(AV vational Semiconductor LM108A/LM208A/LM308A Operational Amplifiers May 1989 General Description The LM108/LM108A series are precision operational ampli- fiers having specifications about a factor of ten better than FET amplifiers over their operating temperature range. In addition to low input currents, these devices have extremely low offset voltage, making it possible to eliminate offset ad- justments, in most cases, and obtain performance ap- proaching chopper stabilized amplifiers. The devices operate with supply voltages from +2V to +18V and have sufficient supply rejection to use unregulat- ed supplies. Although the circuit is interchangeable with and uses the same compensation as the LM101A, an alternate compensation scheme can be used to make it particularly insensitive to power supply noise and to make supply by- pass capacitors unnecessary. The low current error of the LM108A series makes possible many designs that are not practical with conventional ampli- fiers. In fact, it operates from 10 MQ source resistances, introducing less error than devices like the 709 with 10 kN sources. Integrators with drifts less than 500 V/sec and analog time delays in excess of one hour can be made us- ing capacitors no larger than 1 pF. The LM208A is identical to the LM108A, except that the LM208A has its performance guaranteed over a 25C to +85C temperature range, instead of 55C to + 125C. The LM308A devices have slightly-relaxed specifications and performances over a 0C to +70C temperature range. Features & Offset voltage guaranteed less than 0.5 mV B Maximum input bias current of 3.0 nA over temperature m Offset current less than 400 pA over temperature @ Supply current of only 300 pA, even in saturation mB Guaranteed 5 pV/C drift Compensation Circuits Standard Compensation Circuit Ri R2 -Vin LM108A Vour Vin, R1Co > Yo o R1+R2 c,** Co = 30 pF TL/H/7759-1 **Bandwidth and slew rate are proportional to 1/C;. INPUT **Bandwidth and slew rate are proportional to 1/C,. Feedforward Compensation c2 5 pF LM10BA Alternate* Frequency Compensation Al R2 Vin Vout Vin + att LM108A . Cs 100 pF *Improves rejection of power supply noise by a factor of ten. = TL/H/7759-2 OUTPUT TL/H/7759-3 1995 National Semiconductor Corporation TL/H/7759 RRD-B30M115/Printed in U.S. A. suaijduiy jeuojje19dO WE80EW1/V80ZW1/V80LWTILM108A/LM208A Absolute Maximum Ratings If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/Distributors for availability and specifications. (Note 5) Supply Voltage +20V Power Dissipation (Note 1) 500 mW Differential Input Current (Note 2) +10mA Input Voltage (Note 3) +15V Output Short-Circuit Duration Operating Free Air Temperature Range Continuous Storage Temperature Range 65C to + 150C Lead Temperature (Soldering, 10 sec.) (DIP) 260C Soldering Information Dual-In-Line Package Soldering (10 sec.) 260C Small Outline Package Vapor Phase (60 sec.) 215C Infrared (15 sec.) 220C See An-450 Surface Mounting Methods and Their Effect on Product Reliability for other methods of soldering sur- face mount devices. LM108A 55C to + 125C LM208A 25C to +85C ESD Tolerance (Note 6) 2000V Electrical Characteristics (note 4) Parameter Conditions Min Typ Max Units Input Offset Voltage Ta = 25C 0.3 0.5 mV Input Offset Current Ta = 25C 0.05 0.2 nA Input Bias Current Ta = 25C 0.8 2.0 nA Input Resistance Ta = 25C 30 70 MQ Supply Current Ta = 25C 0.3 0.6 mA Large