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| LF147 LF347 Wide Bandwidth Quad JFET Input Operational Amplifiers December 1994 LF147 LF347 Wide Bandwidth Quad JFET Input Operational Amplifiers General Description The LF147 is a low cost high speed quad JFET input operational amplifier with an internally trimmed input offset voltage (BI-FET IITM 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 upgrade the overall performance of existing LF148 and LM124 designs 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 Features Y Y Y Y Y Y Y Y Y Y Internally trimmed offset voltage 5 mV max Low input bias current 50 pA Low input noise current 0 01 pA 0Hz Wide gain bandwidth 4 MHz High slew rate 13 V ms Low supply current 7 2 mA High input impedance 1012X k 0 02% Low total harmonic distortion AV e 10 RL e 10k VO e 20 Vp-p BW e 20 Hzb20 kHz Low 1 f noise corner 50 Hz Fast settling time to 0 01% 2 ms Simplified Schematic Quad Connection Diagram Dual-In-Line Package TL H 5647 - 1 TL H 5647 - 13 Top View Order Number LF147J LF347M LF347BN LF347N LF147D 883 or LF147J 883 See NS Package Number D14E J14A M14A or N14A Available per SMD 8102306 JM38510 11906 BI-FET IITM is a trademark of National Semiconductor Corporation C1995 National Semiconductor Corporation TL H 5647 RRD-B30M115 Printed in U S A Absolute Maximum Ratings If Military Aerospace specified devices are required please contact the National Semiconductor Sales Office Distributors for availability and specifications LF147 LF347B LF347 g22V g18V Supply Voltage g38V g30V Differential Input Voltage g19V g15V Input Voltage Range (Note 1) Output Short Circuit Continuous Continuous Duration (Note 2) Power Dissipation 900 mW 1000 mW (Notes 3 and 9) Tj max 150 C 150 C ijA Cavity DIP (D) Package 80 C W Ceramic DIP (J) Package 70 C W Plastic DIP (N) Package 75 C W Surface Mount Narrow (M) 100 C W Surface Mount Wide (WM) 85 C W Operating Temperature Range Storage Temperature Range Lead Temperature (Soldering 10 sec ) Soldering Information Dual-In-Line Package Soldering (10 seconds) Small Outline Package Vapor Phase (60 seconds) Infrared (15 seconds) See AN-450 ``Surface Mounting on Product Reliability'' for other face mount devices ESD Tolerance (Note 10) LF147 (Note 4) LF347B LF347 (Note 4) b 65 C s TA s 150 C 260 C 260 C 260 C 215 C 220 C Methods and Their Effect methods of soldering sur900V DC Electrical Characteristics Symbol VOS Parameter Input Offset Voltage (Note 5) LF147 Min Typ 1 10 25 50 1012 50 25 100 50 25 g12 g13 5 g11 Conditions RS e 10 kX TA e 25 C Over Temperature RS e 10 kX Tj e 25 C (Notes 5 6) Over Temperature Tj e 25 C (Notes 5 6) Over Temperature Tj e 25 C VS e g15V TA e 25 C VO e g10V RL e 2 kX Over Temperature LF347B Max Min 5 8 Typ 3 10 100 25 200 50 25 50 1012 100 25 15 100 4 200 8 Max Min 5 7 LF347 Typ 5 10 25 50 1012 100 100 4 200 8 Max 10 13 Units mV mV mV C pA nA pA nA X V mV V mV V V V dB dB 11 mA DVOS DT Average TC of Input Offset Voltage IOS IB RIN AVOL Input Offset Current Input Bias Current Input Resistance Large Signal Voltage Gain VO VCM CMRR PSRR IS Output Voltage Swing Input Common-Mode Voltage Range VS e g15V RL e 10 kX g12 g13 5 VS e g15V g11 g12 g13 5 g11 a 15 b 12 a 15 b 12 a 15 b 12 Common-Mode Rejection Ratio RSs10 kX Supply Voltage Rejection Ratio (Note 7) Supply Current 80 80 100 100 72 11 80 80 100 100 72 11 70 70 100 100 72 2 AC Electrical Characteristics (Note 5) Symbol Parameter Amplifier to Amplifier Coupling Conditions Min TA e 25 C f e 1 Hzb20 kHz (Input Referred) VS e g15V TA e 25 C 8 LF147 Typ b 120 LF347B Max Min Typ b 120 LF347 Max Min Typ b 120 Units Max dB SR GBW en in Slew Rate Gain-Bandwidth Product 13 4 20 0 01 8 22 13 4 20 0 01 8 22 13 4 20 0 01 V ms MHz nV 0Hz pA 0Hz VS e g15V TA e 25 C 2 2 Equivalent Input Noise Voltage TA e 25 C RS e 100X f e 1000 Hz Equivalent Input Noise Current Tj e 25 C f e 1000 Hz Note 1 Unless otherwise specified the absolute maximum negative input voltage is equal to the negative power supply voltage Note 2 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 3 For operating at elevated temperature these devices must be derated based on a thermal resistance of ijA Note 4 The LF147 is available In the military temperature range b 55 C s TA s 125 C while the LF347B and the LF347 are available in the commercial temperature range 0 C s TA s 70 C Junction temperature can rise to Tj max e 150 C Note 5 Unless otherwise specified the specifications apply over the full temperature range and for VS e g20V for the LF147 and for VS e g15V for the LF347B LF347 VOS IB and IOS are measured at VCM e 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 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 e TA a ijA PD where ijA 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 from VS e g 5V to g15V for the LF347 and