LMC6772 Dual Micropower Rail-To-Rail Input CMOS Comparator with Open Drain Output General Description Features The LMC6772 is an ultra low power dual comparator with a maximum 10 µA/comparator power supply current. It is designed to operate over a wide range of supply voltages, with a minimum supply voltage of 2.7V. The common mode voltage range of the LMC6772 exceeds both the positive and negative supply rails, a significant advantage in single supply applications. The open drain output of the LMC6772 allows for wired-OR configurations. The open drain output also offers the advantage of allowing the output to be pulled to any voltage rail up to 15V, regardless of the supply voltage of the LMC6772. The LMC6772 is targeted for systems where low power consumption is the critical parameter. Guaranteed operation at supply voltages of 2.7V and rail-to-rail performance makes this comparator ideal for battery-powered applications. Refer to the LMC6762 datasheet for a push-pull output stage version of this device. (Typical unless otherwise noted) n Low power consumption (max): IS = 10 µA/comp n Wide range of supply voltages: 2.7V to 15V n Rail-to-Rail Input Common Mode Voltage Range n Open drain output n Short circuit protection: 40 mA n Propagation delay ( @VS = 5V, 100 mV overdrive): 5 µs Applications n n n n n n n Laptop computers Mobile phones Metering systems Hand-held electronics RC timers Alarm and monitoring circuits Window comparators, multivibrators Connection Diagram 8-Pin DIP/SO DS012347-1 Top View Ordering Information Package Temperature Range NSC Drawing −40˚C to +85˚C Transport Media 8-Pin Molded DIP LMC6772AIN, LMC6772BIN N08E Rails 8-Pin Small Outline LMC6772AIM, LMC6772BIM M08A Rails LMC6772AIMX, LMC6772BIMX M08A Tape and Reel © 1999 National Semiconductor Corporation DS012347 www.national.com LMC6772 Dual Micropower Rail-To-Rail Input CMOS Comparator with Open Drain Output September 1995 Absolute Maximum Ratings (Note 1) 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. −65˚C to +150˚C 150˚C Operating Ratings (Note 1) ESD Tolerance (Note 2) 1.5 kV Differential Input Voltage (V+)+0.3V to (V−)−0.3V Voltage at Input/Output Pin (V+)+0.3V to (V−)−0.3V 16V Supply Voltage (V+–V−) ± 5 mA Current at Input Pin (Note 8) ± 30 mA Current at Output Pin (Notes 3, 7) Current at Power Supply Pin, LMC6772 40 mA Lead Temperature (Soldering, 10 seconds) 260˚C Supply Voltage Junction Temperature Range LMC6772AI, LMC6772BI Thermal Resistance (θJA) N Package, 8-Pin Molded DIP M Package, 8-Pin Surface Mount 2.7 ≤ VS ≤ 15V 40˚C ≤ TJ ≤ +85˚C 100˚C/W 172˚C/W 2.7V Electrical Characteristics Unless otherwise specified, all limits guaranteed for TJ = 25˚C, V+ = 2.7V, V− = 0V, VCM = V+/2. Boldface limits apply at the temperature extremes. Symbol Parameter Conditions Input Offset Voltage VOS TCVOS Typ (Note 5) 3 Input Offset Voltage LMC6772AI LMC6772BI Limit Limit Units (Note 6) (Note 6) 5 15 mV 8 18 max 2.0 µV/˚C 3.3 µV/Month pA Temperature Drift Input Offset Voltage (Note 10) Average Drift IB Input Current 0.02 IOS Input Offset Current 0.01 pA CMRR Common Mode Rejection Ratio 75 dB dB PSRR Power Supply Rejection Ratio ± 1.35V < VS < ± 7.5V 80 AV Voltage Gain (By Design) 100 VCM Input Common-Mode CMRR > 55 dB 3.0 Voltage Range −0.3 VOL Output Voltage Low IS ILeakage ILOAD = 2.5 mA Supply Current For Both Comparators Output Leakage Current (Output Low) VIN(+) = 0.5V, 0.2 12 0.1 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 20 20 µA 25 25 max 500 500 nA VIN(−) = 0V, VO = 15V 5.0V and 15.0V Electrical Characteristics Unless otherwise specified, all limits guaranteed for TJ = 25˚C, V+ = 5.0V and 15.0V, V− = 0V, VCM = V+/2. Boldface limits apply at the temperature extremes. Symbol VOS TCVOS Parameter Conditions Input Offset Voltage Input Offset Voltage Temperature Drift Input Offset Voltage