LM111/LM211/LM311 Voltage Comparator 1.0 General Description The LM111, LM211 and LM311 are voltage comparators that have input currents nearly a thousand times lower than devices like the LM106 or LM710. They are also designed to operate over a wider range of supply voltages: from standard ± 15V op amp supplies down to the single 5V supply used for IC logic. Their output is compatible with RTL, DTL and TTL as well as MOS circuits. Further, they can drive lamps or relays, switching voltages up to 50V at currents as high as 50 mA. Both the inputs and the outputs of the LM111, LM211 or the LM311 can be isolated from system ground, and the output can drive loads referred to ground, the positive supply or the negative supply. Offset balancing and strobe capability are provided and outputs can be wire OR’ed. Although slower than the LM106 and LM710 (200 ns response time vs 40 ns) 3.0 Typical Applications the devices are also much less prone to spurious oscillations. The LM111 has the same pin configuration as the LM106 and LM710. The LM211 is identical to the LM111, except that its performance is specified over a −25˚C to +85˚C temperature range instead of −55˚C to +125˚C. The LM311 has a temperature range of 0˚C to +70˚C. 2.0 Features n n n n n Operates from single 5V supply Input current: 150 nA max. over temperature Offset current: 20 nA max. over temperature Differential input voltage range: ± 30V Power consumption: 135 mW at ± 15V (Note 3) Offset Balancing Strobing 00570436 00570437 Note: Do Not Ground Strobe Pin. Output is turned off when current is pulled from Strobe Pin. Increasing Input Stage Current (Note 1) Detector for Magnetic Transducer 00570438 Note 1: Increases typical common mode slew from 7.0V/µs to 18V/µs. 00570439 © 2004 National Semiconductor Corporation DS005704 www.national.com LM111/LM211/LM311 Voltage Comparator January 2001 LM111/LM211/LM311 3.0 Typical Applications (Note 3) (Continued) Digital Transmission Isolator Relay Driver with Strobe 00570440 00570441 *Absorbs inductive kickback of relay and protects IC from severe voltage transients on V++ line. Note: Do Not Ground Strobe Pin. Strobing off Both Input and Output Stages (Note 2) 00570442 Note: Do Not Ground Strobe Pin. Note 2: Typical input current is 50 pA with inputs strobed off. Note 3: Pin connections shown on schematic diagram and typical applications are for H08 metal can package. Positive Peak Detector Zero Crossing Detector Driving MOS Logic 00570424 00570423 *Solid tantalum www.national.com 2 If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications. LM111 −55˚C to 125˚C LM211 −25˚C to 85˚C Lead Temperature (Soldering, 10 sec) 260˚C Voltage at Strobe Pin V+−5V Soldering Information Total Supply Voltage (V84) 36V Dual-In-Line Package Output to Negative Supply Voltage (V74) 50V Small Outline Package Ground to Negative Supply Voltage (V14) 30V Soldering (10 seconds) ± 30V ± 15V Differential Input Voltage Input Voltage (Note 4) Output Short Circuit Duration 260˚C Vapor Phase (60 seconds) 215˚C Infrared (15 seconds) 220˚C See AN-450 “Surface Mounting Methods and Their Effect on Product Reliability” for other methods of soldering surface mount devices. 10 sec Operating Temperature Range ESD Rating (Note 11) Electrical Characteristics (Note 6) Parameter 300V for the LM111 and LM211 Conditions Min Typ Max Units Input Offset Voltage (Note 7) TA=25˚C, RS≤50k 0.7 3.0 mV Input Offset Current TA=25˚C 4.0 10 nA Input Bias Current TA=25˚C 60 100 nA Voltage Gain TA=25˚C Response Time (Note 8) TA=25˚C 200 Saturation Voltage VIN≤−5 mV, IOUT=50 mA 0.75 1.5 V 40 200 V/mV ns TA=25˚C Strobe ON Current (Note 9) TA=25˚C 2.0 5.0 mA Output Leakage Current VIN≥5 mV, VOUT=35V 0.2 10 nA TA=25˚C, ISTROBE=3 mA Input Offset Voltage (Note 7) RS≤50 k 4.0 mV Input Offset Current (Note 7) 20 nA Input Bias Current 150 nA 13.8,-14.7 13.0 V 0.23 0.4 V Input Voltage Range V+=15V, V−=−15V, Pin 7 Saturation Voltage V+≥4.5V, V−=0 −14.5 Pull-Up