LS204 High performance dual operational amplifier Features ■ Low power consumption ■ Short-circuit protection ■ Low distortion, low noise ■ High gain-bandwidth product ■ High channel separation N DIP8 (Plastic package) Description The LS204 is a high performance dual operational amplifier with frequency and phase compensation built into the chip. The internal phase compensation allows stable operation as voltage follower in spite of its high gain-bandwidth product. D SO-8 (Plastic micro package) The circuit presents very stable electrical characteristics over the entire supply voltage range, and is particularly intended for professional and telecom applications (such as active filtering). June 2008 Pin connections (top view) Rev 2 Output 1 1 Inverting input 1 2 - Non-inverting input 1 3 + V CC - 4 8 VCC+ 7 Output 2 - 6 Inverting input 2 + 5 Non-inverting input 2 1/16 www.st.com 16 Circuit schematics 1 Circuit schematics Figure 1. Schematic diagram (1/2 LS204) 2/16 LS204 LS204 Absolute maximum ratings and operating conditions 2 Absolute maximum ratings and operating conditions Table 1. Absolute maximum ratings Symbol Value Unit ±18 V ±VCC V ±(VCC-1) V Rthja Thermal resistance junction to ambient(4) SO-8 DIP8 125 85 °C/W Rthjc Thermal resistance junction to case(4) SO-8 DIP8 40 41 °C/W VCC Vi Vid Parameter Supply voltage(1) Input voltage (2) (3) Differential input voltage Output short-circuit duration(5) Tj Tstg Junction temperature Storage temperature range HBM: human body ESD Infinite 150 °C -65 to +150 °C 2 kV 200 V 1.5 kV model(6) MM: machine model (7) (8) CDM: charged device model 1. All voltage values, except differential voltage, are with respect to the zero reference level (ground) of the supply voltages where the zero reference level is the midpoint between VCC+ and VCC-. 2. The magnitude of the input voltage must never exceed the magnitude of the supply voltage or 15 volts, whichever is less. 3. Differential voltages are the non-inverting input terminal with respect to the inverting input terminal. 4. Short-circuits can cause excessive heating and destructive dissipation. Values are typical. 5. The output may be shorted to ground or to either supply. Temperature and/or supply voltages must be limited to ensure that the dissipation rating is not exceeded. 6. Human body model: A 100 pF capacitor is charged to the specified voltage, then discharged through a 1.5 kΩ resistor between two pins of the device. This is done for all couples of connected pin combinations while the other pins are floating. 7. Machine model: A 200 pF capacitor is charged to the specified voltage, then discharged directly between two pins of the device with no external series resistor (internal resistor < 5 Ω). This is done for all couples of connected pin combinations while the other pins are floating. 8. Charged device model: all pins and the package are charged together to the specified voltage and then discharged directly to the ground through only one pin. This is done for all pins. Table 2. Operating conditions Symbol Parameter VCC Supply voltage Vicm Common mode input voltage range Toper Operating free-air temperature range LS204C LS204I Unit 6 to 30 V VDD+1.5 to VCC-1.5 V 0 to +70 -40 to +105 °C 3/16 Electrical characteristics LS204 3 Electrical characteristics Table 3. Electrical characteristics at VCC = ±15 V, Tamb = +25° C (unless otherwise specified) LS204I Symbol LS204C Parameter Unit Min. Typ. Max. Min. Typ. Max. ICC Supply