Average Drift www.national.com Typ (Note 5) 3 V+ = 5V V+ = 15V V+ = 5V (Note 10) V+ = 15V (Note 10) 2 2.0 LMC6772AI LMC6772BI Limit Limit Units (Note 6) (Note 6) 5 15 mV 8 18 max µV/˚C 4.0 3.3 4.0 µV/Month 5.0V and 15.0V Electrical Characteristics (Continued) Unless otherwise specified, all limits guaranteed for TJ = 25˚C, V+ = 5.0V and 15.0V, V− = 0V, VCM = V+/2. Boldface limits apply at the temperature extremes. Symbol Parameter IB Input Current IOS Input Offset Current Conditions Typ (Note 5) V = 5V V+ = 5V LMC6772AI LMC6772BI Limit Limit (Note 6) (Note 6) Units 0.04 pA 0.02 pA dB V+ = 5V V+ = 15V 75 Rejection Ratio 82 dB PSRR Power Supply Rejection Ratio ± 2.5V < VS < ± 5V 80 dB AV Voltage Gain Input Common-Mode (By Design) V+ = 5.0V 100 VCM Voltage Range CMRR > 55 dB CMRR Common Mode 5.3 −0.3 V+ = 15.0V 15.3 CMRR > 55 dB −0.3 VOL Output Voltage Low V+ = 5V ILOAD = 5 mA V+ = 15V 0.2 0.2 ILOAD = 5 mA IS ISC Supply Current For Both Comparators Short Circuit Current (Output Low) V+ = 15V, Sinking, VO = 12V 12 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 0.4 0.4 V 0.55 0.55 max 0.4 0.4 V 0.55 0.55 max 20 20 µA 25 25 max 45 mA (Note 7) 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 Conditions Typ (Note 5) tRISE Rise Time tFALL Fall Time f = 10 kHz, CL = 50 pF, Overdrive = 10 mV (Note 9) f = 10 kHz, CL = 50 pF, Propagation Delay Overdrive = 10 mV (Note 9) f = 10 kHz, (High to Low) CL = 50 pF (Note 9) V+ = 2.7V, f = 10 kHz, CL = 50 pF tPHL LMC6772AI LMC6772BI Limit Limit (Note 6) (Note 6) Units 0.3 µs 0.3 µs 10 mV 10 µs 100 mV 4 µs 10 mV 10 µs 100 mV 4 µs (Note 9) 3 www.national.com AC Electrical Characteristics (Continued) 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 tPLH Parameter Conditions Propagation Delay (Low to High) Typ (Note 5) LMC6772AI LMC6772BI Limit Limit (Note 6) (Note 6) Units f = 10 kHz, CL = 50 pF 10 mV 10 µs 100 mV 4 µs (Note 9) V+ = 2.7V, 10 mV 8 µs f = 10 kHz, CL = 50 pF 100 mV 4 µs (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. The output pins of the two comparators (pin 1 and pin 7) have an ESD tolerance of 1.5 kV. All other pins have an ESD tolerance of 2 kV. 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(max), θJA, and TA. The maximum allowable power dissipation at any ambient temperature is PD = (TJ(max) – TA)/θJA. 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. Note 7: Do not short circuit output to V+, when V+ is > 12V or reliability will be adversely affected. Note 8: Limiting input pin current is only necessary for input voltages that exceed absolute maximum input voltage ratings. Note 9: CL inlcudes the probe and jig capacitance. The rise time, fall time and propagation delays are measured with a 2V input step. Note 10: Input offset voltage Average Drift is calculated by dividing the accelerated operating life drift average by the equivalent operational time. The input offset voltage average drift represents the input offset voltage change at worst-case input conditions. Typical Performance Characteristics Supply Current vs Supply Voltage (Output High) V+ = 5V, Single Supply, TA = 25˚C unless otherwise specified Supply Current vs Supply Voltage (Output Low) DS012347-3 Input Current vs Common-Mode Voltage DS012347-4 Input Current vs Common-Mode Voltage DS012347-6 www.national.com Input Current vs Common-Mode Voltage Input Current vs Temperature DS012347-7 4 DS012347-5 DS012347-8 Typical Performance Characteristics V+ = 5V, Single Supply, TA = 25˚C unless otherwise specified (Continued) ∆VOS vs ∆VCM VS = 2.7V ∆VOS vs ∆VCM VS = 5V ∆VOS vs ∆VCM VS = 15V DS012347-9 Output Voltage vs Output Current (Sinking) DS012347-10 Output Voltage vs Output Current (Sinking) DS012347-12 Output Short Circuit Current (Sinking) vs Supply Voltage DS012347-11 Output Voltage vs Output Current (Sinking) DS012347-13 Leakage Current