1/11
SINGLE OR SPLIT SUPPLY OPERATION
LOW POWE R CONSUMPTION
SHORT CIRCUIT PROTECTION
LOW DISTORTION, LOW NOI SE
HIGH GAIN-BANDWIDTH PRODUCT
HIGH CHANNEL SEPARATION
DESCRIPTION
The LS404 is a high performance quad operation-
al am plifier with freq uency and phas e compe nsa-
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 (ac tive filter, etc).
The patented input stage circuit allows small i nput
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 C, +70°C ••
LS404I -40°C, +105 °C ••
LS404M -55°C, +125 °C ••
Example : LS204CN
N
DIP14
(Plastic Package)
D
SO14
(Plastic Micro packa ge)
Inverting Input 2
Non-inverting Input 2
Non-inverting Input 1
CC
V -
CC
V
1
2
3
4
8
5
6
7
9
10
11
12
13
14
+
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
LS404
2/11
SCHEMAT IC DIAGRAM (1/4 LS404)
ABSOLUTE MAXIMUM RATINGS
Inverting input Non-inverting
input
Output
Symbol Parameter Value Unit
VCC Supply voltage ±18 V
ViInput Voltage Positive
Negative +VCC
-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 °C
Ptot Power Dissipation at Tamb = 70°C 400 mW
Tstg Storage Temperature Range -65 to +150 °C
LS404
3/11
ELECTRICAL CHARACTERISTICS
VCC = ±15V, T amb = 25°C (unless otherwise specified)
Symbol Parameter LS404I - LS404M LS404C Unit
Min. Typ. Max. Min. Typ. Max.
Icc Supply Current 1.3 2 1.5 3 mA
Iib Input Bias Current 50 200 100 300 nA
RiInput Resistance (f = 1kHz) 1 1 M
Vio Input Offset Voltage (Rs 10k)0.7 2.5 0.5 5 mV
DVio Input Offset Voltage Drift (Rs 10k)
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
RL = 2k, VCC = ±15V
VCC = ±4V 90 100
95 86 100
95 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,
Rs = 50
Rs = 1k
Rs = 10k
8
10
18
15 10
12
20
THD
Total Harmonic Distortion
Unity Gain
RL = 2kΩ, Vo = 2Vpp
f = 1kHz
f = 20kHz 0.01
0.03 0.4 0.01
0.03
%
±Vopp
Output Voltage Swing
RL = 2k, VCC = ±15V
VCC = ±4V ±13 ±3 ±13 ±3 V
Vopp
Large Signal Voltage Swing
f = 10kHz, RL = 10k
RL = 1k22
20 22
20 Vpp
SR Slew Rate (RL = 2k, 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
------------
LS404
4/11
LS404
5/11
LS404
6/11
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 ge neral purpose l ow-pass fil-
tering.
The cut-off frequency Fc, is the frequency at which
the am plitude res ponse i s down 3dB. The atte nu-
ation rate beyond the cutoff frequency is n6 dB per
octave of frequen cy where n is t he orde r (num ber
of poles) of the filter.
Other characteristics :
Flattest possible amplitude response
Excellent gain accuracy at low fr e quency
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 us ed to provide time delays for low
pass filtering of modulated waveforms and as a
“running average” type filter.
The ma ximum phase s hift is radians where
n is the order (number of poles) of the filter. The
cut-off frequency is defined as the frequency at
which the phase shif t 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 t he -3dB
frequen cy of the filter.
Other characteristics :
Selectivity not as great as Chebyschev or
Butterworth
Very little overshoot response to step inputs
Fast ri se 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
attenuat ion abo ve the cut-off frequency.
The cut-off frequ ency is d efined as the f re quency
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 respons e of the low pass filters to a step
input .
Design of 2n d order acti ve low pas s f ilt er (S al l en and Key confi gurat i on uni ty ga i n op-amp)
n
π2
-----------
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
2
4
6
8
4
11
14
14
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
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
-
-
-
LS404
7/11
Fixed R = R1 = R2, we have (see figure 13)
Fi gure 13 : Filter Configuration
Three param eters are needed to charact erize the
frequen cy an d phas e respons e o f a 2n d order ac-
tive filter: the gain (Gv), the damping factio (ξ) or
the Q fac tor (Q = 2 ξ)1), and the c uttoff frequenc y
(fc).
The higher order response are obtained with a se-
ries 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 1).
