LM615 Quad Comparator and Adjustable Reference General Description Features The comparators have an input range which extends to the negative supply, and have open-collector outputs. Improved over the LM139 series, the input stages of the comparators have lateral PNP input transistors which enable low input currents for large differential input voltages and swings above V a . The voltage reference is a three-terminal shunt-type bandgap, and is referred to the Vb terminal. Two resistors program the reference from 1.24V to 6.3V, with accuracy of g 0.6% available. The reference features operation over a shunt current range of 17 mA to 20 mA, low dynamic impedance, broad capacitive load range, and cathode terminal voltage ranging from a diode-drop below V b to above V a . As a member of National’s Super-Block TM family, the LM615 is a space-saving monolithic alternative to a multichip solution, offering a high level of integration without sacrificing performance. COMPARATORS Y Low operating current Y Wide supply voltage range Y Open-collector outputs Y Input common-mode range Y Wide differential input voltage REFERENCE Y Adjustable output voltage Y Tight initial tolerance available Y Wide operating current range Y Tolerant of load capacitance 600 mA 4V to 36V Vb to (V a b 1.8V) g 36V 1.24V to 6.3V g 0.6% (25§ C) 17 mA to 20 mA Applications Y Y Y Y Y Adjustable threshold detector Time-delay generator Voltage window comparator Power supply monitor RGB level detector Connection Diagram N Package M Package TL/H/11057 – 24 TL/H/11057 – 1 Top View Top View Ordering Information For information about surface-mount packaging of this device, please contact the Analog Product Marketing group at National Semiconductor Corp. headquarters. Reference Tolerances Temperature Range Military b 55§ C s TJ s a 125§ C b 40§ C s TJ s a 85§ C LM615AMN LM615AIN g 0.6% at 25§ C, 80 ppm/§ C max Industrial LM615MN NSC Package Number 16-Pin Molded DIP N16A 16-Pin Ceramic DIP J16A LM615IN 16-Pin Molded DIP N16A LM615IM 16-Pin Narrow Surface Mount M16A LM615AMJ/883 (Note 13) g 2.0% at 25§ C, 150 ppm/§ C max Package Super-BlockTM is a trademark of National Semiconductor Corporation. C1995 National Semiconductor Corporation TL/H/11057 RRD-B30M115/Printed in U. S. A. LM615 Quad Comparator and Adjustable Reference December 1994 Absolute Maximum Ratings (Note 1) If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/Distributors for availability and specifications. Maximum Junction Temperature Voltage on Any Pin Except VRO (referred to Vbpin) (Note 2) (Note 3) Soldering Information N Package Soldering (10 seconds) 260§ C ESD Tolerance (Note 6) g 1 kV 36V (Max) b 0.3V (Min) Current through Any Input Pin and VRO Pin Differential Input Voltage Output Short-Circuit Duration Storage Temperature Range 150§ C Thermal Resistance, Junction-to-Ambient (Note 5) N Package 95§ C/W Operating Temperature Range g 20 mA LM615AI, LM615I LM615A, LM615M g 36V (Note 4) b 40§ C s TJ s a 85§ C b 55§ C s TJ s a 125§ C b 65§ C s TJ s a 150§ C Electrical Characteristics These specifications apply for Vb e GND e 0V, V a e 5V, VCM e VOUT e V a /2, IR e 100 mA, FEEDBACK pin shorted to GND, unless otherwise specified. Limits in standard typeface are for TJ e 25§ C; limits in boldface type apply over the Operating Temperature Range. Symbol Parameter Conditions Typical (Note 7) LM615AM LM615AI Limits (Note 8) LM615M LM615I Limits (Note 8) Units COMPARATORS IS Total Supply Current a V Current, RLOAD e % , a 3V s V s 36V 250 350 550 600 600 650 mA max mA max VOS Offset Voltage over V a Range 4V s V a s 36V, RL e 15 kX 1.0 2.0 3.0 6.0 5.0 7.0 mV max mV max VOS Offset Voltage over VCM Range 0V s VCM s (V a b1.8V) V a e 30V, RL e 15 kX 1.0 1.5 3.0 6.0 5.0 7.0 mV max