LMV821,LMV822,LMV824 LMV821 Single/ LMV822 Dual/ LMV824 Quad Low Voltage, Low Power, R-to-R Output, 5 MHz Op Amps Literature Number: SNOS032D LMV821 Single/ LMV822 Dual/ LMV824 Quad Low Voltage, Low Power, R-to-R Output, 5 MHz Op Amps General Description The LMV821/LMV822/LMV824 bring performance and economy to low voltage / low power systems. With a 5 MHz unity-gain frequency and a guaranteed 1.4 V/µs slew rate, the quiescent current is only 220 µA/amplifier (2.7 V). They provide rail-to-rail (R-to-R) output swing into heavy loads (600 Ω Guarantees). The input common-mode voltage range includes ground, and the maximum input offset voltage is 3.5mV (Guaranteed). They are also capable of comfortably driving large capacitive loads (refer to the application notes section). The LMV821 (single) is available in the ultra tiny SC70-5 package, which is about half the size of the previous title holder, the SOT23-5. Overall, the LMV821/LMV822/LMV824 (Single/Dual/Quad) are low voltage, low power, performance op amps, that can be designed into a wide range of applications, at an economical price. Features Maximum VOS 3.5 mV (Guaranteed) VOS Temp. Drift 1 uV/˚ C GBW product @ 2.7 V 5 MHz ISupply @ 2.7 V 220 µA/Amplifier Minimum SR 1.4 V/us (Guaranteed) CMRR 90 dB PSRR 85 dB VCM @ 5V -0.3V to 4.3V Rail-to-Rail (R-to-R) Output Swing — @600 Ω Load 160 mV from rail 55 mV from rail — @10 kΩ Load n Stable with High Capacitive Loads (Refer to Application Section) n n n n n n n n n Applications n n n n n Cordless Phones Cellular Phones Laptops PDAs PCMCIA (For Typical, 5 V Supply Values; Unless Otherwise Noted) n Ultra Tiny, SC70-5 Package 2.0 x 2.0 x 1.0 mm n Guaranteed 2.5 V, 2.7 V and 5 V Performance Telephone-line Transceiver for a PCMCIA Modem Card 10012833 © 2003 National Semiconductor Corporation DS100128 www.national.com LMV821 / LMV822 / LMV824 Single/Dual Quad Low Voltage, Low Power, RRO, 5 MHz Op Amps November 2003 LMV821 Single/ LMV822 Dual/ LMV824 Quad Absolute Maximum Ratings (Note 1) Operating Ratings (Note 1) If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications. Supply Voltage Thermal Resistance (θ 100V 2000V LMV821 Tiny SOT23-5 Package, 5-Pin Surface Mount 1500V Differential Input Voltage ± Supply Voltage Supply Voltage (V+–V −) 5.5V MSOP Package, 8-Pin Mini Surface Mount Output Short Circuit to V− (Note 3) Infrared or Convection (20 sec) Storage Temperature Range Junction Temperature (Note 4) 235˚C 440 ˚C/W 190 ˚C/W 235 ˚C/W SO Package, 14-Pin Surface Mount Soldering Information ≤85˚C 265 ˚C/W SO Package, 8-Pin Surface Mount Output Short Circuit to V+ (Note 3) J JA) Ultra Tiny SC70-5 Package, 5-Pin Surface Mount Human Body Model LMV822/824 −40˚C ≤T LMV821, LMV822, LMV824 ESD Tolerance (Note 2) Machine Model 2.5V to 5.5V Temperature Range 145 ˚C/W TSSOP Package, 14-Pin 155 ˚C/W −65˚C to 150˚C 150˚C 2.7V DC Electrical Characteristics Unless otherwise specified, all limits guaranteed for TJ = 25˚C. V+ = 2.7V, V Boldface limits apply at the temperature extremes. Symbol VOS Parameter Condition Input Offset Voltage − = 0V, VCM = 1.0V, VO = 1.35V and R LMV821/822/824 Limit (Note 6) 1 3.5 mV 4 max Input Offset Voltage Average Drift 1 IB Input Bias Current 30 IOS Input Offset Current 0.5 +PSRR −PSRR VCM Common Mode Rejection Ratio 0V ≤ VCM ≤ 1.7V > 1 MΩ. Typ (Note 5) TCVOS CMRR L 85 Positive Power Supply