May Go To 5V VIN≤−6 mV, IOUT≤8 mA Output Leakage Current VIN≥5 mV, VOUT=35V 0.1 0.5 µA Positive Supply Current TA=25˚C 5.1 6.0 mA Negative Supply Current TA=25˚C 4.1 5.0 mA Note 4: This rating applies for ± 15 supplies. The positive input voltage limit is 30V above the negative supply. The negative input voltage limit is equal to the negative supply voltage or 30V below the positive supply, whichever is less. Note 5: The maximum junction temperature of the LM111 is 150˚C, while that of the LM211 is 110˚C. For operating at elevated temperatures, devices in the H08 package must be derated based on a thermal resistance of 165˚C/W, junction to ambient, or 20˚C/W, junction to case. The thermal resistance of the dual-in-line package is 110˚C/W, junction to ambient. Note 6: These specifications apply for VS= ± 15V and Ground pin at ground, and −55˚C≤TA≤+125˚C, unless otherwise stated. With the LM211, however, all temperature specifications are limited to −25˚C≤TA≤+85˚C. The offset voltage, offset current and bias current specifications apply for any supply voltage from a single 5V supply up to ± 15V supplies. Note 7: The offset voltages and offset currents given are the maximum values required to drive the output within a volt of either supply with a 1 mA load. Thus, these parameters define an error band and take into account the worst-case effects of voltage gain and RS. Note 8: The response time specified (see definitions) is for a 100 mV input step with 5 mV overdrive. Note 9: This specification gives the range of current which must be drawn from the strobe pin to ensure the output is properly disabled. Do not short the strobe pin to ground; it should be current driven at 3 to 5 mA. Note 10: Refer to RETS111X for the LM111H, LM111J and LM111J-8 military specifications. Note 11: Human body model, 1.5 kΩ in series with 100 pF. 3 www.national.com LM111/LM211/LM311 4.0 Absolute Maximum Ratings for the LM111/LM211(Note 10) LM111/LM211/LM311 5.0 Absolute Maximum Ratings for the LM311(Note 12) Output Short Circuit Duration If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications. Storage Temperature Range Total Supply Voltage (V84) 36V Soldering Information Output to Negative Supply Voltage (V74) 40V Ground to Negative Supply Voltage (V14) 30V 10 sec Operating Temperature Range 0˚ to 70˚C −65˚C to 150˚C Lead Temperature (soldering, 10 sec) 260˚C Voltage at Strobe Pin V+−5V Dual-In-Line Package Soldering (10 seconds) 260˚C Small Outline Package ± 30V ± 15V Differential Input Voltage Input Voltage (Note 13) Power Dissipation (Note 14) 300V Electrical Characteristics (Note 15) Parameter 215˚C Infrared (15 seconds) 220˚C See AN-450 “Surface Mounting Methods and Their Effect on Product Reliability” for other methods of soldering surface mount devices. 500 mW ESD Rating (Note 19) Vapor Phase (60 seconds) for the LM311 Typ Max Units Input Offset Voltage (Note 16) TA=25˚C, RS≤50k Conditions Min 2.0 7.5 mV Input Offset Current(Note 16) TA=25˚C 6.0 50 nA Input Bias Current TA=25˚C 100 250 Voltage Gain TA=25˚C Response Time (Note 17) Saturation Voltage 40 nA 200 V/mV TA=25˚C 200 ns VIN≤−10 mV, IOUT=50 mA 0.75 1.5 V 2.0 5.0 mA 0.2 50 nA 10 mV Input Offset Current (Note 16) 70 nA Input Bias Current 300 nA 13.8,−14.7 13.0 V 0.23 0.4 V TA=25˚C Strobe ON Current (Note 18) TA=25˚C Output Leakage Current VIN≥10 mV, VOUT=35V TA=25˚C, ISTROBE=3 mA V− = Pin 1 = −5V Input Offset Voltage (Note 16) RS≤50K Input Voltage Range −14.5 Saturation Voltage V+≥4.5V, V−=0 Positive Supply Current TA=25˚C 5.1 7.5 mA Negative Supply Current TA=25˚C 4.1 5.0 mA VIN≤−10 mV, IOUT≤8 mA Note 12: “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.” Note 13: This rating applies for ± 15V supplies. The positive input voltage limit is 30V above the negative supply. The negative input voltage limit is equal to the negative supply voltage or 30V below the positive supply, whichever is less. Note 14: The maximum junction temperature of the LM311 