Table 1
EXAMP LE
Fi gure 14 : 5th Order Low-pass Filter (Butterworth) with Unity Gain configuration
C
1 = 1
R
---- ζ
ω
c
-------
C
2 = 1
R
---- 1
ξω
c
-----------
C2
R2R1
Vin
C1 Vout
Filter Response ξQ Cuttoff Frequency fc
Bessel Frequency at which Phase Shift is -90°C
Butterworth Frequency at which Gv = -3dB
Chebyschev Frequency at which the amplitude response
passes through specified max. ripple band and
enters the stop bank.
3
2
------- 1
3
-------
2
2
------- 1
2
-------
2
2
------- 1
2
-------
C2
R2R1
C1
Ri
Ci
C4
R4R3
C3
LS404
8/11
In the circuit of figure 14, for fc = 3.4kHz and Ri =
R1 = R2 = R3 = 10k, we obta in:
The at tenuation 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 d amping facto r is fo und 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 Butterwort h Filters
Fi gure 15 : 5th Order High-pass Filter (Butterworth) with Unity Gain configuration
Ci = 1.354 1
R
---- 1
2π
fc
------------ = 6.33nF
C1 = 0.421 1
R
---- 1
2π
fc
------------ = 1.97nF
C2 = 1.753 1
R
---- 1
2π
fc
------------ = 8.20nF
C3 = 0.309 1
R
---- 1
2π
fc
------------ = 1.45nF
C4 = 3.325 1
R
---- 1
2π
fc
------------ = 15.14nF
Ri = 1
0.354
--------------- 1
C
---- 1
2π
fc
------------ = 25.5k
R1 = 1
0.421
--------------- 1
C
---- 1
2π
fc
------------ = 75.6k
R2 = 1
1.753
--------------- 1
C
---- 1
2π
fc
------------ = 18.2k
R3 = 1
0.309
--------------- 1
C
---- 1
2π
fc
------------ = 103k
R4 = 1
3.325
--------------- 1
C
---- 1
2π
fc
------------ = 9.6k
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
5 1.354 0.421 1.75 0.309 3.235
6 0.966 1.035 0.707 1.414 0.259 3.86
7 1.336 0.488 1.53 0.623 1.604 0.222 4.49
8 0.98 1.02 0.83 1.20 0.556 1.80 0.195 5.125
R2
C2
C1
R1
Ri
Ci
R4
C3
R3
C4
LS404
9/11
Fi gure 16 : Multiple Feed back 8-pole Bandpass Filter
Fi gure 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 0.5 dB at 0 .9fc.
Fi gure 18 : Subsonic Filter (Gv = 0dB)
Fi gure 19 : High Cut filter (Gv = 0dB)
IN C1
0.1 Fm
R1 C2
R4
Vcc
R2
R3 22kW
22kW
1
2
34
R5
C3
C4
0.1 Fm
¼
LS404 ¼
LS404 ¼
LS404 ¼
LS404
R6
R7
C5
C6
R8
R9
R10
C7
220 Fm
C8
C9
R11
7
11
5
6
8
9
10
R12
R13
C10
C11
R14
14
13
12 Out
C12
0.1 Fm
C13
0.22 Fm
56k
0.47 Fµ10k10k
86.1nF
161nF
10k10k
220nF
16.3nF
10k10k
60nF
3.54nF
10k
C
C
22k
Vout
Fc (Hz)
15
22
30
55
100
C ( F)
0.68
0.47
0.33
0.22
0.10
µ
C2
10k
Vin
C1 Vout
10k3
21
Fc (Hz)
3
5
10
15
C1 (nF)
3.9
2.2
1.2
0.68
C2 (nF)
6.8
4.7
2.2
1.5
LS404
10/11
PACKAGE MECHANICAL DATA
14 PINS - PLASTIC PACKAGE
Dimensions Millimeters Inches
Min. Typ. Max. Min. Typ. Max.
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
LS404
11/11
PACKAGE MECHANICAL DATA
14 PINS - PLASTIC MICROPACKAGE (SO)
Dimensions Millimeters Inches
Min. Typ. Max. Min. Typ. Max.
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.
DM
F
14
17
8
be3 eE
LG
C
c1
A
a2
a1
b1
s
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 l i cens e is gra nte d by imp lication or oth erwise under a ny patent or patent rights of STMicroelec tronics. Spec ificat ions
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 with out expres s written approval of STMicroelec tronics .
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