Rejection 1.7V ≤ V+ ≤ 4V, V- = 1V, VO = Ratio 0V, VCM = 0V 85 Negative Power Supply Rejection Ratio -1.0V ≤ V- ≤ -3.3V, V+ = 1.7V, VO = 0V, VCM = 0V 85 Input Common-Mode Voltage Range For CMRR ≥ 50dB Units µV/˚C 90 nA 140 max 30 nA 50 max 70 dB 68 min 75 dB 70 min 73 dB 70 min -0.3 -0.2 V 2.0 1.9 max V min AV Large Signal Voltage Gain www.national.com Sourcing, RL = 600Ω to 1.35V, VO = 1.35V to 2.2V 100 Sinking, RL = 600Ω to 1.35V, VO = 1.35V to 0.5V 90 Sourcing, RL = 2kΩ to 1.35V, VO = 1.35V to 2.2V 100 Sinking, RL = 2kΩ to 1.35, VO = 1.35 to 0.5V 95 2 90 dB 85 min 85 dB 80 min 95 dB 90 min 90 dB 85 min (Continued) Unless otherwise specified, all limits guaranteed for TJ = 25˚C. V+ = 2.7V, V Boldface limits apply at the temperature extremes. Symbol VO Parameter Output Swing − Condition V+ = 2.7V, RL= 600Ω to 1.35V V+ = 2.7V, RL= 2kΩ to 1.35V = 0V, VCM = 1.0V, VO = 1.35V and R Output Current LMV821/822/824 Limit (Note 6) Units 2.58 2.50 V 2.40 min 0.13 0.20 V 0.30 max 2.66 Sourcing, VO = 0V > 1 MΩ. Typ (Note 5) 0.08 IO L 16 2.60 V 2.50 min 0.120 V 0.200 max 12 mA min Sinking, VO = 2.7V 26 12 mA 0.22 0.3 mA 0.5 max min IS Supply Current LMV821 (Single) LMV822 (Dual) 0.45 LMV824 (Quad) 0.72 0.6 mA 0.8 max 1.0 mA 1.2 max 2.5V DC Electrical Characteristics Unless otherwise specified, all limits guaranteed for TJ = 25˚C. V+ = 2.5V, V Boldface limits apply at the temperature extremes. Symbol Parameter VOS Input Offset Voltage VO Output Swing − Condition V+ = 2.5V, RL = 600Ω to 1.25V = 0V, VCM = 1.0V, VO = 1.25V and R > 1 MΩ. Typ (Note 5) LMV821/822/824 Limit (Note 6) Units 1 3.5 mV 4 max 2.37 2.30 V 2.20 min 0.20 V 0.30 max 0.13 V+ = 2.5V, RL = 2kΩ to 1.25V L 2.46 0.08 2.40 V 2.30 min 0.12 V 0.20 max 2.7V AC Electrical Characteristics Unless otherwise specified, all limits guaranteed for TJ = 25˚C. V+ = 2.7V, V Boldface limits apply at the temperature extremes. Symbol Parameter Conditions = 0V, VCM = 1.0V, VO = 1.35V and R Typ (Note 5) LMV821/822/824 Limit (Note 6) L > 1 MΩ. Units SR Slew Rate 1.5 V/µs GBW Gain-Bandwdth Product 5 MHz Φm Phase Margin 61 Deg. Gm Gain Margin en (Note 7) − 10 dB Amp-to-Amp Isolation (Note 8) 135 dB Input-Related Voltage Noise f = 1 kHz, VCM = 1V 28 3 www.national.com LMV821 Single/ LMV822 Dual/ LMV824 Quad 2.7V DC Electrical Characteristics LMV821 Single/ LMV822 Dual/ LMV824 Quad 2.7V AC Electrical Characteristics (Continued) Unless otherwise specified, all limits guaranteed for TJ = 25˚C. V+ = 2.7V, V Boldface limits apply at the temperature extremes. Symbol Parameter Input-Referred Current Noise f = 1 kHz THD Total Harmonic Distortion f = 1 kHz, AV = −2, RL = 10 kΩ, VO = 4.1 V = 0V, VCM = 1.0V, VO = 1.35V and R Typ (Note 5) Conditions in − LMV821/822/824 Limit (Note 6) L > 1 MΩ. Units 0.1 0.01 % PP 5V DC Electrical Characteristics Unless otherwise specified, all limits guaranteed for TJ = 25˚C. V+ = 5V, V Boldface limits apply at the temperature extremes. Symbol Parameter − Condition = 0V, VCM = 2.0V, VO = 2.5V and R LMV821/822/824 Limit (Note 6) Units 3.5 mV Input Offset Voltage 1 TCVOS Input Offset Voltage Average Drift 1 IB Input Bias Current 40 4.0 Input Offset Current 0.5 0V ≤ VCM ≤ 4.0V CMRR Common Mode Rejection Ratio +PSRR Positive Power Supply Rejection 1.7V ≤ V+ ≤ 4V, V- = 1V, VO = Ratio 0V, VCM = 0V 85 90 −PSRR Negative Power Supply Rejection Ratio -1.0V ≤ V- ≤ -3.3V, V+ = 