LMV924MT

LMV921 Single/ LMV922 Dual/ LMV924 Quad 1.8V, 1MHz, Low Power Operational Amplifiers with Rail-To-Rail Input and Output December 1999 LMV921 Single/ LMV922 Dual/ LMV924 Quad 1.8V, 1MHz, Low Power Operational Amplifiers with Rail-To-Rail Input and Output General Description The LMV921 Single/LMV922 Dual/LMV924 Quad are guaranteed to operate from +1.8V to +5.0V supply voltages and have rail-to-rail input and output. This rail-to-rail operation enables the user to make full use of the entire supply voltage range. The input common mode voltage range extends 300mV beyond the supplies and the output can swing rail-to-rail unloaded and within 100mV from the rail with 600Ω load at 1.8V supply. The LMV921/LMV922/LMV924 are optimized to work at 1.8V which make them ideal for portable two-cell battery-powered systems and single cell Li-Ion systems. The LMV921/LMV922/LMV924 exhibit excellent speed-power ratio, achieving 1MHz gain bandwidth product at 1.8V supply voltage with very low supply current. The LMV921/LMV922/LMV924 are capable of driving 600Ω load and up to 1000pF capacitive load with minimal ringing. The LMV921/LMV922/LMV924’s high DC gain of 100dB makes them suitable for low frequency applications. The LMV921 (Single) is offered in a space saving SC70–5 and SOT23–5 packages. The SC70–5 package is only 2.0X2.1X1.0mm. These small packages are ideal solutions for area constrained PC boards and portable electronics such as cellphones and PDAs. Features (Typical 1.8V Supply Values; Unless Otherwise Noted) n Guaranteed 1.8V, 2.7V and 5V specifications n Rail-to-Rail input & output swing — w/600Ω load 100 mV from rail — w/2kΩ load 30 mV from rail n VCM 300mV beyond rails n 90dB gain w/600Ω load n Supply current 145µA/amplifier n Gain bandwidth product 1MHz n LMV921 Maximum VOS 6mV n LMV921 available in Ultra Tiny, SC70-5 package n LMV922 available in MSOP-8 package n LMV924 available in TSSOP-14 package Applications n n n n n n n Cordless/cellular phones Laptops PDAs PCMCIA Portable/battery-powered electronic Equipment Supply current Monitoring Battery monitoring Connection Diagrams 5-Pin SC70-5/SOT23-5 8-Pin MSOP/SOIC DS100979-84 Top View DS100979-2 Top View © 1999 National Semiconductor Corporation DS100979 www.national.com LMV921 Single/ LMV922 Dual/ LMV924 Quad Connection Diagrams (Continued) 14-Pin TSSOP/SOIC DS100979-1 Top View Ordering Information Package Temperature Range Industrial −40˚C to +85˚C LMV921M7 LMV921M7X 5-Pin SOT23-5 8-Pin MSOP 14-Pin TSSOP 8-Pin SOIC 14-Pin SOIC LMV921M5 LMV921M5X LMV922MM LMV922MMX LMV924MT LMV924MTX LMV922M LMV922MX LMV924M LMV924MX Packaging Marking A21 A21 A29A A29A LMV922 LMV922 LMV924 LMV924 LMV922M LMV922M LMV924M LMV924M Transport Media NSC Drawing MAA05A 5-Pin SC70-5 1k Units Tape and Reel 3k Units Tape and Reel 1k Units Tape and Reel 3k Units Tape and Reel 1k Units Tape and Reel 3.5k Units Tape and Reel Rails 2.5k Units Tape and Reel Rails 2.5k Units Tape and Reel Rails 2.5k Units Tape and Reel MA05B MUA08A MTC14 M08A M14A www.national.com 2 LMV921 Single/ LMV922 Dual/ LMV924 Quad Absolute Maximum Ratings (Note 1) If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications. ESD Tolerance (Note 2) Machine Model Human Body Model Differential Input Voltage Supply Voltage (V+–V −) Output Short Circuit to V+ (Note 3) Output Short Circuit to V− (Note 3) Storage