National Semiconductor LMC6484 CMOS Quad Rail-to-Rail Input Output Operational Amplifier handbook
Contents
1. Inverting Large Signal Inverting Large Signal Inverting Small Signal Pulse Response Pulse Response Pulse Response zx 4 2 z 3 E E E D a a E E E gt ES E Ro ZS T 25 C Ty 55 C Z5 Ta 125 C E gt R 2ko e R 2k0 t R 2k0 SE SC xo E z zw 2 a Oo a a a E E E 5 5 5 2 z 2 5 5 5 E ay 1 us 3 e ET 1 us o 50mY 50mY 1ps TIME 1 s DIV TIME 1 us DIV TIME 1 us DIV DS011714 80 DS011714 81 DS011714 82 Inverting Small Signal Inverting Small Signal Stability vs Pulse Response Pulse Response Capacitive Load 10000 a a Ay 1 E Vs 7 5V S ES R 140 E e Ki m S S 1000 Hl UNSTABLE Lulu ZS S EZ 28 Ty 25 C Z5 gt gt E 8 m ao do zm z oM E n 8 S 10 5 5 3 E E 25 OVERSHOOT 5 5 o 50mY 1s o 50mY 1 ys 10 E Ed E 12 34 S 8 TIME 1 us DIV TIME 1 4s DIV DS011714 83 DS011714 84 Vout V DS011714 85 Stability vs Stabilit2. 80 180 Vs 15V 70 R 2k0 Lo so SAIN 135 50 550C o g E iS DES we Fl Se SH mst ts z NR 2 G 3 2 45 10 CLN 0 3 0 85 C 10 75500 PN 20 Weird 45 tk 10k 100k 1M 10M FREQUENCY Hz DS011714 66 Gain and Phase vs Capacitive Load 29 Em Vs 15V PHASE a R 6000 9 30 20 ge 45 S Ce e 10 o o ES 2 z 0 D SZ 3 10 20 0 0 45 30 CL 500pF 40 1000 pF 90 50 10k 100k 1M 10M FREQUENCY Hz DS011714 69 Open Loop Frequency Response 140 120 100 80 GAIN dB 0 1 1 10 100 1k 10k 100k 1M 10M FREQUENCY Hz DS011714 64 Maximum Output Swing vs Frequency 15 o E Mon x I OUTPUT SWING Vpp 0 1 1 10 100 FREQUENCY kHz DS011714 67 Open Loop Output Impedance vs Frequency 1000 Vs 15V OUTPUT IMPEDANCE 2 e o o 0 1
3. DS011714 40 Sourcing Current vs Output Voltage 100 10 THE es HELLE lt H 1 Vg 3V 3 01 0 01 0 001 0 001 0 01 0 1 1 10 Output Voltage Referenced to Ve V DS011714 43 Limiting input pin current is only necessary for input voltages that exceed absolute maximum input voltage ratings Note 13 Guaranteed limits are dictated by tester limitations and not device performance Actual performance is reflected in the typical value Sourcing Current vs Output Voltage Typical Performance Characteristics v 15v Single Supply T 25 C unless otherwise 100 10 ES Vs 15V 2 2 8 01 0 01 0 001 0 01 0 1 1 10 100 Output Voltage Referenced to Vs V Sinking Current vs Output Voltage DS011714 41
4. 100 gt E 30 m 7 HS E 24 21 1 Vs 3V gt E E 18 E 5 a E ds e EE 2 12 amp 0 01 o z 6 a 0 001 5 3 0 001 0 01 oi 1 10 E 3 0 3 6 9 12 15 Output Voltage Referenced to GND V DS011714 46 SUPPLY VOLTAGE V DS011714 47 Input Voltage Noise vs Input Voltage 80 uw 70 I Vs 15V S ep F 1kHz ui a 50 o 2 3 40 E E S 30 20 10k 012345 67 8 910111213141516 COMMON MODE INPUT VOLTAGE V DS011714 48 DS011714 49 Input Voltage Noise Crosstalk Rejection vs Input Voltage vs Frequency 80 170 TT Vs 15V z 70 Vg 3V 180 R 5k0 F 1kHz Z o S 9 z 140 2 50 3 o E z 2 130 3 40 d 120 3 To 38 110 20 100 0 05 1 15 2 25 3 0 1 1 0 10 0 COMMON MODE INPUT VOLTAGE V DS011714 51 FREQUENCY kHz DS011714 52 www national com specified Continued Crosstalk Rejection vs Frequency Positive PSRR vs Frequency
5. Typical Performance Characteristics v 15v Single Supply Ta 25 C unless otherwise Negative PSRR vs Frequency 170 TM 100 100 Vs DN s 90 Vs 5V bz 160 R 5ko S R 5k8 90 F v 5V R Ska 80 80 150 T 70 70 3 Z 140 e S c 60 2 50 so S 130 e 3 2 40 Si 40 E 120 30 30 20 110 20 10 10 1m r 0 0 1 0 10 0 1 10 100 tk 10k 100k 1 10 100 tk 10k 100k FREQUENCY kHz FREQUENCY Hz FREQUENCY Hz DS011714 53 DS011714 54 DS011714 55 CMRR vs Frequency CMRR vs Input Voltage CMRR vs Input Voltage 100 120 120 Vs 7 59 Vs 2 5V 90 F 10kHz F 10kHz 80 100 RL 5k0 100 R 5kQ 70 ee Vs 15V zt P O 60 R 5ka 3 80 2 80 a 50 E cc E ZS 40 Z 60 Z 60 30 20 40 40 10 0 20 20 10 100 1k 10k 100k 7 5 6 0 4 5 3 0 1 5 0 0 1 5 3 0 45 6 0 7 5 2 5 2 0 1 5 1 0 0 5 0 00 5 1 0 1 5 2 0 2 5 FREQUENCY Hz INPUT VOLTAGE V INPUT VOLTAGE V DS011714 56 DS011714 57 DS011714 58 CMRR vs Input Voltage AVos Vs CMR A Vos VS CMR 120 1 0 1 0 Vs 1 5V F 10kHz a ne 100 R 5ka m 06 Vs 2 5V 06 Vg 1 5V gt gt i E 04 E 04 a 80 B 02 8 2 SS Z HHHH E
