LM158/LM258/LM358/LM2904 Low Power Dual Operational Amplifiers General Description Advantages The LM158 series consists of two independent, high gain, internally frequency compensated operational amplifiers which were designed specifically to operate from a single power supply over a wide range of voltages. Operation from split power supplies is also possible and the low power supply current drain is independent of the magnitude of the power supply voltage. Application areas include transducer amplifiers, dc gain blocks and all the conventional op amp circuits which now can be more easily implemented in single power supply systems. For example, the LM158 series can be directly operated off of the standard +5V power supply voltage which is used in digital systems and will easily provide the required interface electronics without requiring the additional 15V power supplies. The LM358 is also available in a chip sized package (8-Bump micro SMD) using National's micro SMD package technology. n Two internally compensated op amps n Eliminates need for dual supplies n Allows direct sensing near GND and VOUT also goes to GND n Compatible with all forms of logic n Power drain suitable for battery operation n Pin-out same as LM1558/LM1458 dual op amp Unique Characteristics n In the linear mode the input common-mode voltage range includes ground and the output voltage can also swing to ground, even though operated from only a single power supply voltage. n The unity gain cross frequency is temperature compensated. n The input bias current is also temperature compensated. Connection Diagrams Features n Available in 8-Bump micro SMD chip sized package, (See AN-1112) n Internally frequency compensated for unity gain n Large dc voltage gain: 100 dB n Wide bandwidth (unity gain): 1 MHz (temperature compensated) n Wide power supply range: -- Single supply: 3V to 32V -- or dual supplies: 1.5V to 16V n Very low supply current drain (500 A) -- essentially independent of supply voltage n Low input offset voltage: 2 mV n Input common-mode voltage range includes ground n Differential input voltage range equal to the power supply voltage n Large output voltage swing: 0V to V+- 1.5V micro SMD Marking Orientation 8-Bump micro SMD DS007787-56 Bumps are numbered counter-clockwise. DS007787-55 Top View (Bump Side Down) (c) 2000 National Semiconductor Corporation DS007787 Top View www.national.com LM158/LM258/LM358/LM2904 Low Power Dual Operational Amplifiers January 2000 LM158/LM258/LM358/LM2904 Connection Diagrams (Continued) DIP/SO Package Metal Can Package DS007787-2 Top View DS007787-1 Top View Ordering Information Package Temperature Range 0C to 70C -40C to 85C SO-8 LM358AM LM358M LM2904M 8-Pin Molded DIP LM358AN LM358N LM2904N 8-Pin Ceramic DIP TO-5, 8-Pin Metal Can -55C to 125C -25C to 85C LM158AJ/883(Note 1) LM158J/883(Note 1) LM158J LM158AJLQML(Note 2) LM158AJQMLV(Note 2) LM158AH/883(Note 1) LM158H/883(Note 1) LM158AH LM158H LM158AHLQML(Note 2) LM158AHLQMLV(Note 2) M08A N08E J08A LM258H LM358H H08C 8-Bump micro SMD LM358BP LM358BPX Note 1: LM158 is available per SMD #5962-8771001 LM158A is available per SMD #5962-8771002 Note 2: See STD Mil DWG 5962L87710 for Radiation Tolerant Devices www.national.com NSC Drawing 2 BPA08AAA If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications. LM158/LM258/LM358 LM158A/LM258A/LM358A 32V 32V -0.3V to +32V LM2904 26V Supply Voltage, V+ Differential Input Voltage 26V Input Voltage -0.3V to +26V Power Dissipation (Note 3) Molded DIP 830 mW 830 mW Metal Can 550 mW Small Outline Package (M) 530 mW 530 mW micro SMD 435mW Output