Temperature Range Junction Temperature (Note 4) Mounting Temp. Infrared or Convection (20 sec) 235˚C −65˚C to 150˚C 150˚C 100V 2000V Operating Ratings (Note 1) Supply Voltage Temperature Range Thermal Resistance (θJA) Ultra Tiny SC70-5 Package 5-Pin Surface Mount Tiny SOT23-5 Package 5-Pin Surface Mount MSOP Package 8-Pin Surface Mount TSSOP Package 14-Pin Surface Mount SOIC Package 8-Pin Surface Mount 14-Pin Surface Mount 440 ˚C/W 265 ˚C/W 235˚C/W 155˚C/W 175˚C/W 127˚C/W 1.5V to 5.0V −40˚C ≤ TJ ≤ 85˚C ± Supply Voltage 5.5V 1.8V DC Electrical Characteristics Unless otherwise specified, all limits guaranteed for TJ = 25˚C. V+ = 1.8V, V RL > 1 MΩ. Boldface limits apply at the temperature extremes. Symbol VOS Parameter Input Offset Voltage Condition LMV921 (Single) LMV922 (Dual) LMV924 (Quad) TCVOS IB IOS IS Input Offset Voltage Average Drift Input Bias Current Input Offset Current Supply Current LMV921 (Single) LMV922 (Dual) LMV924 (Quad) CMRR Common Mode Rejection Ratio 0 ≤ VCM ≤ 0.6V −0.2V ≤ VCM ≤ 0V 1.8V ≤ VCM ≤ 2.0V PSRR VCM Power Supply Rejection Ratio Input Common-Mode Voltage Range 1.8V ≤ V+ ≤ 5V, VCM = 0.5V For CMRR ≥ 50dB − = 0V, VCM = V+/2, VO = V+/2 and Typ (Note 5) −1.8 −1.8 1 12 2 145 330 560 82 74 78 -0.3 2.15 35 50 25 40 185 205 400 550 700 850 62 60 50 67 62 -0.2 0 2.0 1.8 77 73 80 75 65 61 68 63 dB min dB min V max V min dB min µA max Limits (Note 6) 6 8 8 9.5 Units mV max mV max µV/˚C nA max nA max AV Large Signal Voltage Gain LMV921 (Single) RL = 600Ω to 0.9V, VO = 0.2V to 1.6V, VCM = 0.5V RL = 2kΩ to 0.9V, VO = 0.2V to 1.6V, VCM = 0.5V 91 95 79 83 Large Signal Voltage Gain LMV922 (Dual) LMV924 (Quad) RL = 600Ω to 0.9V, VO = 0.2V to 1.6V, VCM = 0.5V RL = 2kΩ to 0.9V, VO = 0.2V to 1.6V, VCM = 0.5V dB min 3 www.national.com LMV921 Single/ LMV922 Dual/ LMV924 Quad 1.8V DC Electrical Characteristics Symbol VO Parameter Output Swing (Continued) − Unless otherwise specified, all limits guaranteed for TJ = 25˚C. V+ = 1.8V, V RL > 1 MΩ. Boldface limits apply at the temperature extremes. Condition RL = 600Ω to 0.9V VIN = ± 100mV = 0V, VCM = V+/2, VO = V+/2 and Typ (Note 5) 1.7 0.075 Limits (Note 6) 1.65 1.63 0.090 0.105 1.75 1.74 0.035 0.040 4 3.3 7 5 Units V min V max V min V max mA min mA min RL = 2kΩ to 0.9V VIN = ± 100mV 1.77 0.025 IO Output Short Circuit Current Sourcing, VO = 0V VIN = 100mV Sinking, VO = 1.8V VIN = −100mV 6 10 1.8V AC Electrical Characteristics Unless otherwise specified, all limits guaranteed for TJ = 25˚C. V+ = 1.8V, V RL > 1 MΩ. Boldface limits apply at the temperature extremes. Symbol SR GBW Φm Gm en in THD Parameter Slew Rate Gain-Bandwidth Product Phase Margin Gain Margin Input-Referred Voltage Noise Input-Referred Current Noise Total Harmonic Distortion Amp-to-Amp Isolation f = 1 kHz, VCM = 0.5V f = 1 kHz f = 1kHz, AV = +1 RL = 600kΩ, VIN = 1 VPP (Note 8) (Note 7) Conditions − = 0V, VCM = V+/2, VO = V+/2 and Typ (Note 5) 0.39 1 60 10 45 0.1 Units V/µs MHz Deg. dB 0.089 140 % dB 2.7V DC Electrical Characteristics Unless otherwise specified, all limits guaranteed for TJ = 25˚C. V+ = 2.7V, V RL > 1 MΩ. Boldface limits apply at the temperature extremes. Symbol VOS Parameter Input Offset Voltage Condition LMV921 (Single) LMV922 (Dual) LMV924 (Quad) TCVOS IB IOS Input Offset Voltage Average Drift Input Bias Current Input Offset Current − = 0V, VCM = V+/2, VO = V+/2 and Typ (Note 