LMV651/LMV652/LMV654 12 MHz, Low Voltage, Low Power Amplifier General Description Features National’s LMV651/LMV652/LMV654 are high performance, low power operational amplifier ICs implemented with National's advanced VIP50 process. This family of parts features 12 MHz of bandwidth while consuming only 116 μA of current, which is an exceptional bandwidth to power ratio in this op amp class. The LMV651/LMV652/LMV654 are unity gain stable and provide an excellent solution for general purpose amplification in low voltage, low power applications. This family of low voltage, low power amplifiers provides superior performance and economy in terms of power and space usage. These op amps have a maximum input offset voltage of 1.5 mV, a rail-to-rail output stage and an input common-mode voltage range that includes ground. The LMV651/ LMV652/LMV654 provide a PSRR of 95 dB, a CMRR of 100 dB and a total harmonic distortion (THD) of 0.003% at 1 kHz frequency and 2 kΩ load. The operating supply voltage range for this family of parts is from 2.7V and 5.5V. These op amps can operate over a wide temperature range (-40°C to +125°C) making these op amps ideal for automotive applications, sensor applications and portable equipment applications. The LMV651 is offered in the ultra tiny 5-Pin SC70 package, which is about half the size of the 5-Pin SOT23. The LMV652 is offered in an 8-Pin MSOP package. The LMV654 is offered in a 14-Pin TSSOP package. (Typical 5V supply, unless otherwise noted) ■ Guaranteed 3.0V and 5.0V performance ■ Low power supply current — LMV651 116 μA — LMV652 118 μA per amplifier — LMV654 122 μA per amplifier 12 MHz ■ High unity gain bandwidth 1.5 mV ■ Max input offset voltage 100 dB ■ CMRR 95 dB ■ PSRR 17 nV/ ■ Input referred voltage noise 120 mV from rail ■ Output swing with 2 kΩ load 0.003% @ 1 kHz, 2 kΩ ■ Total harmonic distortion −40°C to 125°C ■ Temperature range 20123861 High Gain Wide Bandwidth Inverting Amplifier © 2007 National Semiconductor Corporation 201238 Applications ■ ■ ■ ■ Portable equipment Automotive Battery powered systems Sensors and Instrumentation 20123806 Open Loop Gain and phase vs. Frequency www.national.com LMV651/LMV652/LMV654 12 MHz, Low Voltage, Low Power Amplifier March 2007 LMV651/LMV652/LMV654 Soldering Information 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) Human Body Model Machine Model Differential Input VID Supply Voltage (VS = V+ - V−) Input/Output Pin Voltage Storage Temperature Range Junction Temperature (Note 3) Infrared or Convection (20 sec) Wave Soldering Lead Temp (10 235°C sec) 260°C Operating Ratings 2000V (Note 1) Temperature Range (Note 3) Supply Voltage 100V ±0.3V 6V V+ +0.3V, V− −0.3V −65°C to +150°C +150°C −40°C to 125°C 2.7V to 5.5V Package Thermal Resistance (θJA)(Note 3) 5-Pin SC70 14-Pin TSSOP 456°C/W 160°C/W 3V DC Electrical Characteristics Unless otherwise specified, all limits are guaranteed for TA = 25°C, V+ = 3V, V− = 0V, VO = VCM = V+/2, and RL > 1 MΩ. Boldface limits apply at the temperature extremes. Symbol Parameter VOS Input Offset Voltage TC VOS Input Offset Average Drift IB Input Bias Current IOS Input Offset Current CMRR Common Mode Rejection Ratio PSRR Power Supply Rejection Ratio Conditions Min (Note 5) ±1.5 2.7 mV μV/°C 80 120 nA 2.2 15 nA 0 ≤ VCM≤ 2.0 V dB 3.0 ≤ V+ ≤ 5V, VCM = 0.5 87 81 95 dB 2.7 ≤ V+ ≤ 5.5V, VCM = 0.5 87 81 95 0 0 AVOL Large Signal Voltage Gain 0.3 ≤ VO ≤ 2.7, RL = 2 kΩ to V+/2 CMRR ≥ 60 dB 0.4 ≤ VO ≤ 2.6, RL = 2 kΩ to V+/2 0.3 ≤ VO ≤ 2.7, RL = 10 kΩ to V+/2 0.4 ≤ VO ≤ 2.6, RL = 10 kΩ to V+/2 2.1 2.1 80 76 85 86 83 93 80 95 120 RL = 10 kΩ to V+/2 45 50 60 RL = 2 kΩ to V+/2 95 110 125 RL = 10 kΩ to V+/2 60 65 75 Maximum Continuous Output Current Sourcing (Note 8) 17 Sinking (Note 8) 25 Supply Current per Amplifier LMV651 115 LMV652 118 LMV654 122 AV = +1, 10% to 90% (Note 7) 3.0 SR Slew Rate GBW Gain Bandwidth Product en Input-Referred Voltage Noise www.national.com 12 f = 100 kHz 17 f = 1 kHz 17 2 V dB RL = 2 kΩ to V+/2 Output Swing Low IS 0.1 100 CMRR ≥ 75 dB ISC Units 87 80 Input Common-Mode Voltage Range Output Swing High Max (Note 5) 6.6 (Note 6) CMVR VO Typ (Note 4) mV from rail mA 140 175 μA V/μs MHz nV/ in Parameter Input-Referred Current Noise THD Total