mV max DVOS DT Average Offset Voltage Drift IB Input Bias Current b5 b8 25 30 35 40 nA max nA max IOS Input Offset Current 0.2 0.3 4 5 4 5 nA max nA max AV Voltage Gain RL e 10 kX to 36V, 2V s VOUT s 27V 500 50 50 100 V/mV min V/mV tR Large Signal Response Time V a IN e 1.4V, VbIN e TTL Swing, RL e 5.1 kX 1.5 2.0 ms ms ISINK Output Sink Current V a IN e 0V, VbIN e 1V, 15 VOUT e 1.5V VOUT e 0.4V IL Output Leakage Current V a IN e 1V, VbIN e 0V, VOUT e 36V 2 mV/§ C 20 13 10 8 10 8 mA min mA min 2.8 2.4 1.0 0.5 0.8 0.5 mA min mA min 0.1 0.2 10 10 mA max mA Electrical Characteristics These specifications apply for Vb e GND e 0V, V a e 5V, VCM e VOUT e V a /2, IR e 100 mA, FEEDBACK pin shorted to GND, unless otherwise specified. Limits in standard typeface are for TJ e 25§ C; limits in boldface type apply over the Operating Temperature Range. (Continued) Symbol Parameter LM615AM LM615AI Limits (Note 8) LM615M LM615I Limits (Note 8) 1.244 1.2365 1.2515 ( g 0.6%) 1.2191 1.2689 ( g 2%) 18 80 150 Typical (Note 7) Conditions Units VOLTAGE REFERENCE (Note 9) VR Reference Voltage DVR DT Average Drift with Temperature DVR kH Average Drift with Time DVR DTJ Hysteresis (Note 11) DVR DIR VR Change with Current VR[100 mA] b VR[17 mA] 0.05 0.1 1 1.1 1 1.1 mV max mV max VR[10 mA] b VR[100 mA] (Note 12) 1.5 2.0 5 5.5 5 5.5 mV max mV max (Note 10) TJ e 40§ C TJ e 150§ C V min V max ppm/§ C max 400 1000 ppm/kH ppm/kH 3.2 mV/§ C R Resistance DVR[10 mA to 0.1 mA] /9.9 mA DVR[100 mA to 17 mA] /83 mA 0.2 0.6 0.56 13 0.56 13 X max X max DVR DVRO VR Change with VRO VR[VRO 2.5 2.8 5 10 5 10 mV max mV max DVR DV a VR Change with V a Change VR[V a e 5V] b VR[V a e 36V] 0.1 0.1 1.2 1.3 1.2 1.3 mV max mV max VR[V a e 5V] b VR[V a e 3V] 0.01 0.01 1 1.5 1 1.5 mV max mV max 35 40 50 55 nA max nA max e VR] b VR[VRO e 6.3V] IFB FEEDBACK Bias Current Vb s VFB s 5.06V 22 29 en Voltage Noise BW e 10 Hz to 10 kHz 30 mVRMS Note 1: Absolute maximum ratings indicate limits beyond which damage to the component may occur. Electrical specifications do not apply when operating the device beyond its rated operating conditions. Note 2: Input voltage above V a is allowed. As long as one input pin voltage remains inside the common-mode range, the comparator will deliver the correct output. Note 3: More accurately, it is excessive current flow, with resulting excess heating, that limits the voltages on all pins. When any pin is pulled a diode drop below Vb, a parasitic NPN transistor turns ON. No latch-up will occur as long as the current through that pin remains below the Maximum Rating. Operation is undefined and unpredictable when any parasitic diode or transistor is conducting. Note 4: Shorting an Output to Vb will not cause power dissipation, so it may be continuous. However, shorting an Output to any more positive voltage (including V a ), will cause 80 mA (typ.) to be drawn through the output transistor. This current multiplied by the applied voltage is the power dissipation in the output transistor. If the total power from all shorted outputs causes the junction temperature to exceed 150§ C, degraded reliability or destruction of the device may occur. To determine junction temperature, see Note 5. Note 5: Junction temperature may be calculated using TJ e TA a PD iJA. The given thermal resistance is worst-case for packages in sockets in still air. For packages soldered to copper-clad board with dissipation from one comparator or reference output transistor, nominal iJA is 80 § C/W for the N package. Note 6: Human body model, 100 pF discharge through a 1.5 kX resistor. Note 7: Typical values in standard typeface are for TJ e 25§ C; values in boldface type apply for the full operating temperature range. These values represent the most