current 0.7 1.2 0.8 1.5 mA Iib Input bias current Tmin < Tamb < Tmax 50 150 300 100 300 700 nA Ri Input resistance (F = 1kHz) 1 Vio Input offset voltage (Rs ≤ 10kΩ) Tmin < Tamb < Tmax DVio Iio 0.5 Input offset voltage drift (Rs ≤ 10kΩ) Tmin < Tamb < Tmax 5 Input offset current Tmin < Tamb < Tmax 5 DIio Input offset current drift Tmin < Tamb < Tmax Ios Output short-circuit current Avd Large signal voltage gain Tmin < Tamb < Tmax RL = 2kΩ, VCC = ±15V RL = 2kΩ, VCC = ±4V 90 100 95 Gain bandwidth product (F =100kHz) 1.8 3 GBP en Equivalent input noise voltage F = 1kHz, Rs = 100Ω Rs = 50Ω Rs = 1kΩ Rs = 10kΩ THD Total harmonic distortion (F = 1kHz, Av = 20dB, RL = 2kΩ, Vo = 2Vpp) ±Vopp Output voltage swing RL = 2kΩ, VCC = ±15V RL = 2kΩ, VCC = ±4V 1 2.5 3.5 0.5 MΩ 3.5 5 5 20 40 12 mV µV/°C 50 100 nA 0.08 0.1 nA/°C 23 23 mA 86 100 95 dB 1.5 2.5 MHz 8 10 18 10 12 20 nV -----------Hz 0.03 0.03 % ±13 ±13 V ±3 ±3 28 28 Vpp 1.5 1 V/µs Vopp Large signal voltage swing RL = 10kΩ, F= 10kHz SR Slew rate (RL = 2kΩ, unity gain) 0.8 SVR Supply voltage rejection ratio Tmin < Tamb < Tmax 90 86 dB CMR Common mode rejection ratio Vic = ±10V Tmin < Tamb < Tmax 90 86 dB Vo1/Vo2 Channel separation (F= 1 kHz) 4/16 100 120 120 dB LS204 Electrical characteristics Figure 2. Supply current versus supply voltage Figure 3. Figure 4. Output short circuit current versus Figure 5. ambient temperature Open loop frequency and phase response Figure 6. Output loop gain versus ambient temperature Supply voltage rejection versus frequency Figure 7. Supply current versus ambient temperature 5/16 Electrical characteristics Figure 8. Large signal frequency response LS204 Figure 9. Output voltage swing versus load resistance Figure 10. Total input noise versus frequency Figure 11. Amplitude response Figure 12. Amplitude response ( ±1dB ripple) 6/16 LS204 Application information for active low-pass filters 4 Application information for active low-pass filters 4.1 Butterworth The Butterworth is a "maximally flat" amplitude response filter (Figure 11). Butterworth filters are used for filtering signals in data acquisition systems to prevent aliasing errors in samples-data applications and for general purpose low-pass filtering. The cut-off frequency, Fc, is the frequency at which the amplitude response is down 3 dB. The attenuation rate beyond the cut-off frequency is n6 dB per octave of frequency, where n is the order (number of poles) of the filter. Other characteristics: 4.2 ● Flattest possible amplitude response ● Excellent gain accuracy at low frequency end of passband Bessel The Bessel is a type of “linear phase” filter. Because of their linear phase characteristics, these filters approximate a constant time delay over a limited frequency range. Bessel filters pass transient waveforms with a minimum of distortion. They are also used to provide time delays for low pass filtering of modulated waveforms and as a “running average” type filter. n π radians, The maximum phase shift is –---------2 where n is the order (number of poles) of the filter. The cut-off frequency, Fc, is defined as the frequency at which the phase shift is one half of this value. For accurate delay, the cut-off frequency should be twice the maximum signal frequency. Table 4 can be used to obtain the -3 dB frequency of the filter. Table 4. -3 dB frequency of the filter -3 dB frequency 2 Poles 4 Poles 6 Poles 8 Poles 0.77 Fc 0.67 Fc 0.57 Fc 0.50 Fc Other characteristics: 4.3 ● Selectivity not as