Short-Circuit to GND (One Amplifier) (Note 4) Continuous Continuous V+ 15V and TA = 25C 50 mA 50 mA Input Current (VIN < -0.3V) (Note 5) Operating Temperature Range LM358 0C to +70C -40C to +85C LM258 -25C to +85C LM158 -55C to +125C Storage Temperature Range -65C to +150C -65C to +150C Lead Temperature, DIP (Soldering, 10 seconds) 260C 260C Lead Temperature, Metal Can (Soldering, 10 seconds) 300C 300C Soldering Information Dual-In-Line Package Soldering (10 seconds) 260C 260C Small Outline Package Vapor Phase (60 seconds) 215C 215C Infrared (15 seconds) 220C 220C See AN-450 "Surface Mounting Methods and Their Effect on Product Reliability" for other methods of soldering surface mount devices. ESD Tolerance (Note 12) 250V 250V Electrical Characteristics V+ = +5.0V, unless otherwise stated Parameter Conditions LM158A Min Typ Input Offset Voltage Input Bias Current (Note 7), TA = 25C IIN(+) or IIN(-), TA = 25C, Input Common-Mode VCM = 0V, (Note 8) IIN(+) - IIN(-), VCM = 0V, TA = 25C V+ = 30V, (Note 9) Voltage Range (LM2904, V+ = 26V), TA = 25C Supply Current Over Full Temperature Range RL = on All Op Amps V+ = 30V (LM2904 V+ = 26V) Input Offset Current LM158/LM258 Max Min Typ Units Max 1 2 2 3 2 5 mV 50 45 100 45 150 nA 10 5 30 3 30 nA + V -1.5 0 3 Min Typ 20 2 V+ = 5V LM358A Max + 0 V -1.5 + 0 V -1.5 V 1 2 1 2 1 2 mA 0.5 1.2 0.5 1.2 0.5 1.2 mA www.national.com LM158/LM258/LM358/LM2904 Absolute Maximum Ratings (Note 11) LM158/LM258/LM358/LM2904 Electrical Characteristics V+ = +5.0V, unless otherwise stated Parameter Conditions LM358 Min Typ (Note 7) , TA = 25C IIN(+) or IIN(-), TA = 25C, Input Offset Voltage Input Bias Current Input Offset Current Input Common-Mode VCM = 0V, (Note 8) IIN(+) - IIN(-), VCM = 0V, TA = 25C V+ = 30V, (Note 9) LM2904 Max Min Units Typ Max 2 7 2 7 mV 45 250 45 250 nA 5 50 5 V+-1.5 0 0 50 nA V+-1.5 V + Voltage Range (LM2904, V = 26V), TA = 25C Supply Current Over Full Temperature Range RL = on All Op Amps V+ = 30V (LM2904 V+ = 26V) V+ = 5V 1 2 1 2 mA 0.5 1.2 0.5 1.2 mA Electrical Characteristics V+ = +5.0V, (Note 6), unless otherwise stated Parameter Conditions Gain V+ = 15V, TA = 25C, RL 2 k, (For VO = 1V Common-Mode to 11V) TA = 25C, Large Signal Voltage Rejection Ratio VCM = 0V to V+-1.5V V+ = 5V to 30V (LM2904, V+ = 5V Amplifier-to-Amplifier to 26V), TA = 25C f = 1 kHz to 20 kHz, TA = 25C Rejection Ratio Power Supply Coupling Output Current Source VIN- = 1V, VIN+ = 0V TA = 25C, VO = 200 mV, V+ = 15V Short Circuit to Ground TA = 25C, (Note 4), V+ = 15V Input Offset Voltage (Note 7) RS = 0 Input Offset Current Input Common-Mode Voltage Range www.national.com Min Typ Max Min Typ Units Max 100 25 100 50 100 V/mV 70 85 65 85 70 85 dB 65 100 65 100 65 100 dB -120 dB -120 -120 20 40 20 40 20 40 mA 10 20 10 20 10 20 mA 12 50 12 50 12 50 A 40 7 IIN(+) - IIN(-) RS = 0 IIN(+) or IIN(-) V+ = 30 V, (Note 9) (LM2904, V+ = 26V) 60 40 4 0 4 60 40 5 15 7 30 Drift Input Bias Current Max LM158/LM258 50 Drift Input Offset Current LM358A VO = 2V, TA = 25C VIN- = 1V, VIN+ = 0V V+ = 15V, TA = 25C, VO = 2V Input Offset Voltage Min Typ (Input Referred), (Note 10) VIN+ = 1V, VIN- = 0V, V+ = 15V, Sink LM158A 20 75 10 300 10 40 100 40 200 40 V+-2 7 mV V/C 100 200 0 mA 7 10 V+-2 60 0 nA pA/C 300 nA V+-2 V (Continued) V+ = +5.0V, (Note 6), unless otherwise stated Parameter Conditions LM158A Min Typ LM358A Max Min Typ LM158/LM258 Max Min Typ Units Max Gain V+ = +15V (VO = 1V to 11V) 25 15 25 V/mV Output RL 2 k V+ = +30V 26 26 26 V Large Signal Voltage VOH RL = 2 k = (LM2904, V 26V) RL = 10 k + = V 5V, RL = 10 k + Voltage Swing VOL Output Current 27 