LF444

LF444 SYC | Alldatasheet

Document overview

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Technical content

Features

n 1⁄4 supply current of a LM148: 200 µA/Amplifier (max) n Low input bias current: 50 pA (max) n High gain bandwidth: 1 MHz n High slew rate: 1 V/µs n Low noise voltage for low power n Low input noise current n High input impedance: 1012Ω n High gain: 50k (min) Simplified Schematic 1/4 Quad 00915601

Ordering Information

X indicates electrical grade Y indicates temperature range “M” for military, “C” for commercial Z indicates package type “D”, “M” or “N” Connection Diagram Dual-In-Line Package 00915602 Top View Order Number LF444CM, LF444CMX, LF444ACN, LF 444CN or LF444MD/883 See NS Package Number D14E, M14A or N14A LF444 Quad Low Power JFET Input Operational Amplifier

Absolute Maximum Ratings(Note 11) If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications. LF444A LF444 Supply Voltage ±22V ±18V Differential Input Voltage ±38V ±30V Input Voltage Range ±19V ±15V (Note 1) Output Short Circuit Continuous Continuous Duration (Note 2) D Package N, M Packages Power Dissipation 900 mW 670 mW (Notes 3, 9) Tj max 150˚C 115˚C θjA (Typical) 100˚C/W 85˚C/W LF444A/LF444 Operating Temperature Range (Note 4) Storage Temperature Range −65˚C ≤ T A ≤ 150˚C ESD Tolerance (Note 10) Rating to be determined Soldering Information Dual-In-Line Packages (Soldering, 10 sec.) 260˚C Small Outline Package Vapor Phase (60 sec.) 215˚C Infrared (15 sec.) 220˚C See AN-450 “Surface Mounting Methods and Their Effect on Product Reliability” for other methods of soldering surface mount devices. Symbol Parameter Conditions LF444A LF444 Units Min Typ Max Min Typ Max VOS Input Offset Voltage R S = 10k, TA = 25˚C 2 5 3 10 mV 0˚C ≤ TA ≤ +70˚C 6.5 12 mV ∆VOS/∆T Average TC of Input R S =1 0k Ω 10 10 µV/˚C Offset Voltage IOS Input Offset Current V S = ±15V T j = 25˚C 5 25 5 50 pA (Notes 5, 6) T j = 70˚C 1.5 1.5 nA Tj = 125˚C 10 nA IB Input Bias Current V S = ±15V T j = 25˚C 10 50 10 100 pA (Notes 5, 6) T j = 70˚C 3 3 nA Tj = 125˚C 20 nA RIN Input Resistance T j = 25˚C 10 12 1012 Ω AVOL Large Signal Voltage V S = ±15V, VO = ±10V 50 100 25 100 V/mV Gain R L =1 0k Ω,T A = 25˚C Over Temperature 25 15 V/mV VO Output Voltage Swing V S = ±15V, RL =1 0k Ω ±12 ±13 ±12 ±13 V VCM Input Common-Mode ±16 +18 ±11 +14 V Voltage Range −17 −12 V CMRR Common-Mode R S ≤ 10 kΩ 80 100 70 95 dB Rejection Ratio PSRR Supply Voltage (Note 7) 80 100 70 90 dB Rejection Ratio IS Supply Current 0.6 0.8 0.6 1.0 mA LF444

Symbol Parameter Conditions LF444A LF444 Units Min Typ Max Min Typ Max Amplifier-to-Amplifier −120 −120 dB Coupling SR Slew Rate V S = ±15V, TA = 25˚C 1 1 V/µs GBW Gain-Bandwidth Product V S = ±15V, TA = 25˚C 1 1 MHz en Equivalent Input Noise Voltage T A = 25˚C, RS = 100Ω, 35 35 f=1k H z in Equivalent Input Noise Current T A = 25˚C,f=1k H z 0.01 0.01 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 ofθjA. Note 4: The LF444A is available in both the commercial temperature range 0˚C≤ TA ≤ 70˚C and the military temperature range −55˚C≤ TA ≤ 125˚C. The LF444 is available in the commercial temperature range only. 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 “D” package only. Note 5: Unless otherwise specified the specifications apply over the full temperature range and for VS = ±20V for the LF444A and for VS = ±15V for the LF444. VOS,I B, 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 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.T j =T A + 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 7: 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 LF444 and from±20V to ±5V for the LF444A. Note 8: Refer to RETS444X for LF444MD 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 kΩ in series with 100 pF. Note 11: 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. Electrical Characteristics state DC and AC electrical specifications under particular test conditions which guarantee specific performance limits. This assumes that the device is within the Operating Ratings. Specifications are not guaranteed for parameters where no limit is given, however, the typical value is a good indication of device performance. Typical Performance Characteristics Input Bias Current Input Bias Current 00915612 00915613 LF444

Typical Performance Characteristics (Continued) Supply Current Positive Common-Mode Input Voltage Limit 00915614 00915615 Negative Common-Mode Input Voltage Limit Positive Current Limit 00915616 00915617 Negative Current Limit Output Voltage Swing 00915618 00915619 LF444

Typical Performance Characteristics (Continued) Output Voltage Swing Gain Bandwidth 00915620 00915621 Bode Plot Slew Rate 00915622 00915623 Distortion vs Frequency Undistorted Output Voltage Swing 00915624 00915625 LF444

Typical Performance Characteristics (Continued) Open Loop Frequency Response Common-Mode Rejection Ratio 00915626 00915627 Power Supply Rejection Ratio Equivalent Input Noise Voltage 00915628 00915629 Open Loop Voltage Gain Output Impedance 00915630 00915631 LF444

Typical Performance Characteristics (Continued) Inverter Settling Time 00915632 Pulse Response RL =1 0k Ω,C L =1 0p F Small Signal Inverting 00915606 Small Signal Non-Inverting 00915607 Large Signal Inverting 00915608 Large Signal Non-Inverting 00915609 Application Hints This device is a quad low power op amp with JFET input devices ( BI-FET™ ). These JFETs have large reverse break- down voltages from gate to source and drain eliminating the need for clamps across the inputs. Therefore, large differen- tial input voltages can easily be accommodated without a large increase in input current. The maximum differential input voltage is independent of the supply voltages. How- ever, 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. LF444

Application Hints (Continued) 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 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. 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. 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 feed- back 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 feed- back 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. LF444

pH Probe Amplifier/Temperature Compensator 00915610 For R2 = 100k, R4 = 75k±1% For R2 = 200k, R4 = 56k±1% **Polystyrene *Film resistor type RN60C To calibrate, insert probe in pH =7 solution. Set the “TEMPERATURE ADJUST” pot, R2, to correspond to the solution temperature: full clockwise for 0˚C,and proportionately for intermediate temperatures, using a turns-counting dial. Then set “CALIBRATE” pot so output reads 7V. Typical probe = Ingold Electrodes #465-35 LF444

Physical Dimensions inches (millimeters) unless otherwise noted Order Number LF444MD/883 See NS Package Number D14E Order Number LF444CM or LF444CMX See NS Package Number M14A LF444

Physical Dimensions inches (millimeters) unless otherwise noted (Continued) Order Number LF444ACN or LF444CN See NS Package Number N14A LF444 Quad Low Power JFET Input Operational Amplifier