1.7V, VO = 0V, VCM = 0V VCM Input Common-Mode Voltage Range For CMRR ≥ 50dB > 1 MΩ. Typ (Note 5) VOS IOS L max µV/˚C 100 nA 150 max 30 nA 50 max 72 dB 70 min 75 dB 70 min 85 73 dB 70 min -0.3 -0.2 V max 4.3 4.2 V min AV VO Large Signal Voltage Gain Output Swing Sourcing, RL = 600Ω to 2.5V, VO = 2.5 to 4.5V 105 Sinking, RL = 600Ω to 2.5V, VO = 2.5 to 0.5V 105 Sourcing, RL = 2kΩ to 2.5V, VO = 2.5 to 4.5V dB 90 min 95 dB 90 min 105 95 dB 90 min Sinking, RL = 2kΩ to 2.5, VO = 2.5 to 0.5V 105 95 dB 90 min V+ = 5V,RL = 600Ω to 2.5V 4.84 0.17 V+ = 5V, RL = 2kΩ to 2.5V 4.90 0.10 www.national.com 95 4 4.75 V 4.70 min 0.250 V .30 max 4.85 V 4.80 min 0.15 V 0.20 max (Continued) Unless otherwise specified, all limits guaranteed for TJ = 25˚C. V+ = 5V, V Boldface limits apply at the temperature extremes. Symbol IS Supply Current = 0V, VCM = 2.0V, VO = 2.5V and R L > 1 MΩ. Typ (Note 5) LMV821/822/824 Limit (Note 6) Units Sourcing, VO = 0V 45 20 mA 15 min Sinking, VO = 5V 40 20 mA 15 min Parameter Output Current IO − Condition LMV821 (Single) 0.30 LMV822 (Dual) 0.5 LMV824 (Quad) 1.0 0.4 mA 0.6 max 0.7 mA 0.9 max 1.3 mA 1.5 max 5V AC Electrical Characteristics Unless otherwise specified, all limits guaranteed for TJ = 25˚C. V+ = 5V, V Boldface limits apply at the temperature extremes. Symbol Parameter Conditions − = 0V, VCM = 2V, VO = 2.5V and R L > 1 MΩ. Typ (Note 5) LMV821/822/824 Limit (Note 6) Units 2.0 1.4 V/µs min SR Slew Rate GBW Gain-Bandwdth Product (Note 7) 5.6 MHz Φm Phase Margin 67 Deg. Gm Gain Margin 15 dB dB Amp-to-Amp Isolation (Note 8) 135 en Input-Related Voltage Noise f = 1 kHz, VCM = 1V 24 in Input-Referred Current Noise f = 1 kHz THD Total Harmonic Distortion f = 1 kHz, AV = −2, RL = 10 kΩ, VO = 4.1 V 0.25 0.01 % PP 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 wth 100 pF. Machine model, 200Ω 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 45 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)–T A)/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: V+ = 5V. Connected as voltage follower with 3V step input. Number specified is the slower of the positive and negative slew rates. Note 8: Input referred, V+ = 5V and RL = 100kΩ connected to 2.5V. Each amp excited in turn with 1 kHz to produce V O = 3 VPP. 5 www.national.com LMV821 Single/ LMV822 Dual/ LMV824 Quad 5V DC Electrical Characteristics LMV821 Single/ LMV822 Dual/ LMV824 Quad Typical Performance Characteristics Unless otherwise specified, VS = +5V, single supply, TA = 25˚C. Supply Current vs. Supply Voltage (LMV821) Input Current vs. Temperature 10012802 10012801 Sourcing Current vs. Output Voltage (VS = 2.7V) Sourcing Current vs Output Voltage (VS = 5V) 10012803 10012804 Sinking Current vs. Output Voltage (VS = 2.7V) Sinking Current vs. Output Voltage (VS = 5V) 10012805 www.national.com 10012806 6 Output Voltage Swing vs. Supply Voltage (RL = 10kΩ) Output Voltage Swing vs. Supply Voltage (RL = 2kΩ) 10012807 10012886 Output Voltage Swing vs. Supply Voltage (RL = 600Ω) Output Voltage Swing vs. Load Resistance 10012808 10012887 Input Voltage Noise vs. Frequency Input Current Noise vs. Frequency 10012818 10012817 7 www.national.com LMV821 Single/ LMV822 Dual/ LMV824 Quad Typical Performance Characteristics Unless otherwise specified, VS = +5V, single supply, TA = 25˚C. (Continued) LMV821 Single/ LMV822 Dual/ LMV824 Quad Typical Performance Characteristics Unless otherwise specified, VS = +5V, single supply, TA = 25˚C. (Continued) Crosstalk Rejection vs. Frequency +PSRR vs. Frequency 10012809 10012893 -PSRR vs. Frequency CMRR vs. Frequency 10012847 10012810 Gain and Phase Margin vs. Frequency (RL = 100kΩ, 2kΩ, 600Ω) 2.7V Input Voltage vs. Output Voltage 10012888 www.national.com 10012811 8 Gain and Phase Margin vs. Frequency (RL = 100kΩ, 2kΩ, 600Ω) 5V Gain and Phase Margin vs. Frequency (Temp.