6. 100 10 4 e A Vs 15V E x o 0 1 HH H H HH Hi s Hi 0 01 Hi iis HH 0 001 0 01 0 1 1 10 100 Output Voltage Referenced to GND V DS011714 44 www national com Typical Performance Characteristics v specified Sinking Continued Current vs Output Voltage 100 Sink mA Input Vo 0 01 0 1 1 10 Output Voltage Referenced to GND V DS011714 45 Itage Noise vs Frequency Sinking Current vs Output Voltage VOLTAGE NOISE nV V Hz 10 100 1k FREQUENCY Hz Input Voltage Noise vs Input Voltage 80 R 70 Vs DN F 1kHz d 60 a a 50 o 2 SG 40 z E S 30 20 0 1 2 3 4 5 COMMON MODE INPUT VOLTAGE V DS011714 50 Output Voltage Swing vs Supply Voltage 15V Single Supply Ta 25 C unless otherwise
7. 11NC6484 Vin 3000 DS011714 15 FIGURE 6 LMC6484 Non Inverting Amplifier Compensated to Handle a 330 pF Capacitive Load R1 and C1 serve to counteract the loss of phase margin by feeding forward the high frequency component of the output signal back to the amplifier s inverting input thereby preserv ing phase margin in the overall feedback loop The values of R1 and C1 are experimentally determined for the desired pulse response The resulting pulse response can be seen in Figure 7 DS011714 16 FIGURE 7 Pulse Response of LMC6484 Circuit in Figure 6 5 0 Compensating for Input Capacitance It is quite common to use large values of feedback resis tance with amplifiers that have ultra low input current like the LMC6484 Large feedback resistors can react with small values of input capacitance due to transducers photo diodes and circuit board parasitics to reduce phase margins VIN LMC6484 Vout 1 4 DS011714 19 FIGURE 8 Canceling the Effect of Input Capacitance The effect of input capacitance can be compensated for by adding a feedback capacitor The feedback capacitor as in Figure 8 C is first estimated by 1 1 gt Zar Cin 27R2Cf or Ry Cin lt Ra Cr which typically provides significant overcompensation Printed circuit board stray capacitance may be larger or smaller than that of a breadboard so the actual optimum value for C may be different The values o
8. MAX BOTH ENDS 0 100 0 010 0 150 2 540 0 254 540 0 254 3 81 MIN J14A REV G 14 Pin Ceramic Dual In Line Package Order Number LMC6484AMJ 883 LMC6484AMWG 883 NS Package Number J14A WG14A www national com 20 Physical Dimensions inches millimeters unless otherwise noted Continued 0 335 0 344 8 509 8 738 0 228 0 244 5 791 6 198 E LEAD NO 1 E IDENT 0 010 max 0 254 0 150 0 157 3 810 3 988 0 010 0 020 0 053 0 069 0 254 0 508 lt gt 1 346 1 753 8 MAX TYP 0 004 0 010 ALL LEADS _ lm 0 102 0 254 t SEATING LM atts Ke i PLANE A 0 014 0 008 0 010 a 0 050 014 0 0 203 0 254 a 0016 0050 0 358 og er az TYP ALL LEADS 0 004 0 406 1 270 TYP 0 008 0 102 TYP ALL LEADS gt 0 203 TYP ALL LEAD TIPS MAGA REV H 14 Pin Small Outline Order Package Number LMC6484AIM or LMC6484IM NS Package Number M14A 21 www national com LMC6484 CMOS Quad Rail to Rail Input and Output Operational Amplifier Physical Dimensions inches millimeters unless otherwise noted Continued 0 740 0 770 18 80 19 56 0 090 j 2 286 E INDEX AREA 0 250 0 010 O 6 350 0 254 PIN NO 1 PIN NO 1 IDENT IDENT 0 092 0 030 MAX 2 337 0 762 DEPTH OPTION 1 OPTION 02 0 135 0 005 T 3 429 0 127 0 300 0 320 0 145 0 200 0 080 typ 4 YP 7 620 8 128 0 065
9. R 10 kQ Vo 4 1 Map f 10 kHz Ay 2 R 10 kQ Vo 8 5 Vpp 0 01 10V DC Electrical Characteristics Unless otherwise specified all limits guaranteed for T 25 C V 3V V OV Vom Vo V 2 and R gt 1M Typ LMC6484Al LMC6484l LMC6484M Symbol Parameter Conditions Note 5 Limit Limit Limit Units Note 6 Note 6 Note 6 Vos Input Offset Voltage 0 9 2 0 3 0 3 0 mV 2 7 3 7 3 8 max TCVos Input Offset Voltage 2 0 uv C Average Drift lg Input Bias Current 0 02 pA los Input Offset Current 0 01 pA CMRR Common Mode OV Vom 3V 74 64 60 60 dB Rejection Ratio min PSRR Power Supply 3V lt V 15V V DN 80 68 60 60 dB Rejection Ratio min Vom Input Common Mode For CMRR gt 50 dB V 0 25 0 0 0 V Voltage Range max V 0 25 V ve ve V Vo Output Swing RL 2 kQ to V 2 2 8 V 0 2 V DH 6004 to V 2 2 7 2 5 2 5 2 5 V min 0 37 0 6 0 6 0 6 V max ls Supply Current All Four Amplifiers 1 65 2 5 2 5 2 5 mA 3 0 3 0 3 2 max AC Electrical Characteristics Unless otherwise specified V 3V V OV Vem Vo V 2 and R gt 1M Typ LMC6484Al LMC64841 LMC6484M Symbol Parameter Conditions Note 5 Limit Limit Limit Units Note 6 Note 6 Note 6 SR Slew Rate Note 11 0 9 V us GBW Gain Bandwidth Product 1 0 MHz T H D Total Harmonic Distortion f 10 kHz Ay 2 0 01 R 10 KQ Vo 2 Vpp Note 1 Absolute Maximum Ratings indicate limits beyond which damage to the device may
