Current V S = 3.4V, f CLK = MHz (Note 2) 3. ma V S = 4.V, f CLK = MHz (Note 3) 6. ma V S = ±V, f CLK = MHz 9. ma LTC6- (Internal Op Amps) V S = ±V, T A = 2 V, unless otherwise noted. PARAMETER CONDITIONS MIN TYP MAX NITS Operating Supply Voltage Range 3.4 ±. V Voltage Swings V S = 3.4V, R L = k (Note 2).2. V P-P V S = 4.V, R L = k (Note 3) V P-P V S = ±V, R L = k ±3.4 ±4. V Output Short-Circuit Current (Source/Sink) V S = ±3.4V /6 ma V S = ±V 2/ ma DC Open-Loop Gain R L = k db GBW Product V S = ±V 4 MHz Slew Rate V S = ±V V/µs Analog Ground Voltage (Note 4) V S = V, Voltage at AGND 2.V ±2% V LTC6- (Complete Filter) V S = ±V, T A = 2 V, unless otherwise noted. PARAMETER CONDITIONS MIN TYP MAX NITS Clock-to-Center Frequency Ratio (Note ) V S = 3.4V, f CLK = 2kHz, Mode (Note 2), ±.3 ±. % f O = khz, Q =, =.34V RMS, ±.9 % R = R3 = 49.9k, R2 = k V S = ±V, f CLK = khz, Mode, ±.3 ±. % f O = khz, Q =, = V RMS, ±.9 % R = R3 = 49.9k, R2 = K Clock-to-Center Frequency Ratio, V S = 3.4V, f CLK = 2kHz, Q = (Note 2) ±.2 ±.9 % Side-to-Side Matching (Note ) V S = ±V, f CLK = khz, Q = ±.2 ±.9 % Q Accuracy (Note ) V S = 3.4V, f CLK = 2kHz, Q = (Note 2) ± ±3 % V S = ±V, f CLK = khz, Q = ± ±3 % 4 6fb

5 ELECTRICAL CHARACTERISTICS LTC6 Series LTC6-2 (Complete Filter). The denotes the specifications which apply over the full operating temperature range, otherwise specifications are at V S = ±V, T A = 2 V, unless otherwise noted. PARAMETER CONDITIONS MIN TYP MAX NITS f O Temperature Coefficient ± ppm/ C Q Temperature Coefficient ± ppm/ C DC Offset Voltage (Note ) V S = ±V, f CLK = khz, V OS ± mv (See Table ) (DC Offset of Input Inverter) V S = ±V, f CLK = khz, V OS2 2 ±2 mv (DC Offset of First Integrator) V S = ±V, f CLK = khz, V OS3 ±4 mv (DC Offset of Second Integrator) Clock Feedthrough V S = ±V, f CLK = khz.6 mv RMS Max Clock Frequency (Note 6) V S = ±V, Q.6, Mode 3.4 MHz Power Supply Current V S = 3.4V, f CLK = 2kHz (Note 2) 3. ma V S = 4.V, f CLK = 2kHz (Note 3) 4.3 ma V S = ±V, f CLK = khz 6. ma LTC6-2 (Internal Op Amps) V S = ±V, T A = 2 V, unless otherwise noted. PARAMETER CONDITIONS MIN TYP MAX NITS Operating Supply Voltage Range 3.4 ±. V Voltage Swings V S = 3.4V, R L = k (Note 2).2.6 V P-P V S = 4.V, R L = k (Note 3) V P-P V S = ±V, R L = k ±3.4 ±4. V Output Short-Circuit Current (Source/Sink) V S = ±4.V /6 ma V S = ±V 2/ ma DC Open-Loop Gain R L = k db GBW Product V S = ±V 6 MHz Slew Rate V S = ±V V/µs Analog Ground Voltage (Note 4) V S = V, Voltage at AGND 2.V ±2% V LTC6-2 (Complete Filter) V S = ±V, T A = 2 V, unless otherwise noted. PARAMETER CONDITIONS MIN TYP MAX NITS Clock-to-Center Frequency Ratio (Note ) V S = 4.V, f CLK = khz, Mode (Note 3), 2 ±.3 2 ±. % f O = 2kHz, Q =, =.V RMS, 2 ±.9 % R = R3 = 49.9k, R2 = k V S = ±V, f CLK = MHz, Mode, 2 ±.3 2 ±. % f O = 4kHz, Q =, = V RMS, 2 ±.9 % R = R3 = 49.9k, R2 = K Clock-to-Center Frequency Ratio, V S = 4.V, f CLK = khz, Q = (Note 3) ±.2 ±.9 % Side-to-Side Matching (Note ) V S = ±V, f CLK = MHz, Q = ±.2 ±.9 % Q Accuracy (Note ) V S = 4.V, f CLK = khz, Q = (Note 3) ± ±3 % V S = ±V, f CLK = MHz, Q = ± ±3 % f O Temperature Coefficient ± ppm/ C Q Temperature Coefficient ± ppm/ C 6fb

