LTC1064-2 Low Noise, High Frequency, 8th Order Butterworth Lowpass Filter U FEATURES DESCRIPTIO 8th Order Filter in a 14-Pin Package 140kHz Maximum Corner Frequency No External Components 50:1 and 100:1 Clock to Cutoff Frequency Ratio 80VRMS Total Wideband Noise 0.03% THD or Better Operates from 2.37V to 8V Power Supplies U APPLICATIO S Antialiasing Filters Smoothing Filters Tracking High Frequency Lowpass Filters The LTC(R)1064-2 is a monolithic 8th order lowpass Butterworth filter, which provides a maximally flat passband. The attenuation slope is -48dB/octave and the maximum attenuation is in excess of 80db. An external TTL or CMOS clock programs the filter's cutoff frequency. The clock to cutoff frequency ratio is 100:1 (Pin 10 at V -) or 50:1 (Pin 10 at V +). The maximum cutoff frequency is 140kHz. No external components are needed. The LTC1064-2 features low wideband noise and low harmonic distortion even for input voltages up to 3VRMS. In fact the LTC1064-2 overall performance competes with equivalent multiple op amp RC active realizations. The LTC1064-2 is available in a 14-pin DIP or 16-pin surface mounted SW package. The LTC1064-2 is fabricated using LTC's enhanced analog CMOS Si-gate process. The LTC1064-2 is pin compatible with the LTC1064-1. , LTC and LT are registered trademarks of Linear Technology Corporation. U TYPICAL APPLICATIO 8th Order Clock Sweepable Lowpass Butterworth Filter 1 Measured Frequency Response 0 14 OUT C LTC1064-2 2 13 NC VIN 8V 4 5 6 7 AGND V+ AGND NC RIN A V- fCLK 50/100 VOUT NC 12 11 -15 -30 -8V CLOCK = 5MHz 10 VOUT/VIN (dB) 3 VS = 7.5V NC -45 -60 9 -75 8 -90 -105 1064 TA01a NOTE: THE POWER SUPPLIES SHOULD BE BYPASSED BY A 0.1F CAPACITOR CLOSE TO THE PACKAGE. THE NC PINS 1, 6, 8, AND 13 SHOULD BE PREFERABLY GROUNDED. 0 100 200 300 400 500 FREQUENCY (kHz) 600 700 1064-2 TA01b 10642fa 1 LTC1064-2 W W U W ABSOLUTE AXI U RATI GS (Note 1) Total Supply Voltage (V + to V -) ............................ 16.5V Power Dissipation .............................................. 400mW Storage Temperature Range ................. - 65C to 150C Lead Temperature (Soldering, 10 sec).................. 300C Operating Temperature Range LTC1064-2M (OBSOLETE) ............... - 55C to 125C LTC1064-2C ....................................... - 40C to 85C U W U PACKAGE/ORDER I FOR ATIO TOP VIEW ORDER PART NUMBER NC 1 14 OUT C VIN 2 13 NC AGND 3 12 V - V+ 4 11 fCLK AGND 5 10 50/100 NC 6 9 VOUT RIN A 7 8 NC LTC1064-2CN N PACKAGE 14-LEAD PDIP TJMAX = 150C, JA = 110C/W J PACKAGE 14-LEAD CERDIP LTC1064-2MJ LTC1064-2CJ OBSOLETE PACKAGE ORDER PART NUMBER TOP VIEW NC 1 16 OUT C VIN 2 15 NC AGND 3 14 V- V+ 4 13 NC AGND 5 12 fCLK NC 6 11 50/100 NC 7 10 NC RIN A 8 9 LTC1064-2CSW VOUT SW PACKAGE 16-LEAD PLASTIC (WIDE) SO TJMAX = 150C, JA = 130C/W Consider the N14 Package for Alternate Source Consult LTC Marketing for parts specified with wider operating temperature ranges. ELECTRICAL CHARACTERISTICS The denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25C. VS = 7.5V, 100:1, fCLK = 2MHz, R1 = 10k, TTL clock input level unless otherwise specified. PARAMETER CONDITIONS Passband Gain (Note 2) Gain TempCo -3dB Frequency Referenced to 0dB, 1Hz to 1kHz Gain at -3dB Frequency Stopband Attenuation Stopband Attenuation Stopband Attenuation Stopband Attenuation 100:1 50:1 Referenced to 0dB, fIN = 20kHz At 1.5f -3dB , 50:1, fIN = 60kHz At 2f -3dB , 100:1, fIN = 40kHz At 3f -3dB , 100:1, fIN = 60kHz At 4f -3dB , 100:1, fIN = 80kHz Input Frequency Range 100:1 50:1 Output Voltage Swing and Operating Input Voltage Range VS = 2.37V VS = 5V VS = 7.5V Total Harmonic Distortion VS = 5V, Input = 1VRMS at 1kHz VS = 7.5V, Input = 3VRMS at 1kHz Wideband Noise VS = 5V, Input = GND 1Hz - 1.99MHz VS = 7.5V, Input = GND 1Hz - 1.99MHz MIN TYP -0.5 -24 -44 0.0002 20 40 -3 -27 -47 -74 -90 0 0 MAX UNITS 0.15 -2.75 dB dB/C kHz kHz dB dB dB dB dB <fCLK/2 <fCLK kHz kHz V V V 1.1 3.1 5.0 0.015 0.03 80 90 % % VRMS VRMS 10642fa 2 LTC1064-2 ELECTRICAL CHARACTERISTICS The denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25C. VS = 7.5V, 100:1, fCLK = 2MHz, R1 = 10k, TTL clock input level unless otherwise specified. PARAMETER CONDITIONS Output DC Offset (Note 2) Output DC Offset TempCo VS = 7.5V VS = 5V MIN Input Impedance 10 Output Impedance f OUT = 10kHz Output Short-Circuit Current Source/Sink Clock Feedthrough Maximum Clock Frequency 50% Duty Cycle, VS = 5V 50% Duty Cycle, TA = 25C, VS = 7.5V Power Supply Current VS = 2.37V, f CLK = 1MHz VS = 5V, f CLK = 1MHz TYP MAX UNITS 30 90 125 mV V/C 20 k 2 3/1 mA 200 VRMS 11 14 VS = 7.5V, f CLK = 1MHz 17 Power Supply Voltage Range Note 1: Absolute Maximum Ratings are those values beyond which the life of a device may be impaired. 2.37 5 7 MHz MHz 22 23 26 28 32 mA mA mA mA mA 8 V Note 2: For tighter specifications please contact LTC Marketing. U W TYPICAL PERFOR A CE CHARACTERISTICS Amplitude Response Phase Response -90 -30 PHASE (DEG) VOUT/VIN (dB) -45 fCLK = 2MHz f-3dB = 40kHz -45 fCLK = 5MHz f-3dB = 100kHz -60 -105 10k -135 -180 -225 -270 -315 -75 -90 220 VS = 7.5V TA = 25C f CLK = 1MHz 100:1 f-3dB = 10kHz 0 VS = 7.5V; 50:1 TA = 25C 1M 1064 G01 VS = 7.5V 200 T = 25C A 180 f CLK = 1MHz 100:1 160 f -3dB = 10kHz 140 120 100 80 60 -360 40 -405 20 -450 100k fIN (Hz) GROUP DELAY (s) fCLK = 7MHz f-3dB = 140kHz 0 -15 Group Delay vs Frequency 45 15 0 1 2 3 4 6 7 fIN (kHz) 5 8 9 10 11 1064 G02 0 0 1 2 3 4 5 6 7 fIN (kHz) 8 9 10 11 1064 G03 10642fa 3 LTC1064-2 U W TYPICAL PERFOR A CE CHARACTERISTICS Phase vs f -3dB