Order this document by LM308A/D The LM308A operational amplifier provides high input impedance, low input offset and temperature drift, and low noise. These characteristics are made possible by use of a special Super Beta processing technology. This amplifier is particularly useful for applications where high accuracy and low drift performance are essential. In addition high speed performance may be improved by employing feedforward compensation techniques to maximize slew rate without compromising other performance criteria. The LM308A offers extremely low input offset voltage and drift specifications allowing usage in even the most critical applications without external offset nulling. • Operation from a Wide Range of Power Supply Voltages • • • SUPER GAIN OPERATIONAL AMPLIFIER SEMICONDUCTOR TECHNICAL DATA Low Input Bias and Offset Currents Low Input Offset Voltage and Guaranteed Offset Voltage Drift Performance High Input Impedance 8 1 N SUFFIX PLASTIC PACKAGE CASE 626 Frequency Compensation 8 1 Standard Compensation Modified Compensation R2 Inverting Input Noninverting Input R2 R1 R3 + Compen A Cf D SUFFIX PLASTIC PACKAGE CASE 751 (SO–8) Inverting Input Output Noninverting Compen B Input R1 R3 Output + Compen B 100 pF Cf ≥ 30 1 1+ R2 R1 PIN CONNECTIONS Compen A Standard Feedforward Compensation RS > 10 k 5.0 pF 10 k Feedforward Compensations for Decoupling Load Capacitance 500 pF 100 k C2* 10 k + 2 Inputs 10 pF Compen A + 4 Compen B 7 VCC 6 Output 5 NC (Top View) 500 Output + 500 pF Compen B 3.0 k 10 pF Compen A *C2 > CL 75 pF to 0.01µF 5 x 105 pF R2 ORDERING INFORMATION Device Operating Temperature Range Package LM308AN LM308AD TA = 0° to +70°C Plastic DIP SO–8 Motorola, Inc. 1996 MOTOROLA ANALOG IC DEVICE DATA – 8 10 pF 0.01 µF Output Compen B 3.0 k 3 VEE Input Input 1 Rev 0 1 LM308A MAXIMUM RATINGS (TA = +25°C, unless otherwise noted.) Symbol Value Unit VCC, VEE ±18 Vdc Input Voltage (See Note 1) VI ±15 V Input Differential Current ( See Note 2) IID ±10 mA Output Short Circuit Duration tSC Indefinite Operating Ambient Temperature Range TA 0 to +70 °C Tstg –65 to +150 °C TJ +150 °C Rating Power Supply Voltage Storage Temperature Range Junction Temperature NOTES: 1. For supply voltages less than ±15 V, the maximum input voltage is equal to the supply voltage. 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 1.0 V is applied between the inputs, unless some limiting resistance is used. ELECTRICAL CHARACTERISTICS (Unless otherwise noted these specifications apply for supply voltages of +5.0 V ≤ VCC ≤ +15 V and –5.0 V ≥ VEE ≥ –15 V, TA = +25°C.) Characteristic Symbol Min Typ Max Unit Input Offset Voltage VIO – 0.3 0.5 mV Input Offset Current IIO – 0.2 1.0 nA Input Bias Current IIB – 1.5 7.0 nA Input Resistance ri 10 40 – MΩ ICC, IEE – ±0.3 ±0.8 mA AVOL 80 300 – V/mV Input Offset Voltage VIO – – 0.73 mV Input Offset Current IIO – – 1.5 nA ∆VIO/∆T – 1.0 5.0 µV/°C ∆IIO/∆T – 2.0 10 pA/°C IIB – – 10 nA AVOL 60 – – V/mV VICR ±14 – – V CMR 96 110 – dB PSR 96 110 – dB VOR ±13 ±14 – V Power Supply Currents (VCC = +15 V, VEE = –15 V) Large Signal Voltage Gain (VCC = +15 V, VEE = –15 V, VO = ±10 V, RL ≥ 10 kΩ) The following specifications apply over the operating temperature range. Average Temperature Coefficient of Input Offset Voltage TA (min) ≤ TA ≤ TA (max) Average