LMV321 / LMV358 / LMV324 Single/Dual/Quad General Purpose, Low Voltage, Rail-to-Rail Output Operational Amplifiers General Description Features The LMV358/324 are low voltage (2.7-5.5V) versions of the dual and quad commodity op amps, LM358/324, which currently operate at 5-30V. The LMV321 is the single version. The LMV321/358/324 are the most cost effective solutions for the applications where low voltage operation, space saving and low price are needed. They offer specifications that meet or exceed the familiar LM358/324. The LMV321/358/324 have rail-to-rail output swing capability and the input common-mode voltage range includes ground. They all exhibit excellent speed-power ratio, achieving 1 MHz of bandwidth and 1 V/s of slew rate with low supply current. The LMV321 is available in space saving SC70-5, which is approximately half the size of SOT23-5. The small package saves space on pc boards, and enables the design of small portable electronic devices. It also allows the designer to place the device closer to the signal source to reduce noise pickup and increase signal integrity. The chips are built with National's advanced submicron silicon-gate BiCMOS process. The LMV321/358/324 have bipolar input and output stages for improved noise performance and higher output current drive. (For V+ = 5V and V- = 0V, Typical Unless Otherwise Noted) Gain and Phase vs Capacitive Load Output Voltage Swing vs Supply Voltage DS100060-45 (c) 2000 National Semiconductor Corporation DS100060 h Guaranteed 2.7V and 5V Performance h No Crossover Distortion h Space Saving Package SC70-5 2.0x2.1x1.0mm h Industrial Temp.Range -40C to +85C h Gain-Bandwidth Product 1MHz h Low Supply Current LMV321 130A LMV358 210A LMV324 410A h Rail-to-Rail Output Swing V+-10mV @ 10k Load V-+65mV -0.2V to V+-0.8V h VCM Applications n Active Filters n General Purpose Low Voltage Applications n General Purpose Portable Devices DS100060-67 www.national.com LMV321/LMV358/LMV324 Single/Dual/Quad General Purpose, Low Voltage, Rail-to-Rail Output Operational Amplifiers August 2000 LMV321/ LMV358/LMV324 Single/Dual/Quad Absolute Maximum Ratings (Note 1) Storage Temp. Range If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications. Junction Temp. (Tj, max) (Note 5) -65C to 150C 150C Operating Ratings (Note 1) ESD Tolerance (Note 2) Supply Voltage Machine Model 100V Human Body Model LMV358/324 2.7V to 5.5V Temperature Range -40CT J85C LMV321, LMV358, LMV324 2000V LMV321 Thermal Resistance ( 900V Differential Input Voltage Supply Voltage Supply Voltage (V+-V -) 5.5V Output Short Circuit to V + Output Short Circuit to V - (Note 3) (Note 4) Soldering Information Infrared or Convection (20 sec) JA)(Note 10) 5-pin SC70-5 478C/W 5-pin SOT23-5 265C/W 8-Pin SOIC 190C/W 8-Pin MSOP 235C/W 14-Pin SOIC 145C/W 14-Pin TSSOP 155C/W 235C 2.7V DC Electrical Characteristics Unless otherwise specified, all limits guaranteed for T Symbol Parameter J = 25C, V+ = 2.7V, V- = 0V, VCM = 1.0V, VO = V+/2 and RL > 1 M. Conditions Typ (Note 6) Limit (Note 7) Units 1.7 7 mV max VOS Input Offset Voltage TCVOS Input Offset Voltage Average Drift 5 IB Input Bias Current 11 250 nA max IOS Input Offset Current 5 50 nA max CMRR Common Mode Rejection Ratio 0V VCM 1.7V 63 50 dB min PSRR Power Supply Rejection Ratio 2.7V V+ 5V VO = 1V 60 50 dB min VCM Input Common-Mode Voltage Range For CMRR50dB -0.2 0 V min 1.9 1.7 V max V+ -10 V+ -100 mV min 60 180 mV max LMV321 80 170 A max LMV358 Both amplifiers 140 340 A max LMV324 All four amplifiers 260 680 A max VO IS Output Swing Supply Current www.national.com RL = 10k to 1.35V 2 V/C Symbol J Parameter GBWP Gain-Bandwidth Product = 25C, V+ = 2.7V, V- = 0V, VCM = 