5) −1.6 −1.6 1 12 2 35 50 25 40 Limits (Note 6) 6 8 8 9.5 Units mV max mV max µV/˚C nA max nA max www.national.com 4 LMV921 Single/ LMV922 Dual/ LMV924 Quad 2.7V DC Electrical Characteristics Symbol IS Parameter Supply Current (Continued) − Unless otherwise specified, all limits guaranteed for TJ = 25˚C. V+ = 2.7V, V RL > 1 MΩ. Boldface limits apply at the temperature extremes. Condition LMV921 (Single) LMV922 (Dual) LMV924 (Quad) CMRR Common Mode Rejection Ratio 0V ≤ VCM ≤ 1.5V −0.2V ≤ VCM ≤ 0V 2.7V ≤ VCM < 2.9V PSRR VCM Power Supply Rejection Ratio Input Common-Mode Voltage Range 1.8V ≤ V+ ≤ 5V, VCM = 0.5V For CMRR ≥ 50dB = 0V, VCM = V+/2, VO = V+/2 and Typ (Note 5) 147 380 580 84 73 78 -0.3 3.050 Limits (Note 6) 190 210 450 600 750 900 62 60 50 67 62 -0.2 0 2.9 2.7 80 75 83 77 68 63 71 65 2.550 2.530 0.095 0.115 2.650 2.640 0.040 0.045 20 15 22 16 dB min dB min V max V min dB min uA max Units AV Large Signal Voltage Gain LMV921 (Single) RL = 600Ω to 1.35V, VO = 0.2V to 2.5V RL = 2kΩ to 1.35V, VO = 0.2V to 2.5V 98 103 86 91 2.62 0.075 Large Signal Voltage Gain LMV922 (Dual) LMV924 (Quad) VO Output Swing RL = 600Ω to 1.35V, VO = 0.2V to 2.5V RL = 2kΩ to 1.35V, VO = 0.2V to 2.5V RL = 600Ω to 1.35V VIN = ± 100mV dB min V min V max V min V max mA min mA min RL = 2kΩ to 1.35V VIN = ± 100mV 2.675 0.025 IO Output Short Circuit Current Sourcing, VO = 0V VIN = 100mV Sinking, VO = 2.7V VIN = −100mV 27 28 2.7V AC Electrical Characteristics Unless otherwise specified, all limits guaranteed for TJ = 25˚C. V+ = 2.7V, V RL > 1 MΩ. Boldface limits apply at the temperature extremes. Symbol SR GBW Φm Gm en in Slew Rate Gain-Bandwidth Product Phase Margin Gain Margin Input-Referred Voltage Noise Input-Referred Current Noise f = 1 kHz, VCM = 0.5V f = 1 kHz Parameter (Note 7) − = 0V, VCM = 1.0V, VO = 1.35V and Typ (Note 5) 0.41 1 65 10 45 0.1 Units V/µs MHz Deg. dB Conditions 5 www.national.com LMV921 Single/ LMV922 Dual/ LMV924 Quad 2.7V AC Electrical Characteristics Symbol THD Parameter Total Harmonic Distortion Amp-to-Amp Isolation (Continued) − Unless otherwise specified, all limits guaranteed for TJ = 25˚C. V+ = 2.7V, V RL > 1 MΩ. Boldface limits apply at the temperature extremes. = 0V, VCM = 1.0V, VO = 1.35V and Typ (Note 5) 0.077 140 Units % dB Conditions f = 1 kHz, AV = +1 RL = 600kΩ, VIN = 1 VPP (Note 8) 5V DC Electrical Characteristics Unless otherwise specified, all limits guaranteed for TJ = 25˚C. V+ = 5V, V RL > 1 MΩ.Boldface limits apply at the temperature extremes. Symbol VOS Parameter Input Offset Voltage Condition LMV921 (Single) LMV922 (Dual) LMV924 (Quad) TCVOS IB IOS IS Input Offset Voltage Average Drift Input Bias Current Input Offset Current Supply Current LMV921 (Single) LMV922 (Dual) LMV924 (Quad) CMRR Common Mode Rejection Ratio 0V ≤ VCM ≤ 3.8V −0.2V ≤ VCM ≤ 0V 5.0V ≤ VCM ≤ 5.2V PSRR VCM Power Supply Rejection Ratio Input Common-Mode Voltage Range 1.8V ≤ V+ ≤ 5V VCM = 0.5V For CMRR ≥ 50dB − = 0V, VCM = V+/2, VO = V+/2 and Typ (Note 5) −1.5 −1.5 1 12 2 160 400 750 86 72 78 -0.3 5.350 35 50 25 40 210 230 500 700 850 980 62 61 50 67 62 -0.2 0 5.2 5.0 86 82 89 85 72 68 77 73 dB min dB min V max V min dB min µA max Limits (Note 6) 6 8 8 9.5 Units mV max mV max µV/˚C nA max nA max AV Voltage Gain LMV921 (Single) RL = 600Ω to 2.5V VO = 0.2V to 4.8V RL = 2kΩ to 2.5V VO = 0.2V to 4.8V 104 108 90 96 Voltage Gain