10. 3 583 5 080 1524 d TIONAL 1 651 4 0 008 0 016 ul t 90 t4 TYP 0 203 0 406 0 50 TG 0 125 0 150 1 8 175 3 810j 7 DEE nd 0 014 0 023 7 112 0915 0028 walte 0 100 0 010 MIN 0 356 0 584 e D ae I 19 540 0 254 049010010 typ 0 040 1 270 0 254 0 325 Tass 1 016 as n 14 Pin Molded DIP Order Package Number LMC6484AIN LMC6484IN or LMC6484MN NS Package Number N14A 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 2 A critical component is any component of a life systems which a are intended for surgical implant support device or system whose failure to perform into the body or b support or sustain life and can be reasonably expected to cause the failure of whose failure to perform when properly used in the life support device or system or to affect its accordance with instructions for use provided in the safety or effectiveness labeling can be reasonably expected to result in a significant injury to the user National Semiconductor National Semiconductor National Semiconductor National Semiconductor Corporation Europe Asia Pacific Customer Japan Ltd Americas Fax 49 0 1 80 530 85 86 Response Group Tel 81 3 5639 756
11. 1 10 100 1000 10000 FREQUENCY kHz DS011714 70 www national com specified Continued Open Loop Output Impedance vs Frequency 1000 Vs DN OUTPUT IMPEDANCE 2 a o o 0 1 1 10 100 1000 10000 FREQUENCY kHz DS011714 71 Non Inverting Large Signal Pulse Response INPUT SIGNAL 1V DIV UI n M amp o p OUTPUT SIGNAL IN 117 ips TIME 1 s DIV DS011714 74 Non Inverting Small Signal Pulse Response a z a a E FAE gt 265 gt T 25 an E x o Zoo 3 a gt a E gt e 50 mY 50m7 14s TIME 1 us DIV DS011714 77 Slew Rate vs Supply Voltage 1 50 1 45 1 40 1 35 1 30 1 25 1 20 1 15 Ay 1 R 10ko Vin Tier ot SLEW RATE V Sec 1 10 asl 1 05 1 00 3945 6 7 8 9 101112131415 16 SUPPLY VOLTAGE V DS011714 72 Non Inverting Large Signal Pulse Response INPUT SIGNAL 1v DIV E 1 a a o e OUTPUT SIGNAL TIME 1 4s DIV DS011714 75 Non Inverting Small Signal Pulse Respon
12. 2 4 e z z 3 60 w 0 2 w 0 2 2 2 04 04 3 5 40 0 6 0 6 0 8 0 8 20 1 0 1 0 1 5 1 2 0 9 0 6 0 3 0 0 0 3 0 6 0 9 1 2 1 5 3 2 1 0 1 2 3 2 1 5 1 0 5 0 05 1 15 2 INPUT VOLTAGE V Vin V Va V DS011714 59 DS011714 60 DS011714 61 www national com 8 Typical Performance Characteristics v 15v Single Supply Ta 25 C unless otherwise specified Continued Input Voltage vs Output Voltage 160 120 2 Vs 7 5V INPUT VOLTAGE aV o 160 8 6 4 2 0 2 4 6 8 OUTPUT VOLTAGE V DS011714 62 Open Loop Frequency Response 120 RL 500k0 100 80 GAIN dB 0 1 1 10 100 1k 10k 100k 1M 10M FREQUENCY Hz DS011714 65 Gain and Phase vs Capacitive Load mm Vs 15V PHASE 5 40 R 500k0 90 30 20 k PX 45 P GAIN ms S SS 2 0 0 E Z z 3 10 Z 20 Lo 45 C 500 pF 30 40 90 50 10k 100k 1M 10M FREQUENCY Hz DS011714 68 Input Voltage vs Output Voltage 160 120 80 40 INPUT VOLTAGE uV o 80 OUTPUT VOLTAGE V DS011714 63 Open Loop Frequency Response vs Temperature
13. 22 22 20 min V 15V Sinking Vo 12V 30 30 30 30 mA Note 8 24 24 22 min Is Supply Current All Four Amplifiers 2 0 2 8 2 8 2 8 mA Vt 5V Vo V 2 3 6 3 6 3 8 max All Four Amplifiers 2 6 3 0 3 0 3 0 mA Vt 15V Vo V 2 3 8 3 8 4 0 max AC Electrical Characteristics Unless otherwise specified all limits guaranteed for T 25 C V 5V V OV Vom Vo V 2 and R gt 1M Boldface limits apply at the temperature extremes Typ LMC6484A LMC6484I LMC6484M Symbol Parameter Conditions Note 5 Limit Limit Limit Units Note 6 Note 6 Note 6 SR Slew Rate Note 9 1 3 1 0 0 9 0 9 V us 0 7 0 63 0 54 min GBW Gain Bandwidth Product V 15V 1 5 MHz Om Phase Margin 50 Deg Gin Gain Margin 15 dB Amp to Amp Isolation Note 10 150 dB CA Input Referred f 1 kHz 37 nv Hz Voltage Noise Vom 1V ip Input Referred f 1 kHz 0 03 pA Hz Current Noise www national com AC Electrical Characteristics continued Unless otherwise specified all limits guaranteed for T 25 C V 5V V OV Vom Vo V 2 and R gt 1M Boldface limits apply at the temperature extremes Typ LMC6484A LMC64841 LMC6484M Symbol Parameter Conditions Note 5 Limit Limit Limit Units Note 6 Note 6 Note 6 T H D Total Harmonic Distortion f 1 kHz Ay 2 0 01
