NATIONAL SEMICONDUCTOR LMC7211 Tiny CMOS Comparator with Rail-to-Rail Input Push-Pull Output handbook
Contents
1. 5 55 35 15 5 25 45 65 85 105 45 25 15 55 55 75 95 Case Temperature 9C 01233717 Output Sinking Current vs Supply Voltage 100 OS INPUT OV tr 90 NEG INPUT 0 1V 85 Output Current mA HSH CI 00 0123 45 6 7 8 9101112 Supply Voltage V 01233719 Supply Current vs Temperature while Sourcing POS INPUT NEG INPUT 0 1V Supply Current A 5 55 35 15 5 25 45 65 85 105 45 25 5 15 35 55 75 95 Case Temperature 9C 01233716 Output Sourcing Current vs Supply Voltage POS INPUT 0 1V 90 L L L L NEG input ov 85 Output Current mA OI U1U1 00 Supply Voltage V 01233718 Output Sinking Current vs Output Voltage 5V 1000 Output Voltage mV e 0 1 2 5 4 5 6 7 8 9 10 Output Current mA 01233720 www national com 22911 LMC7211 Typical Performance Characteristics singe supply 25 C unless specified Continued Output Sinking Current vs Output Voltage 5V Output Voltage mV 1000 900 500 859C 259C 409C 01 2 3 4 5 6 7 8 9 102. Nim Semiconductor LMC7211 Push Pull Output and PCMCIA cards The rail to rail input voltage makes the LMC7211 a good choice for sensor interfacing such as light detector circuits optical and magnetic sensors and alarm and status circuits H The Tiny Comparator s outside dimensions length x width x height of 3 05mm x 3 00mm x 1 43mm allow it to fit into tight spaces on PC boards See the LMC7221 for a comparator with open drain output L August 2002 Tiny CMOS Comparator with Rail to Rail Input and General Description Features The LMC7211 is micropower CMOS comparator available Tiny SOT 23 5 package saves space in the space saving SOT23 5 package This makes the Package is less than 1 43 mm thick comparator ideal for space and weight critical designs The Guaranteed specs at 2 7V 5V 15V supplies LMC7211 is supplied in two offset voltage grades 5 mV Typical supply current 7 pA at 5V 15 mV m Response time of 4 us at 5V The main benefits of the Tiny package are most apparentin Push pull output small portable electronic devices such as mobile phones Input common mode range beyond V and V pagers notebook computers personal digital assistants Low input current Applications Battery Powered Products Notebooks and PDAs PCMCIA cards Mobile Communications Alarm and Security circuits Direct Sensor Interface Replaces amplifiers used as comparators with better perfo
3. Note 11 Note 9 V 2 7V 10 mV us f 10 kHz 100 mV Cl 50 pF Note 9 Propagation Delay f 10 kHz 10 mV us Low to High Cl 50p 100 mV Note 11 Note 9 V 2 7V 10 mV 7 us f 10 kHz 100 mV 4 CI 2 50 pF Note 9 Note 1 Absolute Maximum Ratings indicate limits beyond which damage to the device may occur Operating Ratings indicate conditions for which the device is intended 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 kQ in series with 100 pF Note 3 Applies to both single supply and split supply operation Continuous short circuit operation at elevated ambient temperature can result in exceeding the maximum allowed junction temperature of 150 C Output currents in excess of 30 mA over long term may adversely affect reliability Note 4 The maximum power dissipation is a function of Tj may and Ta The maximum allowable power dissipation at any ambient temperature is Pp TJ max numbers apply for packages soldered directly into PC board Note 5 Typical values represent the most likely parametric norm Note 6 All limits are guaranteed by testing or statistical analysis Note 7 Limiting input pin current is only necessary for input voltages that exceed absolute maximum input voltage rating Note 8 Do not short circuit output to
4. 5 0V dB Rejection Ration V 15 0V dB PSRR Power Supply 5V lt V lt 10V dB Rejection Ratio Ay Voltage Gain dB CMVR Input Common Mode V 5 0V V Voltage Range CMRR gt 55 dB min V 5 0V V CMRR gt 55 dB max V 15 0V V CMRR gt 55 dB min V 15 0V V CMRR gt 55 dB max Vou Output Voltage High V 5V mV 5 mA min V 15V mV 5 mA min VoL Output Voltage Low V 5V mV 5 mA max V 15V mV 5 mA max ls Supply Current Vout Low Isc Short Circuit Current Sourcing Sinking Note 8 7 14 14 18 18 45 AC Electrical Characteristics Unless otherwise specified all limits guaranteed for T 25 C V 5V V OV Vem Vo V 2 Boldface limits apply at the temperature extreme Typ LMC7211Al LMC7211BI Symbol Parameter Conditions Note 5 Limit Limit Units Note 6 Note 6 tise Rise Time f 10 kHz Cl 50 pF 0 3 Hs Overdrive 10 mV Note 9 tran Fall Time f 10 kHz Cl 50 pF 0 3 us Overdrive 10 mV Note 9 www national com 22211 LMC7211 AC Electrical Characteristics continued Unless otherwise specified all limits guaranteed for T 25 C 5V OV Voy V 2 Boldface limits apply at the temperature extreme LMC7211AI LMC7211BI Symbol Parameter Conditions Limit Limit Units teur Propagation Delay f 10 kHz 10 mV us High to Low Cl 50 pF 100 mV