LMV922 (Dual) LMV924 (Quad) RL = 600Ω to 2.5V VO = 0.2V to 4.8V RL = 2kΩ to 2.5V VO = 0.2V to 4.8V dB min www.national.com 6 LMV921 Single/ LMV922 Dual/ LMV924 Quad 5V DC Electrical Characteristics Symbol VO Parameter Output Swing (Continued) − Unless otherwise specified, all limits guaranteed for TJ = 25˚C. V+ = 5V, V RL > 1 MΩ.Boldface limits apply at the temperature extremes. Condition RL = 600Ω to 2.5V VIN = ± 100mV = 0V, VCM = V+/2, VO = V+/2 and Typ (Note 5) 4.895 0.1 Limits (Note 6) 4.865 4.840 0.135 0.160 4.945 4.935 0.065 0.075 85 68 35 Units V min V max V min V max RL = 2kΩ to 2.5V VIN = ± 100mV 4.965 0.035 IO Output Short Circuit Current LMV921 Sourcing, VO = 0V VIN = 100mV LMV922, LMV924 Sourcing, VO = 0V VIN = 100mV Sinking, VO = 5V VIN = −100mV 98 60 mA min 75 65 45 mA min 5V AC Electrical Characteristics Unless otherwise specified, all limits guaranteed for TJ = 25˚C. V+ = 5V, V R L > 1 MΩ. Boldface limits apply at the temperature extremes. Symbol SR GBW Φm Gm en in THD Slew Rate Gain-Bandwidth Product Phase Margin Gain Margin Input-Referred Voltage Noise Input-Referred Current Noise Total Harmonic Distortion Amp-to-Amp Isolation f = 1 kHz, VCM = 1V f = 1 kHz f = 1 kHz, AV = +1 RL = 600Ω, VO = 1 VPP (Note 8) Parameter (Note 7) − = 0V, VCM = V+/2, VO = 2.5V and Typ (Note 5) 0.45 1 70 15 45 0.1 0.069 140 % dB Units V/µs MHz Deg. dB Conditions 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. 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 5V 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 1kHz to produce VO = 3VPP. 7 www.national.com LMV921 Single/ LMV922 Dual/ LMV924 Quad Simplified Schematic DS100979-A9 www.national.com 8 LMV921 Single/ LMV922 Dual/ LMV924 Quad Typical Performance Characteristics Supply Current vs. Supply Voltage (LMV921) Unless otherwise specified, VS = +5V, single supply, TA = 25˚C. Sourcing Current vs. Output Voltage Input Bias Current vs. VCM DS100979-A1 DS100979-D5 DS100979-B3 Sourcing Current vs. Output Voltage Sourcing Current vs. Output Voltage Sinking Current vs. Output Voltage DS100979-B8 DS100979-B2 DS100979-B4 Sinking Current vs. Output Voltage Sinking Current vs. Output Voltage Offset Voltage vs. Common Mode Voltage DS100979-B7 DS100979-B1 DS100979-D1 9 www.national.com LMV921 Single/ LMV922 Dual/ LMV924 Quad Typical Performance Characteristics TA = 25˚C. (Continued) Offset Voltage vs. Common Mode Voltage Unless otherwise specified, VS = +5V, single supply, Offset Voltage vs. Common Mode Voltage Output Voltage Swing vs. Supply Voltage DS100979-C9 DS100979-C8 DS100979-A2 Output Voltage Swing vs. Supply Voltage Gain and Phase Margin vs. Frequency Gain and Phase Margin vs. Frequency DS100979-A3 DS100979-A6 DS100979-A5 Gain and Phase Margin vs. Frequency Gain and Phase Margin vs. Frequency Gain and Phase Margin vs. Frequency DS100979-A4 DS100979-A8 DS100979-A7 www.national.com 10 LMV921 Single/ LMV922 Dual/ LMV924 Quad Typical Performance Characteristics TA = 25˚C. (Continued) CMRR vs. Frequency Unless otherwise specified, VS = +5V, single supply, PSRR vs. Frequency Input Voltage Noise vs. Frequency DS100979-C7 DS100979-C6 DS100979-F4 Input Current Noise vs. Frequency THD vs. Frequency THD vs. Frequency DS100979-F5 DS100979-D4 DS100979-D3 Slew Rate vs. Supply Voltage Small Signal Non-Inverting Response Small Signal Non-Inverting Response DS100979-99 