LF442 LF442 Dual Low Power JFET Input Operational Amplifier Literature Number: SNOSC03C LF442 Dual Low Power JFET Input Operational Amplifier General Description Features The LF442 dual low power operational amplifiers provide many of the same AC characteristics as the industry standard LM1458 while greatly improving the DC characteristics of the LM1458. The amplifiers have the same bandwidth, slew rate, and gain (10 k load) as the LM1458 and only draw one tenth the supply current of the LM1458. In addition the well matched high voltage JFET input devices of the LF442 reduce the input bias and offset currents by a factor of 10,000 over the LM1458. A combination of careful layout design and internal trimming guarantees very low input offset voltage and voltage drift. The LF442 also has a very low equivalent input noise voltage for a low power amplifier. n n n n n n n n n n 1/10 supply current of a LM1458: 400 A (max) Low input bias current: 50 pA (max) Low input offset voltage: 1 mV (max) Low input offset voltage drift: 10 V/C (max) High gain bandwidth: 1 MHz High slew rate: 1 V/s Low noise voltage for low power: Low input noise current: High input impedance: 1012 High gain VO = 10V, RL = 10k: 50k (min) The LF442 is pin compatible with the LM1458 allowing an immediate 10 times reduction in power drain in many applications. The LF442 should be used where low power dissipation and good electrical characteristics are the major considerations. Typical Connection Connection Diagrams Metal Can Package 00915502 Pin 4 connected to case 00915501 Top View Order Number LF442AMH or LF442MH/883 See NS Package Number H08A Ordering Information Dual-In-Line Package LF442XYZ X indicates electrical grade Y indicates temperature range "M" for military "C" for commercial Z indicates package type "H" or "N" 00915504 Top View Order Number LF442ACN or LF442CN See NS Package Number N08E BI-FET IITM is a trademark of National Semiconductor Corporation. (c) 2004 National Semiconductor Corporation DS009155 www.national.com LF442 Dual Low Power JFET Input Operational Amplifier August 2000 LF442 Absolute Maximum Ratings (Note 1) JA (Typical) (Note 4) (Note 5) If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications. Supply Voltage Differential Input Voltage Input Voltage Range N Package 65C/W 165C/W 114C/W 152C/W LF442A LF442 JC (Typical) 21C/W 22V 38V 19V 18V 30V 15V Operating Temperature (Note 5) (Note 5) Range -65CTA150C-65CTA150C Storage (Note 2) Temperature Range Output Short Circuit Continuous Continuous Lead Temperature Duration (Note 3) 260C 260C (Soldering, 10 sec.) H Package N Package 150C 115C Tj max DC Electrical Characteristics Symbol H Package Parameter ESD Tolerance Rating to be determined (Note 7) Conditions LF442A Min VOS Input Offset Voltage RS = 10 k, TA = 25C VOS/T Average TC of Input RS = 10 k LF442 Typ Max 0.5 7 Min Units Typ Max 1.0 1.0 5.0 10 7 25 5 Over Temperature 7.5 mV mV V/C Offset Voltage IOS Input Offset Current VS = 15V Tj = 25C (Notes 7, 8) Tj = 70C VS = 15V Tj = 25C (Notes 7, 8) Tj = 70C 3 Tj = 125C 20 5 1.5 Tj = 125C IB RIN AVOL Input Bias Current Input Resistance Tj = 25C Large Signal Voltage VS = 15V, VO = 10V, Gain RL = 10 k, TA = 25C Output Voltage Swing VS = 15V, RL = 10 k VCM 50 Input Common-Mode Common-Mode 100 pA 3 nA nA 50 10 nA 200 25 1012 200 V/mV 25 200 15 200 V/mV 12 16 13 12 11 13 V Voltage Range CMRR pA nA 10 10 1012 Over Temperature VO 50 1.5 +18 -17 +14 V -12 V RS 10 k 80 100 70 95 dB (Note 9) 80 100 70 90 dB Rejection Ratio PSRR Supply Voltage Rejection Ratio IS Supply Current www.national.com 300 2 400 400 500 A Symbol Parameter LF442 AC Electrical Characteristics (Note 7) Conditions LF442A Min Amplifier to Amplifier TA = 25C, f = 1 Hz-20 kHz Coupling (Input Referred) Typ LF442 Max Min -120 Typ -120 Units Max dB SR Slew Rate VS = 15V, TA = 25C 0.8 1 0.6 1 V/s GBW Gain-Bandwidth Product VS = 15V, TA = 25C 0.8 1 0.6 1 MHz en Equivalent Input Noise TA = 25C, RS = 100, in Voltage f = 1 kHz Equivalent Input Noise TA = 25C, f = 1 kHz 35 35 0.01 0.01 Current 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. Note 2: Unless otherwise specified the absolute maximum negative input voltage is equal to the negative power supply voltage. Note 3: 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 4: The value given is in 400 linear feet/min air flow. Note 5: The value given is in static air. Note 6: These devices are available in both the commercial temperature range 0C TA 70C and the military temperature range -55C TA 125C. The temperature range is designated by the position just before the package type in the device number. A "C" indicates the commercial temperature range and an "M" indicates the military temperature range. The military temperature range is available in "H" package only. Note 7: Unless otherwise specified, the specifications apply over the full temperature range and for VS = 20V for the LF442A and for VS = 15V for the LF442. VOS, IB, and IOS are measured at VCM = 0. Note 8: The input bias currents are junction leakage currents which approximately double for every 10C 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 = TA + jAPD where jA 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 9: Supply voltage rejection ratio is measured for both supply magnitudes increasing