LTC1565-31 650kHz Continuous Time, Linear Phase Lowpass Filter FEATURES DESCRIPTION n The LTC®1565-31 is a 7th order, continuous time, linear phase lowpass filter. The selectivity of the LTC1565-31, combined with its linear phase and dynamic range, make it suitable for filtering in data communications or data acquisition systems. The filter attenuation is 36dB at 2× fCUTOFF and at least 72dB for frequencies above 3× fCUTOFF. Unlike comparable LC filters, the LTC1565-31 achieves this selectivity with a linear phase response in the passband. With 5% accuracy of the cutoff frequency, the LTC1565-31 can be used in applications requiring pairs of matched filters, such as transceiver I and Q channels. Furthermore, the differential inputs and outputs provide a simple interface for these wireless systems. With a single 5V supply and a 2VP-P input, the LTC1565-31 features an impressive spurious free dynamic range of 75dB. The maximum signal-to-noise ratio is 78dB and it is achieved with a 2.5VP-P input signal. The LTC1565-31 features a shutdown mode where power supply current is typically less than 10μA. For W-CDMA, 3G, CDMA 2000 and other cellular and noncellular cutoff frequencies or single-ended I/O, please contact LTC Marketing for additional information. n n n n n n n n 7th Order, 650kHz Linear Phase Filter in an SO-8 Differential Inputs and Outputs Operates on a Single 5V or a ±5V Supply Low Offset: 5mV Typical 75dB THD and SNR 78dB SNR Shutdown Mode Requires No External Components Requires No External Clock Signal APPLICATIONS n n n n n n CDMA Basestations Data Communications Antialiasing Filters Smoothing or Reconstruction Filters Matched Filter Pairs Replacement for LC Filters L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. TYPICAL APPLICATION Frequency Response 10 Single 5V Supply, Differential 650kHz Lowpass Filter VIN– 2 +IN +OUT –IN –OUT 8 7 VOUT+ VOUT– 3 0.1μF 4 GND V– 5V + V SHDN 6 5V 0.1μF 5 15645-31 TA01 2.0 GAIN 1.9 –10 1.8 –20 1.7 –30 1.6 –40 1.5 DELAY –50 1.4 –60 1.3 –70 1.2 –80 1.1 –90 1.0 –100 104 105 106 FREQUENCY (Hz) DELAY (μs) LTC1565-31 GAIN (dB) VIN+ 1 0 0.9 107 1565 G01 156531fa 1 LTC1565-31 ABSOLUTE MAXIMUM RATINGS PIN CONFIGURATION (Note 1) Total Supply Voltage ............................................... 11V Power Dissipation .............................................. 500mW Operating Temperature Range LTC1565-31CS8 ...................................... 0°C to 70°C LTC1565-31IS8 ................................... – 40°C to 85°C Storage Temperature Range ................. –65°C to 150°C Lead Temperature (Soldering, 10 sec) ................ 