DS100979-E3 DS100979-E2 11 www.national.com LMV921 Single/ LMV922 Dual/ LMV924 Quad Typical Performance Characteristics TA = 25˚C. (Continued) Small Signal Non-Inverting Response Unless otherwise specified, VS = +5V, single supply, Small Signal Inverting Response Small Signal Inverting Response DS100979-E4 DS100979-E0 DS100979-D9 Small Signal Inverting Response Small Signal Non-Inverting Response Small Signal Non-Inverting Response DS100979-D8 DS100979-E6 DS100979-E7 Small Signal Non-Inverting Response Small Signal Inverting Response Small Signal Inverting Response DS100979-E5 DS100979-G3 DS100979-G2 www.national.com 12 LMV921 Single/ LMV922 Dual/ LMV924 Quad Typical Performance Characteristics TA = 25˚C. (Continued) Small Signal Inverting Response Unless otherwise specified, VS = +5V, single supply, *Large Signal Non-Inverting Response *Large Signal Non-Inverting Response DS100979-G1 DS100979-F0 DS100979-E9 *Large Signal Non-Inverting Response *Large Signal Inverting Response *Large Signal Inverting Response DS100979-G0 DS100979-F9 DS100979-F8 *Large Signal Inverting Response *Large Signal Non-Inverting Response *Large Signal Non-Inverting Response DS100979-F7 DS100979-F1 DS100979-F2 *For large signal pulse response in the unity gain follower configuration, the input is 5mV below the positive rail and 5mV above the negative rail at 25˚C and 85˚C. At −40˚C, input is 10mV below the positive rail and 10mV above the negative rail. 13 www.national.com LMV921 Single/ LMV922 Dual/ LMV924 Quad Typical Performance Characteristics TA = 25˚C. (Continued) *Large Signal Inverting Response Unless otherwise specified, VS = +5V, single supply, *Large Signal Inverting Response *Large Signal Inverting Response DS100979-F6 DS100979-D6 DS100979-E1 *Large Signal Inverting Response Short Circuit Current vs. Temperature (sinking) Short Circuit Current vs. Temperature (sourcing) DS100979-D7 DS100979-B5 DS100979-B6 *For large signal pulse response in the unity gain follower configuration, the input is 5mV below the positive rail and 5mV above the negative rail at 25˚C and 85˚C. At −40˚C, input is 10mV below the positive rail and 10mV above the negative rail. www.national.com 14 LMV921 Single/ LMV922 Dual/ LMV924 Quad Application Note 1.0 Unity Gain Pulse Response Considerations The unity-gain follower is the most sensitive configuration to capacitive loading. The LMV921/LMV922/LMV924 family can directly drive 1nF in a unity-gain with minimal ringing. Direct capacitive loading reduces the phase margin of the amplifier. 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. The pulse response can be improved by adding a pull up resistor as shown in Figure 1 DS100979-41 FIGURE 1. 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 2. DS100979-59 FIGURE 3. Canceling the Voltage Offset Effect of Input Bias Current 3.0 Operating Supply Voltage The LMV921/LMV922/LMV924 family is guaranteed to operate from 1.8V to 5.0V. They will begin to function at power voltages as low as 1.2V at room temperature when unloaded. Start up voltage increases to 1.5V when the amplifier is fully loaded (600Ω to mid-supply). Below 1.2V the output voltage is not guaranteed to follow the input. Figure 4 below shows the output voltage vs. supply voltage with the LMV921/LMV922/LMV924 configured as a voltage follower at room temperature. DS100979-43 FIGURE 2. Using