LF347MWC [NSC]
暂无描述;
| 型号： | LF347MWC |
| 厂家： | 
National Semiconductor |
| 描述： | 暂无描述 运算放大器 放大器电路 光电二极管 |
| 文件： | 总13页 (文件大小：409K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
May 1999
LF147/LF347
Wide Bandwidth Quad JFET Input Operational Amplifiers
General Description
The LF147 is a low cost, high speed quad JFET input opera-
tional amplifier with an internally trimmed input offset voltage
Features
n Internally trimmed offset voltage: 5 mV max
n Low input bias current: 50 pA
n Low input noise current:
™
(BI-FET II technology). The device requires a low supply
current and yet maintains a large gain bandwidth product
and a fast slew rate. In addition, well matched high voltage
JFET input devices provide very low input bias and offset
currents. The LF147 is pin compatible with the standard
LM148. This feature allows designers to immediately up-
grade the overall performance of existing LF148 and LM124
designs.
n Wide gain bandwidth: 4 MHz
n High slew rate: 13 V/µs
n Low supply current: 7.2 mA
n High input impedance: 1012Ω
=
<
n Low total harmonic distortion AV 10,:
0.02%
=
=
=
RL 10k, VO 20 Vp-p, BW 20 Hz−20 kHz
n Low 1/f noise corner: 50 Hz
n Fast settling time to 0.01%: 2 µs
The LF147 may be used in applications such as high speed
integrators, fast D/A converters, sample-and-hold circuits
and many other circuits requiring low input offset voltage,
low input bias current, high input impedance, high slew rate
and wide bandwidth. The device has low noise and offset
voltage drift.
Simplified Schematic
Connection Diagram
1
⁄4
Quad
Dual-In-Line Package
DS005647-1
Note 1: Available per SMD #8102306, JM38510/11906.
DS005647-13
Top View
Order Number LF147J, LF347M, LF347BN,
LF347N or LF147J/883 (Note 1)
See NS Package Number J14A, M14A or N14A
™
BI-FET II is a trademark of National Semiconductor Corporation.
© 1999 National Semiconductor Corporation
DS005647
www.national.com
Absolute Maximum Ratings (Note 2)
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.
LF147
LF347B/LF347
85˚C/W
Surface Mount Wide (WM)
Operating Temperature
Range
(Note 6)
(Note 6)
Storage Temperature
Range
LF147
LF347B/LF347
−65˚C≤TA≤150˚C
±
±
±
±
±
±
Supply Voltage
22V
38V
19V
18V
30V
15V
Lead Temperature
Differential Input Voltage
Input Voltage Range
(Note 3)
(Soldering, 10 sec.)
Soldering Information
Dual-In-Line Package
Soldering (10 seconds)
Small Outline Package
Vapor Phase (60 seconds)
Infrared (15 seconds)
260˚C
260˚C
260˚C
Output Short Circuit
Duration (Note 4)
Power Dissipation
(Notes 5, 11)
Continuous
900 mW
150˚C
Continuous
1000 mW
150˚C
215˚C
220˚C
Tj max
θjA
See AN-450 “Surface Mounting Methods and Their Effect
on Product Reliability” for other methods of soldering
surface mount devices.
Ceramic DIP (J) Package
Plastic DIP (N) Package
Surface Mount Narrow (M)
70˚C/W
75˚C/W
100˚C/W
ESD Tolerance (Note 12)
900V
DC Electrical Characteristics (Note 7)
Symbol
Parameter
Conditions
LF147
LF347B
Typ Max Min
LF347
Units
Min
Typ Max Min
Typ Max
=
=
VOS
Input Offset Voltage
RS 10 kΩ, TA 25˚C
1
5
8
3
5
7
5
10
13
mV
mV
Over Temperature
=
∆VOS/∆T
Average TC of Input Offset
Voltage
RS 10 kΩ
10
25
50
10
25
50
10
25
50
µV/˚C
=
IOS
Input Offset Current
Tj 25˚C, (Notes 7, 8)
100
25
100
4
100
4
pA
nA
Over Temperature
=
IB
Input Bias Current
Tj 25˚C, (Notes 7, 8)
200
50
200
8
200
8
pA
Over Temperature
nA
=
RIN
Input Resistance
Tj 25˚C
1012
100
1012
100
1012
100
Ω
=
=
±
AVOL
Large Signal Voltage Gain
VS 15V, TA 25˚C
50
25
50
25
25
15
V/mV
=
=
±
VO 10V, RL 2 kΩ
Over Temperature
V/mV
V
=
=
±
±
±
±
±
±
±
±
VO
Output Voltage Swing
Input Common-Mode Voltage
Range
VS 15V, RL 10 kΩ
12
11
13.5
+15
−12
100
100
7.2
12
11
13.5
+15
−12
100
100
7.2
12
11
13.5
+15
−12
100
100
7.2
=
±
±
±
VCM
VS 15V
V
V
CMRR
PSRR
IS
Common-Mode Rejection Ratio
Supply Voltage Rejection Ratio
Supply Current
RS≤10 kΩ
80
80
80
80
70
70
dB
dB
mA
(Note 9)
11
11
11
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2
AC Electrical Characteristics (Note 7)
Symbol
Parameter
Conditions
LF147
LF347B
Typ Max Min
LF347
Units
Min
Typ Max Min
−120
Typ Max
−120
=
Amplifier to Amplifier Coupling
TA 25˚C,
−120
dB
=
f
1 Hz−20 kHz
(Input Referred)
=
