STMICROELECTRONICS LS404CN

LS404
HIGH PERFORMANCE
QUAD OPERATIONAL AMPLIFIER
■
■
■
■
■
■
SINGLE OR SPLIT SUPPLY OPERATION
LOW POWER CONSUMPTION
SHORT CIRCUIT PROTECTION
LOW DISTORTION, LOW NOISE
HIGH GAIN-BANDWIDTH PRODUCT
N
DIP14
(Plastic Package)
HIGH CHANNEL SEPARATION
DESCRIPTION
The LS404 is a high performance quad 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
SO14
(Plastic Micropackage)
The circuit presents very stable electrical characteristics over the entire supply voltage range, and
is particularly intended for professional and telecom 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.
14 Output 4
Output 1 1
ORDER CODE
Package
Part Number Temperature Range
LS404C
0°C, +70°C
LS404I
-40°C, +105°C
LS404M
-55°C, +125°C
Example : LS204CN
PIN CONNECTIONS (top view)
N
D
•
•
•
•
•
•
Inverting Input 1 2
-
-
13 Inverting Input 4
+
+
12 Non-inverting Input 4
Non-inverting Input 1
3
V CC +
4
Non-inverting Input 2
5
+
+
10 Non-inverting Input 3
Inverting Input 2
6
-
-
9
Inverting Input 3
Output 2
7
8
Output 3
11 VCC -
N = Dual in Line Package (DIP)
D = Small Outline Package (SO) - also available in Tape & Reel (DT)
November 2001
1/11
LS404
SCHEMATIC DIAGRAM (1/4 LS404)
Non-inverting
input
Inverting input
Output
ABSOLUTE MAXIMUM RATINGS
Symbol
VCC
Parameter
Supply voltage
Vi
Input Voltage
Vid
Differential Input Voltage
Operating Temperature Range
Toper
2/11
Ptot
Power Dissipation at Tamb = 70°C
Tstg
Storage Temperature Range
Positive
Negative
LS204C
LS204I
LS204I
Value
Unit
±18
V
+VCC
-VCC - 0.5
V
±(VCC -1)
V
0 to +70
-40 to +105
-55 to +125
°C
400
mW
-65 to +150
°C
LS404
ELECTRICAL CHARACTERISTICS
VCC = ±15V, T amb = 25°C (unless otherwise specified)
LS404I - LS404M
Symbol
LS404C
Parameter
Unit
Min.
Typ.
Max.
Min.
Typ.
Max.
Icc
Supply Current
1.3
2
1.5
3
Iib
Input Bias Current
50
200
100
300
Ri
Input Resistance (f = 1kHz)
1
Vio
Input Offset Voltage (Rs ≤ 10kΩ)
DVio
Iio
Input Offset Voltage Drift (Rs ≤ 10kΩ)
Tmin < Top < Tmax
5
Input Offset Current
10
DIio
Input Offset Current Drift
Tmin < Top < Tmax
Ios
Output Short-circuit Current
Avd
Large Signal Voltage Gain
RL = 2kΩ, VCC = ±15V
VCC = ±4V
GBP
en
THD
±Vopp
0.7
Gain Bandwith Product
f =100kHz, RL = 2k, CL = 100pF
2.5
0.5
20
mV
µV/°C
80
nA
0.08
0.1
nA/°C
23
23
mA
100
95
86
100
95
dB
1.8
3
1.5
2.5
MHz
Total Harmonic Distortion
Unity Gain
RL = 2kΩ, Vo = 2Vpp
f = 1kHz
f = 20kHz
8
10
18
15
10
12
20
0.01
0.03
0.4
0.01
0.03
nV
-----------Hz
%
±13
±13
V
±3
±3
22
20
22
20
Vpp
1
V/µs
Vopp
Large Signal Voltage Swing
f = 10kHz, RL = 10kΩ
RL = 1kΩ
SR
Slew Rate (RL = 2kΩ, unity gain)
0.8
1.5
SVR
Supply Voltage Rejection Ratio
Vic = 1V, f = 100Hz
90
94
86
90
CMR
Common Mode Rejection Ratio
Vic = 10V
90
94
86
90
100
120
Vo1/Vo2 Channel Separation (f= 1kHz)
5
5
40
nA
MΩ
90
Equivalent Input Noise Voltage
f = 1kHz,
Rs = 50Ω
Rs = 1kΩ
Rs = 10kΩ
Output Voltage Swing
RL = 2kΩ, VCC = ±15V
VCC = ±4V
1
mA
120
dB
dB
dB
3/11
LS404
4/11
LS404
5/11
LS404
APPLICATION INFORMATION: Active low-pass filter
BUTTERWORTH
The Butterworth is a "maximally flat" amplitude response filter (figure 10) 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 3dB. The attenuation 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. 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 where
The maximum phase shift is –---------2
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.