an Isolation Resistor to Drive Heavy Capacitive Loads 2.0 Input Bias Current Consideration The LMV921/LMV922/LMV924 family has a bipolar input stage. The typical input bias current (IB) is 12nA. The input bias current can develop a significant offset voltage. This offset is primarily due to IB flowing through the negative feedback resistor, RF. For example, if IB is 50nA (max room) and RF is 100kΩ, then an offset voltage of 5mV will develop (VOS = IBX RF). Using a compensation resistor (RC), as shown in Figure 3, cancels this affect. But the input offset current (IOS) will still contribute to an offset voltage in the same manner. DS100979-D2 FIGURE 4. 4.0 Input and Output Stage The rail-to-rail input stage of this family provides more flexibility for the designer. The LMV921/LMV922/LMV924 use a complimentary PNP and NPN input stage in which the PNP stage senses common mode voltage near V− and the NPN stage senses common mode voltage near V+. The transition from the PNP stage to NPN stage occurs 1V below V+. Since both input stages have their own offset voltage, the offset of the amplifier becomes a function of the input common mode voltage and has a crossover point at 1V below V+ as shown in the VOS vs. VCM curves. 15 www.national.com LMV921 Single/ LMV922 Dual/ LMV924 Quad Application Note (Continued) This VOS crossover point can create problems for both DC and AC coupled signals if proper care is not taken. For large input signals that include the VOS crossover point in their dynamic range, this will cause distortion in the output signal. One way to avoid such distortion is to keep the signal away from the crossover. For example, in a unity gain buffer configuration and with VS = 5V, a 5V peak-to-peak signal will contain input-crossover distortion while a 3V peak-to-peak signal centered at 1.5V will not contain input-crossover distortion as it avoids the crossover point. Another way to avoid large signal distortion is to use a gain of −1 circuit which avoids any voltage excursions at the input terminals of the amplifier. In that circuit, the common mode DC voltage can be set at a level away from the VOS cross-over point. For small signals, this transition in VOS shows up as a VCM dependent spurious signal in series with the input signal and can effectively degrade small signal parameters such as gain and common mode rejection ratio. To resolve this problem, the small signal should be placed such that it avoids the VOS crossover point. In addition to the rail-to-rail performance, the output stage can provide enough output current to drive 600Ω loads. Because of the high current capability, care should be taken not to exceed the 150˚C maximum junction temperature specification. 5.0 Power-Supply Considerations The LMV921/LMV922/LMV924 are ideally suited for use with most battery-powered systems. The LMV921/LMV922/ LMV924 operate from a single +1.8V to +5.0V supply and consumes about 145µA of supply current per Amplifier. A high power supply rejection ratio of 78dB allows the amplifier to be powered directly off a decaying battery voltage extending battery life. Table 1 lists a variety of typical battery types. Batteries have different voltage ratings; operating voltage is the battery voltage under nominal load. End-of-Life voltage is defined as the voltage at which 100% of the usable power of the battery is consumed. Table 1 also shows the typical operating time of the LMV921. 