28 5 27 28 20 5 27 28 20 5 V 20 mV Source VIN+ = +1V, VIN- = 0V, V+ = 15V, VO = 2V 10 20 10 20 10 20 mA Sink VIN- = +1V, VIN+ = 0V, V+ = 15V, VO = 2V 10 15 5 8 5 8 mA Electrical Characteristics V+ = +5.0V, (Note 6), unless otherwise stated Parameter Gain V+ = 15V, TA = 25C, RL 2 k, (For VO = 1V Common-Mode to 11V) TA = 25C, Large Signal Voltage Rejection Ratio VCM = 0V to V+-1.5V V+ = 5V to 30V (LM2904, V+ = 5V Amplifier-to-Amplifier to 26V), TA = 25C f = 1 kHz to 20 kHz, TA = 25C Rejection Ratio Power Supply Coupling Output Current LM358 Conditions Source 25 VO = 2V, TA = 25C VIN- = 1V, VIN+ = 0V V+ = 15V, TA = 25C, VO = 2V Short Circuit to Ground TA = 25C, (Note 4), V+ = 15V Input Offset Voltage (Note 7) RS = 0 Input Offset Current Typ 100 25 100 V/mV 65 85 50 70 dB 65 100 50 100 dB -120 dB Input Common-Mode 40 20 40 mA 10 20 10 20 mA 12 50 12 50 A 40 Voltage Range 60 40 9 7 IIN(+) - IIN(-) RS = 0 45 10 40 0 5 60 mA 10 mV 7 150 IIN(+) or IIN(-) V+ = 30 V, (Note 9) (LM2904, V+ = 26V) Max 20 Drift Input Bias Current Units Min Drift Input Offset Current LM2904 Max -120 VIN- = 1V, VIN+ = 0V TA = 25C, VO = 200 mV, V+ = 15V Input Offset Voltage Typ (Input Referred), (Note 10) VIN+ = 1V, VIN- = 0V, V+ = 15V, Sink Min V/C 200 10 500 V+-2 40 0 nA pA/C 500 nA V+ -2 V www.national.com LM158/LM258/LM358/LM2904 Electrical Characteristics LM158/LM258/LM358/LM2904 Electrical Characteristics (Continued) V+ = +5.0V, (Note 6), unless otherwise stated Parameter Gain V+ = +15V (VO = 1V to 11V) Output RL 2 k V+ = +30V Large Signal Voltage VOH + Voltage Swing Output Current LM358 Conditions VOL (LM2904, V = 26V) V+ = 5V, RL = 10 k Min RL = 2 k RL = 10 k Typ LM2904 Max Min Typ Units Max 15 15 V/mV 26 22 V 27 28 5 23 20 24 5 V 100 mV Source VIN+ = +1V, VIN- = 0V, V+ = 15V, VO = 2V 10 20 10 20 mA Sink VIN- = +1V, VIN+ = 0V, V+ = 15V, VO = 2V 5 8 5 8 mA Note 3: For operating at high temperatures, the LM358/LM358A, LM2904 must be derated based on a +125C maximum junction temperature and a thermal resistance of 120C/W for MDIP, 182C/W for Metal Can, 189C/W for Small Outline package, and 230C/W for micro SMD, which applies for the device soldered in a printed circuit board, operating in a still air ambient. The LM258/LM258A and LM158/LM158A can be derated based on a +150C maximum junction temperature. The dissipation is the total of both amplifiers -- use external resistors, where possible, to allow the amplifier to saturate or to reduce the power which is dissipated in the integrated circuit. Note 4: Short circuits from the output to V+ can cause excessive heating and eventual destruction. When considering short cirucits to ground, the maximum output current is approximately 40 mA independent of the magnitude of V+. At values of supply voltage in excess of +15V, continuous short-circuits can exceed the power dissipation ratings and cause eventual destruction. Destructive dissipation can result from simultaneous shorts on all amplifiers. Note 5: This input current will only exist when the voltage at any of the input leads is driven negative. It is due to the collector-base junction of the input PNP transistors becoming forward biased and thereby acting as input diode clamps. In addition to this diode action, there is also lateral NPN parasitic transistor action on the IC chip. This transistor action can cause the output voltages of the op amps to go to the V+voltage level (or to ground for a large overdrive) for the time duration that an input is driven negative. This is not destructive and normal output states will re-establish when the input voltage, which was negative, again