Temperature Coefficient of Input Offset Current Input Bias Current Large Signal Voltage Gain (VCC +15 V, VEE = –15 V, VO = ±10 V, RL ≥ 10 kΩ) Input Voltage Range (VCC = +15 V, VEE = –15 V) Common Mode Rejection (RS ≤ 50 kΩ) Supply Voltage Rejection (RS ≤ 50 kΩ) Output Voltage Range (VCC = +15 V, VEE = –15 V, RL = 10 kΩ) 2 MOTOROLA ANALOG IC DEVICE DATA LM308A Figure 2. Maximum Equivalent Input Offset Voltage Error versus Input Resistance 0.25 1.8 1.6 0.20 1.4 IIO 1.2 1.0 0.15 IIB 0.8 0.10 0.6 0.4 0.05 0.2 0 –60 –40 –20 0 20 40 60 80 T, TEMPERATURE (°C) 100 0 120 140 EQUIVALENT INPUT OFFSET VOLTAGE (mV) 2.0 I IO, INPUT OFFSET CURRENT (nA) I IB , INPUT BIAS CURRENT (nA) Figure 1. Input Bias and Input Offset Currents 100 10 1.0 0.1 100 k IEE , SUPPLY CURRENTS ( µ A) TA = 0°C +25°C –55°C +70°C +125°C 110 100 = CF = 0 f = 100 Hz 90 500 400 TA = –55°C 0°C 300 +25°C 200 +70°C +125°C 100 I CC AVOL , VOLTAGE GAIN (dB) 120 100 M Figure 4. Power Supply Currents versus Power Supply Voltages Figure 3. Voltage Gain versus Supply Voltages 130 1.0 M 10 M ri, INPUT RESISTANCE (Ω) 80 0 0 5.0 10 15 0 20 5.0 VCC = VEE, SUPPLY VOLTAGES (V) Figure 5. Open Loop Frequency Response VOR, OUTPUT VOLTAGE RANGE (± Vp–p) 20 120 AVOL , VOLTAGE GAIN (dB) 20 Figure 6. Large Signal Frequency Response 140 100 80 CF = 3.0 pF 60 40 CF = 30 pF 20 0 –20 1.0 15 10 VCC = VEE, SUPPLY VOLTAGES (V) CF = 100 pF 10 100 1.0 k 10 k 100 k 1.0 M f, FREQUENCY (Hz) MOTOROLA ANALOG IC DEVICE DATA 10 M 100 M VCC = +15 V VEE = –15 V TA = +25°C 16 12 8.0 CF = 3.0 pF 4.0 CF = 30 pF 0 1.0 k 10 k 100 k f, FREQUENCY (Hz) 1.0 M 3 LM308A SUGGESTED DESIGN APPLICATIONS INPUT GUARDING Special care must be taken in the assembly of printed circuit boards to take full advantage of the low input currents of the LM308A amplifier. Boards must be thoroughly cleaned with alcohol and blown dry with compressed air. After cleaning, the boards should be coated with epoxy or silicone rubber to prevent contamination. Even with properly cleaned and coated boards, leakage currents may cause trouble at +125°C, particularly since the input pins are adjacent to pins that are at supply potentials. This leakage can be significantly reduced by using guarding to lower the voltage difference between the inputs and adjacent metal runs. The guard, which is a conductive ring surrounding the inputs, is connected to a low–impedance point that is at approximately the same voltage as the inputs. Leakage currents from high voltage pins are then absorbed by the guard. Figure 7. Fast (1) Summing Amplifier with Low Input Current Figure 8. Sample and Hold C5 (2) RS VCC Input 150 k R1 0.002 µF R2 1M LM308A (1) Power Bandwidth: 250 kHz Small Signal Bandwidth: 3.5 MHz Slew Rate: 10 V/µs 2 3 1.0 M Compen B 300 pF (2) C5 = 1.0 M R4 0.002 µF Input 150 pF 1 6 Q1 Sample Output Output Q2 1.0 µF (1) LM101A (3) or equiv 30 pF (1) Teflon, Polyethylene or Polycarbonate Dielectric Capacitor (3) In addition to increasing speed, the LM101A raises high and low frequency gain, increases output drive capability and eliminates thermal feedback. 6 X 10–8 R1 Figure 9. Connection of Input Guards Inverting Amplifier R1 Follower Noninverting Amplifier R2 R2 Input R3 (1) R3 (1) Output Output Output Input R1 R3 (1) C1 C1 (1) Used to compensate for large source resistances. 