1.0V, VO = V+/2 and RL > 1 M. Conditions CL = 200 pF Typ (Note 6) Limit (Note 7) Units 1 MHz m Phase Margin 60 Deg Gm Gain Margin 10 dB en Input-Referred Voltage Noise f = 1 kHz 46 in Input-Referred Current Noise f = 1 kHz 0.17 5V DC Electrical Characteristics Unless otherwise specified, all limits guaranteed for T Boldface limits apply at the temperature extremes. Symbol J Parameter = 25C, V+ = 5V, V- = 0V, VCM = 2.0V, VO = V+/2 and R Conditions L > 1 M. Typ (Note 6) Limit (Note 7) Units 1.7 7 9 mV max VOS Input Offset Voltage TCVOS Input Offset Voltage Average Drift 5 IB Input Bias Current 15 250 500 nA max IOS Input Offset Current 5 50 150 nA max CMRR Common Mode Rejection Ratio 0V VCM 4V 65 50 dB min PSRR Power Supply Rejection Ratio 2.7V V+ 5V VO = 1V VCM = 1V 60 50 dB min VCM Input Common-Mode Voltage Range For CMRR50dB -0.2 0 V min 4.2 4 V max 100 15 10 V/mV min V+ -40 V+ -300 V+ -400 mV min 120 300 400 mV max V+ -10 V+ -100 V+ -200 mV min 65 180 280 mV max Sourcing, VO = 0V 60 5 mA min Sinking, VO = 5V 160 10 mA min LMV321 130 250 350 A max LMV358 Both amplifiers 210 440 615 A max LMV324 All four amplifiers 410 830 1160 A max AV Large Signal Voltage Gain (Note 8) RL = 2k VO Output Swing RL = 2k to 2.5V RL = 10k to 2.5V IO IS Output Short Circuit Current Supply Current 3 V/C www.national.com LMV321/ LMV358/LMV324 Single/Dual/Quad 2.7V AC Electrical Characteristics Unless otherwise specified, all limits guaranteed for T LMV321/ LMV358/LMV324 Single/Dual/Quad 5V AC Electrical Characteristics Unless otherwise specified, all limits guaranteed for T Boldface limits apply at the temperature extremes. Symbol SR J Parameter = 25C, V+ = 5V, V- = 0V, VCM = 2.0V, VO = V+/2 and R Typ (Note 6) Conditions Slew Rate (Note 9) CL = 200 pF Limit (Note 7) L > 1 M. Units 1 V/s GBWP Gain-Bandwidth Product 1 MHz m Phase Margin 60 Deg Gm Gain Margin 10 dB en Input-Referred Voltage Noise f = 1 kHz, 39 in Input-Referred Current Noise f = 1 kHz 0.21 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 k in series with 100 pF. Machine model, 0 in series with 200 pF. Note 3: Shorting output to V+ will adversely affect reliability. Note 4: Shorting output to V- will adversely affect reliability. Note 5: The maximum power dissipation is a function of TJ(max), JA, and TA. The maximum allowable power dissipation at any ambient temperature is PD = (TJ(max)-TA)/JA. 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: RL is connected to V-. The output voltage is 0.5V VO 4.5V. Note 9: Connected as voltage follower with 3V step input. Number specified is the slower of the positive and negative slew rates. Note 10: All numbers are typical, and apply for packages soldered directly onto a PC board in still air. Typical Performance Characteristics Supply Current vs Supply Voltage (LMV321) Unless otherwise specified, VS = +5V, single supply, TA = 25C. Input Current vs Temperature Sourcing Current vs Output Voltage DS100060-73 Sourcing Current vs Output Voltage DS100060-A9 Sinking Current vs Output Voltage DS100060-68 www.national.com Sinking Current vs Output Voltage DS100060-70 4 DS100060-69 DS100060-71 Unless otherwise specified, VS = +5V, single supply, TA = 25C. (Continued) Output Voltage Swing vs Supply Voltage Input Voltage Noise vs Frequency Input Current Noise vs Frequency DS100060-56 DS100060-60 DS100060-67 Input Current Noise vs Frequency Crosstalk Rejection vs Frequency DS100060-58 DS100060-61 CMRR vs Frequency CMRR vs Input Common Mode Voltage PSRR vs Frequency DS100060-51 CMRR vs Input Common Mode Voltage DS100060-62 DS100060-64 5 DS100060-63 www.national.com LMV321/ LMV358/LMV324 Single/Dual/Quad Typical Performance Characteristics LMV321/ LMV358/LMV324 