vs Output Voltage DS012347-14 Response Time for Overdrive (tPLH) DS012347-16 DS012347-17 DS012347-15 5 www.national.com Typical Performance Characteristics V+ = 5V, Single Supply, TA = 25˚C unless otherwise specified (Continued) Response Time for Overdrive (tPHL) Response Time for Overdrive (tPLH) DS012347-18 Response Time for Overdrive (tPLH) Response Time for Overdrive (tPHL) DS012347-19 Response Time for Overdrive (tPHL) DS012347-21 DS012347-20 Response Time vs Capacitive Load DS012347-22 DS012347-23 Application Hints 1.0 Input Common-Mode Voltage Range At supply voltages of 2.7V, 5V and 15V, the LMC6772 has an input common-mode voltage range which exceeds both supplies. As in the case of operational amplifiers, CMVR is defined by the VOS shift of the comparator over the common-mode range of the device. A CMRR (∆VOS/∆VCM) of 75 dB (typical) implies a shift of < 1 mV over the entire common-mode range of the device. The absolute maximum input voltage at V+ = 5V is 200 mV beyond either supply rail at room temperature. DS012347-24 FIGURE 1. An Input Signal Exceeds the LMC6772 Power Supply Voltages with No Output Phase Inversion A wide input voltage range means that the comparator can be used to sense signals close to ground and also to the power supplies. This is an extremely useful feature in power supply monitoring circuits. An input common-mode voltage range that exceeds the supplies, 20 fA input currents (typical), and a high input impedance makes the LMC6772 ideal for sensor applications. The LMC6772 can directly interface to sensors without the use of amplifiers or bias circuits. In circuits with sensors which produce outputs in the tens to hundreds of millivolts, the www.national.com 6 1.0 Input Common-Mode Voltage Range (Continued) LMC6772 can compare the sensor signal with an appropriately small reference voltage. This reference voltage can be close to ground or the positive supply rail. 2.0 Low Voltage Operation Comparators are the common devices by which analog signals interface with digital circuits. The LMC6772 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. DS012347-26 FIGURE 3. Canceling the Effect of Input Capacitance The capacitor added across the feedback resistor increases the switching speed and provides more short term hysteresis. This can result in greater noise immunity for the circuit. 5.0 Spice Macromodel A Spice Macromodel is available for the LMC6772. The model includes a simulation of: • Input common-mode voltage range • Quiescent and dynamic supply current • Input overdrive characteristics and many more characteristics as listed on the macromodel disk. Contact the National Semiconductor Customer Response Center at 1-800-272-9959 to obtain an operational amplifier spice model library disk. Typical Applications Universal Logic Level Shifter The output of the LMC6772 is the uncommitted drain of the output NMOS transistor. Many drains can be tied together to provide an output OR’ing function. An output pullup resistor can be connected to any available power supply voltage within the permitted power supply range. DS012347-25 FIGURE 2. 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. 3.0 Output Short Circuit Current The LMC6772 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 is 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. DS012347-27 4.0 Hysteresis FIGURE 4. Universal Logic Level Shifter If the input signal is very noisy, the comparator output might trip several times as the input signal repeatedly passes through the threshold. This problem can be addressed by making use of hysteresis as shown below. The two 1 kΩ resistors bias the input to half of the power supply voltage. The pull-up resistor should go to the output logic supply. Due to its wide operating range, the LMC6772 is ideal for the logic level shifting applications. 