Signal Voltage Gain Ta = 25C, Vg = + 15V, Vout = 10V, RL = 10ko 80 300 viv Input Offset Voltage 1.0 mV Average Temperature Coefficient 3 of Input Offset Voltage 10 5.0 B/C Input Offset Current 0.4 nA Average Temperature Coefficient of Input Offset Current 0.6 25 pArC Input Bias Current 3.0 nA Supply Current Ta = 125C 0.15 0.4 mA Large Signal Voltage Gain Vs = +15V, Vout = +10V, RL > 10k 40 vim Output Voltage Swing Vg = +15V, RL = 10k +13 +14 Input Voltage Range Vs = +15V 413.5 v Common Mode Rejection Ratio 96 110 dB Supply Voltage Rejection Ratio 96 110 dB Note 1; The maximum junction temperature of the LM108A is 150C, while that of the LM208A is 100C. For operating at elevated temperatures, devices in the HO8 package must be derated based on a thermal resistance of 160C/W, junction to ambient, or 20C/W, junction to case. The thermal resistance of the dual-in-line package is 100C/W, junction to ambient. Note 2: The inputs are shunted with back-to-back diodes for overvoltage protection. Therefore, excessive current will flow if a differential input voltage in excess of 1V is applied between the inputs unless some limiting resistance is used. Note 3: For supply voltages less than +15V, the absolute maximum input voltage is equal to the supply voltage. Note 4: These specifications apply for +5V < Vs < 20V and 55C < Ta < 125C, unless otherwise specified. With the LM208A, however, all temperature specifications are limited to 25C < Ta < 85C. Note 5: Refer to RETS108AX for LM108AH and LM108AJ-8 military specifications. Note 6; Human body model, 1.5 k. in series with 100 pF.LM308A Absolute Maximum Ratings If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/Distributors for availability and specifications. Supply Voltage +18V Power Dissipation (Note 1) 500 mW Differential Input Current (Note 2) +10mA Input Voltage (Note 3) +15V Output Short-Circuit Duration Continuous Operating Temperature Range 0C to + 70C Storage Temperature Range 65C to + 150C H-Package Lead Temperature (Soldering, 10 sec.) 300C Electrical Characteristics (note 4) Lead Temperature (Soldering, 10 sec.) (DIP) Soldering Information Dual-In-Line Package Soldering (10 sec.) Small Outline Package Vapor phase (60 sec.) Infrared (15 sec.) 260C 260C 215C 220C See An-450 Surface Mounting Methods and Their Effect on Product Reliability for other methods of soldering sur- face mount devices. ESD rating to be determined. Parameter Conditions Min Typ Max Units Input Offset Voltage Ta = 25C 0.3 0.5 mV Input Offset Current Ta = 25C 0.2 1 nA Input Bias Current Ta = 25C 1.5 7 nA Input Resistance Ta = 25C 10 40 MQ Supply Current Ta = 25C, Vg = +15V 0.3 0.8 mA Large Signal Voltage Gain Ta = 25C, Vg = +15V, Vout = 10V, RL = 10kn 80 300 viv Input Offset Voltage Vg = +15V, Rg = 1002 0.73 mV Average Temperature Coefficient Vs = +15V, Rg = 1002 of Input Offset Voltage 2.0 5.0 BEC Input Offset Current 1.5 nA Average Temperature Coefficient of Input Offset Current 2.0 10 pArC Input Bias Current 10 nA Large Signal Voltage Gain Vs = +15V, Vout = +10V, RL > 10k 60 vim Output Voltage Swing Vg = 15V,R, = 10k +13 +14 V Input Voltage Range Vs = +15V +14 Common Mode Rejection Ratio 96 110 dB Supply Voltage Rejection Ratio 96 110 dB Note 1; The maximum junction temperature of the LM308A is 85C. For operating at elevated temperatures, devices in the HO8 package must be derated based on a thermal resistance of 