= 25, -40, 85˚C, RL = 10kΩ) 2.7V 10012812 10012813 Gain and Phase Margin vs. Frequency (CL = 100pF, 200pF, 0pF, RL = 10kΩ)2.7V Gain and Phase Margin vs. Frequency (Temp.= 25, -40, 85 ˚C, RL = 10kΩ) 5V 10012814 10012815 Gain and Phase Margin vs. Frequency (CL = 100pF, 200pF, 0pF RL = 600Ω) 2.7V Gain and Phase Margin vs. Frequency (CL = 100pF, 200pF, 0pF RL = 10kΩ) 5V 10012816 10012819 9 www.national.com LMV821 Single/ LMV822 Dual/ LMV824 Quad Typical Performance Characteristics Unless otherwise specified, VS = +5V, single supply, TA = 25˚C. (Continued) LMV821 Single/ LMV822 Dual/ LMV824 Quad Typical Performance Characteristics Unless otherwise specified, VS = +5V, single supply, TA = 25˚C. (Continued) Gain and Phase Margin vs. Frequency (CL = 100pF, 200pF, 0pF RL = 600Ω) 5V Slew Rate vs. Supply Voltage 10012862 10012820 Non-Inverting Large Signal Pulse Response Non-Inverting Small Signal Pulse Response 10012821 10012824 Inverting Large Signal Pulse Response Inverting Small Signal Pulse Response 10012827 www.national.com 10012830 10 LMV821 Single/ LMV822 Dual/ LMV824 Quad Typical Performance Characteristics Unless otherwise specified, VS = +5V, single supply, TA = 25˚C. (Continued) THD vs. Frequency 10012882 added in parallel with 220 picofarads capacitance, to increase the φm 20˚(approx.), but at the price of about a 100 kHz of bandwidth. Application Note This application note is divided into two sections: design considerations and Application Circuits. Overall, the LMV821/822/824 family provides good stability for loaded condition. DESIGN CONSIDERATIONS This section covers the following design considerations: 1. Frequency and Phase Response Considerations 2. Unity-Gain Pulse Response Considerations 3. Input Bias Current Considerations FREQUENCY AND PHASE RESPONSE CONSIDERATIONS The relationship between open-loop frequency response and open-loop phase response determines the closed-loop stability performance (negative feedback). The open-loop phase response causes the feedback signal to shift towards becoming positive feedback, thus becoming unstable. The further the output phase angle is from the input phase angle, the more stable the negative feedback will operate. Phase Margin (φm) specifies this output-to-input phase relationship at the unity-gain crossover point. Zero degrees of phasemargin means that the input and output are completely in phase with each other and will sustain oscillation at the unity-gain frequency. The AC tables show φm for a no load condition. But φm changes with load. The Gain and Phase margin vs Frequency plots in the curve section can be used to graphically determine the φm for various loaded conditions. To do this, examine the phase angle portion of the plot, find the phase margin point at the unity-gain frequency, and determine how far this point is from zero degree of phase-margin. The larger the phase-margin, the more