6 LTC6 Series ELECTRICAL CHARACTERISTICS LTC6-2 (Complete Filter). The denotes the specifications which apply over the full operating temperature range, otherwise specifications are at V S = ±V, T A = 2 V, unless otherwise noted. PARAMETER CONDITIONS MIN TYP MAX NITS DC Offset Voltage (Note ) V S = ±V, f CLK = MHz, V OS ± mv (See Table ) (DC Offset of Input Inverter) Table. Output DC Offsets One 2nd Order Section MODE V OSN V OSBP V OSLP V S = ±V, f CLK = MHz, V OS2 2 ±2 mv (DC Offset of First Integrator) V S = ±V, f CLK = MHz, V OS3 ±4 mv (DC Offset of Second Integrator) Clock Feedthrough V S = ±V, f CLK = MHz.2 mv RMS Max Clock Frequency (Note 6) V S = ±V, Q.6, Mode.6 MHz Power Supply Current V S = 3.4V, f CLK = MHz (Note 2) 3. ma V S = 4.V, f CLK = MHz (Note 3) 6. ma V S = ±V, f CLK = MHz 9. ma Note : Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. Exposure to any Absolute Maximum Rating condition for extended periods may affect device reliability and lifetime. Note 2: Production testing for single 3.4V supply is achieved by using the equivalent dual supplies of ±.V. Note 3: Production testing for single 4.V supply is achieved by using the equivalent dual supplies of ±2.3V. V OS [(/Q) HOLP ] V OS3 /Q V OS3 V OSN V OS2 b V OS [(/Q) R2/R] V OS3 /Q V OS3 ~(V OSN V OS2 )( R/R6) 2 [V OS ( R2/R R2/R3 R2/R4) V OS3 (R2/R3)X V OS3 V OSN V OS2 [R4/(R2 R4)] V OS2 [R2/(R2 R4)] Note 4: Pin (AGND) is the internal analog ground of the device. For single supply applications this pin should be bypassed with a µf capacitor. The biasing voltage of AGND is set with an internal resistive divider from Pin to Pin 23 (see Block Diagram). Note : Side D is guaranteed by design. Note 6: See Typical Performance Characteristics. 3 V OS2 V OS3 V OS [ R4/R R4/R2 R4/R3] V OS2 (R4/R2) V OS3 (R4/R3) TYPICAL PERFORMAE CHARACTERISTICS MAXIMM Q LTC6 Maximum Q vs Center Frequency (Modes, b, 2) A. V S = 3.3V, f CLK(MAX) =.MHz B. V S = V, f CLK(MAX) = 3.4MHz C. V S = ±V, f CLK(MAX) =.6MHz (FOR MODE 2 R4 R2) A B C W CENTER FREQEY, f O (khz) 6 G MAXIMM Q LTC6 Maximum Q vs Center Frequency (Modes 2, 3) A. V S = 3.3V, f CLK(MAX) = MHz B. V S = V, f CLK(MAX) = 3MHz C. V S = ±V, f CLK(MAX) = MHz (FOR MODE 2 R4 < R2) A B C CENTER FREQEY, f O (khz) 6 G2 TYPICAL MAXIMM Q LTC6-2 Maximum Q vs Center Frequency (Modes, b, 2) A: V S = 3.3V, f CLK(MAX) =.2MHz B: V S = V, f CLK(MAX) = 3.2MHz C: V S = ±V, f CLK(MAX) = 6.MHz (FOR MODE 2, R4 R2) A B C CENTER FREQEY, f O (khz) 6 G3 6fb

7 TYPICAL PERFORMAE CHARACTERISTICS TYPICAL MAXIMM Q W LTC6-2 Maximum Q vs Center Frequency (Modes 2, 3) A: V S = 3.3V, f CLK(MAX) =.2MHz B: V S = V, f CLK(MAX) = 3.2MHz C: V S = ±V, f CLK(MAX) = 6.MHz (FOR MODE 2, R4 < R2) A B C CENTER FREQEY, f O (khz) TYPICAL MAXIMM Q LTC6- Maximum Q vs Center Frequency (Modes, b, 2) A: V S = 3.3V, f CLK(MAX) =.MHz B: V S = V, f CLK(MAX) = 2.MHz C: V S = ±V, f CLK(MAX) = 3.6MHz (FOR MODE 2, R4 R2) A CENTER FREQEY, f O (khz) B C TYPICAL MAXIMM Q LTC6 Series LTC6- Maximum Q vs Center Frequency (Modes 2, 3) A: V S = 3.3V, f CLK(MAX) =.MHz B: V S = V, f CLK(MAX) = 2.MHz C: V S = ±V, f CLK(MAX) = 3.6MHz (FOR MODE 2, R4 < R2) A CENTER FREQEY, f O (khz) B C 6 G4 6 G 6 G6 TYPICAL MAXIMM Q LTC6-2 Maximum Q vs Center Frequency (Modes, b, 2) A: V S = 3.3V, f CLK(MAX) =.2MHz B: V S = V, f CLK(MAX) = 3.4MHz C: V S = ±V, f CLK(MAX) = 6.MHz (FOR MODE 2, R4 R2) A B C CENTER FREQEY, f O (khz) TYPICAL MAXIMM Q LTC6-2 Maximum Q vs Center Frequency (Modes 2, 3) A: V S = 3.3V, f CLK(MAX) = MHz B: V S = V, f CLK(MAX) = 3MHz C: V S = ±V, f CLK(MAX) = MHz (FOR MODE 2, R4 < R2) A B C FREQEY, f O (khz) CENTER FREQEY VARIATION (% ERROR) LTC6 Center Frequency Variation vs Clock Frequency V S = ±V Q =, REFEREE CENTER FREQEY WITH f CLK =.MHz MODE 3 MODE CLOCK FREQEY (MHz) G 6 G 6 G9 CENTER FREQEY VARIATION (% ERROR) LTC6-2 Center Frequency Variation vs Clock Frequency V S = ±V Q =, REFEREE CENTER FREQEY WITH f CLK =.MHz MODE MODE CLOCK FREQEY (MHz) G CENTER FREQEY VARIATION (% ERROR) LTC6- Center Frequency Variation vs Clock Frequency V S = ±V Q =, REFEREE CENTER FREQEY WITH f CLK =.MHz MODE 3 MODE CLOCK FREQEY (MHz) 6 G BATTERY VOLTAGE (V) LTC6-2 Center Frequency Variation vs Clock Frequency V S = ±V Q =, REFEREE CENTER FREQEY WITH f CLK =.MHz MODE 3 MODE CLOCK FREQEY (MHz) 6 G2 6fb