160C/W, junction to ambient, or 20C/W, junction to case. The thermal resistance of the dual-in-line package is 100C/W, junction to ambient. Note 2: The inputs are shunted with back-to-back diodes for overvoltage protection. Therefore, excessive current will flow if a differential input voltage in excess of 1V is applied between the inputs unless some limiting resistance is used. Note 3: For supply voltages less than +15V, the absolute maximum input voltage is equal to the supply voltage. Note 4: These specifications apply for +5V < Vg < +15V and 0C < Ta < +70C, unless otherwise specified.Typical Applications Sample and Hold vt Rt 1M INPUT OUTPUT C2 tTeflon, polyethylene or polycarbonate dielectric capacitor. 30 pF Worst case drift less than 2.5 mV/sec. TL/H/7759-4 High Speed Amplifier with Low Drift and Low Input Current Rin RE INPUT AA /\$$< I WV OUTPUT 002 pF > 150K 2 150K < 002 uF 150K TL/H/7759-5Application Hints A very low drift amplifier poses some uncommon application and testing problems. Many sources of error can cause the apparent circuit drift to be much higher than would be pre- dicted. Thermocouple effects caused by temperature gradient across dissimilar metals are perhaps the worst offenders. Only a few degrees gradient can cause hundreds of micro- volts of error. The two places this shows up, generally, are the package-to-printed circuit board interface and tempera- ture gradients across resistors. Keeping package leads short and the two input leads close together helps greatly. Resistor choice as well as physical placement is important for minimizing thermocouple effects. Carbon, oxide film and some metal film resistors can cause large thermocouple er- rors. Wirewound resistors of evanohm or manganin are best since they only generate about 2 V/C referenced to cop- per. Of course, keeping the resistor ends at the same tem- perature is important. Generally, shielding a low drift stage electrically and thermally will yield good results. Schematic Diagram COMPENSATION Resistors can cause other errors besides gradient generat- ed voltages. If the gain setting resistors do not track with temperature a gain error will result. For example, a gain of 1000 amplifier with a constant 10 mV input will have a 10V output. If the resistors mistrack by 0.5% over the operating temperature range, the error at the output is 50 mV. Re- ferred to input, this is a 50 pV error. All of the gain fixing resistor should be the same material. Testing low drift amplifiers is also difficult. Standard drift testing technique such as heating the device in an oven and having the leads available through a connector, thermo- probe, or the soldering iron methoddo not work. Thermal gradients cause much greater errors than the amplifier drift. Coupling microvolt signal through connectors is especially bad since the temperature difference across the connector can be 50C or more. The device under test along with the gain setting resistor should be isothermal. COMPENSATION . e a _| . te R4 R5 hb SR? 20K 20K S10K 10K ate R9 2K > ng 013 a1 07 09 a1 5.6K R10 08 rfaro 90 6 a4 015 017 rem | 5 AN 05 06 * S a16 j 240 . o19 . N 2 -e01 eo a23 INPUTS 025 R14 @ 940 + R13 Nn 20K 26 JF $ Alz 420 > aQ24 R16 RID GOK Ri? 20K R15 6.4K 500 1K 4 Nv oW-@ oN oo vo TL/H/7759-6Connection Diagrams Metal Can Package comp 2 TL/H/7759-7 Pin 4 is connected to the case. **Unused pin (no