TL082 Wide Bandwidth Dual JFET Input Operational Amplifier
April 1998
TL082 Wide Bandwidth Dual JFET Input Operational Amplifier
General Description
These devices are low cost, high speed, dual JFET input operational amplifiers with an internally trimmed input offset voltage (BI-FET II™ technology). They require low supply current yet maintain a large gain bandwidth product and fast slew rate. In addition, well matched high voltage JFET input devices provide very low input bias and offset currents. The TL082 is pin compatible with the standard LM1558 allowing designers to immediately upgrade the overall performance of existing LM1558 and most LM358 designs. These amplifiers 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 devices also exhibit low noise and offset voltage drift.
Features
n n n n n n n n n Internally trimmed offset voltage: 15 mV Low input bias current: 50 pA Low input noise voltage: 16nV/√Hz Low input noise current: 0.01 pA/√Hz Wide gain bandwidth: 4 MHz High slew rate: 13 V/µs Low supply current: 3.6 mA High input impedance: 1012Ω 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
Typical Connection
Connection Diagram
DIP/SO Package (Top View)
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Order Number TL082CM or TL082CP See NS Package Number M08A or N08E
Simplified Schematic
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BI-FET II™ is a trademark of National Semiconductor Corp.
© 1999 National Semiconductor Corporation
DS008357
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Absolute Maximum Ratings (Note 1)
If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications. Supply Voltage Power Dissipation Operating Temperature Range Tj(MAX) Differential Input Voltage
± 18V (Note 2) 0˚C to +70˚C 150˚C ± 30V
(Note 5)
Input Voltage Range (Note 3) Output Short Circuit Duration Storage Temperature Range Lead Temp. (Soldering, 10 seconds) ESD rating to be determined.
± 15V Continuous −65˚C to +150˚C 260˚C
Note 1: “Absolute Maximum Ratings” indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is functional, but do not guarantee specific performance limits.
DC Electrical Characteristics
Symbol VOS ∆VOS/∆T IOS IB RIN AVOL Parameter Input Offset Voltage Average TC of Input Offset Voltage Input Offset Current Input Bias Current Input Resistance Large Signal Voltage Gain
Conditions Min RS = 10 kΩ, TA = 25˚C Over Temperature RS = 10 kΩ Tj = 25˚C, (Notes 5, 6) Tj ≤ 70˚C Tj = 25˚C, (Notes 5, 6) Tj ≤ 70˚C Tj = 25˚C VS = ± 15V, TA = 25˚C VO = ± 10V, RL = 2 kΩ Over Temperature VS = ± 15V, RL = 10 kΩ VS = ± 15V RS ≤ 10 kΩ (Note 7) 25 15
TL082C Typ 5 10 25 50 1012 100 200 4 400 8 Max 15 20
Units mV mV µV/˚C pA nA pA nA Ω V/mV V/mV
VO VCM CMRR PSRR IS
Output Voltage Swing Input Common-Mode Voltage Range Common-Mode Rejection Ratio Supply Voltage Rejection Ratio Supply Current
± 12 ± 11
70 70
± 13.5
+15 −12 100 100 3.6 5.6
V V V dB dB mA
AC Electrical Characteristics
Symbol Parameter Amplifier to Amplifier Coupling SR GBW en in Slew Rate Gain Bandwidth Product Equivalent Input Noise Voltage Equivalent Input Noise Current
(Note 5) Conditions Min TA = 25˚C, f = 1Hz20 kHz (Input Referred) VS = ± 15V, TA = 25˚C VS = ± 15V, TA = 25˚C TA = 25˚C, RS = 100Ω, f = 1000 Hz Tj = 25˚C, f = 1000 Hz 8 TL082C Typ −120 13 4 25 0.01 Max dB V/µs MHz nV/√Hz pA/√Hz Units
Note 2: For operating at elevated temperature, the device must be derated based on a thermal resistance of 115˚C/W junction to ambient for the N package. Note 3: Unless otherwise specified the absolute maximum negative input voltage is equal to the negative power supply voltage. Note 4: The power dissipation limit, however, cannot be exceeded. Note 5: These specifications apply for VS = ± 15V and 0˚C ≤TA ≤ +70˚C. VOS, IB and IOS are measured at VCM = 0. Note 6: The input bias currents are junction leakage currents which approximately double for every 10˚C increase in the junction temperature, Tj. Due to the limited production test time, the input bias currents measured are correlated to junction temperature. In normal operation the junction temperature rises above the ambient temperature as a result of internal power dissipation, PD. Tj = TA + θjA PD where θjA is the thermal resistance from junction to ambient. Use of a heat sink is recommended if input bias current is to be kept to a minimum. Note 7: Supply voltage rejection ratio is measured for both supply magnitudes increasing or decreasing simultaneously in accordance with common practice. VS = ± 6V to ± 15V.