5. large shifts in the comparator threshold due to changes in the voltage level the voltage drop at the bypass capacitor should be limited to 100 mV or less The charge needed 100 picocolumb and the allowable voltage drop 100 mV will give us the minimum capacitor value required AQ C AV C AQ AV 100 picocolumb 100 mV 10719101 10 1 nF 0 001 uF 10 1 nF 0 001 uF The voltage drop of 100 mV will cause a threshold shift in the comparator This threshold shift will be reduced by the power supply rejection ratio PSRR The PSRR which is applicable here is not the DC value of PSRR 80 dB but a transient which will be usually about 20 dB 40 dB depending on the circuit and the speed of the transient This will result in an effective threshold shift of about 1 mV to 10 mV For precision and level sensing circuits it is generally a good goal to reduce the voltage delta on the power supply to a value equal to or less than the hysteresis of the comparator circuit If the above circuit was to be used with 50 mV of hysteresis it would be reasonable to increase the bypass capacitor to 0 01 pF to reduce the voltage delta to 10 mV Larger values may be useful for obtaining more accurate and consistent switching www national com 22311 LMC7211 Application Information continued Note that the switching current of the comparator can spread to other parts of the board as noise The bypass capaci
6. Output Current mA 01233721 Output Sinking Current vs Output Voltage 15V Output Voltage mV Response Time for Various Input Overdrives tp Output Voltage Vo Input Voltage Vin 1000 Output Current mA 01233723 Vs 2 7 3 0 Input Overdrive 100 mV 2 7 2 20mV 1 010 mV 0 5 mV 2 1 0 4 Overdrive 0 4 8 12 16 Time ps Input Overdrive Referenced to Vos 01233725 Output Sourcing Current vs Output Voltage 15V 1000 900 800 859C 700 600 500 400 409 259C Output Voltage mV 01 2 3 4 5 6 7 8 9 10 Output Current mA 01233722 Response Time for Various Input Overdrives ut Overdrive 1 Output Voltage Vo Vin V Input Voltage Time ps Input Overdrive Referenced to Vos 01233724 Response Time for Various Input Overdrives Output Voltage Vo 0 Vin V Input Voltage Time ps Input Overdrive Referenced to Vos 01233726 www national com Typical Performance Characteristics single supply 25 C unless specified Continued Response Time for Various Input Overdrives tp Y Output Voltage Vo 0 Vin V Input Voltage Time ps Input Overdrive Referenced to Vos 01233727 Response Time for Various Input Overdrives tp
7. 0 567 1 0 078 0 039 330 00 1 50 13 00 20 20 55 00 8 40 1 50 0 00 14 40 W1 2 00 1 00 Tape Size A B C D N W1 W2 FORMAT Tape Section Cavities Cavity Status Cover Tape Status Leader 0 min Empty Sealed Start End 75 min Empty Sealed Carrier 3000 Filled Sealed 1000 Filled Sealed Trailer 125 min Sealed Hub End Sealed www national com 12 SOT 23 5 Tape and Reel Specification Continued Tape Dimensions 0 061 0 002 TYP 1 55 0 05 0 157 0 079 0 002 2 0 05 CAVITY SYMM B AT TANGENT GAGE LINE POINTS H R0 012 TYP 0 31 1 ALL INSIDE RADII Ns oes 2 0 041 0 002 TYP ot e 0 012 1 04 0 05 DIRECTION OF FEED gt 0 3 GAGE LINE SECTION B B TANGENT POINTS CAVITY R0 012 GAGE LINE TN SYMM 3 TYP q 4 AT GAGE LINE R 1 181 MIN 30 s BEND RADIUS NOT TO SCALE SECTION A A 01233714 0 124 0 130 0 138 0 002 0 055 0 004 0 157 0 315 0 012 3 15 3 3 3 5 0 05 1 4 0 11 4 8 0 3 Sze ___ __ ___ ompi omw 13 www national com 22311 LMC7211 Physical Dimensions inches millimeters unless otherwise noted 063 003 1 62 0 07 038 048 0 97 1 22 004 t0 11 c 0