Single/Dual/Quad Typical Performance Characteristics Unless otherwise specified, VS = +5V, single supply, TA = 25C. (Continued) VOS vs CMR V OS vs CMR Input Voltage vs Output Voltage DS100060-53 DS100060-50 DS100060-54 Input Voltage vs Output Voltage Open Loop Frequency Response DS100060-52 Open Loop Frequency Response vs Temperature DS100060-42 Gain and Phase vs Capacitive Load DS100060-43 www.national.com Open Loop Frequency Response Gain and Phase vs Capacitive Load DS100060-45 6 DS100060-41 DS100060-44 Unless otherwise specified, VS = +5V, single supply, TA = 25C. (Continued) Slew Rate vs Supply Voltage Non-Inverting Large Signal Pulse Response DS100060-88 DS100060-57 Non-Inverting Large Signal Pulse Response Non-Inverting Large Signal Pulse Response Non-Inverting Small Signal Pulse Response DS100060-A0 Non-Inverting Small Signal Pulse Response DS100060-A1 Non-Inverting Small Signal Pulse Response DS100060-89 Inverting Large Signal Pulse Response DS100060-A3 Inverting Large Signal Pulse Response DS100060-90 7 DS100060-A2 DS100060-A4 www.national.com LMV321/ LMV358/LMV324 Single/Dual/Quad Typical Performance Characteristics LMV321/ LMV358/LMV324 Single/Dual/Quad Typical Performance Characteristics Unless otherwise specified, VS = +5V, single supply, TA = 25C. (Continued) Inverting Large Signal Pulse Response Inverting Small Signal Pulse Response DS100060-A5 Inverting Small Signal Pulse Response DS100060-91 Stability vs Capacitive Load Stability vs Capacitive Load DS100060-A6 Stability vs Capacitive Load DS100060-47 DS100060-46 DS100060-A7 Stability vs Capacitive Load DS100060-49 www.national.com Inverting Small Signal Pulse Response DS100060-48 8 THD vs Frequency DS100060-59 Unless otherwise specified, VS = +5V, single supply, TA = 25C. (Continued) Open Loop Output Impedance vs Frequency Short Circuit Current vs Temperature (Sinking) Short Circuit Current vs Temperature (Sourcing) DS100060-55 DS100060-65 DS100060-66 Application Notes Output Voltage (500mV/div) 1.0 Benefits of the LMV321/358/324 Size. The small footprints of the LMV321/358/324 packages save space on printed circuit boards, and enable the design of smaller electronic products, such as cellular phones, pagers, or other portable systems. The low profile of the LMV321/358/324 make them possible to use in PCMCIA type III cards. Signal Integrity. Signals can pick up noise between the signal source and the amplifier. By using a physically smaller amplifier package, the LMV321/358/324 can be placed closer to the signal source, reducing noise pickup and increasing signal integrity. Simplified Board Layout. These products help you to avoid using long pc traces in your pc board layout. This means that no additional components, such as capacitors and resistors, are needed to filter out the unwanted signals due to the interference between the long pc traces. Low Supply Current. These devices will help you to maximize battery life. They are ideal for battery powered systems. Low Supply Voltage. National provides guaranteed performance at 2.7V and 5V. These guarantees ensure operation throughout the battery lifetime. Rail-to-Rail Output. Rail-to-rail output swing provides maximum possible dynamic range at the output. This is particularly important when operating on low supply voltages. Input Includes Ground. Allows direct sensing near GND in single supply operation. The differential input voltage may be larger than V+ without damaging the device. Protection should be provided to prevent the input voltages from going negative more than -0.3V (at 25C). An input clamp diode with a resistor to the IC input terminal can be used. Ease of Use & No Crossover Distortion. The