Dual Low Power JFET Input Operational Amplifier

LF442 Dual Low Power JFET Input Operational Amplifier April 1999 LF442 Dual Low Power JFET Input Operational Amplifier General Description 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 kΩ 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. 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. Features n n n n n n n n n n 1/10 supply current of a LM1458: 400 µA (max) Low input bias current: 50 pA (max) Low input offset voltage: 1 mV (max) Low input offset voltage drift: 10 µV/˚C (max) High gain bandwidth: 1 MHz High slew rate: 1 V/µs Low noise voltage for low power: Low input noise current: High input impedance: 1012Ω High gain VO = ± 10V, RL = 10k: 50k (min) Typical Connection Connection Diagrams Metal Can Package DS009155-2 Pin 4 connected to case DS009155-1 Ordering Information LF442XYZ X indicates electrical grade Y indicates temperature range “M” for military “C” for commercial Z indicates package type “H” or “N” Top View Order Number LF442AMH or LF442MH or LF442MH/883 See NS Package Number H08A Dual-In-Line Package DS009155-4 Top View Order Number LF442ACN or LF442CN See NS Package Number N08E BI-FET II™ is a trademark of National Semiconductor Corporation. © 1999 National Semiconductor Corporation DS009155 www.national.com 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 Differential Input Voltage Input Voltage Range (Note 2) Output Short Circuit Duration (Note 3) Tj max LF442A ± 22V ± 38V ± 19V Continuous H Package 150˚C LF442 ± 18V ± 30V ± 15V Continuous N Package 115˚C θJA (Typical) (Note 4) (Note 5) θJC (Typical) Operating Temperature Range Storage Temperature Range Lead Temperature (Soldering, 10 sec.) ESD Tolerance H Package 65˚C/W 165˚C/W 21˚C/W (Note 5) N Package 114˚C/W 152˚C/W (Note 5) −65˚C≤TA≤150˚C −65˚C≤TA≤150˚C 260˚C 260˚C Rating to be determined DC Electrical Characteristics Symbol VOS ∆VOS/∆T IOS Parameter Input Offset Voltage Average TC of Input Offset Voltage Input Offset Current VS = ± 15V (Notes 7, 8) IB Input Bias Current VS = ± 15V (Notes 7, 8) RIN AVOL Input Resistance Large Signal Voltage Gain VO VCM CMRR PSRR IS Output Voltage Swing Input Common-Mode Voltage Range Common-Mode Rejection Ratio Supply Voltage Rejection Ratio Supply Current (Note 9) RS ≤ 10 kΩ (Note 7) LF442A Min Typ 0.5 7 Tj = 25˚C Tj = 70˚C Tj = 125˚C Tj = 25˚C Tj = 70˚C Tj = 125˚C 1012 50 25 200 200 25 15 5 Max 1.0 10 25 1.5 10 10 50 3 20 1012 200 200 10 100 3 Min LF442 Typ 1.0 7 5 50 1.5 Max 5.0 7.5 mV mV µV/˚C pA nA nA pA nA nA Ω V/mV V/mV V V V dB dB 500 µA Units Conditions RS = 10 kΩ, TA = 25˚C Over Temperature RS = 10 kΩ Tj = 25˚C VS = ± 15V, VO = ± 10V, RL = 10 kΩ, TA = 25˚C Over Temperature VS = ± 15V, RL = 10 kΩ ± 12 ± 16 80 80 ± 13 +18 −17 100 100 300 400 ± 12 ± 11 70 70 ± 13 +14 −12 95 90 400 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 www.national.com (Note 7) LF442A Min Typ −120 0.8 0.8 1 1 35 0.01 0.6 0.6 Max Min LF442 Typ −120 1 1 35 0.01 Max dB V/µs MHz Units Conditions TA = 25˚C, f = 1 Hz-20 kHz (Input Referred) VS = ± 15V, TA = 25˚C VS = ± 15V, TA = 25˚C TA = 25˚C, RS = 100Ω, f = 1 kHz TA = 25˚C, f = 1 kHz 2 AC Electrical Characteristics (Note 7) (Continued) 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 0˚C ≤ TA ≤ 70˚C and the military temperature range −55˚C ≤ TA ≤ 125˚C. 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 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 = TA + θjAPD 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 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. Typical Performance Characteristics Input Bias Current Input Bias Current Supply Current DS009155-17 DS009155-18 DS009155-19 Positive Common-Mode Input Voltage Limit Negative Common-Mode Input Voltage Limit Positive Current Limit DS009155-22 DS009155-20 DS009155-21 3 www.national.com Typical Performance Characteristics Negative Current Limit (Continued) Output Voltage Swing Output Voltage Swing DS009155-23 DS009155-24 DS009155-25 Gain Bandwidth Bode Plot Slew Rate DS009155-26 DS009155-27 DS009155-28 Distortion vs Frequency Undistorted Output Voltage Swing Open Loop Frequency Response DS009155-29 DS009155-30 DS009155-31 www.national.com 4 Typical Performance Characteristics Common-Mode Rejection Ratio (Continued) Power Supply Rejection Ratio Equivalent Input Noise Voltage DS009155-32 DS009155-33 DS009155-34 Open Loop Voltage Gain Output Impedance Inverter Settling Time DS009155-35 DS009155-36 DS009155-37 Pulse Response RL = 10 kΩ, CL = 10 pF Small Signal Non-Inverting Small Signal Inverting DS009155-7 DS009155-8 5 www.national.com Pulse Response RL = 10 kΩ, CL = 10 pF (Continued) Large Signal Non-Inverting Large Signal Inverting DS009155-9 DS009155-10 Application Hints This device is a dual low power op amp with internally trimmed input offset voltages 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 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. 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. The amplifiers will drive a 10 kΩ load resistance to ± 10V over the full temperature range. 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, c