LS404C

LS404CN STMICROELECTRONICS | Alldatasheet

Document overview

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Technical content

■ SINGLE OR SPLIT SUPPLY OPERATION ■ LOW POWER CONSUMPTION ■ SHORT CIRCUIT PROTECTION ■ LOW DISTORTION, LOW NOISE ■ HIGH GAIN-BANDWIDTH PRODUCT ■ HIGH CHANNEL SEPARATION

DESCRIPTION

The LS404 is a high performance quad operation- al amplifier with frequency and phase compensa- tion built into the chip. The internal phase compen- sation allows stable operation as voltage follower in spite of its high Gain-Bandwidth Product. The circuit presents very stable electrical charac- teristics over the entire supply voltage range, and is particularly intended for professional and tele- com applications (active filter, etc). The patented input stage circuit allows small input signal swings below the negative supply voltage and prevents phase inversion when the inputs are over drivers. ORDER CODE N = Dual in Line Package (DIP) D = Small Outline Package (SO) - also available in Tape & Reel (DT) PIN CONNECTIONS (top view) Part Number Temperature Range Package ND LS404C 0°C, +70°C •• Example : LS204CN N DIP14 (Plastic Package) D SO14 (Plastic Micropackage) Inverting Input 2 Non-inverting Input 2 Non-inverting Input 1 CCV -CCV Output 3 Output 4 Non-inverting Input 4 Inverting Input 4 Non-inverting Input 3 Inverting Input 3 Output 1 Inverting Input 1 Output 2 HIGH PERFORMANCE QUAD OPERATIONAL AMPLIFIER November 2001 LS404

SCHEMATIC DIAGRAM (1/4 LS404) ABSOLUTE MAXIMUM RATINGS Inverting input Non-inverting input Output Symbol Parameter Value Unit VCC Supply voltage ±18 V Vi Input Voltage Positive Negative +V CC -VCC - 0.5 V Vid Differential Input Voltage ±(VCC -1) V Toper Operating Temperature Range LS204C LS204I LS204I 0 to +70 -40 to +105 -55 to +125 Ptot Power Dissipation at Tamb = 70°C 400 mW Tstg Storage Temperature Range -65 to +150 °C

ELECTRICAL CHARACTERISTICS

VCC = ±15V, Tamb = 25°C (unless otherwise specified) Symbol Parameter LS404I - LS404M LS404C Unit Icc Supply Current 1.3 2 1.5 3 mA Iib Input Bias Current 50 200 100 300 nA R i Input Resistance (f = 1kHz) 1 1 M Ω Vio Input Offset Voltage (Rs ≤ 10kΩ ) 0.7 2.5 0.5 5 mV DV io Input Offset Voltage Drift (Rs ≤ 10kΩ ) Tmin < Top < Tmax 55 µV/°C Iio Input Offset Current 10 40 20 80 nA DIio Input Offset Current Drift Tmin < Top < Tmax 0.08 0.1 nA/°C Ios Output Short-circuit Current 23 23 mA Avd Large Signal Voltage Gain R L = 2kΩ , VCC = ±15V VCC = ±4V 90 100 86 100 dB GBP Gain Bandwith Product f =100kHz, RL = 2k, CL = 100pF 1.8 3 1.5 2.5 MHz en Equivalent Input Noise Voltage f = 1kHz, R s = 50Ω R s = 1kΩ R s = 10kΩ 15 10 THD Total Harmonic Distortion Unity Gain R L = 2kΩ, Vo = 2Vpp f = 1kHz f = 20kHz 0.01 0.03 0.4 0.01 0.03 ±Vopp Output Voltage Swing R L = 2kΩ , VCC = ±15V VCC = ±4V ±13 ±13 V Vopp Large Signal Voltage Swing f = 10kHz, RL = 10kΩ R L = 1kΩ Vpp SR Slew Rate (RL = 2kΩ , unity gain) 0.8 1.5 1 V/ µs SVR Supply Voltage Rejection Ratio Vic = 1V, f = 100Hz 90 94 86 90 dB CMR Common Mode Rejection Ratio Vic = 10V 90 94 86 90 dB Vo1/Vo2 Channel Separation (f= 1kHz) 100 120 120 dB nV Hz

APPLICATION INFORMATION: Active low-pass filter BUTTERWORTH The Butterworth is a "maximally flat" amplitude re- sponse filter (figure 10) Butterworth filters are used for filtering signals in data acquisition sys- tems to prevent aliasing errors in samples-data applications and for general purpose low-pass fil- tering. The cut-off frequency Fc, is the frequency at which the amplitude response is down 3dB. The attenu- ation rate beyond the cutoff frequency is n6 dB per octave of frequency where n is the order (number of poles) of the filter. Other characteristics : ❑ Flattest possible amplitude response ❑ Excellent gain accuracy at low frequency end of passband BESSEL The Bessel is a type of “linear phase” filter. Be- cause of their linear phase characteristics, these filters approximate a constant time delay over a limited frequency range. Bessel filters pass tran- sient 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. The maximum phase shift is radians 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. The following table can be used to obtain the -3dB frequency of the filter. Other characteristics : ❑ 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 ei- ther Bessel ro Butterworth at the expense of ripple in the passband (figure 11). Chebyschev filters are normally designed with peak-to-peak ripple values from 0.2dB to 2dB. 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 specificed maximum ripple band and enters the stop band. Other characteristics : ❑ Greater selectivity ❑ Very non-linear phase response ❑ High overshoot response to step inputs The table below shows the typical overshoot and setting time response of the low pass filters to a step input. Design of 2nd order active low pass filter (Sallen and Key configuration unity gain op-amp) nπ–