300°C TOP VIEW +IN 1 8 +OUT –IN 2 7 –OUT GND 3 6 V+ – 5 SHDN V 4 S8 PACKAGE 8-LEAD PLASTIC SO TJMAX = 150°C, θJA = 80°C/ W (NOTE 4) ORDER INFORMATION LEAD FREE FINISH TAPE AND REEL PART MARKING PACKAGE DESCRIPTION TEMPERATURE RANGE LTC1565-31CS8#PBF LTC1565-31CS8#TRPBF 156531 8-Lead Plastic SO 0°C to 70°C LTC1565-31IS8#PBF LTC1565-31IS8#TRPBF 56531I 8-Lead Plastic SO –40°C to 85°C Consult LTC Marketing for parts specified with wider operating temperature ranges. Consult LTC Marketing for information on non-standard lead based finish parts. For more information on lead free part marking, go to: http://www.linear.com/leadfree/ For more information on tape and reel specifications, go to: http://www.linear.com/tapeandreel/ ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VS = 5V, RLOAD = 10k from each output to AC ground, and Pin 5 open unless otherwise specified. PARAMETER CONDITIONS MIN Operating Supply Voltage 4.75 Filter Gain VIN = 1VP-P, fIN = 25kHz fIN = 200kHz (Gain Relative to 25kHz) fIN = 300kHz (Gain Relative to 25kHz) fIN = 500kHz (Gain Relative to 25kHz) fIN = 650kHz (Gain Relative to 25kHz) fIN = 900kHz (Gain Relative to 25kHz) fIN = 1.3MHz (Gain Relative to 25kHz) fIN = 2.3MHz (Gain Relative to 25kHz) Filter Phase VIN = 1VP-P, fIN = 25kHz fIN = 200kHz fIN = 300kHz fIN = 500kHz fIN = 600kHz fIN = 650kHz fIN = 900kHz Phase Linearity TYP Ratio of 600kHz Phase/300kHz Phase l l l l l l l –0.3 –0.2 –0.7 –2.2 –4 l –162 l 34 l 1.95 0 0 –0.4 –1.6 –3 –11 –36 –72 –13 –101 –150 113 60 36 –92 2 MAX UNITS 11 V 0.3 0.1 –0.1 –0.95 –2 –7 –31 dB dB dB dB dB dB dB dB –138 85 Deg Deg Deg Deg Deg Deg Deg 2.03 Wideband Noise Noise BW = DC to 2 • fCUTOFF 118 μVRMS THD fIN = 100kHz, 1VP-P (Note 2) 86 dB Filter Differential DC Swing Maximum Difference Between Pins 7 and 8 VS = 5V VS = ±5V ±1.7 ±2.3 V V l l ±1.4 ±2.2 156531fa 2 LTC1565-31 ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VS = 5V, RLOAD = 10k from each output to AC ground, and Pin 5 open unless otherwise specified. PARAMETER CONDITIONS MIN Input Bias Current 0.1 Input Offset Current Common Mode, VIN = 2.5V Differential Input Resistance TYP MAX 0.3 0.6 VS = 5V VS = ±5V (Note 5) Output DC Offset Drift VS = 5V VS = ±5V Ground Voltage (Pin 3) in Single Supply Applications VS = 5V l 2.49 SHDN Pin Logic Thresholds VS = 5V, Minimum Logical “1” VS = 5V, Maximum Logical “0” l l 3.3 VS = ±5V, Minimum Logical “1” VS = ±5V, Maximum Logical “0” l l 2.4 μA ±10 nA 75 145 MΩ MΩ 3 pF Input Capacitance Output DC Offset (Note 3) UNITS ±5 ±5 ±12 ±12 –400 –400 mV mV μV/°C μV/°C 2.51 2.52 V 4.2 V V 2.9 V V SHDN Pin Pull-Up Current VS = 5V VS = ±5V Power Supply Current VS = 5V VS = ±5V l l 24 25 31 33 mA mA Power Supply Current in Shutdown Mode Shutdown. Includes SHDN Pull-Up Current VS = 5V VS = ±5V l l 8 20 16 40 μA μA 5 9 Note 1: 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: Input and output voltages expressed as peak-to-peak numbers are assumed to be fully differential. μA μA Note 3: Output DC offset is measured between Pin 8 and Pin 7 with Pin 1 and Pin 2 connected to Pin 3. Note 4: Thermal resistance varies depending upon the amount of PC board metal attached to the