stable the circuit operation. The bandwidth is also affected by load. The graphs of Figure 1 and Figure 2 provide a quick look at how various loads affect the φm and the bandwidth of the LMV821/822/824 family. These graphs show capacitive loads reducing both φm and bandwidth, while resistive loads reduce the bandwidth but increase the φm. Notice how a 600Ω resistor can be 10012860 FIGURE 1. Phase Margin vs Common Mode Voltage for Various Loads 11 www.national.com LMV821 Single/ LMV822 Dual/ LMV824 Quad Application Note (Continued) 10012854 FIGURE 5. Pulse Response per Figure 4 10012861 INPUT BIAS CURRENT CONSIDERATION Input bias current (IB) can develop a somewhat significant offset voltage. This offset is primarily due to IB flowing through the negative feedback resistor, RF. For example, if IB is 90 nA (max @ room) and RF is 100 kΩ, then an offset of 9 mV will be developed (VOS=IBx RF).Using a compensation resistor (RC), as shown in Figure 6, cancels out this affect. But the input offset current (IOS) will still contribute to an offset voltage in the same manner - typically 0.05 mV at room temp. FIGURE 2. Unity-Gain Frequency vs Common Mode Voltage for Various Loads UNITY GAIN PULSE RESPONSE CONSIDERATION A pull-up resistor is well suited for increasing unity-gain, pulse response stability. For example, a 600 Ω pull-up resistor reduces the overshoot voltage by about 50%, when driving a 220 pF load. Figure 3 shows how to implement the pull-up resistor for more pulse response stability. 10012841 FIGURE 3. Using a Pull-up Resistor at the Output for Stabilizing Capacitive Loads Higher capacitances can be driven by decreasing the value of the pull-up resistor, but its value shouldn’t be reduced beyond the sinking capability of the part. An alternate approach is to use an isolation resistor as illustrated in Figure 4 . Figure 5 shows the resulting pulse response from a LMV824, while driving a 10,000 pF load through a 20Ω isolation resistor. 10012859 FIGURE 6. Canceling the Voltage Offset Effect of Input Bias Current APPLICATION CIRCUITS This section covers the following application circuits: 1. Telephone-Line Transceiver 2. “Simple” Mixer (Amplitude Modulator) 10012843 FIGURE 4. Using an Isolation Resistor to Drive Heavy Capacitive Loads www.national.com 12 (Continued) 3. Dual Amplifier Active Filters (DAAFs) a. Low-Pass Filter (LPF) • b. High-Pass Filter (HPF) • 4. Tri-level Voltage Detector TELEPHONE-LINE TRANSCEIVER The telephone-line transceiver of Figure 7 provides a fullduplexed connection through a PCMCIA, miniature transformer. The differential configuration of receiver portion (UR), cancels reception from the transmitter portion (UT). Note that the input signals for the differential configuration of UR, are the transmit voltage (VT) and VT/2. This is because Rmatch is chosen to match the coupled telephone-line impedance; therefore dividing VT by two (assuming R1 >> Rmatch). The differential configuration of UR has its resistors chosen to cancel the VT and VT/2 inputs according to the following equation: 10012839 FIGURE 8. Amplitude Modulator Circuit f mod f carrier 10012840 FIGURE 9. Output signal per the Circuit of Figure 8 DUAL AMPLIFIER ACTIVE FILTERS (DAAFs) The LMV822/24 bring economy and performance to DAAFs. The low-pass and the high-pass filters of Figure 10 and Figure 11 (respectively), offer