14. complemented by an output stage capable of rail to rail output swing even when driving a large load Rail to rail output swing is obtained by taking the output directly from the internal integrator instead of an output buffer stage 2 0 Input Common Mode Voltage Range Unlike Bi FET amplifier designs the LMC6484 does not ex hibit phase inversion when an input voltage exceeds the negative supply voltage Figure 1 shows an input voltage ex ceeding both supplies with no resulting phase inversion on the output 3v ov 00 hil DS011714 10 FIGURE 1 An Input Voltage Signal Exceeds the LMC6484 Power Supply Voltages with No Output Phase Inversion The absolute maximum input voltage is 300 mV beyond ei ther supply rail at room temperature Voltages greatly ex Stability vs Capacitive Load 10000 Ay 10 Vg 27 8V R 6000 1000 100 CAPACITIVE LOAD nF 25 OVERSHOOT 6 5 4 3 2 10 123456 Your V DS011714 90 ceeding this absolute maximum rating as in Figure 2 can cause excessive current to flow in or out of the input pins possibly affecting reliability Vin 7 5V Vout 1V div DS011714 12 FIGURE 2 A 7 5V Input Signal Greatly Exceeds the 3V Supply in Figure 3 Causing No Phase Inversion Due to R Applications that exceed this rating must externally limit the m
15. distor ion 9 0 Data Acquisition Systems Low power single supply data acquisition system solutions are provided by buffering the ADC12038 with the LMC6484 Figure 14 Capable of using the full supply range the LMC6484 does not require input signals to be scaled down o meet limited common mode voltage ranges The LMC6484 CMRR of 82 dB maintains integral linearity of a 12 bit data acquisition system to 0 325 LSB Other rail to rail input amplifiers with only 50 dB of CMRR will de grade the accuracy of the data acquisition system to only 8 bits www national com Application Information continued 1000 pF Vin LMC6484 FB 330 LMC6484 el ADC12038 DS011714 28 FIGURE 14 Operating from the same Supply Voltage the LMC6484 buffers the ADC12038 maintaining excellent accuracy 10 0 Instrumentation Circuits The LMC6484 has the high input impedance large common mode range and high CMRR needed for designing instrumentation circuits Instrumentation circuits designed with the LMC6484 can reject a larger range of common mode signals than most in amps This makes in strumentation circuits designed with the LMC6484 an excel lent choice for noisy or industrial environments Other appli 10k0 50 kQ 0 1 cations that benefit from these features include analytic medical instruments magnetic field detectors gas detectors and silicon based transducers A small val
16. 0 Tel 1 800 272 9959 Email europe support nsc com Tel 65 2544466 Fax 81 3 5639 7507 Fax 1 800 737 7018 Deutsch Tel 49 0 1 80 530 85 85 Fax 65 2504466 Email support nsc com English Tel 49 0 1 80 532 78 32 Email sea support nsc com Frangais Tel 49 0 1 80 532 93 58 www national com Italiano Tel 49 0 1 80 534 16 80 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
17. C and diode leakage current The ultra low input current of the LMC6484 has a negligible effect on droop 20k0 LMC6484 I i CHoLD 7 CD4066BM SAMPLE T FIGURE 24 Rail to Rail Sample and Hold d 4 Vin DS011714 38 The LMC6484 s high CMRR 85 dB allows excellent accuracy throughout the circuit s rail to rail dynamic capture range C1 Vin 1 elo E o o gt Ei A DS011714 27 1 1 E Ro R1 R2 C1 C2 f DF zT 2mR1C1 2VC VR FIGURE 25 Rail to Rail Single Supply Low Pass Filter The low pass filter circuit in Figure 25 can be used as an anti aliasing filter with the same voltage supply as the A D converter Filter designs can also take advantage of the LMC6484 ultra low input current The ultra low input current yields negligible offset error even when large value resistors are used This in turn allows the use of smaller valued capacitors which take less board space and cost less www national com Physical Dimensions inches millimeters unless otherwise noted 0 785 a 19 939 el MAN 0 025 de 0 220 0 310 5 588 7 874 0 290 0 320 0 005 0 200 7 366 8 128 0 127 i GLASS 0 060 0 005 5 080 MIN TTA SEALANT 1524 012 MAX 029 0 060 0 508 1 524 86 94 TY 0 008 0 012 Y 0 203 0 305 i 0310 0410 0 018 0 003 am 7 874 10 41 0 098 0 457 20 076 0 125 0 200 2 489 3 175 5 080