-3dB Frequency
2 Pole
4 Pole
6 Pole
8 Pole
0.77fc
0.67fc
0.57fc
0.50fc
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 either 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.
Number of Poles
Butterworth
Bessel
Chebyschev (ripple ±0.25dB)
Chebyschev (ripple ±1dB)
2
4
6
8
2
4
6
8
2
4
6
8
2
4
6
8
Peak
Overshoot
Settling Time (% of final value)
% Overshoot
±1%
±0.1%
±0.01%
4
11
14
14
0.4
0.8
0.6
0.1
11
18
21
23
21
28
32
34
1.1Fc sec.
1.7/fc
2.4/fc
3.1/fc
0.8/fc
1.0/fc
1.3/fc
1.6/fc
1.1/fc
3.0/fc
5.9/fc
8.4/fc
1.6/fc
4.8/fc
8.2/fc
11.6/fc
1.7Fc sec.
2.8/fc
3.9S/fc
5.1/fc
1.4/fc
1.8/fc
2.1/fc
2.3/fc
1.6/fc
5.4/fc
10.4/fc
16.4/fc
2.7/fc
8.4/fc
16.3/fc
24.8/fc
1.9Fc sec.
3.8/fc
5.0S/fc
7.1/fc
1.7/fc
2.4/fc
2.7/fc
3.2/fc
-
Design of 2nd order active low pass filter (Sallen and Key configuration unity gain op-amp)
6/11
-
LS404
Fixed R = R1 = R2, we have (see figure 13)
1 ζ
C 1 = ---- ------R ωc
1 1
C 2 = ---- ----------R ξ ωc
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 factio (ξ) or
the Q factor (Q = 2 ξ)1), and the cuttoff frequency
(fc).
The higher order response are 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 1).
Table 1
ξ
Q
Bessel
3
------2
1
------3
Frequency at which Phase Shift is -90°C
Butterworth
2
------2
1
------2
Frequency at which Gv = -3dB
Chebyschev
2
------2
1
------2
Filter Response
Cuttoff Frequency fc
Frequency at which the amplitude response
passes through specified max. ripple band and
enters the stop bank.
EXAMPLE
Figure 14 : 5th Order Low-pass Filter (Butterworth) with Unity Gain configuration
C2
Ri
R1
C4
R2
R3
Ci
R4
C1
C3
7/11
LS404
1 1
Ci = 1.354 ---- ------------ = 6.33nF
R 2 π fc
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 reciprocal of the numbers in table 2. For fc = 5kHz and Ci
= C1 = C2 = C3 = 1nF we obtain:
1 1
C1 = 0.421 ---- ------------ = 1.97nF
R 2 π fc
1 1
1
Ri = --------------- ---- ------------ = 25.5k Ω
0.354 C 2π fc
1 1
C2 = 1.753 ---- ------------ = 8.20nF
R 2 π fc
1
1 1
R1 = --------------- ---- ------------ = 75.6kΩ
0.421 C 2π fc
1 1
C3 = 0.309 ---- ------------ = 1.45nF
R 2 π fc
1
1 1
R2 = --------------- ---- ------------ = 18.2kΩ
1.753 C 2π fc
1 1
C4 = 3.325 ---- ------------ = 15.14nF
R 2π fc
1
1 1
R3 = --------------- ---- ------------ = 103kΩ
0.309 C 2π fc
The attenuation of the filter is 30dB at 6.8kHz and
better than 60dB at 15kHz.