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Typical Performance Characteristics
Input Bias Current Input Bias Current Supply Current
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Positive Common-Mode Input Voltage Limit
Negative Common-Mode Input Voltage Limit
Positive Current Limit
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Negative Current Limit
Voltage Swing
Output Voltage Swing
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Typical Performance Characteristics
Gain Bandwidth Bode Plot
(Continued) Slew Rate
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Distortion vs Frequency
Undistorted Output Voltage Swing
Open Loop Frequency Response
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Common-Mode Rejection Ratio
Power Supply Rejection Ratio
Equivalent Input Noise Voltage
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Typical Performance Characteristics
Open Loop Voltage Gain (V/V)
(Continued) Inverter Setting Time
Output Impedance
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Pulse Response
Small Signal Inverting Small Signal Non-Inverting
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Large Signal Inverting
Large Signal Non-Inverting
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Pulse Response
(Continued) Current Limit (RL = 100Ω)
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Application Hints
These devices are op amps with an internally trimmed input offset 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 accommodated without a large increase in input current. The maximum differential input voltage is independent of the supply 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. Exceeding the negative common-mode limit on either input will cause a reversal of the phase to the output and force the amplifier output to the corresponding high or low state. 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. Exceeding the positive common-mode limit on a single input will not change the phase of the output; however, if both inputs exceed the limit, the output of the amplifier will be forced to a high state. The amplifiers will operate with a common-mode input voltage equal to the positive supply; however, the gain bandwidth 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. Each amplifier is individually biased by a zener reference which allows normal circuit operation on ± 6V power supplies. Supply voltages less than these may result in lower gain bandwidth and slew rate.
The amplifiers will drive a 2 kΩ load resistance to ± 10V over the full temperature range of 0˚C to +70˚C. 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 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. Because these amplifiers are JFET rather than MOSFET input op amps they do not require special handling. 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 feedback pole by minimizing the capacitance from the input to ground. 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 feedback pole is less than approximately 6 times the expected 3 dB frequency a lead capacitor should be placed from the output to the input of the op amp. The value of the added capacitor should be such that the RC time constant of this capacitor and the resistance it parallels is greater than or equal to the original feedback pole time constant.
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Detailed Schematic
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Typical Applications
Three-Band Active Tone Control
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Typical Applications
(Continued)
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• All potentiometers are linear taper • Use the LF347 Quad for stereo applications
Note 8: All controls flat. Note 9: Bass and treble boost, mid flat. Note 10: Bass and treble cut, mid flat. Note 11: Mid boost, bass and treble flat. Note 12: Mid cut, bass and treble flat.
Improved CMRR Instrumentation Amplifier
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C and E are separate isolated grounds Matching of R2’s, R4’s and R5’s control CMRR With AVT = 1400, resistor matching = 0.01%: CMRR = 136 dB • Very high input impedance • Super high CMRR
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Typical Applications
(Continued) Fourth Order Low Pass Butterworth Filter
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Fourth Order High Pass Butterworth Filter
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Typical Applications
(Continued) Ohms to Volts Converter
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Physical Dimensions
inches (millimeters) unless otherwise noted
Order Number TL082CM NS Package M08A
Order Number TL082CP NS Package N08E
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TL082 Wide Bandwidth Dual JFET Input Operational Amplifier
Notes
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