LF347B and from VS e g20V to g5V for the LF147 Note 8 Refer to RETS147X for LF147D and LF147J military specifications Note 9 Max Power Dissipation is defined by the package characteristics Operating the part near the Max Power Dissipation may cause the part to operate outside guaranteed limits Note 10 Human body model 1 5 kX in series with 100 pF 3 Typical Performance Characteristics Input Bias Current Input Bias Current Supply Current Positive Common-Mode Input Voltage Limit Negative Common-Mode Input Voltage Limit Positive Current Limit Negative Current Limit Output Voltage Swing Output Voltage Swing Gain Bandwidth Bode Plot Slew Rate TL H 5647 - 2 4 Typical Performance Characteristics Distortion vs Frequency (Continued) Open Loop Frequency Response Undistorted Output Voltage Swing Common-Mode Rejection Ratio Power Supply Rejection Ratio Equivalent Input Noise Voltage Open Loop Voltage Gain Output Impedance Inverter Settling Time TL H 5647 - 3 5 Pulse Response RL e 2 kX CL e 10 pF Small Signal Non-Inverting Small Signal Inverting TL H 5647-4 TL H 5647 - 5 Large Signal Inverting Large Signal Non-Inverting TL H 5647-6 TL H 5647 - 7 Current Limit (RL e 100X) TL H 5647 - 8 Application Hints The LF147 is an op amp with an internally trimmed input offset voltage and JFET input devices (BI-FET IITM) 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 force the output to a high state potentially causing a reversal of phase to the output Exceeding the negative common-mode limit on both inputs will force the amplifier 6 Application Hints (Continued) 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 g4 5V power supplies Supply voltages less than these may result in lower gain bandwidth and slew rate The LF147 will drive a 2 kX load resistance to g10V 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 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 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 Detailed Schematic TL H 5647 - 9 7 Typical Applications Digitally Selectable Precision Attenuator All resistors 1% tolerance A1 A2 A3 0 0 0 0 1 1 1 1 0 0 1 1 0 0 1 1 0 1 0 1 0 1 0 1 VO Attenuation 0 b 1 dB b 2 dB b 3 dB b 4 dB b 5 dB b 6 dB b 7 dB 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 TL H 5647 - 10 Long Time Integrator with Reset Hold and Starting Threshold Adjustment TL H 5647 - 11 VOUT starts from zero and is equal to the integral of the input voltage with respect to the threshold voltage VOUT e 1t (VIN b VTH)dt RC0 Output starts when VIN t VTH Switch S1 permits stopping and holding any output value Switch S2 resets system to zero 8 Typical Applications (Continued) Universal State Variable Filter TL H 5647 - 12 For circuit shown fo e 3 kHz fNOTCH e 9 5 kHz Qe3 4 Passband gain Highpass Bandpass Lowpass Notch 10 01 1 1 fo c Q s 200 kHz 10V peak sinusoidal output swing without slew limiting to 200 kHz See LM148 data sheet for design equations 9 Physical Dimensions inches (millimeters) Hermetic Dual-In-Line Package (D) Order Number LF147D 883 NS Package Number D14E 10 Physical Dimensions inches (millimeters) (Continued) 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 11 LF147 LF347 Wide Bandwidth Quad JFET Input Operational Amplifiers Physical Dimensions inches (millimeters) (Continued) Molded Dual-In-Line Package (N) Order Number LF347BN or LF347N NS Package Number N14A LIFE SUPPORT POLICY NATIONAL'S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT OF NATIONAL SEMICONDUCTOR CORPORATION As used herein 1 Life support devices or systems are devices or systems which (a) are intended for surgical implant into the body or (b) support or sustain life and whose failure to perform when properly used in accordance with instructions for use provided in the labeling can be reasonably expected to result in a significant injury to the user National Semiconductor Corporation 1111 West Bardin Road Arlington TX 76017 Tel 1(800) 272-9959 Fax 1(800) 737-7018 2 A critical component is any component of a life support device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or system or to affect its safety or effectiveness National Semiconductor Europe Fax (a49) 0-180-530 85 86 Email cnjwge tevm2 nsc com Deutsch Tel (a49) 0-180-530 85 85 English Tel (a49) 0-180-532 78 32 Fran ais Tel (a49) 0-180-532 93 58 Italiano Tel (a49) 0-180-534 16 80 National Semiconductor Hong Kong Ltd 13th Floor Straight Block Ocean Centre 5 Canton Rd Tsimshatsui Kowloon Hong Kong Tel (852) 2737-1600 Fax (852) 2736-9960 National Semiconductor Japan Ltd Tel 81-043-299-2309 Fax 81-043-299-2408 National does not assume any responsibility for use of any circuitry described no circuit patent licenses are implied and National reserves the right at any time without notice to change said circuitry and specifications |
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