LMC7221 Tiny CMOS Comparator with Rail-To-Rail Input and Open Drain Output General Description The LM7221 is a micropower CMOS comparator available in the space saving SOT23-5 package. This makes this comparator ideal for space and weight critical designs. The LMC7221 is also available in the SO-8 package. The LMC7221 is supplied in two offset voltage grades, 5 mV and 15 mV. The open drain output can be pulled up with a resistor to a voltage which can be higher or lower than the supply voltage — this makes the part useful for mixed voltage systems. For a tiny comparator with a push-pull output, please see the LMC7211 datasheet. Features n n n n n n Guaranteed specs at 2.7V, 5V, 15V supplies Typical supply current 7 µA at 5V Response time of 4 µs at 5V LMC7221 — open drain output Input common-mode range beyond V− and V+ Low input current Applications n n n n n n n Mixed voltage battery powered products Notebooks and PDAs PCMCIA cards Mobile communications Alarm and security circuits Driving low current LEDs Direct sensor interface n Tiny SOT 23-5 package saves space n Package is less than 1.43 mm thick Connection Diagrams 8–Pin SO-8 5-Pin SOT23-5 DS012346-1 DS012346-2 Top View Top View Ordering Information Package 8-Pin SO-8 5-Pin SOT 23-5 Ordering NSC Drawing Package Information Number Marking Transport Media LMC7221AIM M08A LMC7221AIM Rails LMC7221AIMX M08A LMC7221AIM 2.5k Units Tape and Reel LMC7221BIM M08A LMC7221BIM Rails LMC7221BIMX M08A LMC7221BIM 2.5k Units Tape and Reel LMC7221AIM5 MA05A C01A 1k Units Tape and Reel LMC7221AIM5X MA05A C01A 3k Units Tape and Reel LMC7221BIM5 MA05A C01B 1k Units Tape and Reel LMC7221BIM5X MA05A C01B 3k Units Tape and Reel © 1999 National Semiconductor Corporation DS012346 www.national.com LMC7221 Tiny CMOS Comparator with Rail-To-Rail Input and Open Drain Output September 1999 Absolute Maximum Ratings (Note 1) (soldering, 10 sec.) Storage Temperature Range Junction Temperature (Note 4) 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 Voltage at Input Voltage at Output Pin Supply Voltage (V+–V−) Current at Input Pin (Note 7) Current at Output Pin (Notes 3, 8) Current at Power Supply Pin Lead Temperature 2 kV (VCC) +0.3V to (−VCC)−0.3V (VCC) + 0.3V to (−VCC)−0.3V 15V 16V 260˚C −65˚C to +150˚C 150˚C Operating Ratings (Note 1) 2.7 ≤ VCC ≤ 15V Supply Voltage Junction Temperature Range LMC7221AI, LMC7221BI Thermal Resistance (θJA) SO-8 Package, 8-Pin Surface Mount M05A Package, 5-Pin Surface Mount ± 5 mA ± 30 mA 40 mA −40˚C ≤ TJ ≤ +85˚C 180˚C/W 325˚C/W 2.7V Electrical Characteristics Unless otherwise specified, all limits guaranteed for TJ = 25˚C, V+ = 2.7V, V− = 0V, VCM = VO = V+/2. Boldface limits apply at the temperature extremes Symbol VOS TCVOS Parameter Conditions Input Offset Voltage Typ LMC7221AI (Note 5) Limit Limit (Note 6) (Note 6) 5 15 mV 8 18 max 3 Input Offset Voltage LMC7221BI Units 1.0 µV/˚C 3.3 µV/Month pA Temperature Drift Input Offset Voltage (Note 10) Average Drift IB Input Current 0.04 IOS Input Offset Current 0.02 pA CMRR Common Mode 0V ≤ VCM ≤ 2.7V 75 dB 2.7V ≤ V+ ≤ 15V 80 dB Rejection Ratio PSRR Power Supply Rejection Ratio AV Voltage Gain CMVR Input Common-Mode 100 CMRR > 55 dB 3.0 Voltage Range CMRR > 55 dB VOL IS www.national.com Output Voltage Low Supply Current −0.3 Iload = 2.5 mA 0.2 VOUT = low 7 2 dB 2.9 2.9 V 2.7 2.7 min −0.2 −0.2 V 0.0 0.0 max 0.3 0.3 V 0.4 0.4 max 12 12 µA 14 14 max 5.0V and 15.0V Electrical Characteristics Unless otherwise specified, all limits guaranteed for TJ = 25˚C, V+ = 5.0V and 15V, V− = 0V, VCM = VO = V+/2. Boldface limits apply at the temperature extremes Symbol VOS TCVOS Parameter Conditions Typ LMC7221AI (Note 5) Limit Limit (Note 6) (Note 6) 5 15 mV 8 18 max Input Offset Voltage 3 V+ = 5V V+ = 15V V+ = 5V (Note 10) V+ = 15V (Note 10) Input Offset Voltage Temperature Drift Input Offset Voltage Average Drift LMC7221BI 1.0 Units µV/˚C 4.0 3.3 µV/Month 4.0 IB Input Current 0.04 pA IOS Input Offset Current 0.02 pA CMRR Common Mode 75 dB V+ = 5.0V V+ = 15.0V Rejection Ration PSRR 5V ≤ V+ ≤ 10V Power Supply 82 dB 80 dB Rejection Ratio AV Voltage Gain CMVR Input Common-Mode V+ = 5.0V Voltage Range CMRR > 55 dB V+ = 5.0V 100 5.3 −0.3 CMRR > 55 dB V+ = 15.0V 15.3 CMRR > 55 dB V+ = 15.0V VOL −0.3 CMRR > 55 dB V+ = 5V Output Voltage Low 0.2 Iload = 5 mA V+ = 15V IS Supply Current ISC 0.2 Iload = 5 mA VOUT = Low Short Circuit Current 7 Sinking (Note 8) dB 5.2 5.2 V 5.0 5.0 min −0.2 −0.2 V 0.0 0.0 max 15.2 15.2 V 15.0 15.0 min −0.2 −0.2 V 0.0 0.0 max 0.40 0.40 mV 0.55 0.55 max 0.40 0.40 mV 0.55 0.55 max 14 14 µA 18 18 max 45 mA Leakage Characteristics TJ = 25˚C Symbol ILEAKAGE Parameter Output Leakage Current Conditions V+ = 2.7V VIN(+) = 0.5V Typ LMC7221AI (Note 5) Limit Limit (Note 6) (Note 6) 500 500 0.1 LMC7221BI Units nA VIN(−) = 0V VOUT = 15V 3 www.national.com AC Electrical Characteristics Unless otherwise specified, all limits guaranteed for TJ = 25˚C, V+ = 5V, V− = 0V, VCM = VO = V+/2. Boldface limits apply at the temperature extreme Symbol Parameter trise Rise Time tfall Fall Time tPHL Conditions LMC7221AI Limit Limit (Note 6) (Note 6) f = 10 kHz, CL = 50 pF, (Note 9) Overdrive = 10 mV, 5 kΩ Pullup f = 10 kHz, CL = 50 pF, (Note 9) (High to Low) Overdrive = 10 mV, 5 kΩ Pullup f = 10 kHz, 10 mV CL = 50 pF, 100 mV (Note 11) 5 kΩ Pullup Propagation Delay Typ (Note 5) LMC7221BI Units 0.3 µs 0.3 µs 10 µs 4 (Note 9) V+ = 2.7V, 10 mV 10 f = 10 kHz, CL = 50 pF, 100 mV 4 µs 5 kΩ Pullup tPLH (Low to High) (Note 9) f = 10 kHz, CL = 50 pF, (Note 11) 5 kΩ Pullup Propagation Delay 10 mV 6 100 mV 4 (Note 9) V+ = 2.7V, 10 mV 7 f = 10 kHz, CL = 50 pF, 100 mV 4 µs µs 5 kΩ Pullup (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 kΩ 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 may adversely affect reliability. Note 4: The maximum power dissipation is a function of TJ(max), θJA, and TA. The maximum allowable power dissipation at any ambient temperature is Note 5: PD = (TJ(max) − TA)/θJA. All numbers apply for packages soldered directly into a PC board. Note 6: Typical values represent the most likely parametric norm. Note 7: All limits are guaranteed by testing or statistical analysis. Note 8: Limiting input pin current is only necessary for input voltages which exceed the absolute maximum input voltage rating. Note 9: Do not short circuit the output to V+ when V+ is greater than 12V or reliability will be adversely affected. Note 10: CL includes the probe and test jig capacitance. Note 11: 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 12: Input step voltage for propagation delay measurement is 2V. www.national.com 4 Typical Performance Characteristics Supply Current vs Supply Voltage Supply Current vs Temperature while Sinking DS012346-3 Output Sinking Current vs Output Voltage @ 5V Output Sinking Current vs Supply Voltage DS012346-4 Output Sinking Current vs Output Voltage @ 15V DS012346-6 DS012346-5 Response Time for Various Input Overdrives −tPHL DS012346-7 DS012346-8 Response Time vs Various Input Overdrives −tPHL Response Time vs Various Input Overdrives −tPHL Input Bias Current vs Common Mode Voltage DS012346-11 DS012346-9 DS012346-10 5 www.national.com Typical Performance Characteristics Input Bias Current vs Common Mode Voltage (Continued) Input Bias Current vs Common Mode Voltage DS012346-12 Input Bias Current vs Temperature DS012346-13 DS012346-14 Leakage Current vs Supply Voltage DS012346-15 Application Information 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 LMC7221 can be thought of as a one-bit a/d converter. Open Drain Output. The open drain output is like the open collector output of a logic gate. This makes the LMC7221 very useful for mixed voltage systems. Driving LEDs (Light Emitting Diodes). With a 5 volt power supply, the LMC7221’s output sinking current can drive small, high efficiency LEDs for indicator and test point circuits. The small size of the Tiny package makes it easy to find space to add this feature to even compact designs. 