LMV321/ 358/324 offer specifications similar to the familiar LM324. In addition, the new LMV321/358/324 effectively eliminate the output crossover distortion. The scope photos in Figure 1 and Figure 2 compare the output swing of the LMV324 and the LM324 in a voltage follower configuration, with V S = 2.5V and RL (= 2k) connected to GND. It is apparent that the crossover distortion has been eliminated in the new LMV324. Time (50s/div) DS100060-97 Output Voltage (500mV/div) FIGURE 1. Output Swing of LMV324 Time (50s/div) DS100060-98 FIGURE 2. Output Swing of LM324 2.0 Capacitive Load Tolerance The LMV321/358/324 can directly drive 200 pF in unity-gain without oscillation. The unity-gain follower is the most sensitive configuration to capacitive loading. Direct capacitive loading reduces the phase margin of amplifiers. The combination of the amplifier's output impedance and the capacitive load induces phase lag. This results in either an underdamped pulse response or oscillation. To drive a heavier capacitive load, circuit in Figure 3 can be used. 9 www.national.com LMV321/ LMV358/LMV324 Single/Dual/Quad Typical Performance Characteristics (Continued) DS100060-4 DS100060-5 FIGURE 3. Indirectly Driving A Capacitive Load Using Resistive Isolation FIGURE 5. Indirectly Driving A Capacitive Load with DC Accuracy In Figure 3 , the isolation resistor RISO and the load capacitor CL form a pole to increase stability by adding more phase margin to the overall system. The desired performance depends on the value of RISO. The bigger the RISO resistor value, the more stable Vout will be. Figure 4 is an output waveform of Figure 3 using 620 for RISO and 510 pF for CL.. (1v/div) Input Signal 3.0 Input Bias Current Cancellation The LMV321/358/324 family has a bipolar input stage. The typical input bias current of LMV321/358/324 is 15 nA with 5V supply. Thus a 100 k input resistor will cause 1.5 mV of error voltage. By balancing the resistor values at both inverting and non-inverting inputs, the error caused by the amplifier's input bias current will be reduced. The circuit in Figure 6 shows how to cancel the error caused by input bias current. Output Signal LMV321/ LMV358/LMV324 Single/Dual/Quad Application Notes Time (2s/div) DS100060-6 DS100060-99 FIGURE 6. Cancelling the Error Caused by Input Bias Current FIGURE 4. Pulse Response of the LMV324 Circuit in Figure 3 4.0 Typical Single-Supply Application Circuits The circuit in Figure 5 is an improvement to the one in Figure 3 because it provides DC accuracy as well as AC stability. If there were a load resistor in Figure 3, the output would be voltage divided by RISO and the load resistor. Instead, in Figure 5, RF provides the DC accuracy by using feed-forward techniques to connect VIN to RL. Caution is needed in choosing the value of RF due to the input bias current of the LMV321/358/324. CF and RISO serve to counteract the loss of phase margin by feeding the high frequency component of the output signal back to the amplifier's inverting input, thereby preserving phase margin in the overall feedback loop. Increased capacitive drive is possible by increasing the value of C F . This in turn will slow down the pulse response. www.national.com 4.1 Difference Amplifier The difference amplifier allows the subtraction of two voltages or, as a special case, the cancellation of a signal common to two inputs. It is useful as a computational amplifier, in making a differential to single-ended conversion or in rejecting a common mode signal. 