6.0 Distortion The two main contributors of distortion in LMV921/LMV922/ LMV924 family is: 1. Output crossover distortion occurs as the output transitions from sourcing current to sinking current. 2. Input crossover distortion occurs as the input switches from NPN to PNP transistor at the input stage. To decrease crossover distortion: 1. Increase the load resistance. This lowers the output crossover distortion but has no effect on the input crossover distortion. 2. Operate from a single supply with the output always sourcing current. 3. Limit the input voltage swing for large signals between ground and one volt below the positive supply. 4. Operate in inverting configuration to eliminate common mode induced distortion. 5. Avoid small input signal around the input crossover region. The discontinuity in the offset voltage will effect the gain, CMRR and PSRR. TABLE 1. LMV921 Characteristics with Typical Battery Systems. Battery Type Operating Voltage (V) 1.5 2.7 1.2 1.2 End-of-Life Voltage (V) 0.9 2.0 0.9 1.0 Capacity AA Size (mA h) 1000 1000 375 500 LMV921 Operating time (Hours) 6802 6802 2551 3401 Alkaline Lithium Ni - Cad NMH www.national.com 16 LMV921 Single/ LMV922 Dual/ LMV924 Quad Typical Applications 1.0 Half-wave Rectifier with Rail-To-Ground Output Swing Since the LMV921 input common mode range includes both positive and negative supply rails and the output can also swing to either supply, achieving half-wave rectifier functions in either direction is an easy task. All that is needed are two external resistors; there is no need for diodes or matched resistors. The half wave rectifier can have either positive or negative going outputs, depending on the way the circuit is arranged. In Figure 5 the circuit is referenced to ground, while in Figure 6 the circuit is biased to the positive supply. These configurations implement the half wave rectifier since the LMV921 can not respond to one-half of the incoming waveform. It can not respond to one-half of the incoming because the amplifier can not swing the output beyond either rail therefore the output disengages during this half cycle. During the other half cycle, however, the amplifier achieves a half wave that can have a peak equal to the total supply voltage. RI should be large enough not to load the LMV921. DS100979-C4 DS100979-C3 DS100979-C2 FIGURE 5. Half-Wave Rectifier with Rail-To-Ground Output Swing Referenced to Ground DS100979-C1 DS100979-C0 DS100979-B9 FIGURE 6. Half-Wave Rectifier with Negative-Going Output Referenced to VCC 17 www.national.com LMV921 Single/ LMV922 Dual/ LMV924 Quad Typical Applications (Continued) 2.0 Instrumentation Amplifier with Rail-To-Rail Input and Output Using three of the LMV924 Amplifiers, an instrumentation amplifier with rail-to-rail inputs and outputs can be made. Some manufacturers use a precision voltage divider array of 5 resistors to divide the common mode voltage to get a rail-to-rail input range. The problem with this method is that it also divides the signal, so in order to get unity gain, the amplifier must be run at high loop gains. This raises the noise and drift by the internal gain factor and lowers the input impedance. Any mismatch in these precision resistors reduces the CMRR as well. Using the LMV924 eliminates all of these problems. In