device. θJA is specified for a 3.8 square inch test board covered with 2 oz copper on both sides. Note 5: Output DC offset measurements are performed by automatic test equipment approximately 0.5 seconds after application of power. TYPICAL PERFORMANCE CHARACTERISTICS Passband Gain and Delay vs Frequency Frequency Response 10 2.0 GAIN 0.5 2.0 GAIN 0 –10 1.8 –0.5 1.8 –20 1.7 –1.0 1.7 –30 1.6 –1.5 1.6 1.5 DELAY –50 1.4 1.3 –60 –2.0 5V 1.9 ±5V 1.5 DELAY –2.5 1.4 1.3 –70 1.2 –3.0 –80 1.1 –3.5 1.2 –90 1.0 –4.0 1.1 –100 104 105 106 FREQUENCY (Hz) 0.9 107 1565 G01 TA = 25°C –4.5 25k 100k FREQUENCY (Hz) DELAY (μs) –40 GAIN (dB) 1.9 DELAY (μs) GAIN (dB) 0 1.0 1M 1565 G02 156531fa 3 LTC1565-31 TYPICAL PERFORMANCE CHARACTERISTICS Passband Gain vs Frequency Over Temperature 0.4 VS = 5V 0.3 –40°C 0.1 GAIN (dB) GAIN (dB) 0.2 85°C 0 25°C –0.1 –40 –40 –50 –50 –60 –60 GAIN (dB) 0.5 Stopband Gain vs Frequency Over Temperature Stopband Gain vs Frequency VS = 5V –70 VS = 5V –40°C 25°C 85°C –70 –0.2 –0.3 –80 –80 VS = ±5V –0.4 –0.5 25k 100k FREQUENCY (Hz) –90 1.5 400k 1.8 2.4 2.1 FREQUENCY (MHz) 2.7 1565 G03 2.7 3.0 70 Supply Current vs Temperature 26 VIN = 200mVP-P VS = 5V TA = 25°C SUPPLY CURRENT (mA) 80 VIN = 1VP-P VS = 5V 100 TA = 25°C PSRR (dB) 90 CMRR (dB) 2.4 2.1 FREQUENCY (MHz) 1565 G05 Power Supply Rejection Ratio Common Mode Rejection Ratio 80 1.8 1565 G04 110 60 50 70 25 VS = ±5V VS = 5V 24 40 60 50 103 –90 1.5 3.0 104 105 106 FREQUENCY (Hz) 107 30 103 104 105 106 FREQUENCY (Hz) 1565 G06 107 1565 G07 23 –50 –30 30 50 –10 10 TEMPERATURE (°C) 70 90 1565 G08 PIN FUNCTIONS +IN, –IN (Pins 1, 2): Input Pins. Signals can be applied to either or both input pins. The typical DC gain from differential inputs (Pin 1 to Pin 2) to the differential outputs (Pin 8 to Pin 7) is 1.0V/V. The input range is described in the Applications Information section. GND (Pin 3): Ground. The ground pin is the reference voltage for the filter and is internally biased to one-half the total power supply voltage of the filter, maximizing the dynamic range of the filter. For single supply operation, the ground pin should be bypassed with a quality 0.1μF ceramic capacitor to Pin 4. For dual supply operation, connect Pin 3 to a high quality DC ground. A ground plane should be used. A poor ground will increase noise and distortion. The impedance seen at Pin 3 is 2.5kΩ in normal mode. In shutdown, the pin is internally biased to the same levels as normal mode. The impedance in shutdown mode is typically 500kΩ but varies with supply voltage and temperature. 