or decreasing simultaneously in accordance with common practice from 15V to 5V for the LF442 and 20V to 5V for the LF442A. Note 10: Refer to RETS442X for LF442MH military specifications. Simplified Schematic 1/2 Dual 00915503 3 www.national.com LF442 Typical Performance Characteristics Input Bias Current Input Bias Current 00915518 00915517 Positive Common-Mode Input Voltage Limit Supply Current 00915519 00915520 Negative Common-Mode Input Voltage Limit Positive Current Limit 00915522 00915521 www.national.com 4 LF442 Typical Performance Characteristics (Continued) Negative Current Limit Output Voltage Swing 00915523 00915524 Output Voltage Swing Gain Bandwidth 00915525 00915526 Bode Plot Slew Rate 00915527 00915528 5 www.national.com LF442 Typical Performance Characteristics (Continued) Undistorted Output Voltage Swing Distortion vs Frequency 00915529 00915530 Open Loop Frequency Response Common-Mode Rejection Ratio 00915531 00915532 Power Supply Rejection Ratio Equivalent Input Noise Voltage 00915534 00915533 www.national.com 6 LF442 Typical Performance Characteristics (Continued) Open Loop Voltage Gain Output Impedance 00915535 00915536 Inverter Settling Time 00915537 7 www.national.com LF442 Pulse Response RL = 10 k, CL = 10 pF Large Signal Inverting Small Signal Inverting 00915509 00915507 Large Signal Non-Inverting Small Signal Non-Inverting 00915510 00915508 www.national.com 8 This device is a dual low power op amp with internally trimmed input offset voltages and JFET input devices (BIFET 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. 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. 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 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. 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 consequenty 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. 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 to allow normal circuit operation with power supplies of 3.0V. Supply voltages less than these may degrade the common-mode rejection and restrict the output voltage swing. Typical Applications Battery Powered Strip Chart Preamplifier 00915511 Runs from 9v batteries ( 9V supplies) Fully settable gain and time constant Battery powered supply allows direct plug-in interface to strip chart recorder without common-mode problems 9 www.national.com LF442 The amplifiers will drive a 10 k load resistance to 10V over the full temperature range. Application Hints LF442 Typical Applications (Continued) "No FET" Low Power VF Converter 00915512 Trim 1M pot for 1 kHz full-scale output 15 mW power drain No integrator reset FET required Mount D1 and D2 in close proximity 1% linearity to 1 kHz High Efficiency Crystal Oven Controller 00915513 * * * * * Tcontrol= 75C A1's output represents the amplified difference between the LM335 temperature sensor and the crystal oven's temperature A2, a free running duty cycle modulator, drives the LM395 to complete a servo loop Switched mode operation yields high efficiency 1% metal film resistor www.national.com 10 LF442 Typical Applications (Continued) Conventional Log Amplifier 00915514 RT = Tel Labs type Q81 Trim 5k for 10 A through the 5k-120k combination *1% film resistor Unconventional Log Amplifier 00915515 Q1, Q2, Q3 are included on LM389 amplifier chip which is temperature-stabilized by the LM389 and Q2-Q3, which act as a heater-sensor pair. Q1, the logging transistor, is thus immune to ambient temperature variation and requires no temperature compensation at all. 11 www.national.com LF442 Detailed Schematic 1/2 Dual 00915516 www.national.com 12 LF442 Physical Dimensions inches (millimeters) unless otherwise noted TO-5 Metal Can Package (H) Order Number LF442AMH or LF442MH/883 NS Package Number H08A 13 www.national.com LF442 Dual Low Power JFET Input Operational Amplifier Physical Dimensions inches (millimeters) unless otherwise noted (Continued) Molded Dual-In-Line Package (N) Order Number LF442ACN or LF442CN NS Package Number N08E 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 AND GENERAL COUNSEL 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. 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. BANNED SUBSTANCE COMPLIANCE National Semiconductor certifies that the products and packing materials meet the provisions of the Customer Products Stewardship Specification (CSP-9-111C2) and the Banned Substances and Materials of Interest Specification (CSP-9-111S2) and contain no ``Banned Substances'' as defined in CSP-9-111S2. National Semiconductor Americas Customer Support Center Email: new.feedback@nsc.com Tel: 1-800-272-9959 www.national.com National Semiconductor Europe Customer Support Center Fax: +49 (0) 180-530 85 86 Email: europe.support@nsc.com Deutsch Tel: +49 (0) 69 9508 6208 English Tel: +44 (0) 870 24 0 2171 Francais Tel: +33 (0) 1 41 91 8790 National Semiconductor Asia Pacific Customer Support Center Email: ap.support@nsc.com National Semiconductor Japan Customer Support Center Fax: 81-3-5639-7507 Email: jpn.feedback@nsc.com Tel: 81-3-5639-7560 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. IMPORTANT NOTICE Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, modifications, enhancements, improvements, and other changes to its products and services at any time and to discontinue