is 110˚C. For operating at elevated temperature, devices in the H08 package must be derated based on a thermal resistance of 165˚C/W, junction to ambient, or 20˚C/W, junction to case. The thermal resistance of the dual-in-line package is 100˚C/W, junction to ambient. Note 15: These specifications apply for VS= ± 15V and Pin 1 at ground, and 0˚C < TA < +70˚C, unless otherwise specified. The offset voltage, offset current and bias current specifications apply for any supply voltage from a single 5V supply up to ± 15V supplies. Note 16: The offset voltages and offset currents given are the maximum values required to drive the output within a volt of either supply with 1 mA load. Thus, these parameters define an error band and take into account the worst-case effects of voltage gain and RS. Note 17: The response time specified (see definitions) is for a 100 mV input step with 5 mV overdrive. Note 18: This specification gives the range of current which must be drawn from the strobe pin to ensure the output is properly disabled. Do not short the strobe pin to ground; it should be current driven at 3 to 5 mA. Note 19: Human body model, 1.5 kΩ in series with 100 pF. www.national.com 4 LM111/LM211/LM311 6.0 LM111/LM211 Typical Performance Characteristics Input Bias Current Input Bias Current 00570443 00570444 Input Bias Current Input Bias Current 00570446 00570445 Input Bias Current Input Bias Current 00570447 00570448 5 www.national.com LM111/LM211/LM311 6.0 LM111/LM211 Typical Performance Characteristics Input Bias Current Input Overdrives (Continued) Input Bias Current Input Overdrives 00570450 00570449 Response Time for Various Input Overdrives Input Bias Current 00570451 00570452 Response Time for Various Input Overdrives Output Limiting Characteristics 00570454 00570453 www.national.com 6 Supply Current LM111/LM211/LM311 6.0 LM111/LM211 Typical Performance Characteristics (Continued) Supply Current 00570455 00570456 Leakage Currents 00570457 7.0 LM311 Typical Performance Characteristics Input Bias Current Input Offset Current 00570458 00570459 7 www.national.com LM111/LM211/LM311 7.0 LM311 Typical Performance Characteristics Offset Error (Continued) Input Characteristics 00570461 00570460 Common Mode Limits Transfer Function 00570462 00570463 Response Time for Various Input Overdrives Response Time for Various Input Overdrives 00570465 00570464 www.national.com 8 LM111/LM211/LM311 7.0 LM311 Typical Performance Characteristics (Continued) Response Time for Various Input Overdrives Output Saturation Voltage 00570466 00570467 Response Time for Various Input Overdrives Output Limiting Characteristics 00570469 00570468 Supply Current Supply Current 00570470 00570471 9 www.national.com LM111/LM211/LM311 7.0 LM311 Typical Performance Characteristics (Continued) Leakage Currents 00570472 lead between the resistors and the input pins can result in oscillations that are very hard to damp. Twisting these input leads tightly is the only (second best) alternative to placing resistors close to the comparator. 5. Since feedback to almost any pin of a comparator can result in oscillation, the printed-circuit layout should be engineered thoughtfully. Preferably there should be a groundplane under the LM111 circuitry, for example, one side of a double-layer circuit card. Ground foil (or, positive supply or negative supply foil) should extend between the output and the inputs, to act as a guard. The foil connections for the inputs should be as small and compact as possible, and should be essentially surrounded by ground foil on all sides, to guard against capacitive coupling from any high-level signals (such as the output). If pins 5 and 6 are not used, they should be shorted together. If they are connected to a trim-pot, the trim-pot should be located, at most, a few inches away from the LM111, and the 0.01 µF capacitor should be installed. If this capacitor cannot be used, a shielding printed-circuit foil may be advisable between pins 6 and 7. The power supply bypass capacitors should be located within a couple inches of the LM111. (Some other comparators require the power-supply bypass to be located immediately adjacent to the comparator.) 