1.0 Benefits of the LMC7221 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 products. 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 simplify board layout in several ways. First, by placing a comparator 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. Input range to Beyond Rail to Rail. The input common mode range of the LMC7221 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. Low Supply Current. The typical 7 µA supply current of the LMC7221 extends battery life in portable applications, and may allow the reduction of the size of batteries in some applications. Wide Voltage Range. The LMC7221 is characterized at 15V, 5V and 2.7V. Performance data is provided at these popular voltages. This wide voltage range makes the LMC7221 a good choice for devices where the voltage may vary over the life of the batteries. www.national.com 6 Application Information 3.0 Open Drain Output (Continued) Zero Crossing Detector. Since the LMC7221’s common mode input range extends below ground even when powered 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 LMC7221 to be used to sense high impedance signals from sensors. They also make it possible to use the LMC7221 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 resistors 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 LMC7221 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 LMC7221 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. Output Stage DS012346-17 2.0 Low Voltage Operation Comparators are the common devices by which analog signals interface with digital circuits. The LMC7221 has been designed to operate at supply voltages of 2.7V without sacrificing performance to meet the demands of 3V digital systems. At supply voltages of 2.7V, the common-mode voltage range extends 200 mV (guaranteed) below the negative supply. This feature, in addition to the comparator being able to sense signals near the positive rail, is extremely useful in low voltage applications. DS012346-21 FIGURE 2. Figure 2 shows the difference between push-pull output and open drain output. Push pull outputs will have a conventional high or low digital output, the same as a logic gate. Low will be the negative supply rail (usually ground) and high will be the positive supply rail. This is useful if the chips you are interfacing to run on the same supply voltage as the comparator. An example would be an all +5V system. Open drain outputs will only pull low — for the high output they depend on an external pull-up resistor. This can pull up to a voltage higher or lower than the comparator supply voltage. This voltage can be as high as 15V. This makes the open drain parts useful in mixed voltage systems. An example would be where the comparator runs at 5V and the logic circuits are at 3.3V. The pull-up resistor would go to the 3.3V supply. Open drain outputs are the CMOS equivalent of open collector outputs. DS012346-16 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 tPLH = 4 µs and tPHL = 4 µs with overdrives of 100 mV. Please refer to the performance curves for more extensive characterization. 