8 LTC6 Series TYPICAL PERFORMAE CHARACTERISTICS W 3 LTC6/LTC6-2 Noise vs Q 3 LTC6- Noise vs Q 3 LTC6-2 Noise vs Q NOISE (µv RMS ) 2 2 V ±V 3.3V NOISE (µv RMS ) 2 2 V ±V 3.3V NOISE (µv RMS ) 2 2 V ±V 3.3V Q 6 G Q 6 G Q 6 G RELATIVE NOISE IREASE (REFEREE NOISE WHEN R2/R4 = ) Noise Increase vs R2/R4 Ratio (Mode 3) R2/R4 RATIO 6 G6 RELATIVE NOISE IREASE (REFEREE NOISE WHEN R/R6 =.2) Noise Increase vs R/R6 Ratio (Mode b) R/R6 RATIO 6 G. LTC6/LTC6-2/ LTC6-2 Power Supply Current vs Power Supply LTC6- Power Supply Current vs Power Supply POWER SPPLY CRRENT (ma) C C 2 C POWER SPPLY CRRENT (ma) C C 2 C TOTAL POWER SPPLY (V) TOTAL POWER SPPLY (V) 6 G 6 G9 6fb

9 LTC6 Series PIN FTIONS Power Supply Pins The and V pins should each be bypassed with a.µf capacitor to an adequate analog ground. The filter s power supplies should be isolated from other digital or high voltage analog supplies. A low noise linear supply is recommended. sing a switching power supply will lower the signal-to-noise ratio of the filter. Figures and 2 show typical connections for dual and single supply operation. Analog Ground Pin The filter s performance depends on the quality of the analog signal ground. For either dual or single supply operation, an analog ground plane surrounding the package is recommended. The analog ground plane should be connected to any digital ground at a single point. For single supply operation, AGND should be bypassed to the analog ground plane with at least a.4µf capacitor (Figure 2). Two internal resistors bias the analog ground pin. For the LTC6, LTC6-2 and LTC6-2, the voltage at the analog ground pin (AGND) for single supply is. and for the LTC6- it is.43. Clock Input Pin Any TTL or CMOS clock source with a square-wave output and % duty cycle (±%) is an adequate clock source for the device. The power supply for the clock source should not be the filter s power supply. The analog ground for the filter should be connected to clock s ground at a single point only. Table 2 shows the clock s low and high level threshold values for dual or single supply operation. Table 2. Clock Source High and Low Threshold Levels POWER SPPLY HIGH LEVEL LOW LEVEL Dual Supply = ±V.3V.3V Single Supply = V.3V.3V Single Supply = 3.3V.2V.3V A pulsed generator can be used as a clock source provided the high level ON time is at least 2% of the pulse period. Sine waves are not recommended for clock input frequencies less than khz, since excessively slow clock rise or fall times generate internal clock jitter (maximum clock rise or fall time µs). The clock signal should be routed from the right side of the IC package and perpendicular to it to avoid coupling to any input or output analog signal ANALOG GROND PLANE ANALOG GROND PLANE V.µF DEVICE LTC6 LTC6-2 LTC6-2 LTC6- R A k R B k.3k.6k LTC µF 9 2 LTC V AGND.µF.4µF (µf FOR STOPBAND FREQEIES khz) 9 2 R A R B STAR SYSTEM GROND CLOCK SORCE 2Ω STAR SYSTEM GROND CLOCK SORCE 2Ω DIGITAL GROND 6 F FOR MODE 3, THE S NODE SHOLD BE TIED TO PIN (AGND) DIGITAL GROND 6 F2 Figure. Dual Supply Ground Plane Connections Figure 2. Single Supply Ground Plane Connections 6fb 9

10 LTC6 Series PIN FTIONS path. A 2Ω resistor between clock source and Pin will slow down the rise and fall times of the clock to further reduce charge coupling (Figures and 2). Output Pins Each 2nd order section of an LTC6 device has three outputs that typically source ma and sink 6mA. Driving coaxial cables or resistive loads less than 2k will degrade the total harmonic distortion performance of any filter design. When evaluating the distortion or noise performance of a particular filter design implemented with a LTC6 device, the final output of the filter should be buffered with a wideband, noninverting high slew rate amplifier (Figure 3). Inverting Input Pins These pins are the inverting inputs of internal op amps and are susceptible to stray capacitive coupling from low impedance signal outputs and power supply lines. k LT 34 6 F3 Figure 3. Wideband Buffer In a printed circuit layout any signal trace, clock source trace or power supply trace should be at least. inches away from any inverting input pins Summing Input Pins These are voltage input pins. If used, they should be driven with a source impedance below k. When they are not used, they should be tied to the analog ground pin. The summing pin connections determine the circuit topology (mode) of each 2nd order section. Please refer to Modes of Operation. BLOCK DIAGRAM INV A (4) AGND () INV B () INV C (2) INV D () W HPA/NA (3) HPB/NB (2) HPC/ (2) HPD/ND (6) Σ SA () Σ SB () Σ SC (24) Σ BPA (2) BPB (3) BPC (26) BPD () LPA () LPB (4) LPC (2) LPD () DEVICE R A R B LTC6 LTC6-2 k k LTC6-2 LTC6-.3k.6k *THE RATIO R A /R B VARIES ±2% AGND () R A * R B * () CLK (2) V (23) (6) (9) (2) (22) SD (9) PIN 2-LEAD SSOP PACKAGE 6 BD 6fb