likely parametric norm. Note 8: All limits are guaranteed for TJ e a 25§ C (standard type face) or over the full operating temperature range (bold type face). Note 9: VRO is the reference output voltage, which may be set for 1.2V to 6.3V (see Application Information). VR is the VRO-to-FEEDBACK voltage (nominally 1.244V). Note 10: Average reference drift is calculated from the measurement of the reference voltage at 25§ C and at the temperature extremes. The drift, in ppm/§ C, is 106 # DVR/VR[25§ C] # DTJ, where DVR is the lowest value subtracted from the highest, VR[25§ C] is the value at 25§ C, and DTJ is the temperature range. This parameter is guaranteed by design and sample testing. Note 11: Hysteresis is the change in VRO caused by a change in TJ, after the reference has been ‘‘dehysterized.’’ To dehysterize the reference; that is minimize the hysteresis to the typical value, its junction temperature should be cycled in the following pattern, spiraling in toward 25§ C: 25§ C, 85§ C, b 40§ C, 70§ C, 0§ C, 25§ C. Note 12: Low contact resistance is required for accurate measurement. Note 13: A military RETS electrical test specification is available on request. The LM615AMJ/883 may also be procured as a Standard Military Drawing. 3 Simplified Schematic Diagrams Comparator TL/H/11057 – 2 Reference Bias TL/H/11057 – 3 4 Typical Performance Characteristics (Reference) TJ e 25§ C, FEEDBACK pin shorted to V b e 0V, unless otherwise noted. Reference Voltage vs Temperature Reference Voltage Drift vs Time Accelerated Reference Voltage Drift vs Time Reference Voltage vs Current and Temperature Reference Voltage vs Reference Current Reference Voltage vs Reference Current Reference AC Stability Range FEEDBACK Current vs FEEDBACK-to-Vb Voltage FEEDBACK Current vs FEEDBACK-to-Vb Voltage Reference Noise Voltage vs Frequency Reference Small-Signal Resistance vs Frequency Reference Voltage vs Current and Temperature TL/H/11057 – 4 5 Typical Performance Characteristics (Reference) (Continued) TJ e 25§ C, FEEDBACK pin shorted to V b e 0V, unless otherwise noted. Reference Power-Up Time Reference Voltage with FEEDBACK Voltage Step Reference Step Response for 100 m E 10 mA Current Step Reference Voltage with 100 E 12 mA Current Step Reference Voltage Change with Supply Voltage Step TL/H/11057 – 5 Typical Performance Characteristics (Comparators) TJ e 25§ C, V a e 5V, Vb e 0V, unless otherwise noted Supply Current vs Supply Voltage Input-Bias Current vs Common-Mode Voltage Input Current vs Differential Input Voltage TL/H/11057 – 6 6 Typical Performance Characteristics (Comparators) (Continued) Output Saturation Voltage vs Sink Current Small-Signal Response TimesÐInverting Input, Negative Transition Small-Signal Response TimesÐInverting Input, Positive Transition Small-Signal Response Times Non-Inverting Input, Positive Transition Small-Signal Response TimesÐNon-Inverting Input, Negative Transition Large-Signal Response TimesÐInverting Input, Positive Transition Large-Signal Response Times-Inverting Input, Negative Transition Large-Signal Response TimesÐNon-Inverting Input, Positive Transition Large-Signal Response TimesÐNon-Inverting Input, Negative Transition TL/H/11057 – 8 7 Application Information Capacitors in parallel with the reference are allowed. See the Reference AC Stability Range typical curve for capacitance valuesÐfrom 20 mA to 3 mA any capacitor value is stable. With the reference’s wide stability range with resistive and capacitive loads, a wide range of RC filter values will perform noise filtering. Adjustable Reference The FEEDBACK pin allows the reference output voltage, Vro, to vary from 1.24V to 6.3V. The reference attempts to hold Vr at 1.24V. If Vr is above 1.24V, the reference will conduct