10 4.2.2 Two-op-amp Instrumentation Amplifier (Continued) A two-op-amp instrumentation amplifier can also be used to make a high-input-impedance dc differential amplifier (Figure 9) . As in the three-op-amp circuit, this instrumentation amplifier requires precise resistor matching for good CMRR. R4 should equal to R1 and R3 should equal R2. DS100060-7 DS100060-11 DS100060-19 DS100060-35 FIGURE 7. Difference Amplifier FIGURE 9. Two-Op-amp Instrumentation Amplifier 4.2 Instrumentation Circuits The input impedance of the previous difference amplifier is set by the resistors R1, R2, R3, and R 4. To eliminate the problems of low input impedance, one way is to use a voltage follower ahead of each input as shown in the following two instrumentation amplifiers. 4.3 Single-Supply Inverting Amplifier There may be cases where the input signal going into the amplifier is negative. Because the amplifier is operating in single supply voltage, a voltage divider using R3 and R4 is implemented to bias the amplifier so the input signal is within the input common-mode voltage range of the amplifier. The capacitor C1 is placed between the inverting input and resistor R1 to block the DC signal going into the AC signal source, VIN. The values of R1 and C 1 affect the cutoff frequency, fc = 1/2R1C1. As a result, the output signal is centered around mid-supply (if the voltage divider provides V+/2 at the non-inverting input). The output can swing to both rails, maximizing the signal-to-noise ratio in a low voltage system. 4.2.1 Three-op-amp Instrumentation Amplifier The quad LMV324 can be used to build a three-op-amp instrumentation amplifier as shown in Figure 8. DS100060-85 FIGURE 8. Three-op-amp Instrumentation Amplifier DS100060-13 The first stage of this instrumentation amplifier is a differential-input, differential-output amplifier, with two voltage followers. These two voltage followers assure that the input impedance is over 100 M. The gain of this instrumentation amplifier is set by the ratio of R2/R 1. R3 should equal R1, and R4 equal R2. Matching of R3 to R1 and R4 to R2 affects the CMRR. For good CMRR over temperature, low drift resistors should be used. Making R4 slightly smaller than R 2 and adding a trim pot equal to twice the difference between R 2 and R4 will allow the CMRR to be adjusted for optimum. DS100060-20 FIGURE 10. Single-Supply Inverting Amplifier 4.4 Active Filter 4.4.1 Simple Low-Pass Active Filter The simple low-pass filter is shown in Figure 11. Its lowfrequency gain ( 0) is defined by -R3/R1. This allows lowfrequency gains other than unity to be obtained. The filter has a -20dB/decade roll-off after its corner frequency fc. R2 should be chosen equal to the parallel combination of R1 and R3 to minimize errors due to bias current. The frequency response of the filter is shown in Figure 12. 11 www.national.com LMV321/ LMV358/LMV324 Single/Dual/Quad Application Notes LMV321/ LMV358/LMV324 Single/Dual/Quad Application Notes (Continued) DS100060-16 FIGURE 13. Sallen-Key 2nd-Order Active Low-Pass Filter DS100060-14 The following paragraphs explain how to select values for R1, R2, R3, R4, C1, and C 2 for given filter requirements, such as ALP, Q, and f c. The standard form for a 2nd-order low pass filter is DS100060-37 FIGURE 11. Simple Low-Pass Active Filter (3) where Q: Pole Quality Factor C: Corner Frequency Comparison between the Equation (2) and Equation (3) yields (4) DS100060-15 FIGURE 12. Frequency Response of Simple Low-Pass Active Filter in Figure 11 (5) To reduce the required calculations in filter design, it is convenient to introduce normalization into the components and design parameters. To normalize, let C = n = 1rad/s, and C1 = C2 = Cn = 1F, and substitute these values into Equation (4) and Equation (5). From Equation (4), we obtain Note that the single-op-amp active filters are