great as Chebyschev or Butterworth ● Very little overshoot response to step inputs ● Fast rise time Chebyschev Chebyschev filters have greater selectivity than either Bessel or Butterworth at the expense of ripple in the passband (Figure 12). Chebyschev filters are normally designed with peak-to-peak ripple values from 0.2 dB to 2 dB. 7/16 Application information for active low-pass filters LS204 Increased ripple in the passband allows increased attenuation above the cut-off frequency. The cut-off frequency is defined as the frequency at which the amplitude response passes through the specified maximum ripple band and enters the stop band. Other characteristics: ● Greater selectivity ● Very non-linear phase response ● High overshoot response to step inputs Table 5 shows the typical overshoot and setting time response of the low pass filters to a step input. Table 5. Overshoot and setting time response of low pass filters to step input Number of poles 4.4 Peak overshoot % Overshoot ±1% ±0.1% ±0.01% 1.1Fc sec. 1.7Fc sec. 1.9Fc sec. 2.8/Fc 3.8/Fc 1.7/Fc 2.4/Fc 3.9S/Fc 5.0S/Fc 3.1/Fc 5.1/Fc 7.1/Fc Butterworth 2 4 6 8 4 11 14 14 Bessel 2 4 6 8 0.4 0.8 0.6 0.1 0.8/Fc 1.0/Fc 1.3/Fc 1.6/Fc 1.4/Fc 1.8/Fc 2.1/Fc 2.3/Fc 1.7/Fc 2.4/Fc 2.7/Fc 3.2/Fc Chebyschev (ripple ±0.25dB) 2 4 6 8 11 18 21 23 1.1/Fc 3.0/Fc 5.9/Fc 8.4/Fc 1.6/Fc 5.4/Fc 10.4/Fc 16.4/Fc - Chebyschev (ripple ±1dB) 2 4 6 8 21 28 32 34 1.6/Fc 4.8/Fc 8.2/Fc 11.6/Fc 2.7/Fc 8.4/Fc 16.3/Fc 24.8/Fc - Design of 2nd order active low pass filter (Sallen and Key configuration unity gain op-amp) For fixed R = R1 = R2, we have (see Figure 13): 1 ζ C1 = ---- -----R ωc 1 1 C2 = ---- ----------R ξ ωc 8/16 Settling time (% of final value) LS204 Application information for active low-pass filters Figure 13. Filter configuration C2 R1 R2 Vin Vout C1 Three parameters are needed to characterize the frequency and phase response of a 2nd order active filter: ● the gain (Gv), ● the damping factor (ξ ) or the Q factor (Q = 2 ξ )1), ● the cut-off frequency (Fc). The higher order response is obtained with a series of 2nd order sections. A simple RC section is introduced when an odd filter is required. The choice of ξ (or Q factor) determines the filter response (see Table 6). Table 6. Filter response to ξ or Q factor Filter response ξ Q Bessel 3 ------2 1 ------3 Frequency at which phase shift is -90°C Butterworth 2 ------2 1 ------2 Frequency at which Gv = -3 dB Chebyschev 2 ------2 1 ------2 Cut-off frequency (Fc) Frequency at which the amplitude response passes through specified max. ripple band and enters the stop bank. 9/16 Application information for active low-pass filters 4.5 LS204 Example Figure 14. 5th order low-pass filter (Butterworth) with unity gain configuration C2 Ri R1 C4 R2 R3 Ci R4 C1 C3 In the circuit of Figure 14, for Fc = 3.4 kHz and Ri = R1 = R2 = R3 = 10 kW, we obtain: 1 1 Ci = 1.354 ---- ------------ = 6.33nF R 2πfc 1 1 C1 = 0.421 ---- ------------ = 1.97nF R 2πfc 1 1 C2 = 1.753 ---- ------------ = 8.20nF R 2πfc 1 1 C3 = 0.309 ---- ------------ = 1.45nF R 2πfc 1 1 C4 = 3.325 ---- ------------ = 15.14nF R 2πfc The attenuation of the filter is 30 dB at 6.8 kHz and better than 60 dB at 15 kHz. The same method, referring to Table 7 and Figure 15 is used to design high-pass filters. In this case the damping factor is found by taking the reciprocal of the numbers in Table 7. For Fc = 5 kHz and Ci = C1 = C2 = C3 = 1 nF we obtain: 1 1 1 Ri = --------------- ---- ------------ = 25.5kΩ 0.354 C 2πfc 1 1 1 R1 = --------------- ---- ------------ = 75.6kΩ 0.421 C 2πfc 1 1 1 R2 = --------------- ---- ------------ = 18.2kΩ 1.753 C 2πfc 1 1 1 R3 = --------------- ---- ------------ = 103kΩ 0.309 C 2πfc 1 1 1 R4 = --------------- ---- ------------ = 9.6kΩ 3.325 C 2πfc Figure 15. 