8. 11 is capable of operating with very high impedance inputs so precautions should be taken to reduce noise pickup with high impedance 100 kQ and greater designs and in electrically noisy environments Keeping high value resistors close to the LMC7211 and minimizing the size of the input nodes is a good practice With multilayer designs try to avoid long loops which could act as inductors coils Sensors which are not close to the comparator may need twisted pair or shielded connections to reduce noise 8 0 Open Drain Output Dual Versions The LMC7221 is a comparator similar to the LMC7211 but with an open drain output which allows the output voltage to be different higher or lower than the supply voltage The open drain output is like the open collector output of a logic gate This makes the LMC7221 very useful for mixed voltage systems Many systems will have different voltages for the analog and microprocessor sections Please see the LMC7221 datasheet for details The performance of the LMC7211 is available in dual de vices Please see the LMC6762 datasheet for details on a dual push pull output device For a dual device with open drain outputs please see the LMC6772 datasheet Rail to Rail Input Low Power Comparators Push Pull Output LMC7211 SOT23 5 SO 8 Single LMC6762 SO 8 Dual Open Drain Output LMC7221 SOT23 5 SO 8 Single LMC6772 SO 8 DIP Dual 9 0 Additional SOT23 5 Tiny Devices National Semiconduct
9. 43230 0631 0170 0025 edid 002 006 to 05 0 151 008 10 210 89 0060 0015 0 15219 938 1 102 2 591 d 039 3 0 993 E 027 0 69 LAND PATTERN RECOMMENDATION R 004 MIN TYP 0 11 R 004 MIN TYP 0 11 CONTROLLING DIMENSION IS INCH VALUES IN ARE MILLIMETERS 5 Pin SOT Package NS Package Number MF05A 0 189 0 197 4 800 5 004 8 7 8 5 0 228 0 244 5 781 6 198j 0 010 max 0 254 LEAD NO 1 222 IDENT au TYP 0 150 0 157 3 810 3 988 0 053 0 089 TETTE 45 1 346 1 753 0 254 0 508 8 MAX TYP JE ALL 0 004 7 0 192 0 080910 LEAD TIPS 0 203 0 254 TYP ALL LEADS f 0 016 0 050 0 406 1 270 TYP ALL LEADS 0 014 0 356 D050 0 008 0 203 8 Small Outline Package NS Package Number M08A EUM PLANE 0 102 0 254 SEATING NS 014 0 020 DEG 356 0 508 REV 0 8 014 022 10 36 0 551 Rev www national com 14 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 su
10. Output Voltage Vo Vin Input Voltage Time ps Input Overdrive Referenced to Vos 01233729 Input Bias Current vs Common Mode Voltage 100 80 T Vs 5 Input Bias Current fA 100 0 05 1 15 2 25 3 35 4 45 5 Common Mode Voltage V 01233731 Response Time for Various Input Overdrives tp Input Overdrive 100 mV Vs 15V 15 0 20mV mV 5 mV Output Voltage Vo wo Overdrive Vin V Input Voltage 0 4 8 12 16 Time ps Input Overdrive Referenced to Vos 01233728 Input Bias Current vs Common Mode Voltage 100 Vs 2 7V Input Bias Current fA Common Mode Voltage V 01233730 Input Bias Current vs Common Mode Voltage Input Bias Current fA 01234567 8 9101112131415 Common Mode Voltage V 01233732 www national com 22911 LMC7211 Typical Performance Characteristics single supply T 25 C unless specified Continued Input Bias Current vs Temperature 1500 Input Bias Current fA Case Temperature C Application Information 1 0 Benefits of the LMC7211 Tiny Comparator Size The small footprint of the SOT 23 5 packaged Tiny Comparator 0 120 x 0 118 inches 3 05 x 3 00 mm saves space on printed circuit boards and enable the design of smaller electronic pro
11. V when V is greater than 12V or reliability will be adversely affected Note 9 C includes the probe and jig capacitance Note 10 Input offset voltage average drift is calculated by dividing the accelerated operating life Vos drift by the equivalent operational time This represents worst case input conditions and includes the first 30 days of drift Note 11 Input step voltage for propagation delay measurement is 2V Ordering Information Package Ordering NSC Drawing Package Transport Media Information Number Marking LMC7211AIM M08A LM7211AIM LMC7211AIMX __ LM7211AIM ___ 2 5 Units Tape and Reel LMC7211BIM LM7211BIM LMC7211BIMX _ LM7211BIM 2 5 Units tape and Reel LMC7211AIM5 MF05A 1k Units Tape and Reel LMC7211AIM5X MFO5A 3k Units Tape and Reel 5 Pin SOT 23 5 LMC7211BIM5 MF05A COOB 1k Units Tape and Reel LMC7211BIM5X MFO5A COOB 3k Units Tape and Reel www national com 4 Typical Performance Characteristics singe supply 25 unless specified Supply Current vs Supply Voltage 10 IT TT POS INPUT OV NEG INPUT 0 1V 9 lt 8 859C 2 259C 7 409C e 6 5 01234567 8 9101112131415 Supply Voltage V 01233715 Supply Current vs Temperature while Sinking POS INPUT NEG INPUT 0 1 Supply Current pA