used in to the applications that require low quality factor, Q( 10), low frequency ( 5 kHz), and low gain ( 10), or a small value for the product of gain times Q ( 100). The op amp should have an open loop voltage gain at the highest frequency of interest at least 50 times larger than the gain of the filter at this frequency. In addition, the selected op amp should have a slew rate that meets the following requirement: SlewRate 0.5 x ( HVOPP) x 10-6 V/sec (6) From Equation (5), we obtain where H is the highest frequency of interest, and Vopp is the output peak-to-peak voltage. (7) For minimum dc offset, V+ = V-, the resistor values at both inverting and non-inverting inputs should be equal, which means 4.4.2 Sallen-Key 2nd-Order Active Low-Pass Filter The Sallen-Key 2nd-order active low-pass filter is illustrated in Figure 13. The dc gain of the filter is expressed as (1) (8) Its transfer function is From Equation (1) and Equation (8), we obtain (9) (2) www.national.com 12 An adjustment to the scaling may be made in order to have realistic values for resistors and capacitors. The actual value used for each component is shown in the circuit. (Continued) 4.4.3 2nd-order High Pass Filter (10) A 2nd-order high pass filter can be built by simply interchanging those frequency selective components (R1, R 2, C1, C2) in the Sallen-Key 2nd-order active low pass filter. As shown in Figure 14, resistors become capacitors, and capacitors become resistors. The resulted high pass filter has the same corner frequency and the same maximum gain as the previous 2nd-order low pass filter if the same components are chosen. The values of C1 and C2 are normally close to or equal to As a design example: Require: ALP = 2, Q = 1, fc = 1KHz Start by selecting C1 and C2. Choose a standard value that is close to From Equations (6), (7), (9), (10), R1= 1 R2= 1 R3= 4 R4= 4 The above resistor values are normalized values with n=1rad/s and C1 = C2 = Cn = 1F. To scale the normalized cut-off frequency and resistances to the real values, two scaling factors are introduced, frequency scaling factor (kf) and impedance scaling factor (km). DS100060-83 FIGURE 14. Sallen-Key 2nd-Order Active High-Pass Filter 4.4.4 State Variable Filter A state variable filter requires three op amps. One convenient way to build state variable filters is with a quad op amp, such as the LMV324 (Figure 15). This circuit can simultaneously represent a low-pass filter, high-pass filter, and bandpass filter at three different outputs. The equations for these functions are listed below. It is also called Bi-Quad active filter as it can produce a transfer function which is quadratic in both numerator and denominator. Scaled values: R2 = R1 = 15.9 k R3 = R4 = 63.6 k C1 = C2 = 0.01 F DS100060-39 FIGURE 15. State Variable Active Filter 13 www.national.com LMV321/ LMV358/LMV324 Single/Dual/Quad Application Notes LMV321/ LMV358/LMV324 Single/Dual/Quad Application Notes (Continued) where for all three filters, (11) (12) A design example for a bandpass filter is shown below: Assume the system design requires a bandpass filter with f O = 1 kHz and Q = 50. What needs to be calculated are capacitor and resistor values. First choose convenient values for C1, R1 and R2: C1 = 1200 pF 2R2 = R1 = 30 k Then from Equation (11), DS100060-81 FIGURE 16. Pulse Generator From Equation (12), When the output voltage VO is first at its high, VOH, the capacitor C is charged toward VOH through R2. The voltage across C rises exponentially with a time constant = R2C, and this voltage is applied to the inverting input of the op amp. Meanwhile, the voltage at the non-inverting input is set at the positive threshold voltage (VTH+) of the generator. The capacitor voltage continually increases until it reaches VTH+, at which point the output of the generator will switch to its low, VOL (=0V in this case). The voltage at the non-inverting input is switched to the negative threshold voltage (VTH-) of the generator. The capacitor then starts to discharge toward VOL exponentially through R1, with a time constant = R1C. When the capacitor voltage reaches VTH-, the output of the pulse generator switches to V OH. The capacitor starts to charge, and the cycle repeats itself. From the above calculated values, the midband gain is H 0 = R3/R2 = 100 (40dB). The nearest 5% standard values have been added to Figure 15. 4.5 Pulse Generators and Oscillators A pulse generator is shown in Figure 16. Two diodes have been used to separate the charge and discharge paths to capacitor C. www.national.com 14 (Continued) DS100060-76 FIGURE 19. Squarewave Generator 4.6 Current Source and Sink The LMV321/358/324 can be used in feedback loops which regulate the current in external PNP transistors to provide current sources or in external NPN transistors to provide current sinks. 4.6.1 Fixed Current Source A multiple fixed current source is show in Figure 20. A voltage (VREF = 2V) is established across resistor R3 by the voltage divider (R3 and R 4). Negative feedback is used to cause the voltage drop across R 1 to be equal to VREF. This controls the emitter current of transistor Q1 and if we neglect the base current of Q1 and Q2, essentially this same current is available out of the collector of Q1. Large input resistors can be used to reduce current loss and a Darlington connection can be used to reduce errors due to the of Q1. The resistor, R2, can be used to scale the collector current of Q2 either above or below the 1 mA reference value. DS100060-86 FIGURE 17. Waveforms of the Circuit in Figure 16 As shown in the waveforms in Figure 17, the pulse width (T1) is set by R2, C and VOH, and the time between pulses (T2) is set by R 1, C and VOL. This pulse generator can be made to have different frequencies and pulse width by selecting different capacitor value and resistor values. Figure 18 shows another pulse generator, with separate charge and discharge paths. The capacitor is charged through R1 and is discharged through R2. DS100060-77 FIGURE 18. Pulse Generator Figure 19 is a squarewave generator with the same path for charging and discharging the capacitor. DS100060-80 FIGURE 20. Fixed Current Source 15 www.national.com LMV321/ LMV358/LMV324 Single/Dual/Quad Application Notes LMV321/ LMV358/LMV324 Single/Dual/Quad Application Notes 4.8 LED Driver (Continued) The LMV321/358/324 can be used to drive an LED as shown in Figure 23. 4.6.2 High Compliance Current Sink A current sink circuit is shown in Figure 21. The circuit requires only one resistor (RE) and supplies an output current which is directly proportional to this resistor value. DS100060-84 FIGURE 23. LED Driver 4.9 Comparator with Hysteresis The LMV321/358/324 can be used as a low power comparator. Figure 24 shows a comparator with hysteresis. The hysteresis is determined by the ratio of the two resistors. VTH+ = VREF/(1+R 1/R2)+VOH/(1+R2/R1) VTH- = VREF/(1+R 1/R2)+VOL/(1+R2/R1) VH = (VOH-VOL)/(1+R 2/R1) DS100060-82 FIGURE 21. High Compliance Current Sink where VTH+: Positive Threshold Voltage VTH-: Negative Threshold Voltage 4.7 Power Amplifier A power amplifier is illustrated in Figure 22. This circuit can provide a higher output current because a transistor follower is added to the output of the op amp. VOH: Output Voltage at High VOL: Output Voltage at Low VH: Hysteresis Voltage Since LMV321/358/324 have rail-to-rail