this example, amplifiers A and B act as buffers to the differential stage. These buffers assure that the input imped- ance is very high and require no precision matched resistors in the input stage. They also assure that the difference amp is driven from a voltage source. This is necessary to maintain the CMRR set by the matching R1-R2 with R3-R4. The gain is set by the ratio of R2/R1 and R3 should equal R1 and R4 equal R2. With both rail-to-rail input and output ranges, the input and output are only limited by the supply voltages. Remember that even with rail-to-rail outputs, the output can not swing past the supplies so the combined common mode voltages plus the signal should not be greater that the supplies or limiting will occur. For additional applications, see National Semiconductor application notes AN–29, AN–31, AN–71, and AN–127. DS100979-G4 FIGURE 7. Rail-to-rail instrumentation amplifier www.national.com 18 LMV921 Single/ LMV922 Dual/ LMV924 Quad SC70–5 Tape Dimensions DS100979-96 SOT23–5 and SC70–5 Tape Format Tape Format Tape Section Leader (Start End) Carrier Trailer (Hub End) # Cavities 0 (min) 75 (min) 3000 250 125 (min) 0 (min) Cavity Status Empty Empty Filled Filled Empty Empty Cover Tape Status Sealed Sealed Sealed Sealed Sealed Sealed 19 www.national.com LMV921 Single/ LMV922 Dual/ LMV924 Quad SOT23–5 Tape Dimensions DS100979-97 8 mm Tape Size 0.130 (3.3) DIM A 0.124 (3.15) DIM Ao 0.130 (3.3) DIM B 0.126 (3.2) DIM Bo 0.138 ± 0.002 (3.5 ± 0.05) DIM F 0.055 ± 0.004 (1.4 ± 0.11) DIM Ko 0.157 (4) DIM P1 0.315 ± 0.012 (8 ± 0.3) DIM W www.national.com 20 LMV921 Single/ LMV922 Dual/ LMV924 Quad SOT23–5 and SC70–5 Reel Dimensions DS100979-98 8 mm Tape Size 7.00 330.00 A 0.059 0.512 0.795 2.165 1.50 B 13.00 20.20 55.00 C D N 0.331 + 0.059/−0.000 8.40 + 1.50/−0.00 W1 0.567 14.40 W2 W1+ 0.078/−0.039 W1 + 2.00/−1.00 W3 21 www.national.com LMV921 Single/ LMV922 Dual/ LMV924 Quad Physical Dimensions inches (millimeters) unless otherwise noted SC70-5 Order Number LMV921M7 or LMV921M7X NS Package Number MAA05A www.national.com 22 LMV921 Single/ LMV922 Dual/ LMV924 Quad Physical Dimensions inches (millimeters) unless otherwise noted (Continued) SOT 23-5 Order Number LMV921M5 or LMV921M5X NS Package Number MA05B 23 www.national.com LMV921 Single/ LMV922 Dual/ LMV924 Quad Physical Dimensions inches (millimeters) unless otherwise noted (Continued) 8-Pin MSOP Order Number LMV922MM or LMV922MMX NS Package Number MUA08A www.national.com 24 LMV921 Single/ LMV922 Dual/ LMV924 Quad Physical Dimensions inches (millimeters) unless otherwise noted (Continued) 14-Pin TSSOP Order Number LMV924MT or LMV924MTX NS Package Number MTC14 25 www.national.com LMV921 Single/ LMV922 Dual/ LMV924 Quad Physical Dimensions inches (millimeters) unless otherwise noted (Continued) 8-Pin SOIC Order Number LMV922M or LMV922MX NS Package Number M08A www.national.com 26 LMV921 Single/ LMV922 Dual/ LMV924 Quad 1.8V, 1MHz, Low Power Operational Amplifiers with Rail-To-Rail Input and Output Physical Dimensions inches (millimeters) unless otherwise noted (Continued) 14-Pin SOIC Order Number LMV924M or LMV924MX NS Package Number MA14 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) 1 80-530 85 86 Email: europe.support@nsc.com 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. 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