4.0 Output Short Circuit Current The LMC7221 has short circuit protection of 40 mA. However, 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 7 www.national.com Application Information 8.0 Additional SOT23-5 Tiny Devices National Semiconductor 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 µA typical current 2.7V, 3V, 5V and 15V specifications. (Continued) 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 Input Protection If input signals are likely to exceed the common mode range of the LMC7221, or it is likely that signals may be present when power is off, damage to the LMC7221 may occur. Large value (100 kΩ to MΩ) input resistors may reduce the likelihood of damage by limiting the input currents. Since the LMC7221 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 3. Note that diode leakage current may affect accuracy during normal operation. LMC7111 Low power 50 kHz gain-bandwidth rail-to-rail input and output amplifier with 25 µA 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 mA Ultra Low-Dropout Regulator. The R-C time constant of RIN and the diode capacitance may also slow response time. 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. 9.0 Spice Macromodel A Spice Macromodel is available for the LMC7221 comparator on the National Semiconductor Amplifier Macromodel disk. Contact your National Semiconductor representative to obtain the latest version. DS012346-18 FIGURE 3. 6.0 Layout Considerations The LMC7221 is not an especially fast comparator, so high speed design practices are not required. The LMC7221 is capable of operating with very high impedance inputs, so precautions should be taken to reduce noise pickup with high impedance (∼ 100 kΩ and greater) designs and in electrically noisy environments. Keeping high value resistors close to the LMC7221 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. 7.0 Push-Pull Outputs, Dual Versions The LMC7211 is a comparator similar to the LMC7221, but with push-pull outputs which can source current. The performance of the LMC7221 is available in a dual device. Please see the LMC6772 datasheet. For a dual device with push-pull outputs, please see the LMC6762 datasheet. Rail-to-Rail Input Low Power Comparators — Push-Pull Output LMC7221 SOT23-5, SO-8 Single LMC6762 SO-8, DIP Dual Open Drain Output LMC7221 SOT23-5, SO-8 Single LMC6772 SO-8, DIP Dual www.national.com 8 Application Information (Continued) REEL DIMENSIONS DS012346-19 8 mm 7.00 Tape Size 0.059 0.512 0.795 2.165 330.00 1.50 A B 0.331 + 0.059/−0.000 0.567 W1+ 0.078/−0.039 8.40 + 1.50/−0.00 14.40 W1 + 2.00/−1.00 W1 W2 W3 13.00 20.20 55.00 C D N SOT-23-5 Tape and Reel Specification TAPE 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) Empty Sealed (Hub End) 0 (min) Empty Sealed 9 www.national.com SOT-23-5 Tape and Reel Specification (Continued) Tape Dimensions DS012346-20 8 mm Tape Size www.national.com 0.130 0.124 0.130 0.126 0.138 ± 0.002 0.055 ± 0.004 0.157 0.315 ± 0.012 (3.3) (3.15) (3.3) (3.2) (3.5 ± 0.05) (1.4 ± 0.11) (4) (8 ± 0.3) DIM A DIM Ao DIM B DIM Bo DIM F DIM Ko DIM P1 DIM W 10 Physical Dimensions inches (millimeters) unless otherwise noted 5-Pin SOT Package Order Number LMC7221AIM5, LMC7221AIM5X, LMC7221BIM5, or LMC7221BIMX NS Package Number MA05A 8-Pin Small Outline Package Order Number LMC7221AIM, LMC7221AIMX, LMC7221BIM, or LMC7221BIMX NS Package Number M08A 11 www.national.com LMC7221 Tiny CMOS Comparator with Rail-To-Rail Input and Open Drain Output 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 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. National Semiconductor Corporation Americas Tel: 1-800-272-9959 Fax: 1-800-737-7018 Email: [email protected] www.national.com National Semiconductor Europe Fax: +49 (0) 1 80-530 85 86 Email: [email protected] Deutsch Tel: +49 (0) 1 80-530 85 85 English Tel: +49 (0) 1 80-532 78 32 Français Tel: +49 (0) 1 80-532 93 58 Italiano Tel: +49 (0) 1 80-534 16 80 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. 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