Harmonic Distortion Conditions Min (Note 5) Typ (Note 4) f = 100 kHz 0.1 f = 1 kHz 0.15 f = 1 kHz, AV = 2, RL = 2 kΩ 0.003 Max (Note 5) Units pA/ % 5V DC Electrical Characteristics Unless otherwise specified, all limits are guaranteed for TJ = 25°C, V+ = 5V, V− = 0V,VO = VCM = V+/2, and RL > 1 MΩ. Boldface limits apply at the temperature extremes. Symbol Parameter Conditions Min (Note 5) Typ (Note 4) Max (Note 5) Units ±1.5 2.7 mV VOS Input Offset Voltage 0.1 TC VOS Input Offset Average Drift 6.6 IB Input Bias Current IOS Input Offset Current CMRR Common Mode Rejection Ratio 0 ≤ VCM≤ 4.0 V 90 83 100 dB PSRR Power Supply Rejection Ratio 3V ≤ V+ ≤ 5V, VCM = 0.5V 87 81 95 dB 2.7V ≤ V+ ≤ 5.5V, VCM = 0.5V 87 81 95 (Note 6) 80 120 nA 2.2 15 nA CMVR Input Common-Mode Voltage Range CMRR ≥ 80 dB 0 0 AVOL Large Signal Voltage Gain 0.3 ≤ VO ≤ 4.7V, RL = 2 kΩ to V+/2 79 76 84 0.3 ≤ VO ≤ 4.7V, RL = 10 kΩ to V+/2 87 84 94 CMRR ≥ 68 dB 0.4 ≤ VO ≤ 4.6, RL = 2 kΩ to V+/2 0.4 ≤ VO ≤ 4.6, RL = 10 kΩ to V+/2 VO Output Swing High IS dB 140 185 RL = 10 kΩ to V+/2 75 90 120 RL = 2 kΩ to V+/2 110 130 150 RL = 10 kΩ to V+/2 70 80 95 Maximum Continuous Output Current Sourcing (Note 8) 18.5 Sinking (Note 8) 25 Supply Current per Amplifier LMV651 116 LMV652 118 LMV654 122 AV = +1, VO = 1 VPP 10% to 90% (Note 7) 3.0 V/μs 12 MHz Slew Rate GBW Gain Bandwidth Product en Input-Referred Voltage Noise THD V 120 SR in 4.1 4.1 RL = 2 kΩ to V+/2 Output Swing Low ISC μV/°C Input-Referred Current Noise Total Harmonic Distortion f = 100 kHz 17 f = 1 kHz 17 f = 100 kHz 0.1 f = 1 kHz 0.15 f = 1 kHz, AV = 2, RL = 2 kΩ 0.003 3 mV from rail mA 140 175 μA nV/ pA/ % www.national.com LMV651/LMV652/LMV654 Symbol LMV651/LMV652/LMV654 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 Tables. Note 2: Human Body Model, applicable std. MIL-STD-883, Method 3015.7. Machine Model, applicable std. JESD22-A115-A (ESD MM std. of JEDEC) Field-Induced Charge-Device Model, applicable std. JESD22-C101-C (ESD FICDM std. of JEDEC). Note 3: The maximum power dissipation is a function of TJ(MAX, θJA, and TA. The maximum allowable power dissipation at any ambient temperature is PD = (TJ(MAX) - TA)/ θJA. All numbers apply for packages soldered directly onto a PC board. Note 4: Typical values represent the most likely parametric norm as determined at the time of characterization. Actual typical values may vary over time and will also depend on the application and configuration. The typical values are not tested and are not guaranteed on shipped production material. Note 5: Limits are 100% production tested at 25°C. Limits over the operating temperature range are guaranteed through correlations using Statistical Quality Control (SQC) method. Note 6: Positive current corresponds to current flowing into the device. Note 7: Slew rate is the average of the rising and falling slew rates. Note 8: The part is not short circuit protected and is not recommended for operation with low resistive loads. Typical sourcing and sinking output current curves are provided in the Typical Performance Characteristics and should be consulted before designing for heavy loads. Connection Diagrams 5-Pin SC70 8-Pin MSOP 14-Pin TSSOP 20123802 Top View 20123803 Top View 20123804 Top View Ordering Information Package 5-Pin SC70 8-Pin MSOP 14-Pin TSSOP www.national.com Part Number LMV651MG LMV651MGX LMV652MM LMV652MMX LMV654MT LMV654MTX Package Marking Transport Media 1k Units Tape and Reel A93 3k Units Tape and Reel 1k Units Tape and Reel AB3A 3.5k Units Tape and Reel 94 Units/Rail LMV654MT 2.5k Units Tape and Reel 4 NSC Drawing MAA05A MUA08A MTC14 Unless otherwise Specified, TA= 25°C, VS= 5V, V+= 5V, V−= 0V, VCM= VS/2 Supply Current vs. Supply Voltage (LMV651) Supply Current per Channel vs. Supply Voltage (LMV652) 20123865 20123834 Supply Current per Channel vs. Supply Voltage (LMV654) VOS vs. VCM 20123864 20123825 VOS vs. VCM VOS vs. Supply Voltage 20123826 20123821 5 www.national.com LMV651/LMV652/LMV654 Typical Performance Characteristics LMV651/LMV652/LMV654 IBIAS vs. VCM IBIAS vs. VCM 20123823 20123824 IBIAS vs. Supply Voltage Positive Output Swing vs. Supply Voltage 20123822 20123828 Negative Output Swing vs. Supply Voltage Positive Output Swing