5th order high-pass filter (Butterworth) with unity gain configuration R2 Ci C1 R4 C2 C3 Ri 10/16 C4 R1 R3 LS204 Application information for active low-pass filters Table 7. Damping factor for low-pass Butterworth filters Order Ci 2 3 1.392 4 5 1.354 6 7 8 1.336 C1 C2 C3 C4 0.707 1.41 0.202 3.54 0.92 C5 C6 1.08 0.38 2.61 0.421 1.75 0.309 3.235 0.966 1.035 0.707 1.414 0.259 3.86 0.488 1.53 0.623 1.604 0.222 4.49 0.98 1.02 0.83 1.20 0.556 1.80 C7 C8 0.195 5.125 11/16 Package information 5 LS204 Package information In order to meet environmental requirements, STMicroelectronics offers these devices in ECOPACK® packages. These packages have a lead-free second level interconnect. The category of second level interconnect is marked on the package and on the inner box label, in compliance with JEDEC Standard JESD97. The maximum ratings related to soldering conditions are also marked on the inner box label. ECOPACK is an STMicroelectronics trademark. ECOPACK specifications are available at: www.st.com. 12/16 LS204 5.1 Package information DIP8 package information Figure 16. DIP8 package mechanical drawing Table 8. DIP8 package mechanical data Dimensions Ref. Millimeters Min. Typ. A Inches Max. Min. Typ. 5.33 Max. 0.210 A1 0.38 0.015 A2 2.92 3.30 4.95 0.115 0.130 0.195 b 0.36 0.46 0.56 0.014 0.018 0.022 b2 1.14 1.52 1.78 0.045 0.060 0.070 c 0.20 0.25 0.36 0.008 0.010 0.014 D 9.02 9.27 10.16 0.355 0.365 0.400 E 7.62 7.87 8.26 0.300 0.310 0.325 E1 6.10 6.35 7.11 0.240 0.250 0.280 e 2.54 0.100 eA 7.62 0.300 eB L 10.92 2.92 3.30 3.81 0.430 0.115 0.130 0.150 13/16 Package information 5.2 LS204 SO-8 package information Figure 17. SO-8 package mechanical drawing Table 9. SO-8 package mechanical data Dimensions Ref. Millimeters Min. Typ. A Max. Min. Typ. 1.75 0.25 Max. 0.069 A1 0.10 A2 1.25 b 0.28 0.48 0.011 0.019 c 0.17 0.23 0.007 0.010 D 4.80 4.90 5.00 0.189 0.193 0.197 E 5.80 6.00 6.20 0.228 0.236 0.244 E1 3.80 3.90 4.00 0.150 0.154 0.157 e 0.004 0.010 0.049 1.27 0.050 h 0.25 0.50 0.010 0.020 L 0.40 1.27 0.016 0.050 k 1° 8° 1° 8° ccc 14/16 Inches 0.10 0.004 LS204 6 Ordering information Ordering information Table 10. Order codes Order code Temperature range Package Packing Marking DIP8 Tape LS204CN SO-8 Tape or Tape & reel 204C DIP8 Tape LS204IBN SO-8 Tape or Tape & reel 204I SO-8 (Automotive grade) Tape or Tape & reel 204IYD LS204CN 0°C, +70°C LS204CD LS204CDT LS204IN LS204ID LS204IDT -40°C, +105°C LS204IYD(1) LS204IYDT(1) 1. Qualification and characterization according to AEC Q100 and Q003 or equivalent, advanced screening according to AEC Q001 & Q 002 or equivalent are on-going. 7 Revision history Table 11. Document revision history Date Revision Changes 29-Nov-2001 1 Initial release. 4-Jun-2008 2 Updated document format. Added automotive grade order codes. 15/16 LS204 Please Read Carefully: Information in this document is provided solely in connection with ST products. STMicroelectronics NV and its subsidiaries (“ST”) reserve the right to make changes, corrections, modifications or improvements, to this document, and the products and services described herein at any time, without notice. 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