6. It is a standard procedure to use hysteresis (positive feedback) around a comparator, to prevent oscillation, and to avoid excessive noise on the output because the comparator is a good amplifier for its own noise. In the circuit of Figure 2, the feedback from the output to the positive input will cause about 3 mV of hysteresis. However, if RS is larger than 100Ω, such as 50 kΩ, it would not be reasonable to simply increase the value of the positive feedback resistor above 510 kΩ. The circuit of Figure 3 could be used, but it is rather awkward. See the notes in paragraph 7 below. 8.0 Application Hints 8.1 CIRCUIT TECHNIQUES FOR AVOIDING OSCILLATIONS IN COMPARATOR APPLICATIONS When a high-speed comparator such as the LM111 is used with fast input signals and low source impedances, the output response will normally be fast and stable, assuming that the power supplies have been bypassed (with 0.1 µF disc capacitors), and that the output signal is routed well away from the inputs (pins 2 and 3) and also away from pins 5 and 6. However, when the input signal is a voltage ramp or a slow sine wave, or if the signal source impedance is high (1 kΩ to 100 kΩ), the comparator may burst into oscillation near the crossing-point. This is due to the high gain and wide bandwidth of comparators like the LM111. To avoid oscillation or instability in such a usage, several precautions are recommended, as shown in Figure 1 below. 1. The trim pins (pins 5 and 6) act as unwanted auxiliary inputs. If these pins are not connected to a trim-pot, they should be shorted together. If they are connected to a trim-pot, a 0.01 µF capacitor C1 between pins 5 and 6 will minimize the susceptibility to AC coupling. A smaller capacitor is used if pin 5 is used for positive feedback as in Figure 1. 2. Certain sources will produce a cleaner comparator output waveform if a 100 pF to 1000 pF capacitor C2 is connected directly across the input pins. 3. When the signal source is applied through a resistive network, RS, it is usually advantageous to choose an RS' of substantially the same value, both for DC and for dynamic (AC) considerations. Carbon, tin-oxide, and metal-film resistors have all been used successfully in comparator input circuitry. Inductive wirewound resistors are not suitable. 4. When comparator circuits use input resistors (eg. summing resistors), their value and placement are particularly important. In all cases the body of the resistor should be close to the device or socket. In other words there should be very little lead length or printed-circuit foil run between comparator and resistor to radiate or pick up signals. The same applies to capacitors, pots, etc. For example, if RS=10 kΩ, as little as 5 inches of www.national.com 10 7. tive supply. This signal is centered around the nominal voltage at pin 5, so this feedback does not add to the VOS of the comparator. As much as 8 mV of VOS can be trimmed out, using the 5 kΩ pot and 3 kΩ resistor as shown. (Continued) When both inputs of the LM111 are connected to active signals, or if a high-impedance signal is driving the positive input of the LM111 so that positive feedback would be disruptive, the circuit of Figure 1 is ideal. The positive feedback is to pin 5 (one of the offset adjustment pins). It is sufficient to cause 1 to 2 mV hysteresis and sharp transitions with input triangle waves from a few Hz to hundreds of kHz. The positive-feedback signal across the 82Ω resistor swings 240 mV below the posi- 8. These application notes apply specifically to the LM111, LM211, LM311, and LF111 families of comparators, and are applicable to all high-speed comparators in general, (with the exception that not all comparators have trim pins). 