LTC1562 Linear Technology, LTC1562 Datasheet

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... dual 4th order Butterworth lowpass filter with 94dB signal-to-noise ratio from a single 5V power supply. Low level signals can exploit the built-in gain capability of the LTC1562. Varying the gain of a section can achieve a dynamic range as high as 118dB with a 5V supply. ...

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... Maximum Input Voltage – at Any Pin ....................(V – 0.3V Operating Temperature Range LTC1562C................................................ LTC1562I ............................................ – Storage Temperature Range ................. – 150 C Lead Temperature (Soldering, 10 sec).................. 300 C ELECTRICAL CHARACTERISTICS unless otherwise noted. AC specs are for a single 2nd order section, R SYMBOL ...

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... Q = 2.5 0.50 0.25 0 – 0.25 – 0. – 0.75 –1.00 –1.25 –1.50 150 100 110 120 NOMINAL f (kHz) O LTC1562 = 25 C, SHDN pin to logic “low”, A =10k 0.1 100kHz, unless noted MIN TYP = 30pF + 4.5 – 96 – 78 1.5 1.0 2.5 – 100 5 Q Error vs Nominal ...

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... LTC1562 W U TYPICAL PERFOR A CE CHARACTERISTICS Q Error vs Nominal 2.5V 2 – 100 110 120 130 140 150 NOMINAL f (kHz) O 1562 G04 LP Noise vs Nominal 5V (Figure 3, ...

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... small pull-up current source at the SHDN input defaults 16 the LTC1562 to the shutdown state if the SHDN pin is left 15 floating . Therefore, the user must connect the SHDN pin logic “low” (0V for 5V supplies supply) for normal operation of the LTC1562. (This con- 12 vention permits true “ ...

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... LTC1562 PIN FUNCTIONS INV A, INV B, INV C, INV D: Each of the INV pins is a virtual- ground summing point for the corresponding 2nd order section. For each section, external components Z R connect to the INV pin as shown in Figure 3 and Q described further in the Applications Information. Note ...

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... 10k and C = 159pF are internal to the LTC1562 while R2 and R A typical design procedure proceeds from the desired f and Q as follows, using finite-tolerance fixed resistors. First find the ideal R2 value for the desired f R Ideal 2 Then select a practical R2 value from the available finite- tolerance resistors ...

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... THD and other effects. At the other extreme, a lower f limit of 10kHz reflects an arbitrary upper O resistor limit The LTC1562’s MOS input circuitry can accommodate higher resistor values than this, but junction leakage current from the input protection cir- cuitry may cause DC errors. ...

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... still be used with high performance in such situations as OUT INV V1 V2 long as this constraint is followed. 2nd ORDER For an LTC1562 section as in Figure 3, the magnitudes of 1/4 LTC1562 1562 F06 the two outputs V2 and V1 frequency (b) Capacitive Input the ratio ...

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... V across the external impedance Z To accept beyond-the-supply input voltages impor- tant to keep the LTC1562 powered on, not in shutdown mode, and to avoid saturating the output of the 2nd order section that receives the input. If any of these ...

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... INA INB INV 2nd ORDER 1/4 LTC1562 Figure 9. Lowpass “T” Input Circuit The procedure therefore is to begin with the target extra pole frequency f . Determine the series value R P gain requirement. Select a capacitor value C = 1/( greater than ...

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... LTC1562 Demo Board The LTC1562 demo board is assembled with an LTC1562 or LTC1562A in a 20-pin SSOP package and power supply decoupling capacitors. Jumpers on the board configure the LTC1562 for dual or single supply operation and power measures, O shutdown. Pads for surface mount resistors and capaci- tors are provided to build application-specific filters ...

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... R and C values. All resistor values are 1% INA INB IN LTC1562 Amplitude Response 100kHz – 3dB V IN2 0 –10 –20 –30 –40 –50 V IN4 –60 10k 100k 1562 TA05a FREQUENCY (Hz – 3dB – ...

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... C C 100kHz 100kHz 7.26k 100kHz 100kHz 7.097k C C 100kHz 100kHz 17.53k use LTC1562 “A” grade 50kHz. from the formulas above, R21 = R23 = 10k(100kHz/50kHz) IN2 IN4 Amplitude Response BUTTERWORTH 100kHz – 3dB 10k 100k 1M FREQUENCY (Hz) 1562 TA03b ...

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... R24 = 26. IN4 2.2 C 100kHz R = 8.75k use LTC1562 “A” grade. *The resistor values marked with an asterisk (*) in the C and R respectively). IN1 IN4 = 100kHz. The formulas above give R21 = 7.51k, nearest standard 1% value 7.50k 16.5k, already a standard 1% value 18.075k, nearest 1% value 18.2k 11.02k, nearest 1% value 11k. R23 = ...