returns to a value greater than -0.3V (at 25C). Note 6: These specifications are limited to -55C TA +125C for the LM158/LM158A. With the LM258/LM258A, all temperature specifications are limited to -25C TA +85C, the LM358/LM358A temperature specifications are limited to 0C TA +70C, and the LM2904 specifications are limited to -40C TA +85C. Note 7: VO 1.4V, RS = 0 with V+ from 5V to 30V; and over the full input common-mode range (0V to V+ -1.5V) at 25C. For LM2904, V+ from 5V to 26V. Note 8: The direction of the input current is out of the IC due to the PNP input stage. This current is essentially constant, independent of the state of the output so no loading change exists on the input lines. Note 9: The input common-mode voltage of either input signal voltage should not be allowed to go negative by more than 0.3V (at 25C). The upper end of the common-mode voltage range is V+ -1.5V (at 25C), but either or both inputs can go to +32V without damage (+26V for LM2904), independent of the magnitude of V+. Note 10: Due to proximity of external components, insure that coupling is not originating via stray capacitance between these external parts. This typically can be detected as this type of capacitance increases at higher frequencies. Note 11: Refer to RETS158AX for LM158A military specifications and to RETS158X for LM158 military specifications. Note 12: Human body model, 1.5 k in series with 100 pF. Typical Performance Characteristics Input Voltage Range Input Current Supply Current DS007787-34 www.national.com DS007787-35 6 DS007787-36 Voltage Gain LM158/LM258/LM358/LM2904 Typical Performance Characteristics (Continued) Open Loop Frequency Response Common-Mode Rejection Ratio DS007787-37 DS007787-38 DS007787-39 Voltage Follower Pulse Response Voltage Follower Pulse Response (Small Signal) DS007787-40 Output Characteristics Current Sourcing Large Signal Frequency Response DS007787-41 Output Characteristics Current Sinking DS007787-42 Current Limiting DS007787-45 DS007787-43 DS007787-44 7 www.national.com LM158/LM258/LM358/LM2904 Typical Performance Characteristics (Continued) Input Current (LM2902 only) Voltage Gain (LM2902 only) DS007787-46 DS007787-47 Capacitive loads which are applied directly to the output of the amplifier reduce the loop stability margin. Values of 50 pF can be accomodated using the worst-case non-inverting unity gain connection. Large closed loop gains or resistive isolation should be used if larger load capacitance must be driven by the amplifier. The bias network of the LM158 establishes a drain current which is independent of the magnitude of the power supply voltage over the range of 3 VDC to 30 VDC. Output short circuits either to ground or to the positive power supply should be of short time duration. Units can be destroyed, not as a result of the short circuit current causing metal fusing, but rather due to the large increase in IC chip dissipation which will cause eventual failure due to excessive function temperatures. Putting direct short-circuits on more than one amplifier at a time will increase the total IC power dissipation to destructive levels, if not properly protected with external dissipation limiting resistors in series with the output leads of the amplifiers. The larger value of output source current which is available at 25C provides a larger output current capability at elevated temperatures (see typical performance characteristics) than a standard IC op amp. The circuits presented in the section on typical applications emphasize operation on only a single power supply voltage. If complementary