18. D LMCe48T 0 LMC6484 Amplifier General Description The LMC6484 provides a common mode range that extends to both supply rails This rail to rail performance combined with excellent accuracy due to a high CMRR makes it unique among rail to rail input amplifiers It is ideal for systems such as data acquisition that require a large input signal range The LMC6484 is also an excellent upgrade for circuits using limited common mode range am plifiers such as the TLC274 and TLC279 Maximum dynamic signal range is assured in low voltage and single supply systems by the LMC6484 s rail to rail out put swing The LMC6484 s rail to rail output swing is guaran teed for loads down to 6000 Guaranteed low voltage characteristics and low power dissi pation make the LMC6484 especially well suited for battery operated systems See the LMC6482 data sheet for a Dual CMOS operational amplifier with these same features National Semiconductor CMOS Quad Rail to Rail Input and Output Operational May 1999 Features Typical unless otherwise noted m Rail to Rail Input Common Mode Voltage Range Guaranteed Over Temperature m Rail to Rail Output Swing within 20 mV of supply rail 100 kQ load m Guaranteed 3V 5V and 15V Performance m Excellent CMRR and PSRR 82 dB m Ultra Low Input Current 20 fA m High Voltage Gain D 500 kQ m Specified for 2 KQ and 6004 loads 130 dB Applications m Data Acquisition Systems
19. Transducer Amplifiers Hand held Analytic Instruments Medical Instrumentation Active Filter Peak Detector Sample and Hold pH Meter Current Source Improved Replacement for TLC274 TLC279 3V Single Supply Buffer Circuit Rail to Rail Input DS011714 1 1 ele 4 Rail to Rail Output Re 018 8 3v DS011714 3 DS011714 2 1999 National Semiconductor Corporation DS011714 www national com Jett ug jeuoneaedo 1ndino pue 1nduj 1ey 01 1184 PEND SOMO Foto Connection Diagram a i Ordering Information DS011714 4 Package Temperature Range NSC Transport Military Industrial Drawing Media 55 C to 125 C 40 C to 85 C 14 pin LMC6484MN LMC6484AIN N14A Rail Molded DIP LMC6484IN 14 pin LMC6484AIM M14A Rail Small Outline LMC64841M Tape and Reel 14 pin Ceramic LMC6484AMJ 883 J14A Rail DIP 14 pin LMC6484AMWG 883 WG14A Tray Ceramic SOIC 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 ESD Tolerance Note 2 Differential Input Voltage Supply Voltage Voltage at Input Output Pin V 0 3V V7 0 3V Supply Voltage V V 16V 2 0 kV Current at Input Pin Note 12 5 mA Current at Output Pin Notes 3 8 30 mA Current at Power Supply Pin 40 mA Lead Temp Solde
20. ally considered a very large resistance could leak 5 pA if the trace were a 5V bus adjacent to the pad of the input This would cause a 250 times degradation from the LMC6484 s actual performance However if a guard ring is held within 5 mV of the inputs then even a resistance of 10 Q would cause only 0 05 pA of leakage current See Figure 10 for typical connections of guard rings for standard op amp configurations OUT4 O INA O IN4 O Guard Ring DS011714 20 FIGURE 9 Example of Guard Ring in P C Board Layout C1 H R2 1 1 MC6484 OUTPUT DS011714 21 T Guard Rin 1 gt OUTPUT INPUT a DS011714 22 Non Inverting Amplifier cl S gt H LMC6484 OUTPUT LI INPUT I Li 3 DS011714 23 Follower FIGURE 10 Typical Connections of Guard Rings The designer should be aware that when it is inappropriate to lay out a PC board for the sake of just a few circuits there is another technique which is even better than a guard ring on a PC board Don t insert the amplifier s input pin into the board at all but bend it up in the air and use only air as an in sulator Air is an excellent insulator In this case you may have to forego some of the advantages of PC board con struction but the advantages are sometimes well worth the effort of using point to point up in the air wiring See Figure 11 FEEDBACK CAPACITOR IPAE T SOLDER CONNECTION DS011714 24 Input pi
21. aximum input current to 5 mA with an input resistor as shown in Figure 3 Vout Vin RI 10ka DS011714 11 FIGURE 3 R Input Current Protection for Voltages Exceeding the Supply Voltage 3 0 Rail To Rail Output The approximated output resistance of the LMC6484 is 1800 sourcing and 1302 sinking at Vs 3V and 1100 sourcing and 83Q sinking at Vs 5V Using the calculated output resistance maximum output voltage swing can be es timated as a function of load 4 0 Capacitive Load Tolerance The LMC6484 can typically directly drive a 100 pF load with Vs 15V at unity gain without oscillating The unity gain fol lower is the most sensitive configuration Direct capacitive www national com Application Information continued loading reduces the phase margin of op amps The combi nation of the op amp s output impedance and the capacitive load induces phase lag This results in either an under damped pulse response or oscillation Capacitive load compensation can be accomplished using resistive isolation as shown in Figure 4 This simple tech nique is useful for isolating the capacitive input of multiplex ers and A D converters DS011714 17 FIGURE 4 Resistive Isolation of a 330 pF Capacitive Load DS011714 18 FIGURE 5 Pulse Response of the LMC6484 Circuit in Figure 4 Improved frequency response is achieved by indirectly driv ing capacitive loads as shown in Figure 6 10k0 Vout Eo