Frequency Phase Matching 2.4 30 fCLK = 2MHz f-3dB = 40kHz PHASE (DEG) PHASE MATCH (DEG) fCLK = 500kHz f-3dB = 10kHz -90 fCLK = 1MHz f-3dB = 20kHz -120 -150 -180 -210 1.6 1.2 0.8 0.4 -240 VS = 7.5V 50:1 -270 100 0 1k FREQUENCY (Hz) 10k 0 4 20 8 12 16 FREQUENCY (kHz) 1064 G04 800 fCLK = 2MHz 600 100:1, f-3dB = 20kHz (530) 400 (335) fCLK = 5MHz 200 100:1, f-3dB = 50kHz 0 0.1k 24 1k 10k FREQUENCY (Hz) 100k 1064-2 G06 Harmonic Distortion vs Amplitude 1 fCLK = 1MHz, f-3dB = 20kHz, 50:1 HARMONIC DISTORTION (%) HARMONIC DISTORTION (%) fCLK = 500kHz 100:1, f-3dB = 5kHz 1200 (1060) 1000 1064-2 G05 Harmonic Distortion vs Frequency 0.1 1400 2.0 -30 -60 VS = 7.5V, fCLK = 1MHz, f-3dB = 20kHz, 50:1 50 UNIT SAMPLE (TA = 25C TO 125C) OUTPUT NOISE (nV/Hz) 0 Noise Spectral Density 1600 5V, 1VRMS INPUT 7.5V, 3VRMS INPUT 0.01 2.5V 5V 0.1 7V 0.01 fCLK = 1MHz, f-3dB = 20kHz 50:1, 1kHz INPUT 0.001 1k 10k 20k 0.001 0.5 FREQUENCY (Hz) 1.0 AMPLITUDE (VRMS) 1064-2 G08 1064-2 G07 Amplitude Response with Pin 10 at Ground Power Suppy vs Current 48 15 44 PIN 10 AT GROUND fCLK =1MHz 0 40 36 -15 32 28 24 TA = -55C 20 TA = 25C 16 TA = 125C VOUT/VIN (dB) POWER SUPPLY CURRENT (mA) 5.0 -30 -45 -60 -75 12 8 -90 4 -105 0 0 2 4 6 8 10 12 14 16 18 20 22 24 POWER SUPPLY VOLTAGE (V) 1064 G09 1 10 fIN (kHz) 100 1064-2 G10 10642fa 4 LTC1064-2 U W TYPICAL PERFOR A CE CHARACTERISTICS Table 1. Gain/Delay, f -3dB = 1kHz, LTC1064-2 Typical Response VS = 5V, TA = 25C, fCLK = 50kHz, Ratio = Pin 10 at V + (fltr 50:1) FREQUENCY (kHz) GAIN (dB) Table 3. Gain/Delay, f -3dB = 1kHz, LTC1064-2 Typical Response VS = 5V, TA = 25C, fCLK = 100kHz, Ratio = Pin 10 at V - (fltr 100:1) DELAY (ms) FREQUENCY (kHz) GAIN (dB) DELAY (ms) 0.200 -0.247 0.857 0.200 -0.213 0.821 0.300 -0.270 0.872 0.300 -0.240 0.837 0.400 -0.290 0.893 0.400 -0.260 0.858 0.500 -0.300 0.929 0.500 -0.280 0.893 0.600 -0.320 0.983 0.600 -0.310 0.947 0.700 -0.370 1.071 0.700 -0.370 1.034 0.800 -0.520 1.210 0.800 -0.530 1.172 0.900 -1.200 1.364 0.900 -1.200 1.325 1.000 -3.380 1.381 1.000 -3.370 1.346 1.100 -7.530 1.192 1.100 -7.500 1.158 1.200 -12.670 0.935 1.200 -12.640 0.899 Table 2. Gain, f -3dB = 1kHz, LTC1064-2 Typical Response VS = 5V, TA = 25C, fCLK = 50kHz, Ratio = Pin 10 at V + (fltr 50:1) FREQUENCY (kHz) GAIN (dB) Table 4. Gain, f-3dB = 1kHz, LTC1064-2 Typical Response VS = 5V, TA = 25C, fCLK = 100kHz, Ratio = Pin 10 at V - (fltr 100:1) FREQUENCY (kHz) GAIN (dB) 0.500 -0.298 0.500 -0.279 1.000 -3.380 1.000 -3.370 1.500 -27.500 1.500 -27.500 2.000 -47.200 2.000 -47.200 2.500 -63.300 2.500 -62.300 3.000 -75.190 3.000 -75.130 3.500 -86.100 3.500 -86.090 4.000 -95.310 4.000 -95.210 4.500 -104.240 4.500 -103.030 5.000 -109.650 5.000 -108.690 5.500 -121.930 5.500 -114.830 6.000 -123.920 6.000 -120.540 6.500 -114.150 6.500 -114.750 7.000 -116.990 7.000 -116.430 7.500 -120.070 7.500 -120.790 8.000 -113.470 8.000 -121.290 8.500 -130.090 8.500 -119.970 9.000 -114.770 9.000 -120.020 9.500 -117.760 9.500 -125.170 10642fa 5 LTC1064-2 U W TYPICAL PERFOR A CE CHARACTERISTICS Table 5. Gain, f -3dB = 20kHz, LTC1064-2 Typical Response VS = 7.5V, TA = 25C, fCLK = 1MHz, Ratio = Pin 10 at V + (fltr 50:1) Table 6. Gain, f-3dB = 140kHz, LTC1064-2 Typical Response VS = 7.5V, TA = 25C, fCLK = 7MHz, Ratio = Pin 10 at V+ (fltr 50:1) FREQUENCY (kHz) GAIN (dB) FREQUENCY (kHz) GAIN (dB) 10.000 -0.308 50.00 -0.238 20.000 -3.350 60.00 -0.140 30.000 -27.400 70.00 0.050 40.000 -47.100 80.00 0.350 50.000 -62.300 90.00 0.810 60.000 -74.890 100.00 1.450 70.000 -85.430 110.00 2.110 80.000 -95.070 120.00 1.830 90.000 -103.150 130.00 -0.700 100.000 -108.700 140.00 -4.840 110.000 -107.520 150.00 -9.350 120.000 -108.030 160.00 -13.690 130.000 -104.990 170.00 -17.760 140.000 -106.090 180.00 -21.600 150.000 -105.320 190.00 -25.200 200.00 -28.500 210.00 -31.800 220.00 -34.800 Table 7. Gain Non-Butterworth Response (Pin 10 to GND), LTC1064-2 Typical Response VS = 5V, TA = 25C, fCLK = 100kHz 230.00 -37.700 GAIN (dB) 240.00 -40.500 0.500 -0.012 250.00 -43.200 1.000 1.240 260.00 -45.700 1.500 -14.690 270.00 -48.200 2.000 -28.600 280.00 -50.500 2.500 -41.100 290.00 -52.700 3.000 -52.500 300.00 -54.900 3.500 -62.800 4.000 -71.500 4.500 -79.370 5.000 -86.730 5.500 -93.340 FREQUENCY (kHz) 6.000 -99.350 6.500 -105.270 7.000 -113.270 7.500 -114.600 8.000 -114.010 8.500 -122.810 9.000 -122.980 9.500 -119.450 10642fa 6 LTC1064-2 U U U PI FU CTIO S (Pin Numbers Refer to the 14-Pin Package) NC (Pins 1, 6, 8 and 13): The "no connection" pins should be preferably grounded. These pins are not internally connected. VIN, VOUT (Pins 2, 9): The input Pin 2 is connected to an 18k resistor tied to the inverting input of an op amp. Pin 2 is protected against static discharge. The device's output, Pin 9, is the output of an op amp which can typically source/sink 3mA/1mA. Although the internal op amps are unity gain stable, driving long coax cables is not recommended. When testing the device for noise and distortion, the output, Pin 9, should be buffered. (Figure 1) The op amp power supply wire (or trace) should be connected directly to the power source. To eliminate switching transients from filter output, buffer filter output with a third order lowpass (Figure 5). AGND (Pins 3, 5): For dual supply operation these pins should be connected to a ground plane. For single supply operation both pins should be tied to one half supply, (Figure 3). V +, V - (Pins 4, 12): Should be bypassed with a 0.1F capacitor to an adequate AGND. Low noise, nonswitching power supplies are recommended. To