156531fa 4 LTC1565-31 PIN FUNCTIONS V–, V+ (Pins 4, 6): Power Supply Pins. For a single 5V supply (Pin 4 grounded), a quality 0.1μF ceramic bypass capacitor is required from the positive supply pin (Pin 6) to the negative supply pin (Pin 4). The bypass should be as close as possible to the IC. For dual supply applications (Pin 3 is grounded), bypass Pin 6 to Pin 3 and Pin 4 to Pin 3 with a quality 0.1μF ceramic capacitor. The maximum voltage difference between the ground pin (Pin 3) and the positive supply pin (Pin 6) should not exceed 5.5V. SHDN (Pin 5): Shutdown. When the Pin 5 voltage is low, the LTC1565-31 goes into the current saving shutdown mode. Pin 5 has a 4μA pull-up current. Leaving Pin 5 open will place the LTC1565-31 in its normal operating mode. – OUT, +OUT (Pins 7, 8): Output Pins. Pins 7 and 8 are the filter differential output. Each pin can drive 1kΩ or 300pF loads. The common mode voltage at the output pins is the same as the voltage at Pin 3. BLOCK DIAGRAM +IN 1 + 8 +OUT – R + R – – 7th ORDER LINEAR PHASE FILTER NETWORK OUTPUT BUFFER OUTPUT BUFFER 7 –OUT –IN 2 + INPUT BUFFERS WITH COMMON MODE TRANSLATION CIRCUIT V+ ~1M SHUTDOWN SWITCH 5k 6 V+ GND 3 5k ~1M SHUTDOWN SWITCH V+ V– V– 4 4μA SHUTDOWN 5 SHDN 1565-31 BD 156531fa 5 LTC1565-31 APPLICATIONS INFORMATION Interfacing to the LTC1565-31 Input Common Mode and Differential Voltage Range The difference between the voltages at Pin 1 and Pin 2 is the “differential input voltage.” The average of the voltages at Pin 1 and Pin 2 is the “common mode input voltage.” The difference between the voltages at Pin 7 and Pin 8 is the “differential output voltage.” The average of the voltages at Pin 7 and Pin 8 is the “common mode output voltage.” The input and output common mode voltages are independent. The input common mode voltage is set by the signal source, if DC coupled, or by the biasing network if AC coupled (Figures 1 and 2). The output common mode voltage is equal to the voltage of Pin 3, the GND pin. The GND pin is biased to one-half of the supply voltage by an internal resistive divider (see Block Diagram). To alter the common mode output voltage, Pin 3 can be driven with an external voltage source or resistor network. If external resistors are used, it is important to note that the internal 5k resistors can vary ± 20% (their ratio only varies ±1%). The output can also be AC coupled. The range of voltage each input can support while operating in its linear region is typically 0.8V to 3.7V for a single 5V supply and – 4.2V to 3.2V for a ±5V supply. Therefore, the filter can accept a variety of common mode input voltages. Figures 3 and 4 show the THD of the filter versus common mode input voltage with a 2VP-P differential input signal. 1 2 + – VIN+ + – +IN –IN VIN– –OUT VOUT+ 7 VOUT– 4 V+ 6 SHDN 5 GND V– –40 VS = ±5V THD (dB) –50 –70 –80 –90 –30 0.1μF THD (dB) Figure 1 –60 –80 1 2 VIN –50 –70 0.1μF VIN– 0.1μF 100k +IN +OUT –IN –OUT 100k 8 VOUT+ 7 VOUT– 5V LTC1565-31 3 1μF VS = 5V –40 V + + VIN– VIN (COMMON MODE) = IN 2 V + + VOUT– V+ = VOUT (COMMON MODE) = OUT 2 2 + – 5 Figure 3. THD vs Common Mode Input Voltage DC COUPLED INPUT + VIN = 2VP-P fIN = 100kHz –5 –4 –3 –2 –1 0 1 2 3 4 INPUT COMMON MODE VOLTAGE (V) 15645-31 