one key feature: excellent sensitivity performance. Good sensitivity is when deviations in component values cause relatively small deviations in a filter’s parameter such as cutoff frequency (Fc). Single amplifier active filters like the Sallen-Key provide relatively poor sensitivity performance that sometimes cause problems for high production runs; their parameters are much more likely to deviate out of specification than a DAAF would. The DAAFs of Figure 10 and Figure 11 are well suited for high volume production. 10012833 FIGURE 7. Telephone-line Transceiver for a PCMCIA Modem Card Note that Cr is included for canceling out the inadequacies of the lossy, miniature transformer. Refer to application note AN-397 for detailed explanation. “SIMPLE” MIXER (AMPLITUDE MODULATOR) The mixer of Figure 8 is simple and provides a unique form of amplitude modulation. Vi is the modulation frequency (FM), while a +3V square-wave at the gate of Q1, induces a carrier frequency (FC). Q1 switches (toggles) U1 between inverting and non-inverting unity gain configurations. Offsetting a sine wave above ground at Vi results in the oscilloscope photo of Figure 9. The simple mixer can be applied to applications that utilize the Doppler Effect to measure the velocity of an object. The difference frequency is one of its output frequency components. This difference frequency magnitude (/FM-FC/) is the key factor for determining an object’s velocity per the Doppler Effect. If a signal is transmitted to a moving object, the reflected frequency will be a different frequency. This difference in transmit and receive frequency is directly proportional to an object’s velocity. 13 www.national.com LMV821 Single/ LMV822 Dual/ LMV824 Quad Application Note LMV821 Single/ LMV822 Dual/ LMV824 Quad Application Note Note that this information provides insight on how to fine tune the cutoff frequency, if necessary. It should be also noted that R4 and R5 of each circuit also caused variations in the pass band gain. Increasing R4 by ten percent, increased the gain by 0.4 dB, while increasing R5 by ten percent, decreased the gain by 0.4 dB. (Continued) TABLE 1. 10012836 Component (LPF) Sensitivity (LPF) Component (HPF) Sensitivity (HPF) -0.7 Ra -1.2 Ca C1 -0.1 Rb -1.0 R2 -1.1 R1 +0.1 R3 +0.7 C2 -0.1 C3 -1.5 R3 +0.1 R4 -0.6 R4 -0.1 R5 +0.6 R5 +0.1 Active filters are also sensitive to an op amp’s parameters -Gain and Bandwidth, in particular. The LMV822/24 provide a large gain and wide bandwidth. And DAAFs make excellent use of these feature specifications. Single Amplifier versions require a large open-loop to closed-loop gain ratio - approximately 50 to 1, at the Fc of the filter response. Figure 12 shows an impressive photograph of a network analyzer measurement (hp3577A). The measurement was taken from a 300 kHz version of Figure 10. At 300 kHz, the open-loop to closed-loop gain ratio @ Fc is about 5 to 1. This is 10 times lower than the 50 to 1 “rule of thumb” for Single Amplifier Active Filters. FIGURE 10. Dual Amplifier, 3 kHz Low-Pass Active Filter with a Butterworth Response and a Pass Band Gain of Times Two 10012837 FIGURE 11. Dual Amplifier, 300 Hz High-Pass Active Filter with a Butterworth Response and a Pass Band Gain of Times Two 10012892 FIGURE 12. 