22. f C should be checked on the actual circuit Refer to the LMC660 quad CMOS amplifier data sheet tor a more detailed discussion 6 0 Printed Circuit Board Layout for High Impedance Work It is generally recognized that any circuit which must operate with less than 1000 pA of leakage current requires special layout of the PC board when one wishes to take advantage www national com Application Information continued of the ultra low input current of the LMC6484 typically less than 20 fA it is essential to have an excellent layout Fortu nately the techniques of obtaining low leakages are quite simple First the user must not ignore the surface leakage of the PC board even though it may sometimes appear accept ably low because under conditions of high humidity or dust or contamination the surface leakage will be appreciable To minimize the effect of any surface leakage lay out a ring of foil completely surrounding the LMC6484 s inputs and the terminals of capacitors diodes conductors resistors relay terminals etc connected to the op amp s inputs as in Fig ure 9 To have a significant effect guard rings should be placed in both the top and bottom of the PC board This PC foil must then be connected to a voltage which is at the same voltage as the amplifier inputs since no leakage current can flow between two points at the same potential For example a PC board trace to pad resistance of 10120 which is nor m
23. ns are lifted out of PC board and soldered directly to components All other pins connected to PC board FIGURE 11 Air Wiring www national com Application Information Continued 7 0 Offset Voltage Adjustment Offset voltage adjustment circuits are illustrated in Figures 13 14 Large value resistances and potentiometers are used to reduce power consumption while providing typically 2 5 mV of adjustment range referred to the input for both con figurations with Vg 5V V R4 500k0 VIN LMC6484 Your 1ko 5V 500 KQ Nout _ _ R4 Ve R3 a DS011714 25 FIGURE 12 Inverting Configuration Offset Voltage Adjustment R4 Vt 500k0 11NC6484 Your A 1 R R2 lt lt R3 Vn R3 DS011714 26 FIGURE 13 Non Inverting Configuration Offset Voltage Adjustment 8 0 Upgrading Applications The LMC6484 quads and LMC6482 duals have industry standard pin outs to retrofit existing applications System performance can be greatly increased by the LMC6484 s eatures The key benefit of designing in the LMC6484 is in creased linear signal range Most op amps have limited in put common mode ranges Signals that exceed this range generate a non linear output response that persists long af er the input signal returns to the common mode range Linear signal range is vital in applications such as filters where signal peaking can exceed input common mode ranges resulting in output phase inversion or severe
24. occur Operating Ratings indicate conditions for which the device is in tended to be functional but specific performance is not guaranteed For guaranteed specifications and the test conditions see the Electrical Characteristics Note 2 Human body model 1 5 kO in series with 100 pF All pins rated per method 3015 6 of MIL STD 883 This is a class 2 device rating 5 www national com Note 7 Note 9 Note 10 Note 11 Note 12 Note 14 specified Supply Current vs Supply Voltage 3 5 T 125 C 3 0 E 4859C a 25 OL sec E L 3 1 z 20 55 C E E o 15 gt gt amp 1 0 5 0 5 0 0 0 2 4 6 8 10 12 14 16 SUPPLY VOLTAGE V DS011714 39 Sourcing Current vs Output Voltage 100 10 E 1 Vg 5V 2 2 8 01 0 01 0 001 0 001 0 01 0 1 1 10 Output Voltage Referenced to Vs V DS011714 42 AC Electrical Characteristics continued Note 3 Applies to both single supply and split supply operation Continuous short circuit operation at elevated ambient temperature can result in exceeding the maxi mum allowed junction temperature of 150 C Output cur