F01 + – –60 1565-31 F03 5V LTC1565-31 3 0.1μF +OUT 8 –30 4 GND V– V+ 6 SHDN 5 VIN (COMMON MODE) = VOUT (COMMON MODE) = Figure 2 V+ 2 0.5 3.0 1.0 2.0 2.5 1.5 INPUT COMMON MODE VOLTAGE (V) 3.5 1565-31 F04 Figure 4. THD vs Common Mode Input Voltage 0.1μF 15645-31 F02 AC COUPLED INPUT VIN = 2VP-P fIN = 100kHz Figure 5 shows the THD and S/N ratio versus differential input voltage level for both a single 5V supply and a ±5V supply. The common mode voltage of the input signal is one-half the total power supply voltage of the filter. The spurious free dynamic range, where the THD and S/N ratio are equal, is 75dB to 76dB when the differential input voltage level is 2VP-P; that is, for a single 5V supply, the 156531fa 6 LTC1565-31 APPLICATIONS INFORMATION THD, SNR (dB) –40 Output Common Mode and Differential Voltage Range THD: VS = 5V, VCM = 2.5V THD: VS = ±5V, VCM = 0V SNR fIN = 100kHz The output is a fully differential signal with a common mode level equal to the voltage at Pin 3. The specifications in the Electrical Characteristics table assume the inputs are driven differentially and the output is observed differentially. However, Pin 8 can be used as a single-ended output by simply floating Pin 7. Pin 7 can be used as an inverting single-ended output by floating Pin 8. Using Pins 7 or 8 as single-ended outputs will decrease the performance. –50 –60 –70 –80 –90 0.5 1.0 1.5 2.0 2.5 3.0 DIFFERENTIAL INPUT (P-P) 3.5 1565-31 F05 Figure 5. Dynamic Range Diff-In, Diff-Out input voltages are Pin 1 = 2.5V DC ±0.5V and Pin 2 = 2.5V DC ±0.5V. Also note Figure 5 shows a 78dB SNR ratio for higher THD levels. As seen in Figures 3 and 4, the spurious free dynamic range can be optimized by setting the input common mode voltage slightly below one-half of the power supply voltage, i.e., 2V for a single 5V supply and –0.5V for a ±5V supply. Figure 6 shows the THD and SNR ratio versus differential input voltage level for both a single 5V supply and a ±5V supply when the common mode input voltage is 2V and –0.5V respectively. The common mode output voltage can be adjusted by overdriving the voltage present on Pin 3. The best performance is achieved using a common mode output voltage that is equal to mid supply (the default Pin 3 voltage). Figures 7 and 8 illustrate the THD versus output common mode voltage for a 2VP-P differential input voltage and a common mode input voltage that is 0.5V below mid supply. 0 VIN = 2VP-P 100kHz VS = 5V VIN(CM) = 2V –10 –20 THD (dB) –30 –30 –40 –50 –60 –70 For best performance, the inputs should be driven differentially. For single-ended signals, connect the unused input to Pin 3 or a common mode reference. –80 1.0 2.0 2.5 3.5 4.0 1.5 3.0 COMMON MODE OUTPUT VOLTAGE (V) 1565-31 F07 –30 0 VIN = 2VP-P 100kHz –10 VS = ±5V VIN(CM) = –0.5V –20 –50 –30 –60 THD (dB) THD, SNR (dB) –40 Figure 7. THD vs Common Mode Output Voltage THD: VS = 5V, VCM = 