11 LTC6 Series MODES OF OPERATION W Linear Technology s universal switched-capacitor filters are designed for a fixed internal, nominal f CLK /f O ratio. The f CLK /f O ratio is for the LTC6, 2 for the LTC6-2, for the LTC6- and 2 for the LTC6-2. Filter designs often require the f CLK /f O 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 f CLK /f O ratios. By choosing the proper mode, the f CLK /f O 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 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 lowpass 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 f CLK /f O ratio. Listed here are four of the nearly twenty modes available. To make the design process simpler and quicker, Linear Technology has developed the FilterCAD for Widows 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 ( or you can order the FilterCAD CD-ROM by contacting Linear Technology Marketing. Mode In Mode, 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 4 illustrates Mode providing 2nd order notch, lowpass and bandpass outputs. Mode can be used to make high order Butterworth 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 is faster than Mode 3. Please refer to the Operating Limits paragraph under Applications Information for a guide to the use of capacitor C C. R AGND R3 R2 N S BP LP Σ Figure 4. Mode, 2nd Order Filter Providing Notch, Bandpass and Lowpass Outputs C C f f O = CLK ; f n = f RATIO O Q = R3 R2 R3 ; H ON = ; H OBP = R2 R R H OLP = H ON DEVICE RATIO LTC6 LTC6-2 2 LTC6- LTC F4 Mode b Mode b is derived from Mode. In Mode b (Figure ) two additional resistors R 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 b maintains the speed advantages of Mode and should be considered an optimum mode for high Q designs with f CLK to f CTOFF (or f CENTER ) ratios greater than the part s nominal ratio. The parallel combination of R and R6 should be kept below k. Please refer to the Operating Limits paragraph under Applications Information for a guide to the use of capacitor C C. 6fb

12 MODES OF OPERATION W LTC6 Series C C C C R6 R R4 R Mode 3 In Mode 3, the ratio of the external clock frequency to the center frequency of each 2nd order section can be adjusted above or below the parts nominal ratio. Figure 6 illustrates Mode 3, the classical state variable configuration, providing highpass, bandpass and lowpass 2nd order filter functions. Mode 3 is slower than Mode. Mode 3 can be used to make high order all-pole bandpass, lowpass and highpass filters. Please refer to the Operating Limits paragraph under Applications Information for a guide to the use of capacitor C C. Mode 2 Mode 2 is a combination of Mode and Mode 3, shown in Figure. With Mode 2, the clock-to-center frequency ratio, f CLK /f O, is always less than the part s nominal ratio. The advantage of Mode 2 is that it provides less sensitivity to resistor tolerances than does Mode 3. Mode 2 has a highpass notch output where the notch frequency depends solely on the clock frequency and is therefore less than the center frequency, f O. Please refer to the Operating Limits paragraph under Applications Information for a guide to the use of capacitor C C. 2 R3 R2 N S BP LP Σ AGND LTC6 LTC6-2 f f O = CLK ; f n = f RATIO R6 LTC6- O LTC6-2 (R6 R) Q = R3 R2 R3 ; H ON = ; H OBP = R2 R6 (R6 R) R R R2 R6 R H OLP = R R6 ( ) DEVICE RATIO Figure. Mode b, 2nd Order Filter Providing Notch, Bandpass and Lowpass Outputs F R AGND R AGND R3 R2 HP S BP LP Σ /4 LTC6 ( ) f O = f CLK R3 RATIO R2 ; Q =. R2 R2 R4 R4 H OHP = R2 R3 ; H OBP = R R DEVICE RATIO LTC6 LTC6-2 2 LTC6- LTC6-2 2 R4 R3 R2 R3 ( (RATIO)(.32)(R4)) R3 ( (RATIO)(.32)(R4)) ; H R4 OLP = R 6 F6 HPN S BP LP Figure. Mode 2, 2nd Order Filter Providing Highpass Notch, Bandpass and Lowpass Outputs C C f f O = CLK f ; f n = CLK R2 RATIO R4 RATIO Q =. ( R3 R2) R2 R4 R3 (RATIO)(.32)(R4) Σ ( ) R2 H OHPN = (AC GAIN, f >> f O ); H OHPN = R H OBP = R3 R Figure 6. Mode 3, 2nd Order Section Providing Highpass, Bandpass and Lowpass Outputs R2 R ; H R2 R3 OLP = R ( (RATIO)(.32)(R4)) R2 R4 ( ) DEVICE RATIO LTC6 LTC6-2 2 LTC6- LTC6-2 2 R2 R4 ( ) (DC GAIN) 6 F 6fb