vs. Supply Voltage 20123829 www.national.com 20123827 6 LMV651/LMV652/LMV654 Negative Output Swing vs. Supply Voltage Sourcing Current vs. Output Voltage 20123832 20123830 Sinking Current vs. Output Voltage (LMV651) Sinking Current vs. Output Voltage (LMV652) 20123833 20123866 Sinking Current vs. Output Voltage (LMV654) Open Loop Gain and Phase with Capacitive Load 20123863 20123811 7 www.national.com LMV651/LMV652/LMV654 Open Loop Gain and Phase with Resistive Load Phase Margin vs. Capacitive Load (Stability) 20123812 20123813 Input Referred Voltage Noise vs. Frequency Input Referred Current Noise vs. Frequency 20123814 20123815 Slew Rate vs. Supply Voltage THD+N vs. VOUT 20123809 20123816 www.national.com 8 LMV651/LMV652/LMV654 THD+N vs. VOUT THD+N vs. Frequency 20123807 20123810 THD+N vs. Frequency Small Signal Transient Response 20123818 20123808 Small Signal Transient Response Large Signal Transient Response 20123817 20123819 9 www.national.com LMV651/LMV652/LMV654 PSRR vs. Frequency CMRR vs. Frequency 20123835 20123836 Closed Loop Output Impedance vs. Frequency 20123837 www.national.com 10 LMV651/LMV652/LMV654 Application Information ADVANTAGES OF THE LMV651/LMV652/LMV654 Low Voltage and Low Power Operation The LMV651/LMV652/LMV654 have performance guaranteed at supply voltages of 3V and 5V. These parts are guaranteed to be operational at all supply voltages between 2.7V and 5.5V. The LMV651 draws a low supply current of 116 μA, the LMV652 draws 118 μA/channel and the LMV654 draws 122 μA/channel. This family of op amps provides the low voltage and low power amplification which is essential for portable applications. Wide Bandwidth Despite drawing the very low supply current of 116 µA, the LMV651/LMV652/LMV654 manage to provide a wide unity gain bandwidth of 12 MHz. This is easily one of the best bandwidth to power ratios ever achieved, and allows these op amps to provide wideband amplification while using the minimum amount of power. This makes this family of parts ideal for low power signal processing applications such as portable media players and other accessories. 20123859 FIGURE 1. Gain vs. Frequency for an Op Amp An op amp, ideally, has a dominant pole close to DC, which causes its gain to decay at the rate of 20 dB/decade with respect to frequency. If this rate of decay, also known as the rate of closure (ROC), remains the same until the op amp's unity gain bandwidth, the op amp is stable. If, however, a large capacitance is added to the output of the op amp, it combines with the output impedance of the op amp to create another pole in its frequency response before its unity gain frequency ( Figure 1 ). This increases the ROC to 40 dB/decade and causes instability. In such a case a number of techniques can be used to restore stability to the circuit. The idea behind all these schemes is to modify the frequency response such that it can be restored to an ROC of 20 dB/decade, which ensures stability. Low Input Referred Noise The LMV651/LMV652/LMV654 provide a flatband input re, which is signififerred voltage noise density of 17 nV/ cantly better than the noise performance expected from a low power op amp. These op amps also feature exceptionally low 1/f noise, with a very low 1/f noise corner frequency of 4 Hz. This makes these parts ideal for low power applications which require decent noise performance, such as PDAs and portable sensors. Ground Sensing and Rail-to-Rail Output The LMV651/LMV652/LMV654 each have a rail-to-rail output stage, which provides the maximum possible output dynamic range. This is especially important for applications requiring a large output swing. The input common mode range of this family of devices includes the negative supply rail which allows direct sensing at ground in a single supply operation. In The Loop Compensation Figure 2 illustrates a compensation technique, known as ‘in the loop’ compensation, that employs an RC feedback circuit within the feedback loop to stabilize a non-inverting amplifier configuration. A small series resistance, RS, is used to isolate the amplifier output from the load capacitance, CL, and a small capacitance, CF, is inserted across the feedback resistor to bypass CL at higher frequencies. Small