12. W 325 C W 2 7V OV Vom Vo 2 Boldface limits apply Rejection Ratio Ay Voltage Gain Typ LMC7211AI LMC7211BI Symbol Parameter Conditions Note 5 Limit Limit Units Note 6 Note 6 Vos Input Offset Voltage 3 5 15 mV 8 18 max TCVos Input Offset Voltage 1 0 uV C Temperature Drift Input Offset Voltage Note 10 3 3 y V Month Average Drift lg Input Current 0 04 pA los Input Offset Current 0 02 pA CMRR Common Mode OV Vom 2 7V 75 dB Rejection Ratio PSRR Power Supply 2 7V lt lt 15V 80 2 9 2 9 CMVR Input Common Mode CMRR gt 55 dB 3 0 V Voltage Range min CMRR gt 55 dB 0 3 V max Vou Output Voltage High 2 5 MA 2 5 V min VoL Output Voltage Low 2 5 mA 0 2 V max ls Supply Current Vout Low 7 www national com 5 0V and 15 0V Electrical Characteristics Unless otherwise specified all limits guaranteed for T 25 C V 5 0V and 15V V OV Vom Vo V 2 Boldface lim its apply at the temperature extremes Typ LMC7211AI LMC7211BI Symbol Parameter Conditions Note 5 Limit Limit Units Note 6 Note 6 Vos Input Offset Voltage 3 5 15 mV 8 18 max TCVos Input Offset Voltage Vt 5V 1 0 V C Temperature Drift V 15V 4 0 Input Offset Voltage V 5V O O yV Month lg Input Current ow a los Input Offset Current pA CMRR Common Mode V
13. at a 2 7 volt supply This can allow the LMC7211 to drive multiple logic gates Driving LEDs Light Emitting Diodes With a 5 volt power supply the LMC7211 s output sinking current can drive small high efficiency LEDs for indicator and test point cir cuits The small size of the Tiny package makes it easy to find space to add this feature to even compact designs 01233733 Input range to Beyond Rail to Rail The input common mode range of the LMC7211 is slightly larger than the actual power supply range This wide input range means that the comparator can be used to sense signals close to the power supply rails This wide input range can make design easier by eliminating voltage dividers amplifiers and other front end circuits previously used to match signals to the limited input range of earlier comparators This is useful to power supply monitoring circuits which need to sense their own power supply and compare it to a reference voltage which is close to the power supply voltage The wide input range can also be useful for sensing the voltage drop across a current sense resistor for battery chargers Zero Crossing Detector Since the LMC7211 s common mode input range extends below ground even when pow ered by a single positive supply it can be used with large input resistors as a zero crossing detector Low Input Currents and High Input Impedance These characteristics allow the LMC7211 to be used to sense high impedance signa
14. ducts Because they are easier to carry many customers prefer smaller and lighter products Height The height 0 056 inches 1 43 mm of the Tiny Comparator makes it possible to use it in PCMCIA type III cards Simplified Board Layout The Tiny Comparator can sim plify board layout in several ways First by placing a com parator where comparators are needed instead of routing signals to a dual or quad device long pc traces may be avoided By using multiple Tiny Comparators instead of duals or quads complex signal routing and possibly crosstalk can be reduced Low Supply Current The typical 7 pA supply current of the LMC7211 extends battery life in portable applications and may allow the reduction of the size of batteries in some applications Wide Voltage Range The LMC7211 is characterized at 15V 5V and 2 7V Performance data is provided at these popular voltages This wide voltage range makes the LMC7211 a good choice for devices where the voltage may vary over the life of the batteries Digital Outputs Representing Signal Level Comparators provide a high or low digital output depending on the voltage levels of the and inputs This makes comparators useful for interfacing analog signals to microprocessors and other digital circuits The LMC7211 can be thought of as a one bit a d converter Push Pull Output The push pull output of the LMC7211 is capable of both sourcing and sinking milliamp level currents even