300 kHz, Low-Pass Filter, Butterworth Response as Measured by the HP3577A Network Analyzer Table 1 provides sensitivity measurements for a 10 MΩ load condition. The left column shows the passive components for the 3 kHz low-pass DAAF. The third column shows the components for the 300 Hz high-pass DAAF. Their respective sensitivity measurements are shown to the right of each component column. Their values consists of the percent change in cutoff frequency (Fc) divided by the percent change in component value. The lower the sensitivity value, the better the performance. Each resistor value was changed by about 10 percent, and this measured change was divided into the measured change in Fc. A positive or negative sign in front of the measured value, represents the direction Fc changes relative to components’ direction of change. For example, a sensitivity value of negative 1.2, means that for a 1 percent increase in component value, Fc decreases by 1.2 percent. www.national.com In addition to performance, DAAFs are relatively easy to design and implement. The design equations for the lowpass and high-pass DAAFs are shown below. The first two equation calculate the Fc and the circuit Quality Factor (Q) for the LPF (Figure 10). The second two equations calculate the Fc and Q for the HPF (Figure 11). 14 (Continued) Notice that R3 could also be calculated as 0.707 of Ra or R2. The circuit was implemented and its cutoff frequency measured. The cutoff frequency measured at 2.92 kHz. The circuit also showed good repeatability. Ten different LMV822 samples were placed in the circuit. The corresponding change in the cutoff frequency was less than a percent. To simplify the design process, certain components are set equal to each other. Refer to Figure 10 and Figure 11. These equal component values help to simplify the design equations as follows: TRI-LEVEL VOLTAGE DETECTOR The tri-level voltage detector of Figure 13 provides a type of window comparator function. It detects three different input voltage ranges: Min-range, Mid-range, and Max-range. The output voltage (VO) is at VCC for the Min-range. VO is clamped at GND for the Mid-range. For the Max-range, VO is at Vee. Figure 14 shows a VO vs. VI oscilloscope photo per the circuit of Figure 13. Its operation is as follows: VI deviating from GND, causes the diode bridge to absorb IIN to maintain a clamped condition (VO= 0V). Eventually, IIN reaches the bias limit of the diode bridge. When this limit is reached, the clamping effect stops and the op amp responds open loop. The design equation directly preceding Figure 14, shows how to determine the clamping range. The equation solves for the input voltage band on each side GND. The mid-range is twice this voltage band. To illustrate the design process/implementation, a 3 kHz, Butterworth response, low-pass filter DAAF (Figure 10) is designed as follows: 1. Choose C1 = C3 = C = 1 nF 2. Choose R4 = R5 = 1 kΩ 3. Calculate Ra and R2 for the desired Fc as follows: 10012889 4. Calculate R3 for the desired Q. The desired Q for a Butterworth (Maximally Flat) response is 0.707 (45 degrees into the s-plane). R3 calculates as follows: 15 www.national.com LMV821 Single/ LMV822 Dual/ LMV824 Quad Application Note (Continued) 10012834 FIGURE 13. Tri-level Voltage Detector ∆v | ∆v | +Vo | OV -Vo LMV821 Single/ LMV822 Dual/ LMV824 Quad Application Note -VIN OV +VIN 10012835 FIGURE 14. X, Y Oscilloscope Trace showing VOUT vs VIN