13 APPLICATIONS INFORMATION W Operating Limits The Maximum Q vs Center Frequency (f O ) graphs, under Typical Performance Characteristics, define an upper limit of operating Q for each LTC6 device 2nd order section. These graphs indicate the power supply, f O and Q value conditions under which a filter implemented with an LTC6 device will remain stable when operated at temperatures of C or less. For a 2nd order section, a bandpass gain error of 3dB or less is arbitrarily defined as a condition for stability. When the passband gain error begins to exceed db, the use of capacitor C C will reduce the gain error (capacitor C C is connected from the lowpass node to the inverting node of a 2nd order section). Please refer to Figures 4 through. The value of C C can be best determined experimentally, and as a guide it should be about pf for each db of gain error and not to exceed pf. When operating an LTC6 device near the limits defined by the Maximum Q vs Frequency graphs, passband gain variations of 2dB or more should be expected. Clock Feedthrough Clock feedthrough is defined as the RMS value of the clock frequency and its harmonics that are present at the filter s output pins. The clock feedthrough is tested with the filter s input grounded and depends on PC board layout and on the value of the power supplies. With proper layout techniques, the typical values of clock feedthrough are listed under Electrical Characteristics. Any parasitic switching transients during the rising and falling edges of the incoming clock are not part of the clock feedthrough specifications. Switching transients have frequency contents much higher than the applied clock; their amplitude strongly depends on scope probing techniques as well as grounding and power supply bypassing. The clock feedthrough, can be greatly reduced by adding a simple RC lowpass network at the final filter output. This RC will completely eliminate any switching transients. Wideband Noise The wideband noise of the filter is the total RMS value of the device s noise spectral density and is used to deter- LTC6 Series mine the operating signal-to-noise ratio. Most of its frequency contents lie within the filter passband and cannot be reduced with post filtering. For a notch filter the noise of the filter is centered at the notch frequency. The total wideband noise (µv RMS ) is nearly independent of the value of the clock. The clock feedthrough specifications are not part of the wideband noise. For a specific filter design, the total noise depends on the Q of each section and the cascade sequence. Please refer to the Noise vs Q graphs under the Typical Performance Characteristics. Aliasing Aliasing is an inherent phenomenon of switched-capacitor filters and occurs when the frequency of the input signals that produce the strongest aliased components have a frequency, f IN, such as (f SAMPLING f IN ) that falls into the filter s passband. For an LTC6 device the sampling frequency is twice f CLK. If the input signal spectrum is not band-limited, aliasing may occur. Demonstration Circuit 4 DC4 is a surface mount printed circuit board for the evaluation of Linear Technology s LTC6 product family in a 2-lead SSOP package. The LTC6 product family consists of four monolithic clock-tunable filter building blocks. Demo Board 4 is available in four assembled versions: Assembly 4-A features the low noise LTC6CG (clockto-center frequency ratio = ), assembly 4-B features the low noise LTC6-2CG (clock-to-center frequency ratio = 2), assembly 4-C features the high frequency LTC6-2CG (clock-to-center frequency ratio = 2) and assembly 4-D features the low power LTC6-CG (clock-to-center frequency ratio = ). All DC4 boards are assembled with input, output and power supply test terminals, a 2-lead SSOP filter device (LTC6CG Series), a dual op amp in an SO- for input or output buffers and decoupling capacitors for the filter and op amps. The filter and dual op amps share the power 6fb 3

14 LTC6 Series APPLICATIONS INFORMATION W supply inputs to the board. Jumpers JPA to JPD on the board configure the filter s second order circuit modes, jumper JP configures the filter for dual or single supply operation and jumpers JP2 (A-D) to JP3 (A-D) configure the op amp buffers as inverting or noninverting. Surface mount pads are available on the board for 26 size surface mount resistors. The printed circuit layout of DC4 is arranged so that most of the resistor connections for one th order filter or two 4th order filters are available on the board. A resistor makes a connection between two filter nodes on the board and for most filter designs, no wiring is required. DC4 Component Side Silkscreen DC4 Component Side DC4 Solder Side 4 6fb

15 LTC6 Series APPLICATIONS INFORMATION W E9 E SGND E V E VIN2 E2 SGND E2 FGND E3 VIN E3 CLK E4 SGND V C6 µf 6V C µf 6V FGND LPB 3 2 JPB R6 RI R JP DAL SPPLY CI 2 3 SINGLE SPPLY C µf V R63 C.µF 2 JPA R3 3 FGND LPD R2 BFFERS CONFIGRATION ASSEMBLED AS NONINVERTING BFFER DAL SPPLY INVERTING BFFER DAL SPPLY NONINVERTING BFFER SINGLE SPPLY FOR NONINVERTING BFFER SINGLE SPPLY R RG2 SHORT RES SHORT RES DC4 Schematic BOLD LINE INDICATES FGND RL R B R H R2 R3 R4 R43 R33 R23 RH INV B HPB/NB BPB LPB SB AGND SA LPA BPA HPA/NA INV A INV C HPC/ BPC LPC SC V CLK SD LPD BPD HPD/ND INV D RB2 R L2 RH3 R B3 RL3 JP2A 2A JP2B JP2C JP2D R G JP3A OPEN SHORT OPEN OPEN SHORT OPEN SHORT OPEN OPEN SHORT RES SHORT OPEN SHORT OPEN OPEN SHORT OPEN SHORT OPEN SHORT OPEN RES SHORT R H R22 R32 R42 R2 R 2Ω R44 R34 R24 2A JP3B JP3C SHORT OPEN OPEN OPEN SHORT OPEN OPEN SHORT CO2 R B RL JP2A JP2B 2 3 JP2C 3 6 JP2D 4 2 2A V 4 LPC FGND 3 2 JPC R62 V C2.µF R4 3 LPD FGND CO 2 JPD R64 RH4 RB4 R L4 JP3A JP3B 2 JP3C B JP3D 4 JP3D OPEN SHORT OPEN OPEN DEMO BOARD DC4B-A DC4B-B DC4B-C DC4B-D LTC6CG LTC6-2CG LTC6-2CG LTC6-CG 2 LT2 LT2 LT23 LT49 R G2 C3.µF C4.µF RG 6 TA3 BFFER 2 E VOT2 E6 SGND BFFER E VOT E SGND 6fb