7 www.national.com Typical Applications Zero Crossing Detector (Continued) One-Shot Multivibrator DS012347-28 FIGURE 5. One-Shot Multivibrator DS012347-29 A monostable multivibrator has one stable state in which it can remain indefinitely. It can be triggered externally to another quasi-stable state. A monostable multivibrator can thus be used to generate a pulse of desired width. The desired pulse width is set by adjusting the values of C2 and R4. The resistor divider of R1 and R2 can be used to determine the magnitude of the input trigger pulse. The LMC6772 will change state when V1 < V2. Diode D2 provides a rapid discharge path for capacitor C2 to reset at the end of the pulse. The diode also prevents the non-inverting input from being driven below ground. FIGURE 7. Zero Crossing Detector A voltage divider of R4 and R5 establishes a reference voltage V1 at the non-inverting input. By making the series resistance of R1 and R2 equal to R5, the comparator will switch when VIN = 0. Diode D1 insures that V3 never drops below −0.7V. The voltage divider of R2 and R3 then prevents V2 from going below ground. A small amount of hysteresis is setup to ensure rapid output voltage transitions. Oscillator Bi-Stable Multivibrator DS012347-30 FIGURE 6. Bi-Stable Multivibrator A bi-stable multivibrator has two stable states. The reference voltage is set up by the voltage divider of R2 and R3. A pulse applied to the SET terminal will switch the output of the comparator high. The resistor divider of R1, R4, and R5 now clamps the non-inverting input to a voltage greater than the reference voltage. A pulse applied to RESET will now toggle the output low. www.national.com DS012347-31 FIGURE 8. Square Wave Generator Figure 8 shows the application of the LMC6772 in a square wave generator circuit. The total hysteresis of the loop is set by R1, R2 and R3. R4 and R5 provide separate charge and discharge paths for the capacitor C. The charge path is set through R4 and D1. So, the pulse width t1 is determined by the RC time constant of R4 and C. Similarly, the discharge path for the capacitor is set by R5 and D2. Thus, the time t2 between the pulses can be changed by varying R5, and the pulse width can be altered by R4. The frequency of the output can be changed by varying both R4 and R5. 8 Typical Applications (Continued) Time Delay Generator DS012347-32 FIGURE 9. Time Delay Generator nentially through R. This is indicated above. The output voltages of comparators 1, 2, and 3 swtich to the high state when VC1 rises above the reference voltages VA, VB and VC. A small amount of hysteresis has been provided to insure fast switching when the RC time constant is chosen to give long delay times. The circuit shown above provides output signals at a prescribed time interval from a time reference and automatically resets the output when the input returns to ground. Consider the case of VIN = 0. The output of comparator 4 is also at ground. This implies that the outputs of comparators 1, 2, and 3 are also at ground. When an input signal is applied, the output of comparator 4 swings high and C charges expo- 9 www.national.com Physical Dimensions inches (millimeters) unless otherwise noted 8-Pin Small Outline Package Order Number LMC6772AI or LMC6772BI NS Package Number M08A 8-Pin Molded Dual-In-Line Package Order Number LMC6772AI or LMC6772BI NS Package Number N08E www.national.com 10 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 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. National Semiconductor Asia Pacific Customer Response Group Tel: 65-2544466 Fax: 65-2504466 Email: [email protected] National Semiconductor Japan Ltd. Tel: 81-3-5639-7560 Fax: 81-3-5639-7507 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. LMC6772 Dual Micropower Rail-To-Rail Input CMOS Comparator with Open Drain Output Notes