current from Cathode to Anode; FEEDBACK current always remains low. If FEEDBACK is connected to Anode, then Vro e Vr e 1.24V. For higher voltages FEEDBACK is held at a constant voltage above AnodeÐsay 3.76V for Vro e 5V. Connecting a resistor across the constant Vr generates a current I e R1/Vr flowing from Cathode into FEEDBACK node. A Thevenin equivalent 3.76V is generated from FEEDBACK to Anode with R2 e 3.76/I. Keep I greater than one thousand times larger than FEEDBACK bias current for k0.1% errorÐI t 32 mA for the military grade over the military temperature range (I t 5.5 mA for a 1% untrimmed error for an industrial temperature range part). VOLTAGE REFERENCE Reference Biasing The voltage reference is of a shunt regulator topology that models as a simple zener diode. With current Ir flowing in the ‘‘forward’’ direction there is the familiar diode transfer function. Ir flowing in the reverse direction forces the reference voltage to be developed from cathode to anode. The cathode may swing from a diode drop below Vb to the reference voltage or to the avalanche voltage of the parallel protection diode, nominally 7V. A 6.3V reference with V a e 3V is allowed. TL/H/11057–9 FIGURE 1. Voltage Associated with Reference (Current Source Ir is External) The reference equivalent circuit reveals how Vr is held at the constant 1.2V by feedback, and how the FEEDBACK pin passes little current. To generate the required reverse current, typically a resistor is connected from a supply voltage higher than the reference voltage. Varying that voltage, and so varying Ir, has small effect with the equivalent series resistance of less than an ohm at the higher currents. Alternatively, an active current source, such as the LM134 series, may generate Ir. TL/H/11057 – 12 FIGURE 4. Thevenin Equivalent of Reference with 5V Output TL/H/11057–10 FIGURE 2. Reference Equivalent Circuit TL/H/11057 – 13 R1 e Vr/I e 1.24/32m e 39k R2 e R1 [(Vro/Vr) b 1] e 39k [(5/1.24) b 1] e 118k FIGURE 5. Resistors R1 and R2 Program Reference Output Voltage to be 5V TL/H/11057–11 FIGURE 3. 1.2V Reference 8 Application Information (Continued) Understanding that Vr is fixed and that voltage sources, resistors, and capacitors may be tied to the FEEDBACK pin, a range of Vr temperature coefficients may be synthesized. Connecting a resistor across VRO-to-FEEDBACK creates a 0 TC current source, but a range of TCs may be synthesized. TL/H/11057 – 14 TL/H/11057 – 17 FIGURE 6. Output Voltage has Negative Temperature Coefficient (TC) if R2 has Negative TC I e Vr/R1 e 1.24/R1 FIGURE 9. Current Source is Programmed by R1 TL/H/11057 – 15 FIGURE 7. Output Voltage has Positive TC if R1 has Negative TC TL/H/11057 – 18 FIGURE 10. Proportional-to-Absolute-Temperature Current Source TL/H/11057 – 19 FIGURE 11. Negative-TC Current Source Reference Hysteresis The reference voltage depends, slightly, on the thermal history of the die. Competitive micro-power products varyÐalways check the data sheet for any given device. Do not assume that no specification means no hysteresis. TL/H/11057 – 16 FIGURE 8. Diode in Series with R1 Causes Voltage Across R1 and R2 to be Proportional to Absolute Temperature (PTAT) 9 Application Information (Continued) It is often a good idea to decrease the amount of hysteresis until oscillations are observed, then use three times that minimum hysteresis in the final circuit. Note that the amount of hysteresis needed is greatly affected by layout. The amount of hysteresis should be rechecked each time the layout is changed, such as changing from a breadboard to a P.C. board. COMPARATORS Any of the comparators or the reference may be biased in any way with no effect on the other sections of the LM615, except when a substrate diode