16 LTC6 Series APPLICATIONS INFORMATION W A Surface Mount Printed Circuit Layout A very compact surface mount printed circuit layout can be designed with 63 size surface mount resistors, capacitors and a 2-pin SSOP of the LTC6 product family. An example of a printed circuit layout is shown in the following figures for an th order elliptic bandpass filter. The total board area of this th order filter is " by.". No attempt was made to design the smallest possible printed circuit layout. khz Elliptic Bandpass Filter, f CENTER = f CLK /2 (Maximum f CENTER is khz, V S = ±V) R H 2k R L2 23.2k V R 29.4k R H2.3k R2 INV B INV C 2 HPB/NB HPC/ 2 R22 R3 24.9k 3 BPB BPC 26 R32 k R4 2.k 4 LPB LPC 2 R R2 R62 6.2k R6.3k C.µF R k R33 9k R23 R L3 4.3K SB SC 24 LTC6-2 V 23 AGND 22 CLK SA LPA BPA SD LPD BPD HPA/NA HPD/ND 6 4 INV A INV D R H3.4k C2.µF R64 k R4 R44.4k R k R24.k V.MHz V OT 6 TA4 FilterCAD Custom Inputs for f C = khz 2nd ORDER SECTION f O (khz) Q f N (khz) TYPE MODE B HPN 2b C LPN bn A LPN 2n D BP 2b GAIN (db) Gain vs Frequency FREQEY (khz) 6 TA 6 6fb

17 LTC6 Series APPLICATIONS INFORMATION W Surface Mount Components (Board Area = ".") R R H R2 R R6 R3 R4 R43 C C2 R22 R32 R44 R2 R62 R64 R33 R34 R4 R23 R24 R H2 R L3 R L2 R H3 6 TA6 Component Side Solder Side R R H GND R R6 R2 R3 R4 R22 R32 R2 R62 GND V R43 R33 R23 R H2 R L3 R34 R24 R44 R64 R4 R L2 R H3 V OT 6 TA 6 TA 6fb

18 LTC6 Series TYPICAL APPLICATIONS LTC6-2 th Order Linear Phase Lowpass, f CTOFF = f CLK /4 for ltralow Frequency Applications R L 23.2k R L2 4.3k V 2 INV B INV C R2 2.4k 2 2 R22.4k R HPB/NB HPC/ 4.3k R3 k 3 26 R32 k BPB BPC R4.4k 4 2 R2.k LPB LPC 24 R62 9.9k SB SC 6 LTC V 22 AGND.µF 2 CLK.µF 9 2 R64 9.9k 9 R4.k SA SD R43 2.4k LPA LPD R33 2.4k 2 R34 k BPA BPD R23 k 3 6 R24.4k HPA/NA HPD/ND 4 INV A INV D V 4kHz V OT GAIN (db) Gain and Group Delay vs Frequency GAIN GROP DELAY FREQEY (Hz) 6 TA GROP DELAY (SEC) R L3 23.2k R B3 23.2k 6 TA9 FilterCAD Custom Inputs for f C = Hz 2nd ORDER SECTION f O (Hz) Q Q N TYPE MODE B LP 3 C.62.9 LP b A LPBP 3s D.6.2 LP b 6fb

19 LTC6 Series TYPICAL APPLICATIONS LTC6- th Order Linear Phase Lowpass, f CTOFF = f CLK / for Single Supply Low Power Applications. Maximum f CTOFF is 2kHz with a 3.3V Supply and 4kHz with a V Supply R A 6.2k R B 3.3k R L2 9.9k R H2 34k INV B INV C 2 R R2 2.k 2 2 R k HPB/NB HPC/ 22.6k R3 k 3 26 R k BPB BPC R4 22.6k 4 2 R42 96k LPB LPC SB SC 24 6 LTC6- V V AGND CLK 22 2 khz.µf 9 SA SD 2 9 R43 4.k R44 34.k LPA LPD µf R33 2.k 2 R34 4.3k BPA BPD R23.k 3 6 R24 6.9k HPA/NA HPD/ND 4 INV A INV D R L3 R B3 24.9k 26.k V OT GAIN (db) Gain and Group Delay vs Frequency GAIN GROP DELAY 6 FREQEY (khz) 6 TA GROP DELAY (µs) 6 TA FilterCAD Custom Inputs for f C = khz 2nd ORDER SECTION f O (khz) Q f N (khz) Q N TYPE MODE B AP 4a3 C LPN 2n A LPBP 2s D LP 3 6fb 9

20 LTC6 Series TYPICAL APPLICATIONS LTC6-2 th Order Lowpass, f CTOFF = f CLK /32, Attenuation db at (.2)(f CTOFF )and 6dB at (.)(f CTOFF ). Maximum f CTOFF = 2kHz V R 32.4k INV B INV C 2 R2 k 2 HPB/NB HPC/ 2 R22 k R3 k 3 BPB BPC 26 R k 4 LPB LPC 2 R R2 R62.9k R6 2.2k R63.4k R33 k R23 k R L 26.k.µF R3 SB SC LTC6-2 V AGND 22 CLK SA LPA BPA HPA/NA INV A R H.2k SD LPD BPD HPD/ND INV D µF R H2 36.k R64 3.6k R4 R L2 4.2k R34 k R24 k V 3.2MHz GAIN (db) Gain vs Frequency FREQEY (khz) R L3 2.K R H3 3.6k V OT 69 TA4 6 TA3 FilterCAD Custom Inputs for f C = khz 2nd ORDER SECTION f O (khz) Q f N (khz) TYPE MODE B LPN bn C LPN bn A LPN bn D LP b 2 6fb