power supplies are available, all of the standard op amp circuits can be used. In general, introducing a pseudo-ground (a bias voltage reference of V+/2) will allow operation above and below this value in single power supply systems. Many application circuits are shown which take advantage of the wide input common-mode voltage range which includes ground. In most cases, input biasing is not required and input voltages which range to ground can easily be accommodated. Application Hints The LM158 series are op amps which operate with only a single power supply voltage, have true-differential inputs, and remain in the linear mode with an input common-mode voltage of 0 VDC. These amplifiers operate over a wide range of power supply voltage with little change in performance characteristics. At 25C amplifier operation is possible down to a minimum supply voltage of 2.3 VDC. Precautions should be taken to insure that the power supply for the integrated circuit never becomes reversed in polarity or that the unit is not inadvertently installed backwards in a test 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. Large differential input voltages can be easily accomodated and, as input differential voltage protection diodes are not needed, no large input currents result from large differential input voltages. The differential input voltage may be larger than V+ without damaging the device. Protection should be provided to prevent the input voltages from going negative more than -0.3 VDC (at 25C). An input clamp diode with a resistor to the IC input terminal can be used. To reduce the power supply current drain, the amplifiers have a class A output stage for small signal levels which converts to class B in a large signal mode. This allows the amplifiers to both source and sink large output currents. Therefore both NPN and PNP external current boost transistors can be used to extend the power capability of the basic amplifiers. The output voltage needs to raise approximately 1 diode drop above ground to bias the on-chip vertical PNP transistor for output current sinking applications. For ac applications, where the load is capacitively coupled to the output of the amplifier, a resistor should be used, from the output of the amplifier to ground to increase the class A bias current and prevent crossover distortion. Where the load is directly coupled, as in dc applications, there is no crossover distortion. www.national.com 8 LM158/LM258/LM358/LM2904 Typical Single-Supply Applications (V+ = 5.0 VDC) Non-Inverting DC Gain (0V Output) DS007787-7 DS007787-6 *R not needed due to temperature independent IIN DC Summing Amplifier (VIN'S 0 VDC and VO 0 VDC) Power Amplifier DS007787-9 DS007787-8 Where: VO = V1 + V2 + V3 + V4 (V1 + V2) (V3 + V4) to keep VO VO = 0 VDC for VIN = 0 VDC AV = 10 > 0 VDC 9 www.national.com LM158/LM258/LM358/LM2904 Typical Single-Supply Applications (V+ = 5.0 VDC) (Continued) "BI-QUAD" RC Active Bandpass Filter DS007787-10 fo = 1 kHz Q = 50 Av = 100 (40 dB) Fixed Current Sources Lamp Driver DS007787-12 DS007787-11 www.national.com 10 LM158/LM258/LM358/LM2904 Typical Single-Supply Applications (V+ = 5.0 VDC) (Continued) LED Driver Current Monitor DS007787-13 DS007787-14 *(Increase R1 for IL small) VL V+ -2V Driving TTL Voltage Follower DS007787-15 DS007787-17 VO = VIN Pulse Generator DS007787-16 11 www.national.com LM158/LM258/LM358/LM2904 Typical Single-Supply Applications (V+ = 5.0 VDC) (Continued) Squarewave Oscillator Pulse Generator DS007787-18 DS007787-19 Low Drift Peak Detector DS007787-20 HIGH ZIN LOW ZOUT www.national.com 12 