=
±
SR
Slew Rate
VS 15V, TA 25˚C
8
13
4
8
13
4
8
13
4
V/µs
MHz
=
=
±
GBW
en
Gain-Bandwidth Product
Equivalent Input Noise Voltage
VS 15V, TA 25˚C
2.2
2.2
2.2
=
=
TA 25˚C, RS 100Ω,
20
20
20
=
f
1000 Hz
=
=
in
Equivalent Input Noise Current
Tj 25˚C, f 1000 Hz
0.01
0.01
0.01
Note 2: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is func-
tional, but do not guarantee specific performance limits.
Note 3: Unless otherwise specified the absolute maximum negative input voltage is equal to the negative power supply voltage.
Note 4: Any of the amplifier outputs can be shorted to ground indefinitely, however, more than one should not be simultaneously shorted as the maximum junction
temperature will be exceeded.
Note 5: For operating at elevated temperature, these devices must be derated based on a thermal resistance of θ
.
jA
Note 6: The LF147 is available in the military temperature range −55˚C≤T ≤125˚C, while the LF347B and the LF347 are available in the commercial temperature
A
=
range 0˚C≤T ≤70˚C. Junction temperature can rise to T max 150˚C.
A
j
=
=
±
15V for the LF347B/LF347.
±
Note 7: Unless otherwise specified the specifications apply over the full temperature range and for V
20V for the LF147 and for V
S
S
=
are measured at V 0.
CM
V
, I , and I
OS OS
B
Note 8: The input bias currents are junction leakage currents which approximately double for every 10˚C increase in the junction temperature, T . Due to limited pro-
j
duction test time, the input bias currents measured are correlated to junction temperature. In normal operation the junction temperature rises above the ambient tem-
=
perature as a result of internal power dissipation, P . T
D
T
A
+θ
P where θ is the thermal resistance from junction to ambient. Use of a heat sink is recommended
D jA
j
jA
if input bias current is to be kept to a minimum.
Note 9: Supply voltage rejection ratio is measured for both supply magnitudes increasing or decreasing simultaneously in accordance with common practice from
=
=
±
±
±
±
20V to 5V for the LF147.
V
5V to 15V for the LF347 and LF347B and from V
S
S
Note 10: Refer to RETS147X for LF147D and LF147J military specifications.
Note 11: Max. Power Dissipation is defined by the package characteristics. Operating the part near the Max. Power Dissipation may cause the part to operate out-
side guaranteed limits.
Note 12: Human body model, 1.5 kΩ in series with 100 pF.
3
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Typical Performance Characteristics
Input Bias Current
Input Bias Current
Supply Current
DS005647-14
DS005647-16
DS005647-15
Positive Common-Mode
Input Voltage Limit
Negative Common-Mode
Input Voltage Limit
Positive Current Limit
DS005647-19
DS005647-17
DS005647-18
Negative Current Limit
Output Voltage Swing
Output Voltage Swing
DS005647-20
DS005647-21
DS005647-22
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4
Typical Performance Characteristics (Continued)
Gain Bandwidth
Bode Plot
Slew Rate
DS005647-23
DS005647-24
DS005647-25
Distortion vs Frequency
Undistorted Output Voltage
Swing
Open Loop Frequency
Response
DS005647-26
DS005647-27
DS005647-28
Common-Mode Rejection
Ratio
Power Supply Rejection
Ratio
Equivalent Input Noise
Voltage
DS005647-29
DS005647-30
DS005647-31
5
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Typical Performance Characteristics (Continued)
Open Loop Voltage Gain
Output Impedance
Inverter Settling Time
DS005647-34
DS005647-33
DS005647-32
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6
=
=
Pulse Response RL 2 kΩ, CL 10 pF
Small Signal Inverting
Small Signal Non-Inverting
DS005647-5
DS005647-4
Large Signal Inverting
Large Signal Non-Inverting
DS005647-6
DS005647-7
=
Current Limit (RL 100Ω)
DS005647-8
Exceeding the negative common-mode limit on either input
will force the output to a high state, potentially causing a re-
versal of phase to the output. Exceeding the negative
common-mode limit on both inputs will force the amplifier
output to a high state. In neither case does a latch occur
since raising the input back within the common-mode range
again puts the input stage and thus the amplifier in a normal
operating mode.