21 LTC6 Series TYPICAL APPLICATIONS LTC6 th Order Linear Phase Bandpass, f CENTER = f CLK /2, Passband 3dB at (.)(f CENTER ) and (.2)(f CENTER ). Maximum f CENTER = 4kHz with ±V Supplies R L 63.4k R H.k R B2 6.2k R 26.k V R2 R3 9.6k R4 2.k R43.k R33 4.k R23.µF INV B INV C 24 HPB/NB HPC/ 23 BPB BPC 22 LPB LPC 2 LTC6 SB SC 2 AGND V 9 R22 R32 2.k R2 R62.k V.µF CLK.2MHz SA SD R64.k R4 LPA LPD 6 R34 V OT BPA BPD 2.k R24 HPA/NA HPD/ND 4 INV A INV D 3 GAIN(dB) Gain vs Frequency FREQEY (khz) 6 TA6 R L3 4.k R H3 4.2k 24-Lead Package 6 TA FilterCAD Custom Inputs for f C = khz 2nd ORDER SECTION f O (khz) Q f N (khz) TYPE MODE B HPN 3a C BP b A LPN 3a D BP b 6fb 2

22 LTC6 Series TYPICAL APPLICATIONS LTC6 th Order Linear Phase Bandpass, f CENTER = f CLK /, Passband 3dB at (.)(f CENTER ) and (.2)(f CENTER ). Maximum f CENTER = khz with ±V Supplies R L 24.9k R B2 4.3k R H.k R 24.3k R k V R2 k R3 2.k R4 k R43 6.9k R33.4k R23.32k.µF R3 9 2 INV B INV C 24 HPB/NB HPC/ 23 BPB BPC 22 LPB LPC 2 SB SC 2 AGND V 9 LTC6 fclk MHz SA SD LPA LPD 6 BPA BPD HPA/NA HPD/ND 4 INV A INV D 3 R B3.k R22 k R k R42 26.k R44 2.k R34 9.k R24 k V OT V.µF GAIN(dB) Lead Package Gain vs Frequency FREQEY (khz) 6 TA 6 TA FilterCAD Custom Inputs for f C = khz 2nd ORDER SECTION f O (khz) Q f N (khz) TYPE MODE B LPN 2n C BP 2 A BP 2b D BP fb

23 LTC6 Series TYPICAL APPLICATIONS LTC6 th Order Linear Phase Bandpass, f CENTER = f CLK /, Passband 3dB at (.)(f CENTER ) and (.3)(f CENTER ), Superior Sinewave Burst Response, Maximum f CENTER = 6kHz with ±V Supplies R L 34k R L2 k R H k R H2 2k R k V R2 4.k R3 k R4 4.3k R43 2.k R33.3k R23 2k.µF INV B INV C 24 HPB/NB HPC/ 23 BPB BPC 22 LPB LPC 2 SB SC 2 AGND V 9 LTC6 fclk MHz SA SD LPA LPD 6 BPA BPD HPA/NA HPD/ND 4 INV A INV D 3 R44 k R34.k R24.4k R22.2k R32 k R42.k V.µF GAIN(dB) Gain vs Frequency FREQEY (khz) 6 TA2 R H3 9.3k V OT R L3 2.4k 24-Lead Package 6 TA9 FilterCAD Custom Inputs for f C = khz 2nd ORDER SECTION f O (khz) Q f N (khz) Q N TYPE MODE B HPN 3a C LPN 3a A LPN 3a D BP 3 6fb 23

24 LTC6 Series TYPICAL APPLICATIONS LTC6- th Order Linear Phase Bandpass, f CENTER = f CLK /4, Passband 3dB at (.)(f CENTER ) and (.2)(f CENTER ) for Single Supply Low Power Applications. Maximum f CENTER = 2kHz with a Single V Supply R H.2k R L2.k V R 36.k INV B INV C 2 R2 k 2 HPB/NB HPC/ 2 R22.3k R3 3.k 3 BPB BPC 26 R k R4.k 4 R42 k LPB LPC 2 R R6.4k µf.µf R43 2.k R33 26.k R23 k SB SC LTC6- V AGND 22 CLK SA LPA BPA HPA/NA INV A SD LPD BPD HPD/ND INV D R H2 4.k R44 22.k R34 2k R24 k 4kHz GAIN (db) Gain vs Frequency FREQEY (khz) 6 TA22 R L3.K R H3 4.k V OT 6 TA2 FilterCAD Custom Inputs for f C = khz 2nd ORDER SECTION f O (khz) Q f N (khz) TYPE MODE B HPN 2b C LPN 2n A LPN 2n D BP fb

25 LTC6 Series TYPICAL APPLICATIONS LTC6-2 th Order Bandpass, f CENTER = f CLK /32, Passband 3dB at (.96)(f CENTER ) and (.3)(f CENTER ). Maximum f CENTER = khz with ±V Supplies R H k R B2 4.k V R 2k INV B INV C 2 R2 2 HPB/NB HPC/ 2 R22 R3 9.6k 3 BPB BPC 26 R32 3k 4 LPB LPC 2 R R2 R62 9.3k R6.k R k.µF SB SC LTC6-2 V AGND 22 CLK 2 9 SA SD 2 9.µF R64 6.9k R4 R3 LPA LPD R33 24k 2 R34 2k BPA BPD R R24 HPA/NA HPD/ND 4 INV A INV D R L3.K V 32kHz V OT GAIN (db) Gain vs Frequency FREQEY (khz) 6 TA24 6 TA23 FilterCAD Custom Inputs for f C = khz 2nd ORDER SECTION f O (khz) Q TYPE MODE B BP b C BP b A LP b D LP b 6fb 2