2V THD: VS = ±5V, VCM = –0.5V SNR fIN = 100kHz –70 –40 –50 –60 –80 –70 –90 0.5 1.5 2.0 2.5 3.0 1.0 DIFFERENTIAL INPUT VOLTAGE (VP-P) 3.5 1565-31 F06 Figure 6. THD vs VIN for a Common Mode Input Voltage 0.5V Below Mid Supply –80 –90 –4 0 1 2 –3 –2 –1 3 COMMON MODE OUTPUT VOLTAGE (V) 4 1565-31 F08 Figure 8. THD vs Common Mode Output Voltage 156531fa 7 LTC1565-31 APPLICATIONS INFORMATION in the filter passband and cannot be removed with post filtering (Table 1). Table 2 lists the typical change in wideband noise with supply voltage. Output Drive Pin 7 and Pin 8 can drive a 1kΩ or 300pF load connected to AC ground with a ± 0.5V signal (corresponding to a 2VP-P differential signal). For differential loads (loads connected from Pin 7 to Pin 8) the outputs can produce a 2VP-P differential signal across 2kΩ or 150pF. For smaller signal amplitudes the outputs can drive correspondingly larger loads. Table 1. Wideband Noise vs Bandwidth, Single 5V Supply BANDWIDTH TOTAL INTEGRATED NOISE DC to fCUTOFF 104μVRMS DC to 2 • fCUTOFF 118μVRMS Table 2. Wideband Noise vs Supply Voltage, fCUTOFF = 650kHz Noise The wideband noise of the filter is the RMS value of the device’s output noise spectral density. The wideband noise data is used to determine the operating signal-to-noise at a given distortion level. Most of the noise is concentrated POWER SUPPLY TOTAL INTEGRATED NOISE DC TO 2 • fCUTOFF 5V 118μVRMS ± 5V 120μVRMS TYPICAL APPLICATIONS Test Circuit for Single 5V Supply Operation 4.99k AMPLIFIERS A1, A2 AND A3 ALLOW THE USE OF A GROUND-REFERENCED SINGLE-ENDED AC SOURCE AS THE INPUT SIGNAL AND A SEPARATE GROUND-REFERENCED DC SOURCE TO PROVIDE THE INPUT DC COMMON MODE VOLTAGE AMPLIFIERS A4 AND A5 ALLOW MONITORING/MEASURING THE DIFFERENTIAL OUTPUT WITH A SINGLE-ENDED, GROUND-REFERENCED INSTRUMENT 5V 4.99k 2.49k 2 3 – 0.1μF 7 A1 LT®1809 6 + 4 10μF 2.49k 4.99k 5V 4.99k VIN 2 – + – 3 0.1μF 7 +VIN/2 + VCM 1 6 A2 VCM 2.49k 5V +LT1809 –VIN/2 + VCM 2 4 4.99k +IN –IN 10μF +OUT –OUT 8 4.99k 7 2.49k GND V+ + 6 V– SHDN A4 LT1809 6 VOUT (SINGLE ENDED) 5V 1k 0.1μF 4 0.1μF 7 4 0.1μF 4.99k 3 – 2.49k LTC1565-31 3 2 5 5V 0.01μF 19k 5V 2 4.99k 2 – 7 6 A3 2.49k 3 +LT1809 4 – 0.1μF V+/2 1k 3 + 0.1μF 7 A5 LT1812 6 20Ω 2.2μF 4 0.1μF 1565-31 TA08 156531fa 8 LTC1565-31 TYPICAL APPLICATIONS Single-Ended Input/Output Dual Supply Filter 4.99k 5V VIN 1 2 +IN +OUT –IN –OUT 8 4.99k 2 – 7 2.49k 3 + 0.1μF 7 6 LT1809 4 LTC1565-31 3 GND V+ 6 SHDN 5 5V 0.1μF –5V R2 2.49k 0.1μF 4 V– VOUT 0.1μF –5V 1565-31 TA09 0.1μF NOTE: FOR SINGLE 5V SUPPLY CONNECTION, PIN 4 (LTC1565-31) AND PIN 4 (LT1809) SHOULD BE GROUNDED AND RESISTOR R2 SHOULD BE DC BIASED AT APPROXIMATELY 2.5V (SEE TEST CIRCUIT FOR SINGLE SUPPLY OPERATION) A Fully Differential Filter with Adjustable Output Common Mode Voltage VIN+* 1 VIN–* 2 +IN +OUT –IN –OUT 8 VOUT+ 7 VOUT– VOUT(CM) = V– + (V+ – V–)R2 R1 + R2 LTC1565-31 3 GND V+ 6 5V 0.1μF 4 –5V