Application Hints
The LF147 is an op amp with an internally trimmed input off-
set voltage and JFET input devices (BI-FET II). These JFETs
have large reverse breakdown voltages from gate to source
and drain eliminating the need for clamps across the inputs.
Therefore, large differential input voltages can easily be ac-
commodated without a large increase in input current. The
maximum differential input voltage is independent of the sup-
ply voltages. However, neither of the input voltages should
be allowed to exceed the negative supply as this will cause
large currents to flow which can result in a destroyed unit.
7
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or that the unit is not inadvertently installed backwards in a
socket as an unlimited current surge through the resulting
forward diode within the IC could cause fusing of the internal
conductors and result in a destroyed unit.
Application Hints (Continued)
Exceeding the positive common-mode limit on a single input
will not change the phase of the output; however, if both in-
puts exceed the limit, the output of the amplifier will be forced
to a high state.
As with most amplifiers, care should be taken with lead
dress, component placement and supply decoupling in order
to ensure stability. For example, resistors from the output to
an input should be placed with the body close to the input to
minimize “pick-up” and maximize the frequency of the feed-
back pole by minimizing the capacitance from the input to
ground.
The amplifiers will operate with a common-mode input volt-
age equal to the positive supply; however, the gain band-
width and slew rate may be decreased in this condition.
When the negative common-mode voltage swings to within
3V of the negative supply, an increase in input offset voltage
may occur.
A feedback pole is created when the feedback around any
amplifier is resistive. The parallel resistance and capacitance
from the input of the device (usually the inverting input) to AC
ground set the frequency of the pole. In many instances the
frequency of this pole is much greater than the expected 3
dB frequency of the closed loop gain and consequently there
is negligible effect on stability margin. However, if the feed-
back pole is less than approximately 6 times the expected 3
dB frequency a lead capacitor should be placed from the out-
put to the input of the op amp. The value of the added ca-
pacitor should be such that the RC time constant of this ca-
pacitor and the resistance it parallels is greater than or equal
to the original feedback pole time constant.
Each amplifier is individually biased by a zener reference
±
which allows normal circuit operation on 4.5V power sup-
plies. Supply voltages less than these may result in lower
gain bandwidth and slew rate.
±
The LF147 will drive a 2 kΩ load resistance to 10V over the
full temperature range. If the amplifier is forced to drive
heavier load currents, however, an increase in input offset
voltage may occur on the negative voltage swing and finally
reach an active current limit on both positive and negative
swings.
Precautions should be taken to ensure that the power supply
for the integrated circuit never becomes reversed in polarity
Detailed Schematic
DS005647-9
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8
Typical Applications
Digitally Selectable Precision Attenuator
DS005647-10
All resistors 1% tolerance
•
•
•
•
Accuracy of better than 0.4
% with standard 1% value resistors
No offset adjustment necessary
Expandable to any number of stages
Very high input impedance
A1 A2 A3
VO
Attenuation
0
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
−1 dB
−2 dB
−3 dB
−4 dB
−5 dB
−6 dB
−7 dB
9
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Typical Applications (Continued)
Long Time Integrator with Reset, Hold and Starting Threshold Adjustment
DS005647-11
•
VOUT starts from zero and is equal to the integral of the input voltage with respect to the threshold voltage:
•
•
•
Output starts when VIN≥VTH
Switch S1 permits stopping and holding any output value
Switch S2 resets system to zero
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10
Typical Applications (Continued)
Universal State Variable Filter
DS005647-12
For circuit shown:
=
=
=
9.5 kHz
f
Q
3 kHz, f
3.4
o
NOTCH
Passband gain:
Highpass — 0.1
Bandpass — 1
Lowpass — 1
Notch — 10
• f xQ≤200 kHz
o
• 10V peak sinusoidal output swing without slew limiting to 200 kHz
• See LM148 data sheet for design equations
11
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Physical Dimensions inches (millimeters) unless otherwise noted
Ceramic Dual-In-Line Package (J)
Order Number LF147J or LF147J/883
NS Package Number J14A
S.O. Package (M)
Order Number LF347M
NS Package Number M14A
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12
Physical Dimensions inches (millimeters) unless otherwise noted (Continued)
Molded Dual-In-Line Package (N)
Order Number LF347BN or LF347N
NS Package Number N14A
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