4 C1 Input R1 R2 Note: must be an impedance. R1 +R2 MOTOROLA ANALOG IC DEVICE DATA LM308A Representative Circuit Schematic Compensation A Compensation B VCC 3.5 k 5.6 k 7.5 k 15 pF 17.4 k 17.4 k 1.0 k 1.4 k 7.5 k 200 7.0 k 1.0 k VCC 65 Output 1.0 k 150 80 k Inputs 2.0 k VEE 2.0 k ) 20 k 10 k MOTOROLA ANALOG IC DEVICE DATA 362 1.2 k 50 k VEE 5 LM308A OUTLINE DIMENSIONS N SUFFIX PLASTIC PACKAGE CASE 626–05 ISSUE K 8 NOTES: 1. DIMENSION L TO CENTER OF LEAD WHEN FORMED PARALLEL. 2. PACKAGE CONTOUR OPTIONAL (ROUND OR SQUARE CORNERS). 3. DIMENSIONING AND TOLERANCING PER ANSI Y14.5M, 1982. 5 –B– 1 4 DIM A B C D F G H J K L M N F –A– NOTE 2 L C J –T– N SEATING PLANE D MILLIMETERS MIN MAX 9.40 10.16 6.10 6.60 3.94 4.45 0.38 0.51 1.02 1.78 2.54 BSC 0.76 1.27 0.20 0.30 2.92 3.43 7.62 BSC ––– 10_ 0.76 1.01 INCHES MIN MAX 0.370 0.400 0.240 0.260 0.155 0.175 0.015 0.020 0.040 0.070 0.100 BSC 0.030 0.050 0.008 0.012 0.115 0.135 0.300 BSC ––– 10_ 0.030 0.040 M K G H 0.13 (0.005) T A M M B M D SUFFIX PLASTIC PACKAGE CASE 751–05 (SO–8) ISSUE R D A NOTES: 1. DIMENSIONING AND TOLERANCING PER ASME Y14.5M, 1994. 2. DIMENSIONS ARE IN MILLIMETERS. 3. DIMENSION D AND E DO NOT INCLUDE MOLD PROTRUSION. 4. MAXIMUM MOLD PROTRUSION 0.15 PER SIDE. 5. DIMENSION B DOES NOT INCLUDE MOLD PROTRUSION. ALLOWABLE DAMBAR PROTRUSION SHALL BE 0.127 TOTAL IN EXCESS OF THE B DIMENSION AT MAXIMUM MATERIAL CONDITION. C 8 5 0.25 H E M B M 1 4 h B e X 45 _ q A C SEATING PLANE L 0.10 A1 B 0.25 6 M C B S A S DIM A A1 B C D E e H h L q MILLIMETERS MIN MAX 1.35 1.75 0.10 0.25 0.35 0.49 0.18 0.25 4.80 5.00 3.80 4.00 1.27 BSC 5.80 6.20 0.25 0.50 0.40 1.25 0_ 7_ MOTOROLA ANALOG IC DEVICE DATA LM308A Motorola reserves the right to make changes without further notice to any products herein. Motorola makes no warranty, representation or guarantee regarding the suitability of its products for any particular purpose, nor does Motorola assume any liability arising out of the application or use of any product or circuit, and specifically disclaims any and all liability, including without limitation consequential or incidental damages. “Typical” parameters which may be provided in Motorola data sheets and/or specifications can and do vary in different applications and actual performance may vary over time. All operating parameters, including “Typicals” must be validated for each customer application by customer’s technical experts. Motorola does not convey any license under its patent rights nor the rights of others. Motorola products are not designed, intended, or authorized for use as components in systems intended for surgical implant into the body, or other applications intended to support or sustain life, or for any other application in which the failure of the Motorola product could create a situation where personal injury or death may occur. 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Box 20912; Phoenix, Arizona 85036. 1–800–441–2447 or 602–303–5454 JAPAN: Nippon Motorola Ltd.; Tatsumi–SPD–JLDC, 6F Seibu–Butsuryu–Center, 3–14–2 Tatsumi Koto–Ku, Tokyo 135, Japan. 03–81–3521–8315 MFAX: [email protected] – TOUCHTONE 602–244–6609 INTERNET: http://Design–NET.com ASIA/PACIFIC: Motorola Semiconductors H.K. Ltd.; 8B Tai Ping Industrial Park, 51 Ting Kok Road, Tai Po, N.T., Hong Kong. 852–26629298 8 ◊ *LM308A/D* MOTOROLA ANALOG IC DEVICE DATA LM308A/D