V– SHDN 5 0.1μF –3V ≤ VOUT(CM) ≤ 3V 5V V+ 2 – 3 + R1 7 LT1812 *–3.4V ≤ VIN(CM) ≤ 2.5V VIN(CM) CAN BE EQUAL OR DIFFERENT FROM VOUT(CM) 0.1μF NOTE: FOR SINGLE 5V SUPPLY OPERATION, PIN 4 (LTC1565-31), PIN 4 (LT1812) AND RESISTOR R2 SHOULD BE GROUNDED 6 4 R2 0.1μF V– –5V 0.1μF 100pF 1565-31 TA10 156531fa 9 LTC1565-31 TYPICAL APPLICATIONS Simple Pulse Shaping Circuit for Single 5V Operation, 1.25Mbps 2 Level Data 5V 1.25Mbps DATA 1 2 4.99k +IN –IN +OUT –OUT 8 VOUT+ 7 VOUT– LTC1565-31 3 0.1μF 4 GND – V V+ 6 SHDN 5 5V 500mV/DIV 4.99k 4.99k 0.1μF 15645-31 TA04 250ns/DIV 1565-31 TA05 Simple Pulse Shaping Circuit for Single 5V Operation, 2Mbps (1Msps) 4 Level Data 5V 4.99k 4.99k 1 10k 2 D0 4.99k +OUT –IN –OUT 8 VOUT+ 7 VOUT– LTC1565-31 3 0.1μF +IN 500mV/DIV D1 1Msps DATA 4 GND V– V+ 6 SHDN 5 5V 0.1μF 15645-31 TA06 200ns/DIV 1565-31 TA07 156531fa 10 LTC1565-31 TYPICAL APPLICATIONS Narrowband Cellular Basestation Receiver LTC1565-31 LPF 0° ADC I RF/IF SECTION 90° LO DSP Q 90° LTC1565-31 LPF ADC 1565-31 TA03 PACKAGE DESCRIPTION S8 Package 8-Lead Plastic Small Outline (Narrow .150 Inch) (Reference LTC DWG # 05-08-1610) .189 – .197 (4.801 – 5.004) NOTE 3 .045 ±.005 .050 BSC 8 .245 MIN 7 6 5 .160 ±.005 .150 – .157 (3.810 – 3.988) NOTE 3 .228 – .244 (5.791 – 6.197) .030 ±.005 TYP 1 RECOMMENDED SOLDER PAD LAYOUT .010 – .020 × 45° (0.254 – 0.508) .008 – .010 (0.203 – 0.254) 3 4 .053 – .069 (1.346 – 1.752) .004 – .010 (0.101 – 0.254) 0°– 8° TYP .016 – .050 (0.406 – 1.270) NOTE: 1. DIMENSIONS IN 2 .014 – .019 (0.355 – 0.483) TYP INCHES (MILLIMETERS) 2. DRAWING NOT TO SCALE 3. THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS. MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED .006" (0.15mm) .050 (1.270) BSC SO8 0303 156531fa 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 LTC1565-31 TYPICAL APPLICATION Selective 620kHz CDMA Filter R5 1k 5V R4 1.13k C6 0.1μF R6 1k C3 18pF R1 562Ω R2 562Ω 1 R3 1.24k 2 VIN1 3 C1 150pF R7 562Ω C2 1000pF R8 562Ω 8 U1 LT1813 4 C4 18pF 1 C5 180pF 7 2 6 FGND 3 5 C7 0.1μF R9 1.24k 4 +IN +OUT –OUT –IN U2 LTC1565-31 GND V– R10 1.13k VOUT1 7 V+ 6 SHDN 5 R11 1k VIN2 8 VOUT2 C8 0.1μF 15645-31 TA11 5V R12 1k Frequency Response 0 –6 GAIN (dB) –12 –18 –24 –30 –36 –42 –48 1M 100k FREQUENCY (Hz) 1565 TA12 RELATED PARTS PART NUMBER DESCRIPTION COMMENTS LTC1560-1 1MHz/500kHz Continuous Time, Low Noise, Lowpass Elliptic Filter fCUTOFF = 500kHz or 1MHz LTC1562/LTC1562-2 Universal 8th Order Active RC Filters fCUTOFF(MAX) = 150kHz (LTC1562), fCUTOFF(MAX) = 300kHz (LTC1562-2) LTC1563-2/LTC1563-3 4th Order Active RC Lowpass Filters fCUTOFF(MAX) = 256kHz LTC1569-6/LTC1569-7 Self Clocked, 10th Order Linear Phase Lowpass Filters fCLK/fCUTOFF = 64/1, fCUTOFF(MAX) = 75kHz (LTC1569-6) fCLK/fCUTOFF = 32/1, fCUTOFF(MAX) = 300kHz (LTC1569-7) 156531fa 12 Linear Technology Corporation LT 0809 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 2000