LM158/LM258/LM358/LM2904 Typical Single-Supply Applications (V+ = 5.0 VDC) (Continued) High Compliance Current Sink Comparator with Hysteresis DS007787-22 DS007787-21 IO = 1 amp/volt VIN (Increase RE for IO small) Voltage Controlled Oscillator (VCO) DS007787-23 *WIDE CONTROL VOLTAGE RANGE: 0 VDC VC 2 (V+ -1.5V DC) 13 www.national.com LM158/LM258/LM358/LM2904 Typical Single-Supply Applications (V+ = 5.0 VDC) (Continued) AC Coupled Inverting Amplifier DS007787-24 Ground Referencing a Differential Input Signal DS007787-25 www.national.com 14 LM158/LM258/LM358/LM2904 Typical Single-Supply Applications (V+ = 5.0 VDC) (Continued) AC Coupled Non-Inverting Amplifier DS007787-26 Av = 11 (As Shown) DC Coupled Low-Pass RC Active Filter DS007787-27 fo = 1 kHz Q=1 AV = 2 15 www.national.com LM158/LM258/LM358/LM2904 Typical Single-Supply Applications (V+ = 5.0 VDC) (Continued) Bandpass Active Filter DS007787-28 fo = 1 kHz Q = 25 High Input Z, DC Differential Amplifier DS007787-29 www.national.com 16 LM158/LM258/LM358/LM2904 Typical Single-Supply Applications (V+ = 5.0 VDC) (Continued) Photo Voltaic-Cell Amplifier Bridge Current Amplifier DS007787-30 DS007787-33 High Input Z Adjustable-Gain DC Instrumentation Amplifier DS007787-31 17 www.national.com LM158/LM258/LM358/LM2904 Typical Single-Supply Applications (V+ = 5.0 VDC) (Continued) Using Symmetrical Amplifiers to Reduce Input Current (General Concept) DS007787-32 Schematic Diagram (Each Amplifier) DS007787-3 www.national.com 18 LM158/LM258/LM358/LM2904 Physical Dimensions inches (millimeters) unless otherwise noted Metal Can Package (H) Order Number LM158AH, LM158AH/883, LM158H, LM158H/883, LM258H or LM358H NS Package Number H08C Cerdip Package (J) Order Number LM158J, LM158J/883, LM158AJ or LM158AJ/883 NS Package Number J08A 19 www.national.com LM158/LM258/LM358/LM2904 Physical Dimensions inches (millimeters) unless otherwise noted (Continued) S.O. Package (M) Order Number LM358M, LM358AM or LM2904M NS Package Number M08A www.national.com 20 LM158/LM258/LM358/LM2904 Physical Dimensions inches (millimeters) unless otherwise noted (Continued) Molded Dip Package (N) Order Number LM358AN, LM358N or LM2904N NS Package Number N08E 21 www.national.com LM158/LM258/LM358/LM2904 Physical Dimensions inches (millimeters) unless otherwise noted (Continued) NOTES: UNLESS OTHERWISE SPECIFIED 1. EPOXY COATING 2. 63Sn/37Pb EUTECTIC BUMP 3. RECOMMEND NON-SOLDER MASK DEFINED LANDING PAD. 4. PIN 1 IS ESTABLISHED BY LOWER LEFT CORNER WITH RESPECT TO TEXT ORIENTATION REMAINING PINS ARE NUMBERED COUNTERCLOCKWISE. 5. XXX IN DRAWING NUMBER REPRESENTS PACKAGE SIZE VARIATION WHERE X1 IS PACKAGE WIDTH, X2 IS PACKAGE LENGTH AND X3 IS PACKAGE HEIGHT. 6. REFERENCE JEDEC REGISTRATION MO-211, VARIATION BC. 8-Bump micro SMD NS Package Number BPA08AAA X1 = 1.285 X2 = 1.285 X3 = 0.700 www.national.com 22 LM158/LM258/LM358/LM2904 Low Power Dual Operational Amplifiers Notes 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. National Semiconductor Corporation Americas Tel: 1-800-272-9959 Fax: 1-800-737-7018 Email: support@nsc.com www.national.com National Semiconductor Europe Fax: +49 (0) 1 80-530 85 86 Email: europe.support@nsc.com Deutsch Tel: +49 (0) 1 80-530 85 85 English Tel: +49 (0) 1 80-532 78 32 Francais Tel: +49 (0) 1 80-532 93 58 Italiano Tel: +49 (0) 1 80-534 16 80 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 Asia Pacific Customer Response Group Tel: 65-2544466 Fax: 65-2504466 Email: sea.support@nsc.com National Semiconductor Japan Ltd. Tel: 81-3-5639-7560 Fax: 81-3-5639-7507 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.