avoid latchup when the power supplies exhibit high turn-on transients, a 1N5817 Schottky diode should be added from the V + and V - pins to ground (Figures 1, 2 and 3). RIN A, OUT C (Pins 7, 14): A very short connection between Pin 7 and Pin 14 is recommended. This connection should be preferably done under the IC package. In a breadboard use a one inch, or less, shielded coaxial cable: the shield should be grounded. In a PC board, use a one inch trace or less; surround the trace by a ground plane. 50/100 (Pin 10): The DC level at this pin determines the ratio of clock frequency to the -3dB frequency of the filter. The ratio is 50:1 when Pin 10 is at V + and 100:1 when Pin 10 is at V -. This pin should be bypassed with a 0.1F capacitor to analog ground when it's connected to V - or V + (Figure 1). See Tables 1 through 7 for typical gain and delay responses for the two ratios. fCLK (Pin 11): For 5V supplies the logic threshold level is 1.4V. For 8V and 0V to 5V supplies the logic threshold levels are 2.2V and 3V respectively. The logic threshold levels vary 100mV over the full military temperature range. The recommended duty cycle of the input clock is 50% although for clock frequencies below 500kHz the clock "on" time can be as low as 200ns. The maximum clock frequency for 5V supplies is 4MHz. For 7V supplies and above, the maximum clock frequency is 7MHz. Do not allow the clock levels to exceed the power supplies. For single supply operation 6V use level shifting at Pin 11 with T2L levels (Figure 4). 10642fa 7 LTC1064-2 U TYPICAL APPLICATIO S 1 2 3 4 0.1F 5 6 NC POWER SOURCE V+ V- OUT C 14 1 13 2 LTC1064-2 12 V- AGND 3 NC VIN V+ AGND fCLK 50/100 NC 7 RIN A VOUT NC 0.1F 11 10 9 8 20k 0.1F 1N5817 V+/V - 20k 4 V+ 0.1F 6 - 0.1F 8 7 VOUT LT1006 + 4 RECOMMENDED OP AMPS: LT1022, LT318, LT1056 5 NC OUT C VIN NC 14 13 LTC1064-2 12 V- AGND V+ AGND NC RIN A fCLK 50/100 VOUT NC 11 V- 1N5817 0.1F 10 9 8 750 1064-2 F02 1064-2 F01 Figure 2. Using Schottky Diodes to Protect the IC from Transient Supply Reversal. 0.1F Figure 1. Buffering the Filter Output. The Buffer Op Amp Should Not Share the LTC1064-2 Power Lines. 1 2 NC OUT C 14 13 NC LTC1064-2 3 12 V- AGND 4 V+= 15V 0.1F 5 5k 6 V+/2 0.1F 5k 7 VIN V+ AGND NC RIN A fCLK 50/100 VOUT NC 11 10 0V TO 10V 9 8 1064-2 F03 Figure 3. Single Supply Operation. If Fast Power Up or Down Transients are Expected, Use a 1N5817 Schottky Diode Between Pin 4 and Pin 5. For V+ = 5V, Derive the Mid-Supply Voltage with a 7.5k Resistor and an LT1004 2.5V Reference. 