25. put Common Mode V 5V and 15V V 0 3 0 25 0 25 0 25 V Voltage Range For CMRR 2 50 dB 0 0 0 max V 0 3 V 0 25 Vt 0 25 Vt 0 25 V vr vt vr min Ay Large Signal R 2kQ Sourcing 666 140 120 120 V mV Voltage Gain Notes 7 13 84 72 60 min Sinking 75 35 35 35 V mV 20 20 18 min H 6000 Sourcing 300 80 50 50 V mV Notes 7 13 48 30 25 min Sinking 35 20 15 15 V mV 13 10 8 min www national com DC Electrical Characteristics continued Unless otherwise specified all limits guaranteed for T 25 C V 5V V OV Voy Vo V 2 and R gt 1M Boldface limits apply at the temperature extremes Typ LMC6484AI LMC6484l LMC6484M Symbol Parameter Conditions Note 5 Limit Limit Limit Units Note 6 Note 6 Note 6 Vo Output Swing V EN 4 9 48 48 4 8 V Ri 2 kQ to V 2 4 7 4 7 4 7 min 0 1 0 18 0 18 0 18 V 0 24 0 24 0 24 max Vt DM 4 7 45 4 5 4 5 V R 6004 to V 2 4 24 4 24 4 24 min 0 3 0 5 0 5 0 5 V 0 65 0 65 0 65 max Vt 15V 14 7 14 4 14 4 14 4 V Ri 2 kQ to V 2 14 2 14 2 14 2 min 0 16 0 32 0 32 0 32 V 0 45 0 45 0 45 max Vt 15V 14 1 13 4 13 4 13 4 V R 6004 to V 2 13 0 13 0 13 0 min 0 5 1 0 1 0 1 0 V 1 3 1 3 1 3 max Isc Output Short Circuit Sourcing Vo ON 20 16 16 16 mA Current 12 12 10 min V DM Sinking Vo 5V 15 11 11 11 mA 9 5 9 5 8 0 min Iso Output Short Circuit Sourcing Vo OV 30 28 28 28 mA Current
26. rents in excess of 30 mA over long term may adversely affect reliability Note 4 The maximum power dissipation is a function of Tymax s Oya and T4 The maximum allowable power dissipation at any ambient temperature is Pp TJ max Ta O ya All numbers apply for packages soldered directly into a PC board Note 5 Typical Values represent the most likely parametric norm Note 6 All limits are guaranteed by testing or statistical analysis VI 15V Vom 7 5V and R connected to 7 5V For Sourcing tests 7 5V lt Vo lt 11 5V For Sinking tests 3 5V lt Vo lt 7 5V Note 8 Do not short circuit output to V when V is greater than 13V or reliability will be adversely affected V 15V Connected as Voltage Follower with 10V step input Number specified is the slower of either the positive or negative slew rates Input referred V 15V and Hu 100 kQ connected to 7 5V Each amp excited in turn with 1 kHz to produce Vo 12 Vpp Connected as Voltage Follower with 2V step input Number specified is the slower of either the positive or negative slew rates For guaranteed Military Temperature Range parameters see RETSMC6484X Input Current vs Temperature 100 10 amp a amp 1 5 3 n 2 Zz Di 0 01 25 50 75 100 TEMPERATURE C 125 150
27. ring 10 sec 260 C DC Electrical Characteristics 65 C to 150 C 150 C Storage Temperature Range Junction Temperature Note 4 Operating Ratings note 1 Supply Voltage Junction Temperature Range LMC6484AM LMC6484Al LMC64841 Thermal Resistance 8 4 3 0V x V lt 15 5V 55 C lt T lt 125 C 40 C lt T lt 85 C N Package 14 Pin Molded DIP 70 C W M Package 14 Pin Surface Mount 110 C W Unless otherwise specified all limits guaranteed for T 25 C V 5V V OV Vom Vo V 2 and R gt 1M Boldface limits apply at the temperature extremes Typ LMC6484Al LMC64841 LMC6484M Symbol Parameter Conditions Note 5 Limit Limit Limit Units Note 6 Note 6 Note 6 Vos Input Offset Voltage 0 110 0 750 3 0 3 0 mV 1 35 3 7 3 8 max TCVos Input Offset Voltage 1 0 UNI Average Drift lg Input Current Note 13 0 02 4 0 4 0 100 pA max los Input Offset Current Note 13 0 01 2 0 2 0 50 pA max Cin Common Mode 3 pF Input Capacitance Rin Input Resistance gt 10 Tera Q CMRR Common Mode OV lt Vom lt 15 0V 82 70 65 65 dB Rejection Ratio V 15V 67 62 60 min OV Vom 5 0V 82 70 65 65 V 5V 67 62 60 PSRR Positive Power Supply 5V lt V lt 15V 82 70 65 65 dB Rejection Ratio V OV Vo 2 5V 67 62 60 min PSRR Negative Power Supply 5V lt V lt 15V 82 70 65 65 dB Rejection Ratio Vt OV Vo 2 5V 67 62 60 min Vom In