2 Pole 4 Pole 6 Pole 8 Pole

-3dB Frequency 0.77fc 0.67fc 0.57fc 0.50fc Number of Poles Peak Overshoot Settling Time (% of final value) % Overshoot ±1% ±0.1% ±0.01% Butterworth 1.1Fc sec. 1.7/fc 2.4/fc 3.1/fc 1.7Fc sec. 2.8/fc 3.9S/fc 5.1/fc 1.9Fc sec. 3.8/fc 5.0S/fc 7.1/fc Bessel 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) 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) 1.6/fc 4.8/fc 8.2/fc 11.6/fc 2.7/fc 8.4/fc 16.3/fc 24.8/fc

In the circuit of figure 14, for fc = 3.4kHz and Ri = R1 = R2 = R3 = 10kΩ , we obtain: The attenuation of the filter is 30dB at 6.8kHz and better than 60dB at 15kHz. The same method, referring to table 2 and figure 15 is used to design high-pass filter. In this case the damping factor is found by taking the recipro- cal of the numbers in table 2. For fc = 5kHz and Ci = C1 = C2 = C3 = 1nF we obtain: Table 2 : Damping Factor for Low-pass Butterworth Filters Figure 15 : 5th Order High-pass Filter (Butterworth) with Unity Gain configuration Ci = 1.354 1 R---- 1 C1 = 0.421 1 R---- 1 C2 = 1.753 1 R---- 1 C3 = 0.309 1 R---- 1 C4 = 3.325 1 R---- 1 Ri = 1 C---- 1 R1 = 1 C---- 1 R2 = 1 C---- 1 R3 = 1 C---- 1 R4 = 1 C---- 1 Order Ci C1 C2 C3 C4 C5 C6 C7 C8 2 0.707 1.41 3 1.392 0.202 3.54 4 0.92 1.08 0.38 2.61 C2C1 R1Ri Ci

Figure 16 : Multiple Feedback 8-pole Bandpass Filter Figure 17 : Six pole 355Hz Low-pass Filter (chebychev type) This is a - pole Chebychev type with ±0.25dB ripple in the passband. A decoupling stage is used to avoid the influence of the input impedance on the filter’s characteristics. The attenuation is about 55dB at 710Hz and reaches 80dB at 1065Hz. the in band attenuation is limited in practise to the ±0.25dB ripple and does not exceed 0.5dB at 0.9fc. Figure 18 : Subsonic Filter (Gv = 0dB) Figure 19 : High Cut filter (Gv = 0dB) IN

0.1 F/c109

LS404 ¼ LS404 ¼ LS404 ¼ LS404 R10

220 F/c109

0.22 F/c109

56kΩ 0.47 Fµ 10kΩ 10kΩ 86.1nF 161nF 10kΩ 10kΩ 220nF 16.3nF 10kΩ 10kΩ 60nF 3.54nF 10kΩ CC 22kΩ Vout Fc (Hz) 100 C ( F) 0.68 0.47 0.33 0.22 0.10 µ 10kΩ Vin C1 Vout 10kΩ 3 Fc (Hz) C1 (nF) 3.9 2.2 1.2 0.68 C2 (nF) 6.8 4.7 2.2 1.5

14 PINS - PLASTIC PACKAGE

a1 0.51 0.020 B 1.39 1.65 0.055 0.065 b 0.5 0.020 b1 0.25 0.010 D 20 0.787 E 8.5 0.335 e 2.54 0.100 e3 15.24 0.600 F 7.1 0.280 i 5.1 0.201 L 3.3 0.130 Z 1.27 2.54 0.050 0.100

14 PINS - PLASTIC MICROPACKAGE (SO)

A 1.75 0.069 a1 0.1 0.2 0.004 0.008 a2 1.6 0.063 b 0.35 0.46 0.014 0.018 b1 0.19 0.25 0.007 0.010 C 0.5 0.020 c1 45° (typ.) D (1) 8.55 8.75 0.336 0.344 E 5.8 6.2 0.228 0.244 e 1.27 0.050 e3 7.62 0.300 F (1) 3.8 4.0 0.150 0.157 G 4.6 5.3 0.181 0.208 L 0.5 1.27 0.020 0.050 M 0.68 0.027 S 8° (max.) Note : (1) D and F do not include mold flash or protrusions - Mold flash or protrusions shall not exceed 0.15mm (.066 inc) ONLY FOR DATA BOOK. D M F 1 7 b e E LG C c1 A b1s Information furnished is believed to be accurate and reliable. However, STMicroelectronics assumes no responsibility for the consequences of use of such information nor for any infringement of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of STMicroelectronics. Specifications mentioned in this publication are subject to change without notice. This publication supersedes and replaces all information previously supplied. STMicroelectronics products are not authorized for use as critical components in life support devices or systems without express written approval of STMicroelectronics. © The ST logo is a registered trademark of STMicroelectronics © 2001 STMicroelectronics - Printed in Italy - All Rights Reserved STMicroelectronics GROUP OF COMPANIES Australia - Brazil - Canada - China - Finland - France - Germany - Hong Kong - India - Israel - Italy - Japan - Malaysia Malta - Morocco - Singapore - Spain - Sweden - Switzerland - United Kingdom - United States © http://www.st.com