10642fa 8 LTC1064-2 U TYPICAL APPLICATIO S 1 2 3 4 V+ 5 5k 6 0.1F 7 5k NC OUT C VIN NC 14 13 V+ LTC1064-2 12 V- AGND V+ AGND NC RIN A fCLK 50/100 VOUT NC 2.2k T 2L LEVEL 11 10 RATIO 5k 1F 9 8 1064-2 F04 Figure 4. Level Shifting the Input T2L Clock for Single Supply Operation 6V. 1 2 V+ 0.1F NC OUT C VIN NC 14 3 LTC1064-2 12 V- AGND 4 V+ 5 6 7 AGND NC RIN A fCLK 50/100 VOUT NC 20k 13 V- 0.1F 11 10 + V /GND/V - 9 8 VOUT 100pF 15V 10k 10k - 50 LT1056 220pF 0.027F + 1064-2 F05 -15V Figure 5. Adding an Output Buffer-Filter to Eliminate Any Clock Feedthrough. Passband 0.1dB to 50kHz, -3dB at 94kHz. 10642fa 9 LTC1064-2 U PACKAGE DESCRIPTIO J Package 14-Lead CERDIP (Narrow 0.300, Hermetic) (LTC DWG # 05-08-1110) .005 (0.127) MIN .785 (19.939) MAX 14 13 12 11 10 9 8 .220 - .310 (5.588 - 7.874) .025 (0.635) RAD TYP 1 2 3 4 5 6 7 .300 BSC (7.62 BSC) .200 (5.080) MAX .015 - .060 (0.381 - 1.524) .008 - .018 (0.203 - 0.457) 0 - 15 .045 - .065 (1.143 - 1.651) NOTE: LEAD DIMENSIONS APPLY TO SOLDER DIP/PLATE OR TIN PLATE LEADS .014 - .026 (0.360 - 0.660) .100 (2.54) BSC .125 (3.175) MIN J14 0801 OBSOLETE PACKAGE 10642fa 10 LTC1064-2 U PACKAGE DESCRIPTIO N Package 14-Lead PDIP (Narrow 0.300) (LTC DWG # 05-08-1510) .770* (19.558) MAX 14 13 12 11 10 9 8 1 2 3 4 5 6 7 .255 .015* (6.477 0.381) .300 - .325 (7.620 - 8.255) .045 - .065 (1.143 - 1.651) .130 .005 (3.302 0.127) .020 (0.508) MIN .065 (1.651) TYP .008 - .015 (0.203 - 0.381) +.035 .325 -.015 ( +0.889 8.255 -0.381 NOTE: 1. DIMENSIONS ARE ) .120 (3.048) MIN .005 (0.125) .100 MIN (2.54) BSC INCHES MILLIMETERS *THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS. MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED .010 INCH (0.254mm) .018 .003 (0.457 0.076) N14 1002 10642fa 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. 11 LTC1064-2 U PACKAGE DESCRIPTIO SW Package 16-Lead Plastic Small Outline (Wide .300 Inch) (Reference LTC DWG # 05-08-1620) .050 BSC .045 .005 .030 .005 TYP .398 - .413 (10.109 - 10.490) NOTE 4 16 N 15 14 13 12 11 10 9 N .325 .005 .420 MIN .394 - .419 (10.007 - 10.643) NOTE 3 1 2 3 N/2 N/2 RECOMMENDED SOLDER PAD LAYOUT 1 .005 (0.127) RAD MIN .009 - .013 (0.229 - 0.330) .291 - .299 (7.391 - 7.595) NOTE 4 .010 - .029 x 45 (0.254 - 0.737) 2 3 4 5 6 .093 - .104 (2.362 - 2.642) 7 8 .037 - .045 (0.940 - 1.143) 0 - 8 TYP .050 (1.270) BSC NOTE 3 .016 - .050 (0.406 - 1.270) NOTE: 1. DIMENSIONS IN .004 - .012 (0.102 - 0.305) .014 - .019 (0.356 - 0.482) TYP INCHES (MILLIMETERS) 2. DRAWING NOT TO SCALE 3. PIN 1 IDENT, NOTCH ON TOP AND CAVITIES ON THE BOTTOM OF PACKAGES ARE THE MANUFACTURING OPTIONS. THE PART MAY BE SUPPLIED WITH OR WITHOUT ANY OF THE OPTIONS 4. THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS. MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED .006" (0.15mm) S16 (WIDE) 0502 10642fa 12 Linear Technology Corporation LW/TP 1202 1K REV A * PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 FAX: (408) 434-0507 www.linear.com LINEAR TECHNOLOGY CORPORATION 1990