00570429 Pin connections shown are for LM111H in the H08 hermetic package FIGURE 1. Improved Positive Feedback 00570430 Pin connections shown are for LM111H in the H08 hermetic package FIGURE 2. Conventional Positive Feedback 11 www.national.com LM111/LM211/LM311 8.0 Application Hints LM111/LM211/LM311 8.0 Application Hints (Continued) 00570431 FIGURE 3. Positive Feedback with High Source Resistance 9.0 Typical Applications (Pin numbers refer to H08 package) Zero Crossing Detector Driving MOS Switch 100 kHz Free Running Multivibrator 00570413 00570414 *TTL or DTL fanout of two www.national.com 12 LM111/LM211/LM311 9.0 Typical Applications (Pin numbers refer to H08 package) (Continued) 10 Hz to 10 kHz Voltage Controlled Oscillator 00570415 *Adjust for symmetrical square wave time when VIN = 5 mV †Minimum capacitance 20 pF Maximum frequency 50 kHz Driving Ground-Referred Load Using Clamp Diodes to Improve Response 00570417 00570416 *Input polarity is reversed when using pin 1 as output. TTL Interface with High Level Logic 00570418 *Values shown are for a 0 to 30V logic swing and a 15V threshold. †May be added to control speed and reduce susceptibility to noise spikes. 13 www.national.com LM111/LM211/LM311 9.0 Typical Applications (Pin numbers refer to H08 package) Crystal Oscillator (Continued) Comparator and Solenoid Driver 00570420 00570419 Precision Squarer 00570421 *Solid tantalum †Adjust to set clamp level www.national.com 14 LM111/LM211/LM311 9.0 Typical Applications (Pin numbers refer to H08 package) (Continued) Low Voltage Adjustable Reference Supply 00570422 *Solid tantalum Positive Peak Detector Zero Crossing Detector Driving MOS Logic 00570424 00570423 *Solid tantalum Negative Peak Detector 00570425 *Solid tantalum 15 www.national.com LM111/LM211/LM311 9.0 Typical Applications (Pin numbers refer to H08 package) (Continued) Precision Photodiode Comparator 00570426 *R2 sets the comparison level. At comparison, the photodiode has less than 5 mV across it, decreasing leakages by an order of magnitude. Switching Power Amplifier 00570427 www.national.com 16 LM111/LM211/LM311 9.0 Typical Applications (Pin numbers refer to H08 package) (Continued) Switching Power Amplifier 00570428 17 www.national.com LM111/LM211/LM311 10.0 Schematic Diagram (Note 20) 00570405 Note 20: Pin connections shown on schematic diagram are for H08 package. www.national.com 18 LM111/LM211/LM311 11.0 Connection Diagrams Metal Can Package 00570406 Note: Pin 4 connected to case Top View Order Number LM111H, LM111H/883(Note 21) , LM211H or LM311H See NS Package Number H08C Dual-In-Line Package Dual-In-Line Package 00570434 Top View Order Number LM111J-8, LM111J-8/883(Note 21), LM311M, LM311MX or LM311N See NS Package Number J08A, M08A or N08E 00570435 Top View Order Number LM111J/883(Note 21) See NS Package Number J14A or N14A 00570433 Order Number LM111W/883(Note 21), LM111WG/883 See NS Package Number W10A, WG10A Note 21: Also available per JM38510/10304 19 www.national.com LM111/LM211/LM311 12.0 Physical Dimensions inches (millimeters) unless otherwise noted Metal Can Package (H) Order Number LM111H, LM111H/883, LM211H or LM311H NS Package Number H08C Cavity Dual-In-Line Package (J) Order Number LM111J-8, LM111J-8/883 NS Package Number J08A www.national.com 20 LM111/LM211/LM311 12.0 Physical Dimensions inches (millimeters) unless otherwise noted (Continued) Dual-In-Line Package (J) Order Number LM111J/883 NS Package Number J14A Dual-In-Line Package (M) Order Number LM311M, LM311MX NS Package Number M08A 21 www.national.com LM111/LM211/LM311 12.0 Physical Dimensions inches (millimeters) unless otherwise noted (Continued) Dual-In-Line Package (N) Order Number LM311N NS Package Number N08E Order Number LM111W/883, LM111WG/883 NS Package Number W10A, WG10A www.national.com 22 LM111/LM211/LM311 Voltage Comparator Notes 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. 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