26 LTC6 Series TYPICAL APPLICATIONS LTC6-2 th Order Highpass, f CENTER = f CLK /2, Attenuation 6dB at (.6)(f CENTER ). Maximum f CTOFF = 2kHz with ±V Supplies V R.2k R63 2.k R L 66.k INV B INV C 2 R2 k 2 HPB/NB HPB/ 2 R22 2.k R3 6.k 3 BPB BPC 26 R32.2k R4.3k 4 R42.k LPB LPC 2.µF SB SC 24 6 LTC6-2 V 23 AGND 22 CLK 2 9 R H.k 9 R3 SA SD R43 2.k R44 2k LPA LPD R33 36.k 2 R34 4.3k BPA BPD R23 k 3 6 R24 2.k HPA/NA HPD 4 INV A INV D 2.µF R L2 249k R H2 2.k V 2kHz GAIN (db) Gain vs Frequency FREQEY (khz) 6 TA26 R H3 k C23 [/(2π R23 C23) = (6)(f CTOFF )] V OT 6 TA2 FilterCAD Custom Inputs for f C = khz 2nd ORDER SECTION f O (khz) Q f N (khz) TYPE MODE B HPN 3a C HPN 3a A HPN 2b D.9.. HP fb

27 LTC6 Series PACKAGE DESCRIPTION Dimensions in inches (millimeters) unless otherwise noted. G Package 2-Lead Plastic SSOP (.3mm) (Reference LTC DWG # --64).2 ± * (.39.43) ( ).42 ±.3.6 BSC RECOMMENDED SOLDER PAD LAYOT..6** (.9.22) (.9) MAX.9.2 (.3.)..9 (.22.3) NOTE:. CONTROLLING DIMENSION: MILLIMETERS MILLIMETERS 2. DIMENSIONS ARE IN (IHES) 3. DRAWING NOT TO SCALE.6 (.26) BSC.22.3 (.9.) TYP * DIMENSIONS DO NOT ILDE MOLD FLASH. MOLD FLASH SHALL NOT EXCEED.2mm (.6") PER SIDE ** DIMENSIONS DO NOT ILDE INTERLEAD FLASH. INTERLEAD FLASH SHALL NOT EXCEED.24mm (.") PER SIDE. (.2) MIN G2 SSOP 24 N Package 24-Lead PDIP (Narrow.3 Inch) (Reference LTC DWG # --).2* (32.2) MAX ±.* (6.4 ±.3) (.62.2).3 ±. (3.32 ±.2).4.6 (.43.6).. (.23.3) (.2.3) NOTE:.2 (.) MIN.2 (3.4) MIN IHES. DIMENSIONS ARE MILLIMETERS *THESE DIMENSIONS DO NOT ILDE MOLD FLASH OR PROTRSIONS. MOLD FLASH OR PROTRSIONS SHALL NOT EXCEED. IH (.24mm). (2.4) BSC. ±.3 (.4 ±.6) Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use. Linear Technology Corporation makes no representation that the interconnection of its circuits as described herein will not infringe on existing patent rights. N (.6) TYP 6fb 2

28 LTC6 Series TYPICAL APPLICATION LTC6-2 th Order Notch, f NOTCH = f CLK /26, f 3dB at (.9) (f NOTCH ) and (.)(f NOTCH ), Attenuation at f NOTCH Greater Than db for f NOTCH in the Frequency Range 2Hz to khz R H.k C22 4pF V R.k INV B INV C 2 R2.k 2 HPB/NB HPB/ 2 R k R3.k 3 BPB BPC 26 R32 4.3k R4 k 4 LPB LPC 2 R R2 R L2 66.k.k.k R62.6k R6.6k R63.6k C2 4pF R43 k.µf R33 24k R23 k R3.k C23 4pF SB SC 24 6 LTC6-2 V 23 AGND 22 CLK SA LPA BPA SD LPD BPD HPA/NA HPD 6 4 INV A INV D R H3.k.µF R4.k R H2.k R64.k R34 k R24.32k R H4.k R L4 4k V f CLK = (26)(f NOTCH ) R G k LT34 V OT 6 TA2 GAIN (db) Gain vs Frequency RELATIVE FREQEY (f IN /f NOTCH ) 6 TA2 RELATED PARTS PART NMBER DESCRIPTION COMMENTS LTC64 niversal Filter, Quad 2nd Order : and : Clock-to-f O Ratios, f O to khz, V S = p to ±.V LTC6/LTC6- Low Power, Dual 2nd Order Rail-to-Rail, V S = 3V to ±V LTC64 Low Power niversal Filter, Quad 2nd Order : and : Clock-to-f O Ratios, f O to 2kHz, V S = p to ±.V LTC264 High Speed niversal Filter, Quad 2nd Order 2: Clock-to-f O Ratio, f O to 2kHz, V S = p to ±.V 2 Linear Technology Corporation 63 McCarthy Blvd., Milpitas, CA 93-4 (4) FAX: (4) fb LT 6 REV B PRINTED IN SA LINEAR TECHNOLOGY CORPORATION 996