internal connection) to allow for input anti-leakage guard ting on printed circuit board layout. Order Number LM108AH, LM208AH or LM208AH See NS Package Number H08C Physical Dimensions inches (millimeters) 0.350-0.370 *~ (g.8909,398) o Dual-In-Line Package comp 4 ~ ee comp 2 INPUT 4 yt inpuTt 4 ee ourpuT v4 Pc TL/H/7759-8 Top View Order Number LM 108AJ-8, LM208AJ-8, LM308AJ-8, LM308AM or LM308AN See NS Package Number JO8A, MO8A or NO8E 1A 0.315 -0.335 p44 (6.007 8.509) MAX 0.025 0.165 0.185 4 7635) UNCONTROLLED (1914.60) Y | YY REFERENCE PLANE YY _ A A 0.035 AE cots 0, pais_v.oap SEATING PLANE 0.500 (0.889) . . (12.70) = MAX MIN ll [ Y 0,029 0.045 \ (0.737 1.143) 0.028 0.034 45 EQUALLY SPACED ~~2- Metal Can Package (H) Order Number LM108AH, LM208AH or LM308AH NS Package Number HO8C i (0.381 1.016) |e 0.016 0.019 (0.406 0.483) D/ATYP 0.195 0.205 DIA (4.953 5.207) PC. | 0.115 0.145 (2.921 3.683) DIA HO8C (REV E}Physical Dimensions inches (millimeters) (Continued) RO.010 TYP \ - RO.025 J 0 [7] [] -400 MAX sal I 0.220 0.291 | I 0.310 MAX GLASS | LY 2] By i] 0.045 ~ 0.065 1? 0.290 lx 0.005 GLASS 0.320 MIN // seats t ft 0.180 | | MAX 0.200 [ Ss 9.020 MAX 0.060 4 f F 0.150 ! 0.125 MIN 0.055 MAX >| BOTH ENDS 0.008 0.012 TYP 0.310 0.410 | eee Ceramic Dual-In-Line Package (J) . 0.200 90 + 4 TYP 0.018 40.003 TYP 0.100 40.010 TYP JO8A (REV K} Order Number LM108AJ-8, LM208AJ-8 or LM308AJ-8 NS Package Number J08A 0.1890.197 {2 e005.004) 8 7 6 5 .-t fA Af 0.228 -0.244 5.791 6.198) | 0.010 max __| S (0.254) + _/ BY Ge uexnno. if 1 2 9 A Bh IDENT vp .150 0.157 (3.810 3.988) 0.000.020 45 ge) oe a (0.2540.508) (1346-1753) 0,008 0.010 | Be MAX TYP 1 9.004 0.010, ALL LEADS {0.102 0.254) _ 1 __ Ep J ' SEATING 5 oom # i i A i A PLANE {0.1025 i 0.014 0.0080.010 ay ean rips o.0160.060 joase) 2.950 0.014 0.020 typ (0.2030.254) Sate 00 (1.275) (0-386 0.508) TYP ALL LEADS (0.406 1 270) TYR 0.008 typ TYP ALL LEADS 0203) Wno8a (REV) $.0. Package (M) Order Number LM308AM NS Package Number M08ALM108A/LM208A/LM308A Operational Amplifiers Physical Dimensions: inches (mitimeters) (Continued) 0.3730.400 [*"{9.47410.16) >| 0.090 > (2.286) 0.092 yy [3 [71 f6) I) 0.032 +0.005 (2.337) SN ues (0.813 +0.127) ~ + on 0.250 + 0.005 RAD b PIN NO. 1 IDENT 1 {6.35 + 0.127} PIN NO. 1 IDENT ortion1 Le re LY LZ] Ls] ts] 0.280 0.040 <_ . ata) MIN 0.030 aay (1.016) re>| be 10 OPTION 2 0.3000.320 (0.762) | 0.039 0.145 -0.200 (7.628.128) { 20 1 / (0.881) (3.683 5.080) 4 I \ hood A 0.1304 0,005 4 : TL] y _ (3.30240.127) 95 +5" LA AL 0.125 0.140 A - 0,065 (3.175 3.556) 0125 0.020 0.009 0.015 = amy (81) 90 +4" 0.508) (0.229 0.381) DIA TP MIN +0.040 Nom 0.018 0,003. 0.325 5 ons Prt (9.457 0.076) +1016) ~* 0.100+0.010 (2.256 ) se 9 0.381 (2.540 0.254) 0.045+0.015 0.045 0.015 _ le (1.143 0.381) 0.060 0.050 > (1.524) (1.270) NOBE (REV Fi Molded Dual-In-Line Package (N) Order Number LM308AN NS Package Number NO8E LIFE SUPPORT POLICY NATIONALS 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. 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 Corporation 1111 West Bardin Road Arlington, TX 76017 Tel: 1(800) 272-9959 Fax: 1(800) 737-7018 National Semiconductor Europe Fax: (+49) 0-180-530 85 86 Email: cnjwge@tevm2.nsc.com Deutsch Tek (+49) 0-180-530 85 85 English Tel: (+49) 0-180-532 78 32 Frangais Tel: (+49) 0-180-532 93 58 Italiano Tek (+49) 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.