conducts (see Electrical Characteristics Note 3). For example, one or both inputs of one comparator may be outside the input voltage range limits, the reference may be unpowered, and the other comparators will still operate correctly. Unused comparators should have inverting input and output tied to Vb, and non-inverting input tied to V a . Input Stage The input stage uses lateral PNP input transistors which, unlike those of many op amps, have breakdown voltage BVEBO equal to the absolute maximum supply voltage. Also, they have no diode clamps to the positive supply nor across the inputs. These features make the inputs look like high impedances to input sources producing large differential and common-mode voltages. The guaranteed common-mode input voltage range for an LM615 is Vb s VCM s (V a b 1.8V), over temperature. This is the voltage range in which the comparisons must be made. If both inputs are within this range, the output will be at the correct state. If one input is within this range, and the other input is less than (V b a 32V), even if this is greater than V a , the output will be at the correct state. If, however, either or both inputs are driven below Vb, and either input current exceeds 10 mA, the output state is not guaranteed to be correct. If both inputs are above (V a b 1.8V), the output state is also not guaranteed to be correct. Hysteresis Any comparator may oscillate or produce a noisy output if the applied differential input voltage is near the comparator’s offset voltage. This usually happens when the input signal is moving very slowly across the comparator’s switching threshold. This problem can be prevented by the addition of hysteresis, or positive feedback, as shown in Figure 12 . Output Stage The comparators have open-collector output stages which require a pull-up resistor from each output pin to a positive supply voltage of the output to switch properly. When the internal output transistor is off, the output (HIGH) voltage will be pulled up to this external positive voltage. To ensure that the LOW output voltage is under the TTL-low threshold, the output transistor’s load current must be less than 0.8 mA (over temperature) when it turns on. This impacts the minimum value of the pull-up resistor. TL/H/11057–20 FIGURE 12. RS and RF Add Hysteresis to Comparator The amount of hysteresis added in Figure 12 is VH e V a x RS (RF a RS) R & Va x S for RF n RS RF A good rule of thumb is to add hysteresis of at least the maximum specified offset voltage. More than about 50 mV of hysteresis can substantially reduce the accuracy of the comparator, since the offset voltage is effectively being increased by the hysteresis when the comparator output is high. 10 Typical Applications Power Supply Monitor VOUT1 and VOUT2 are optional digital outputs, and are LOW when the corresponding LED is ON. All resistors 1% tolerance or better. Tracking Comparator TL/H/11057 – 21 4-Threshold Level Detector TL/H/11057 – 22 R1–C1 removes the low-frequency signal component, so that through R2–C2 the higherfrequency component is detected. TL/H/11057 – 23 11 12 Physical Dimensions inches (millimeters) Ceramic Dual-In-Line Package (J) Order Number LM615AMJ/883 NS Package Number J16A 16-Pin Narrow Surface Mount Package (M) Order Number LM615IM NS Package Number M16A 13 LM615 Quad Comparator and Adjustable Reference Physical Dimensions inches (millimeters) (Continued) 16-Pin Molded Dual-In-Line Package (N) Order Number LM615IN or LM615MN NS Package Number N16A 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 1111 West Bardin Road Arlington, TX 76017 Tel: 1(800) 272-9959 Fax: 1(800) 737-7018 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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