per the Circuit of Figure 13 www.national.com 16 5-Pin SC70-5/SOT23-5 8-Pin SO/MSOP 14-Pin SO/TSSOP 10012884 Top View 10012863 10012885 Top View Top View Ordering Information Temperature Range Package Industrial Packaging Marking Transport Media NSC Drawing A15 1k Units Tape and Reel MAA05 −40˚C to +85˚C 5-Pin SC-70-5 LMV821M7 LMV821M7X 5-Pin SOT23-5 LMV821M5 3k Units Tape and Reel A14 LMV821M5X 8-Pin SOIC LMV822M LMV822M LMV822MX 8-Pin MSOP LMV822MM LMV824M LMV822 LMV824MT Rails M08A 1k Units Tape and Reel MUA08A 3.5k Units Tape and Reel LMV824M LMV824MX 14-Pin TSSOP MF05A 2.5k Units Tape and Reel LMV822MMX 14-Pin SOIC 1k UnitsTape and Reel 3k Units Tape and Reel Rails M14A 2.5k Units Tape and Reel LMV824MT LMV824MTX Rails MTC14 2.5k Units Tape and Reel 17 www.national.com LMV821 Single/ LMV822 Dual/ LMV824 Quad Connection Diagrams LMV821 Single/ LMV822 Dual/ LMV824 Quad SC70-5 Tape and Reel Specification 10012896 SOT-23-5 Tape and Reel Specification Tape Format www.national.com Tape Section # Cavities Cavity Status Cover Tape Status Leader 0 (min) Empty Sealed (Start End) 75 (min) Empty Sealed Carrier 3000 Filled Sealed 250 Filled Sealed Trailer 125 (min) Empty Sealed (Hub End) 0 (min) Empty Sealed 18 LMV821 Single/ LMV822 Dual/ LMV824 Quad Tape Dimensions 10012897 8 mm Tape Size 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 19 www.national.com LMV821 Single/ LMV822 Dual/ LMV824 Quad Reel Dimensions 10012898 8 mm Tape Size www.national.com 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 20 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 LMV821 Single/ LMV822 Dual/ LMV824 Quad Physical Dimensions inches (millimeters) unless otherwise noted SC70-5 NS Package Number MAA05 SOT 23-5 NS Package Number MF05A 21 www.national.com LMV821 Single/ LMV822 Dual/ LMV824 Quad Physical Dimensions inches (millimeters) unless otherwise noted (Continued) 8-Pin Small Outline NS Package Number M08A 14-Pin Small Outline NS Package Number M14A www.national.com 22 LMV821 Single/ LMV822 Dual/ LMV824 Quad Physical Dimensions inches (millimeters) unless otherwise noted (Continued) 8-Pin MSOP NS Package Number MUA08A 14-Pin TSSOP NS Package Number MTC14 23 www.national.com LMV821 / LMV822 / LMV824 Single/Dual Quad Low Voltage, Low Power, RRO, 5 MHz Op Amps 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. 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. BANNED SUBSTANCE COMPLIANCE National Semiconductor certifies that the products and packing materials meet the provisions of the Customer Products Stewardship Specification (CSP-9-111C2) and the Banned Substances and Materials of Interest Specification (CSP-9-111S2) and contain no ‘‘Banned Substances’’ as defined in CSP-9-111S2. National Semiconductor Americas Customer Support Center Email: [email protected] Tel: 1-800-272-9959 www.national.com National Semiconductor Europe Customer Support Center Fax: +49 (0) 180-530 85 86 Email: [email protected] Deutsch Tel: +49 (0) 69 9508 6208 English Tel: +44 (0) 870 24 0 2171 Français Tel: +33 (0) 1 41 91 8790 National Semiconductor Asia Pacific Customer Support Center Email: [email protected] National Semiconductor Japan Customer Support Center Fax: 81-3-5639-7507 Email: [email protected] Tel: 81-3-5639-7560 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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