LMC7221AIM5X

LMC7221 Tiny CMOS Comparator with Rail-To-Rail Input and Open Drain Output September 2006 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 5-Pin SOT23 package. This makes this comparator ideal for space and weight critical designs. The LMC7221 is also available in the 8-Pin SOIC 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 n n Tiny 5-Pin SOT23 package saves space Package is less than 1.43 mm thick 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 Connection Diagrams 8-Pin SOIC 5-Pin SOT23 01234601 01234602 Top View Top View Ordering Information Package Part Number LMC7221AIM 8-Pin SOIC LMC7221AIMX LMC7221BIM LMC7221BIMX LMC7221AIM5 5-Pin SOT23 LMC7221AIM5X LMC7221BIM5 LMC7221BIM5X Package Marking LMC7221AIM LMC7221BIM C01A C01B Transport Media 95 Units/Rail 2.5k Units Tape and Reel 95 Units/Rail 2.5k Units Tape and Reel 1k Units Tape and Reel 3k Units Tape and Reel 1k Units Tape and Reel 3k Units Tape and Reel MF05A M08A NSC Drawing © 2006 National Semiconductor Corporation DS012346 www.national.com LMC7221 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 Voltage at Input Voltage at Output Pin Supply Voltage (V+–V−) Current at Input Pin (Note 6) Current at Output Pin (Notes 3, 7) Current at Power Supply Pin 2 kV V+ +0.3V, V− −0.3V V+ +0.3V, V− −0.3V 15V 16V Lead Temperature (soldering, 10 sec.) Junction Temperature (Note 4) 260˚C 150˚C Operating Ratings (Note 1) Supply Voltage Temperature Range (Note 4) LMC7221AI, LMC7221BI Thermal Resistance (θJA) 8-Pin SOIC 180˚C/W 325˚C/W 5-Pin SOT23 −40˚C to +85˚C 2.7 ≤ VCC ≤ 15V ± 5 mA ± 30 mA 40 mA 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. Typ Symbol VOS TCVOS Parameter Input Offset Voltage Input Offset Voltage Temperature Drift Input Offset Voltage Average Drift IB IOS CMRR PSRR AV CMVR Input Current Input Offset Current Common Mode Rejection Ratio Power Supply Rejection Ratio Voltage Gain Input Common-Mode Voltage Range CMRR > 55 dB VOL IS Output Voltage Low Supply Current ILOAD = 2.5 mA VOUT = Low −0.3 0.2 7 CMRR > 55 dB 100 3.0 2.9 2.7 −0.2 0.0 0.3 0.4 12 14 2.9 2.7 −0.2 0.0 0.3 0.4 12 14 dB V min V max V max µA max 2.7V ≤ V+ ≤ 15V 80 dB 0V ≤ VCM ≤ 2.7V 0.04 0.02 75 pA pA dB (Note 9) 3.3 µV/Month Conditions (Note 5) 3 1.0 LMC7221AI Limit (Note 6) 5 8 LMC7221BI Limit (Note 6) 15 18 mV max µV/˚C Units www.national.com 2 LMC7221 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. Typ Symbol VOS TCVOS Parameter Input Offset Voltage Input Offset Voltage Temperature Drift Input Offset Voltage Average Drift IB IOS CMRR PSRR AV CMVR Input Current Input Offset Current Common Mode Rejection Ration Power Supply Rejection Ratio Voltage Gain Input Common-Mode Voltage Range V+ = 5.0V CMRR > 55 dB V+ = 5.0V CMRR > 55 dB V+ = 15.0V CMRR > 55 dB V+ = 15.0V CMRR > 55 dB VOL Output Voltage Low V+ = 5V ILOAD = 5 mA V+ = 15V ILOAD = 5 mA IS ISC Supply Current Short Circuit Current VOUT = Low Sinking (Note 7) 7 45 0.2 0.2 −0.3 15.3 −0.3 100 5.3 5.2 5.0 −0.2 0.0 15.2 15.0 −0.2 0.0 0.40 0.55 0.40 0.55 14 18 5.2 5.0 −0.2 0.0 15.2 15.0 −0.2 0.0 0.40 0.55 0.40 0.55 14 18 dB V min V max V min V max mV max mV max µA max mA V+ = 5.0V V+ = 15.0V 5V ≤ V+ ≤ 10V V+ = 5V V+ = 15V V = 5V (Note 9) V+ = 15V (Note 9) + LMC7221AI Limit (Note 6) 5 8 LMC7221BI Limit (Note 6) 15 18 mV max µV/˚C µV/Month pA pA dB dB dB Units Conditions (Note 5) 3 1.0 4.0 3.3 4.0 0.04 0.02 75 82 80 Leakage Characteristics TJ = 25˚C Typ Symbol ILEAKAGE Parameter Output Leakage Current Conditions V+ = 2.7V VIN(+) = 0.5V VIN(−) = 0V VOUT = 15V 0.1 500 500 nA (Note 5) LMC7221AI Limit (Note 6) LMC7221BI Limit (Note 6) Units 3 www.national.com LMC7221 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. Typ Symbol trise tfall tPHL Parameter Rise Time Fall Time Propagation Delay (High to Low) (Note 10) Conditions f = 10 kHz, CL = 50 pF, (Note 8) Overdrive = 10 mV, 5 kΩ Pullup f = 10 kHz, CL = 50 pF, (Note 8) Overdrive = 10 mV, 5 kΩ Pullup f = 10 kHz, CL = 50 pF, 5 kΩ Pullup (Note 8) V+ = 2.7V, f = 10 kHz, CL = 50 pF, 5 kΩ Pullup (Note 8) tPLH Propagation Delay (Low to High) (Note 10) f = 10 kHz, CL = 50 pF, 5 kΩ Pullup (Note 8) V+ = 2.7V, f = 10 kHz, CL = 50 pF, 5 kΩ Pullup (Note 8) 10 mV 100 mV 10 mV 100 mV 10 mV 100 mV 10 mV 100 mV 10 4 10 4 6 4 7 4 µs µs µs 0.3 µs (Note 5) 0.3 LMC7221AI LMC7221BI Limit (Note 6) Limit (Note 6) µs Units µs 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, applicable std. MIL-STD-883, Method 3015.7. Machine Model, applicable std. JESD22-A115-A (ESD MM std. of JEDEC) Field-Induced Charge-Device Model, applicable std. JESD22-C101-C (ESD FICDM std. of JEDEC). 