15. ely useful in low voltage applications A4 0 015V 01233705 FIGURE 1 Even at Low Supply Voltage of 2 7V an Input Signal which Exceeds the Supply Voltages Produces No Phase Inversion at the Output At V 2 7V propagation delays are 4 us and 4 us with overdrives of 100 mV Please refer to the performance curves for more extensive characterization 3 0 Shoot Through Current The shoot through current is defined as the current surge above the quiescent supply current between the positive and negative supplies of a device The current surge occurs when the output of the device switches states The shoot through current results in glitches in the supply volt ages Usually glitches in the supply lines are prevented by bypass capacitors When the glitches are minimal the value of the bypass capacitors can be reduced 01233706 FIGURE 2 Circuit for Measurement of the Shoot Through Current AV2 01233707 FIGURE 3 Measurement of the Shoot Through Current From Figure 3 the shoot through current for the LMC7211 can be calculated to be 0 2 mA typical and the duration is 1 us The values needed for the bypass capacitors can be calculated as follows IShoot Through v Supply Lines Di 1 Time 01233708 Area of A 12 1 us x 200 uA 100 pC The capacitor needs to supply 100 picocolumb To avoid
16. er noise immunity for the circuit See Figure 4 Figure 5 and Figure 6 Note that very heavy loading of the comparator output such as LED drive or bipolar logic gates will change the output voltage and shift the voltage thresholds 01233709 Rp gt and Re gt Ro FIGURE 4 Positive Feedback for Hysteresis Without Positive Feedback No Hysteresis yr Vout 1 GROUND Inputs Equal VIN 01233710 FIGURE 5 With Positive Feedback Hysteresis or Memory v Vour GROUND Inputs LOW Equal 1 Vy HIGH VIN 01233711 FIGURE 6 6 0 Input Protection If input signals are like to exceed the common mode range of the LMC7211 or it is likely that signals may be present when power is off damage to the LMC7211 may occur Large value 100 kO to MQ input resistors may reduce the likeli hood of damage by limiting the input currents Since the LMC7211 has very low input leakage currents the effect on accuracy will be small Additional protection may require the use of diodes as shown in Figure 7 Note that diode leakage current may affect accuracy during normal operation The R C time constant of Rij and the diode capacitance may also slow response time www national com Application Information continued yt 01233712 FIGURE 7 7 0 Layout Considerations The LMC7211 is not an especially fast comparator so high speed design practices are not required The LMC72
17. ls from sensors They also make it possible to use the LMC7211 in timing circuits built with large value resistors This can reduce the power dissipation of timing circuits For very long timing circuits using high value resis tors can reduce the size and cost of large value capacitors for the same R C time constant Direct Sensor Interfacing The wide input voltage range and high impedance of the LMC7211 may make it possible to directly interface to a sensor without the use of amplifiers or bias circuits In circuits with sensors which can produce outputs in the tens to hundreds of millivolts the LMC7211 can compare the sensor signal with an appropriately small reference voltage This may be done close to ground or the positive supply rail Direct sensor interfacing may eliminate the need for an amplifier for the sensor signal Eliminating the amplifier can save cost space and design time 2 0 Low Voltage Operation Comparators are the common devices by which analog sig nals interface with digital circuits The LMC7211 has been designed to operate at supply voltages of 2 7V without sac rificing performance to meet the demands of 3V digital sys tems At supply voltages of 2 7V the common mode voltage range extends 200 mV guaranteed below the negative supply www national com Application Information continued This feature in addition to the comparator being able to sense signals near the positive rail is extrem