any product or service without notice. Customers should obtain the latest relevant information before placing orders and should verify that such information is current and complete. All products are sold subject to TI's terms and conditions of sale supplied at the time of order acknowledgment. TI warrants performance of its hardware products to the specifications applicable at the time of sale in accordance with TI's standard warranty. Testing and other quality control techniques are used to the extent TI deems necessary to support this warranty. Except where mandated by government requirements, testing of all parameters of each product is not necessarily performed. TI assumes no liability for applications assistance or customer product design. Customers are responsible for their products and applications using TI components. To minimize the risks associated with customer products and applications, customers should provide adequate design and operating safeguards. TI does not warrant or represent that any license, either express or implied, is granted under any TI patent right, copyright, mask work right, or other TI intellectual property right relating to any combination, machine, or process in which TI products or services are used. Information published by TI regarding third-party products or services does not constitute a license from TI to use such products or services or a warranty or endorsement thereof. Use of such information may require a license from a third party under the patents or other intellectual property of the third party, or a license from TI under the patents or other intellectual property of TI. Reproduction of TI information in TI data books or data sheets is permissible only if reproduction is without alteration and is accompanied by all associated warranties, conditions, limitations, and notices. Reproduction of this information with alteration is an unfair and deceptive business practice. TI is not responsible or liable for such altered documentation. Information of third parties may be subject to additional restrictions. Resale of TI products or services with statements different from or beyond the parameters stated by TI for that product or service voids all express and any implied warranties for the associated TI product or service and is an unfair and deceptive business practice. TI is not responsible or liable for any such statements. TI products are not authorized for use in safety-critical applications (such as life support) where a failure of the TI product would reasonably be expected to cause severe personal injury or death, unless officers of the parties have executed an agreement specifically governing such use. Buyers represent that they have all necessary expertise in the safety and regulatory ramifications of their applications, and acknowledge and agree that they are solely responsible for all legal, regulatory and safety-related requirements concerning their products and any use of TI products in such safety-critical applications, notwithstanding any applications-related information or support that may be provided by TI. Further, Buyers must fully indemnify TI and its representatives against any damages arising out of the use of TI products in such safety-critical applications. TI products are neither designed nor intended for use in military/aerospace applications or environments unless the TI products are specifically designated by TI as military-grade or "enhanced plastic." Only products designated by TI as military-grade meet military specifications. Buyers acknowledge and agree that any such use of TI products which TI has not designated as military-grade is solely at the Buyer's risk, and that they are solely responsible for compliance with all legal and regulatory requirements in connection with such use. TI products are neither designed nor intended for use in automotive applications or environments unless the specific TI products are designated by TI as compliant with ISO/TS 16949 requirements. Buyers acknowledge and agree that, if they use any non-designated products in automotive applications, TI will not be responsible for any failure to meet such requirements. Following are URLs where you can obtain information on other Texas Instruments products and application solutions: Products Applications Audio www.ti.com/audio Communications and Telecom www.ti.com/communications Amplifiers amplifier.ti.com Computers and Peripherals www.ti.com/computers Data Converters dataconverter.ti.com Consumer Electronics www.ti.com/consumer-apps DLP(R) Products www.dlp.com Energy and Lighting www.ti.com/energy DSP dsp.ti.com Industrial www.ti.com/industrial Clocks and Timers www.ti.com/clocks Medical www.ti.com/medical Interface interface.ti.com Security www.ti.com/security Logic logic.ti.com Space, Avionics and Defense www.ti.com/space-avionics-defense Power Mgmt power.ti.com Transportation and Automotive www.ti.com/automotive Microcontrollers microcontroller.ti.com Video and Imaging RFID www.ti-rfid.com OMAP Mobile Processors www.ti.com/omap Wireless Connectivity www.ti.com/wirelessconnectivity TI E2E Community Home Page www.ti.com/video e2e.ti.com Mailing Address: Texas Instruments, Post Office Box 655303, Dallas, Texas 75265 Copyright (c) 2011, Texas Instruments Incorporated