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. The maximum allowable power dissipation at any ambient temperature is PD = (TJ(MAX) – TA)/ θJA. All numbers apply for packages soldered directly onto a PC Board. Note 5: Typical values represent the most likely parametric norm as determined at the time of characterization. Actual typical values may vary over time and will also depend on the application and configuration. The typical values are not tested and are not guaranteed on shipped production material. Note 6: All limits are guaranteed by testing or statistical analysis. Note 7: Limiting input pin current is only necessary for input voltages which exceed the absolute maximum input voltage rating. Note 8: Do not short circuit the output to V+ when V+ is greater than 12V or reliability will be adversely affected. Note 9: CL includes the probe and test 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. www.national.com 4 LMC7221 Typical Performance Characteristics Supply Current vs. Supply Voltage Supply Current vs. Temperature while Sinking 01234603 01234604 Output Sinking Current vs. Supply Voltage Output Sinking Current vs. Output Voltage @ 5V 01234605 01234606 Output Sinking Current vs. Output Voltage @ 15V Response Time for Various Input Overdrives −tPHL 01234607 01234608 5 www.national.com LMC7221 Typical Performance Characteristics Response Time vs. Various Input Overdrives −tPHL (Continued) Response Time vs Various Input Overdrives −tPHL 01234609 01234610 Input Bias Current vs. Common Mode Voltage Input Bias Current vs. Common Mode Voltage 01234611 01234612 Input Bias Current vs. Common Mode Voltage Input Bias Current vs. Temperature 01234613 01234614 www.national.com 6 LMC7221 Typical Performance Characteristics Leakage Current vs. Supply Voltage (Continued) 01234615 Application Information 1.0 BENEFITS OF THE LMC7221 TINY COMPARATOR Size The small footprint of the 5-Pin SOT23 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. 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. 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. 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. 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. 7 www.national.com LMC7221 Application Information Direct Sensor Interfacing (Continued) 3.0 OPEN DRAIN OUTPUT Output Stage 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. 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. 01234617 01234621 01234616 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. 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. www.national.com 8 LMC7221 Application Information (Continued) 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 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. The R-C time constant of RIN and the diode capacitance may also slow response time. 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 LMC6762 5-Pin SOT23, 8-Pin SOIC 8-Pin SOIC Single Dual Open Drain Output LMC7221 LMC6772 5-Pin SOT23, 8-Pin SOIC 8-Pin SOIC Single Dual 8.0 ADDITIONAL 5-Pin SOT23 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. 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. 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. 01234618 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. 9 www.national.com LMC7221 Application Information (Continued) REEL DIMENSIONS 01234619 8 mm Tape Size 7.00 330.00 A 0.059 0.512 0.795 2.165 1.50 B 13.00 20.20 55.00 C D N 0.331 + 0.059/−0.000 8.40 + 1.50/−0.00 W1 0.567 14.40 W2 W1+ 0.078/−0.039 W1 + 2.00/−1.00 W3 SOT-23-5 Tape and Reel Specification TAPE FORMAT Tape Section Leader (Start End) Carrier Trailer (Hub End) # Cavities 0 (min) 75 (min) 3000 1000 125 (min) 0 (min) Cavity Status Empty Empty Filled Filled Empty Empty Cover Tape Status Sealed Sealed Sealed Sealed Sealed Sealed www.national.com 10 LMC7221 SOT-23-5 Tape and Reel Specification (Continued) Tape Dimensions 01234620 8 mm Tape Size 0.130 (3.3) DIM A 0.124 (3.15) DIM Ao 0.130 (3.3) DIM B 0.126 (3.2) DIM Bo 0.138 ± 0.002 (3.5 ± 0.05) DIM F 0.055 ± 0.004 (1.4 ± 0.11) DIM Ko 0.157 (4) DIM P1 0.315 ± 0.012 (8 ± 0.3) DIM W 11 www.national.com LMC7221 Physical Dimensions inches (millimeters) unless otherwise noted 8-Pin Small Outline Package NS Package Number M08A 5-Pin SOT Package NS Package Number MF05A www.national.com 12 LMC7221 Tiny CMOS Comparator with Rail-To-Rail Input and Open Drain Output 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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