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... R IN2 C IN1 INV C INV R21 – 5V LTC1562 AGND SHDN R23 INV D INV A R IN4 C IN3 SCHEMATIC INCLUDES PIN NUMBERS FOR 20-PIN PACKAGE. ...

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... The formulas give R21 = R23 = 11.7k, nearest standard 1% value 11.5k. C This value gives 82.46k, nearest 1% value 82.5k. R IN1 IN3 R22 = R24 = 8.66k, already a standard 1% value. This gives 63.45k, nearest 1% value 63.4k. If LTC1562A is used, resistor tolerances tighter than 1% will further Q2 Q4 improve the passband gain accuracy. (Basic ...

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... R IN2 R IN1 20 1 INV C V INV R21 – LTC1562 SHDN AGND R23 INV D INV A R IN4 R IN3 SCHEMATIC INCLUDES PIN NUMBERS FOR 20-PIN PACKAGE. ...

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... R , 5.11k Q2 19 R22, 5.23k 18 16 –5V 0 R24, 5.23k 3.74k OUT 1562 TA11a – LTC1562 Amplitude Response 10 0 – 10 – 20 – 30 – 40 – 50 – 100 FREQUENCY (kHz) 1562 TA09b Amplitude Response 10 0 –10 –20 –30 –40 –50 – ...

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... I resistor values Nello Sevastopoulos, et al. “How to Design High Order Filters with Stopband Notches Using the LTC1562 Quad Operational Filter.” Attached to this data sheet, available on the LTC web site (www.linear-tech.com). R R21 IN2 INV V1 ...

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... N (assuming the internal capacitor value in the Operational Filter (in the LTC1562, 159pF). The configuration of Figure 11 is most useful for a stopband from N notch in a lowpass filter upper stopband notch in a bandpass filter, since the two resistors R replace the input resistor R (Figure resistor-input bandpass section (Figure 6a) built from a second Operational Filter ...

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... and C are the internal precision components (in the 1 LTC1562, 10k and 159pF respectively) as described above in Setting f The configuration of Figure 14 is most useful as a lower stopband notch in a bandpass filter, because the resistors = 0), R and R IN1 IN2 bandpass section made from a second Operational Filter Figure 6a ...

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... DC Gain and C are the internal precision components (in the LTC1562, 10k and 159pF respectively) as described above in Setting f Unlike the notch methods of Figures 11 and 14, notch depth from Figure 16 is inherent, not derived from compo- nent matching. Errors in the R frequency, f Also, the notch frequency, f ...

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... FF2 R IN1 95. INVB IN R 86. IN1 V1B 5.6pF R21 10.7k 3 V2B LTC1562 0 SHDN R23 10k 8 V2A R 71. V1A R 294k IN3 10 INVA C 18pF IN3 R 332k FF4 SCHEMATIC INCLUDES PIN NUMBERS FOR 20-PIN PACKAGE. PINS 4, 7, 14, 17 (NOT SHOWN) ALSO CONNECT TO V ...

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... IN4 SCHEMATIC INCLUDES PIN NUMBERS FOR 20-PIN PACKAGE. PINS 4, 7, 14, 17 (NOT SHOWN) ALSO CONNECT TO V – 40 – 45 – 50 – 55 – 60 – 65 –70 –75 – 80 – 85 – 1562 TA14b LTC1562 C IN3 27pF TO PIN 10 182k R IN3 536k – V 0.1 F 66.5k 301k V OUT 1562 F14a – ...

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... Dual 5th Order Lowpass “Elliptic” Filter C IN2 R R IN1A IN1B 1 V INVB IN1 IN1 V1B R21 3 V2B LTC1562 0 SHDN R21 8 V2A V1A R R IN1A IN1B 10 V INVA IN2 C IN1 C IN2 SCHEMATIC INCLUDES PIN NUMBERS FOR 20-PIN PACKAGE. ...

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... Dimensions in inches (millimeters) unless otherwise noted. G Package 20-Lead Plastic SSOP (0.209) (LTC DWG # 05-08-1640 – 8 0.0256 (0.65) BSC 0.010 – 0.015 (0.25 – 0.38) LTC1562 0.278 – 0.289* (7.07 – 7.33 0.301 – 0.311 (7.65 – 7.90) 0.068 – 0.078 (1.73 – ...

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... FREQUENCY (kHz) 1562 TA16b 4-Level Eye Diagram f = 16kHz, Data Clock = 32kHz C 1562 TA16c 10 s/DIV R22 = R24 340k 34k 84.5k 16.9k 21k 8.45k COMMENTS Clock-Tuned No External Components, SO8 Same Pinout as the LTC1562 1562f LT/TP 0199 4K • PRINTED IN USA LINEAR TECHNOLOGY CORPORATION 1998 ...