18. or has additional parts available in the space saving SOT23 Tiny package including amplifiers voltage references and voltage regulators These devices include LMC7101 1 MHz gain bandwidth rail to rail input and output amplifier high input impedance and high gain 700 typical current 2 7V 3V 5V and 15V specifications LMC7111 Low power 50 kHz gain bandwidth rail to rail in put and output amplifier with 25 typical current specified at 2 7V 3 0V 3 3V 5V and 10V LM7131 Tiny Video amp with 70 MHz gain bandwidth 3V 5V and 5V specifications LP2980 Micropower SOT 50 Ultra Low Dropout Regulator LM4040 Precision micropower shunt voltage reference Fixed voltages of 2 500V 4 096V 5 000V 8 192V and 10 000V LM4041 Precision micropower shut voltage reference 1 225V and adjustable LM385 Low current voltage reference Fixed Voltages of 1 2V and 2 5V Contact your National Semiconductor representative for the latest information 10 0 Spice Macromodel A Spice Macromodel is available for the LMC7211 compara tor on the National Semiconductor Amplifier Macromodel disk Contact your National Semiconductor representative to obtain the latest version www national com 22911 LMC7211 SOT 23 5 Tape and Reel Specification REEL DIMENSIONS TAPE SLOT DETAIL X N C SCALE 3X 1 Ws Wo 01233713 8 mm 7 00 0 059 0 512 0 795 2 165 0 331 0 059 0 000
19. pport devices or systems are devices or 2 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 National Semiconductor Corporation Europe Americas Fax 49 0 180 530 85 86 Email support nsc com Email europe support Q nsc com Deutsch Tel 49 0 69 9508 6208 English Tel 44 0 870 24 0 2171 www national com Fran ais Tel 33 0 1 41 91 8790 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 National Semiconductor Asia Pacific Customer Japan Ltd Response Group Tel 81 3 5639 7560 Tel 65 2544466 Fax 81 3 5639 7507 Fax 65 2504466 Email ap support nsc com 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 indino SOWO AULL 112720
20. rmance and lower current Connection Diagrams 8 Pin SO 8 5 Pin SOT23 5 1 5 NC 1 8 NC OUTPUT V INVERTING INPUT 2 v yt 2 rae s 3 6 OUTPUT v 4 5 NC NON INVERTING 3 4 INVERTING INPUT INPUT 01233701 01233702 Top View Top View 2002 National Semiconductor Corporation DS012337 www national com indino SONO LLZZOWT LMC7211 Absolute Maximum Ratings note 1 If Military Aerospace specified devices are required please contact the National Semiconductor Sales Office Distributors for availability and specifications Storage Temperature Range Junction Temperature 65 C to 150 C 150 C ESD Tolerance Note 2 Differential Input Voltage Voltage at Input Output Pin at the temperature extremes 2 kV Voc 0 3V to 0 3 Voc 0 3V to 0 3 Supply Voltage V V 16V Current at Input Pin Note 7 5 mA Current at Output Pin Notes 3 8 30 mA Current at Power Supply Pin 40 mA Lead Temperature soldering 10 sec 260 C 2 7V Electrical Characteristics Unless otherwise specified all limits guaranteed for T 25 C V Note 4 Operating Ratings note 1 Supply Voltage Junction Temperature Range LMC7211Al LMC7211BI Thermal Resistance 0 SO 8 Package 8 Pin Surface Mount Package 5 Pin Surface Mount 2 7 lt Voc lt 15V 40 C lt T lt 85 C 180 C
21. tor reduces this noise For low noise systems this may be reason to make the capacitor larger For non precision circuits such as using a comparator to determine if a push button switch is on or off it is often cheaper and easier to use a larger value of hysteresis and a small value or bypass capacitance The low shoot through current of the LMC7211 can allow the use of smaller and less expensive bypass capacitors in non critical circuits 4 0 Output Short Circuit Current The LMC7211 has short circuit protection of 40 mA How ever it is not designed to withstand continuous short circuits transient voltage or current spikes or shorts to any voltage beyond the supplies A resistor in series with the output should reduce the effect of shorts For outputs which send signals off PC boards additional protection devices such as diodes to the supply rails and varistors may be used 5 0 Hysteresis If the input signal is very slow or very noisy the comparator output might trip several times as the input signal passes through the threshold Using positive feedback to add hys teresis to the switching can reduce or eliminate this problem The positive feedback can be added by a high value resistor Rg This will result in two switching thresholds one for increasing signals and one for decreasing signals A capaci tor be added across to increase the switching speed and provide more short term hysteresis This can result in great
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NATIONAL SEMICONDUCTOR LMC7211 Tiny CMOS Comparator with Rail to Rail Input Push Pull Output handboo