output, (VOH-VOL) equals to VS, which is the supply voltage. VH = VS/(1+R2/R 1) the The differential voltage at the input of the op amp should not exceed the specified absolute maximum ratings. For real comparators that are much faster, we recommend you to use National's LMV331/393/339, which are single, dual and quad general purpose comparators for low voltage operation. DS100060-79 FIGURE 22. Power Amplifier DS100060-78 FIGURE 24. Comparator with Hysteresis Connection Diagrams 5-Pin SC70-5/SOT23-5 8-Pin SO/MSOP DS100060-1 Top View DS100060-2 Top View www.national.com 16 (Continued) 14-Pin SO/TSSOP DS100060-3 Top View Ordering Information Temperature Range Package Industrial Packaging Marking Transport Media NSC Drawing -40C to +85C 5-Pin SC70-5 5-Pin SOT23-5 8-Pin Small Outline 8-Pin MSOP 14-Pin Small Outline 14-Pin TSSOP LMV321M7 A12 LMV321M7X A12 LMV321M5 A13 LMV321M5X A13 1k Units Tape and Reel 1k Units Tape and Reel MA05B 3k Units Tape and Reel LMV358M LMV358M Rails LMV358MX LMV358M 2.5k Units Tape and Reel LMV358MM LMV358 1k Units Tape and Reel LMV358MMX LMV358 3.5k Units Tape and Reel LMV324M LMV324M Rails LMV324MX LMV324M 2.5k Units Tape and Reel LMV324MT LMV324MT Rails LMV324MTX LMV324MT 2.5k Units Tape and Reel 17 MAA05 3k Units Tape and Reel M08A MUA08A M14A MTC14 www.national.com LMV321/ LMV358/LMV324 Single/Dual/Quad Connection Diagrams LMV321/ LMV358/LMV324 Single/Dual/Quad SC70-5 Tape and Reel Specification DS100060-B3 SOT-23-5 Tape and Reel Specification TAPE FORMAT Tape Section # Cavities Cavity Status Cover Tape Status Sealed Leader 0 (min) Empty (Start End) 75 (min) Empty Sealed Carrier 3000 Filled Sealed 250 Filled Sealed Trailer 125 (min) Empty Sealed (Hub End) 0 (min) Empty Sealed TAPE DIMENSIONS DS100060-B1 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 18 LMV321/ LMV358/LMV324 Single/Dual/Quad SOT-23-5 Tape and Reel Specification (Continued) REEL DIMENSIONS DS100060-B2 8 mm Tape Size 7.00 0.059 0.512 0.795 2.165 330.00 1.50 A B 13.00 20.20 55.00 C D N 19 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 www.national.com LMV321/ LMV358/LMV324 Single/Dual/Quad Physical Dimensions inches (millimeters) unless otherwise noted 5-Pin SC70-5 Tape and Reel Order Number LMV321M7 and LMV321M7X NS Package Number MAA05A www.national.com 20 LMV321/ LMV358/LMV324 Single/Dual/Quad Physical Dimensions inches (millimeters) unless otherwise noted (Continued) 5-Pin SOT23-5 Tape and Reel Order Number LMV321M5 and LMV321M5X NS Package Number MA05B 8-Pin Small Outline Order Number LMV358M and LMV358MX NS Package Number M08A 21 www.national.com LMV321/ LMV358/LMV324 Single/Dual/Quad Physical Dimensions inches (millimeters) unless otherwise noted (Continued) 8-Pin MSOP Order Number LMV358MM and LMV358MMX NS Package Number MUA08A www.national.com 22 LMV321/ LMV358/LMV324 Single/Dual/Quad Physical Dimensions inches (millimeters) unless otherwise noted (Continued) 14-Pin Small Outline Order Number LMV324M and LMV324MX NS Package Number M14A 23 www.national.com LMV321/LMV358/LMV324 Single/Dual/Quad General Purpose, Low Voltage, Rail-to-Rail Output Operational Amplifiers Physical Dimensions inches (millimeters) unless otherwise noted (Continued) 14-Pin TSSOP Order Number LMV324MT and LMV324MTX NS Package Number MTC14 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: support@nsc.com www.national.com National Semiconductor Europe Fax: +49 (0) 180-530 85 86 Email: europe.support@nsc.com Deutsch Tel: +49 (0) 69 9508 6208 English Tel: +44 (0) 870 24 0 2171 Francais Tel: +33 (0) 1 41 91 8790 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: ap.support@nsc.com 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.