28. romodel disk Contact your local National Semiconductor sales office to obtain an operational amplifier spice model library disk Typical Single Supply Applications V 3V DS011714 32 FIGURE 18 Half Wave Rectifier Waveform The circuit in Figure 17 use a single supply to half wave rec tify a sinusoid centered about ground R limits current into Vout the amplifier caused by the input voltage exceeding the sup ply voltage Full wave rectification is provided by the circuit in Figure 19 1 z LMC6484 DS011714 31 FIGURE 17 Half Wave Rectifier with Input Current Protection Rl DS011714 33 FIGURE 19 Full Wave Rectifier with Input Current Protection Rj 17 www national com Typical Single Supply Applications Continued V DS011714 34 FIGURE 20 Full Wave Rectifier Waveform LMC6484 I lout V ja lout R DS011714 35 FIGURE 21 Large Compliance Range Current Source Vout 1kQ R1 R2 R1 lt lt R2 DS011714 36 FIGURE 22 Positive Supply Current Sense www national com 18 Typical Single Supply Applications continued 20k0 1 uc6484 E n Y 1 OUT LMC6484 Vin DS011714 37 FIGURE 23 Low Voltage Peak Detector with Rail to Rail Peak Capture Range In Figure 23 dielectric absorption and leakage is minimized by using a polystyrene or polyethylene hold capacitor The droop rate is primarily determined by the value of
29. se zi z E 5 HEH E Ro gt Zz E 3 gt Ta 55 a R 2k0 SZ A s o E 5 2 E 5 o 1 ys TIME 1 us DIV DS011714 78 Typical Performance Characteristics vs 15v single Supply Ta 25 C unless otherwise Non Inverting Large Signal Pulse Response INPUT SIGNAL 1V DIV Ty 125 OUTPUT SIGNAL TIME 1 us DIV DS011714 73 Non Inverting Small Signal Pulse Response i E a i zo gt 26 2 gt a E Zo 35 e a i 5 5 e 50 mY 50m7 tus TIME 1 us DIV DS011714 76 Inverting Large Signal Pulse Response e a d g 22 T 125 C ks R 2ko z Do z e a 5 5 o vy oV lus TIME 1 s DIV DS011714 79 www national com 10 Typical Performance Characteristics vs 15v Single Supply Ta 25 C unless otherwise specified Continued
30. ued potentiometer is used in series with Rg to set the differential gain of the 3 op amp instrumentation circuit in Figure 15 This combination is used instead of one large val ued potentiometer to increase gain trim accuracy and reduce error due to vibration AC CMR ADJUST 50k0 0 1 Re AS Vin 4 1MC6484 Vout 50k0 0 1 gt 48 7 kQ LA R 4146484 DC CMR ADJUST T R2 5000 10kQ 10 pF O VREFERENCE DS011714 29 FIGURE 15 Low Power 3 Op Amp Instrumentation Amplifier A 2 op amp instrumentation amplifier designed for a gain of 100 is shown in Figure 16 Low sensitivity trimming is made www national com 16 Application Information Continued Higher frequency and larger common mode range applica tions are best facilitated by a three op amp instrumentation for offset voltage CMRR and gain Low cost and low power amplifier consumption are the main advantages of this two op amp circuit 100 10k 0 175 10k 0 175 A2 4 LMC6484 Vout 100Vp DS011714 30 FIGURE 16 Low Power Two Op Amp Instrumentation Amplifier 11 0 Spice Macromodel A spice macromodel is available for the LMC6484 This model includes accurate simulation of input common mode voltage range frequency and transient response GBW dependence on loading conditions quiescent and dynamic supply current output swing dependence on loading conditions and many more characteristics as listed on the mac
31. y vs Stability vs Capacitive Load Capacitive Load Capacitive Load 10000 x 10000 PET 10000 nn Vs 7 5V Vg 7 5V 8 7 Vg 7 5V a R 6000 S c R 2ka c J Y c D 1M0 e EUM amp UNSTABLE Z 1000 UNSTABLE Z 1000 Z 1000 z z z 3 H 3 gt gt E E Q 100 4 Q 100 Q 100 z E E 4 E E i ji 3 25 OVERSHOOT 25 OVERSHOOT 25 OVERSHOOT 10 10 10 6 4 3 2 10 12345 6 6 5 4 3 2 10 12 34 56 6 5 4 3 2 10 12 34 56 Your V Vout DI Vour V DS011714 86 DS011714 87 DS011714 88 11 www national com Typical Performance Characteristics vs 15v Single Supply Ta 25 C unless otherwise specified Continued Stability vs Capacitive Load 10000 Ay 10 Vs 17 5V R 2k0 1000 100 CAPACITIVE LOAD nF f 25 OVERSHOOT 10 76 5 4 3 2 10 12 34 5 6 Your V DS011714 89 Application Information 1 0 Amplifier Topology The LMC6484 incorporates specially designed wide compliance range current mirrors and the body effect to extend input common mode range to each supply rail Complementary paralleled differential input stages like the type used in other CMOS and bipolar rail to rail input ampli fiers were not used because of their inherent accuracy prob lems due to CMRR cross over distortion and open loop gain variation The LMC6484 s input stage design is
Download Pdf Manuals
Related Search
National Semiconductor LMC6484 CMOS Quad Rail to Rail Input Output Operational Amplifier handbook