1
1 1
R4 = --------------- ---- ------------ = 9.6kΩ
3.325 C 2π fc
In the circuit of figure 14, for fc = 3.4kHz and Ri =
R1 = R2 = R3 = 10kΩ, we obtain:
Table 2 : Damping Factor for Low-pass Butterworth Filters
Order
Ci
2
3
1.392
4
5
1.354
6
7
1.336
8
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
Figure 15 : 5th Order High-pass Filter (Butterworth) with Unity Gain configuration
R2
Ci
C1
R4
C2
C3
Ri
8/11
C4
R1
R3
C7
C8
0.195
5.125
LS404
Figure 16 : Multiple Feedback 8-pole Bandpass Filter
C3
C6
R5
C1
R1
C2
IN
0.1m F
R4
C9
3
¼
LS404
1
R6
R11
C5
6
¼
4
R3
R9
7
5 LS404
11
R7
Vcc
R2
C11
R8
2
C8
R10
R14
9
R12
8
¼
10 LS404
C10
R13
C4
0.1m F
22kW
13
14
C12
0.1m F
Out
C13
0.22m F
C7
220m F
22kW
12
¼
LS404
Figure 17 : Six pole 355Hz Low-pass Filter (chebychev type)
10kΩ
10kΩ
10kΩ
10kΩ
0.47µF
10kΩ
3.54nF
10kΩ
16.3nF
60nF
86.1nF
220nF
161nF
56kΩ
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)
10kΩ
C
Fc (Hz)
C (µF)
15
22
30
55
100
0.68
0.47
0.33
0.22
0.10
C
Vout
22kΩ
Figure 19 : High Cut filter (Gv = 0dB)
C2
10kΩ
10kΩ
3
Vin
1
C1
2
Vout
Fc (Hz)
C1 (nF)
C2 (nF)
3
5
10
15
3.9
2.2
1.2
0.68
6.8
4.7
2.2
1.5
9/11
LS404
PACKAGE MECHANICAL DATA
14 PINS - PLASTIC PACKAGE
Millimeters
Inches
Dimensions
Min.
a1
B
b
b1
D
E
e
e3
F
i
L
Z
10/11
Typ.
0.51
1.39
Max.
Min.
1.65
0.020
0.055
0.5
0.25
Typ.
0.065
0.020
0.010
20
0.787
8.5
2.54
15.24
0.335
0.100
0.600
7.1
5.1
0.280
0.201
3.3
1.27
Max.
0.130
2.54
0.050
0.100
LS404
PACKAGE MECHANICAL DATA
14 PINS - PLASTIC MICROPACKAGE (SO)
G
c1
b1
e
a1
b
A
a2
C
L
s
e3
E
D
M
8
1
7
F
14
Millimeters
Inches
Dimensions
Min.
A
a1
a2
b
b1
C
c1
D (1)
E
e
e3
F (1)
G
L
M
S
Typ.
Max.
Min.
1.75
0.2
1.6
0.46
0.25
0.1
0.35
0.19
Typ.
0.069
0.008
0.063
0.018
0.010
0.004
0.014
0.007
0.5
Max.
0.020
45° (typ.)
8.55
5.8
8.75
6.2
0.336
0.228
1.27
7.62
3.8
4.6
0.5
0.344
0.244
0.050
0.300
4.0
5.3
1.27
0.68
0.150
0.181
0.020
0.157
0.208
0.050
0.027
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.
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.
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© 2001 STMicroelectronics - Printed in Italy - All Rights Reserved
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11/11