Size The small footprint of the packages for the LMV651/LMV652/ LMH654 saves space on printed circuit boards, and enables the design of smaller and more compact electronic products. Long traces between the signal source and the op amp make the signal path susceptible to noise. By using a physically smaller package, these op amps can be placed closer to the signal source, reducing noise pickup and enhancing signal integrity. STABILITY OF OP AMP CIRCUITS Stability and Capacitive Loading If the phase margin of the LMV651/LMV652/LMV654 is plotted with respect to the capacitive load (CL) at its output, it is seen that the phase margin reduces significantly if CL is increased beyond 100 pF. This is because the op amp is designed to provide the maximum bandwidth possible for a low supply current. Stabilizing it for higher capacitive loads would have required either a drastic increase in supply current, or a large internal compensation capacitance, which would have reduced the bandwidth of the op amp. Hence, if these devices are to be used for driving higher capacitive loads, they would have to be externally compensated. 20123858 FIGURE 2. In the Loop Compensation 11 www.national.com LMV651/LMV652/LMV654 The values for RS and CF are decided by ensuring that the zero attributed to CF lies at the same frequency as the pole attributed to CL. This ensures that the effect of the second pole on the transfer function is compensated for by the presence of the zero, and that the ROC is maintained at 20 dB/ decade. For the circuit shown in Figure 2 the values of RS and CF are given by Equation 1. Values of RS and CF required for maintaining stability for different values of CL, as well as the phase margins obtained, are shown in Table 1. RF and RIN are taken to be 10 kΩ, RL is 2 kΩ, while ROUT is taken as 340Ω. than 0.003% distortion. Two amplifier circuits are shown in Figure 4 and Figure 5. Figure 4 is an inverting amplifier, with a 100 kΩ feedback resistor, R2, and a 1 kΩ input resistor, R1, and provides a gain of −100. With the LMV651/LMV652/ LMV654 these circuits can provide gain of −100 with a −3 dB bandwidth of 120 kHz, for a quiescent current as low as 116 μA. Similarly, the circuit in Figure 5, a non-inverting amplifier with a gain of 1001, can provide that gain with a −3 dB bandwidth of 12 kHz, for a similar low quiescent power dissipation. Coupling capacitors CC1 and CC2 can be added to isolate the circuit from DC voltages, while RB1 and RB2 provide DC biasing. A feedback capacitor CF can also be added to improve compensation. (1) TABLE 1. CL (pF) RS (Ω) CF (pF) Phase Margin (°) 150 340 15 39.4 200 340 20 34.6 250 340 25 31.1 Although this methodology provides circuit stability for any load capacitance, it does so at the price of bandwidth. The closed loop bandwidth of the circuit is now limited by RF and CF. Compensation By External Resistor In some applications it is essential to drive a capacitive load without sacrificing bandwidth. In such a case, in the loop compensation is not viable. A simpler scheme for compensation is shown in Figure 3. A resistor, RISO, is placed in series between the load capacitance and the output. This introduces a zero in the circuit transfer function, which counteracts the effect of the pole formed by the load capacitance, and ensures stability. The value of RISO to be used should be decided depending on the size of CL and the level of performance desired. Values ranging from 5Ω to 50Ω are usually sufficient to ensure stability. A larger value of RISO will result in a system with lesser ringing and overshoot, but will also limit the output swing and the short circuit current of the circuit. 20123861 FIGURE 4. High Gain Inverting Amplifier 20123862 FIGURE 5. High Gain Non-Inverting Amplifier 20123860 FIGURE 3. Compensation by Isolation Resistor ACTIVE FILTERS With a wide unity gain bandwidth of 12 MHz, low input referred noise density and a low power supply current, the LMV651/ LMV652/LMV654 are well suited for low-power filtering applications. Active filter topologies, like the Sallen-Key low pass filter shown in Figure 6, are very versatile, and can be used to design a wide variety of filters (Chebyshev, Butterworth or Bessel). The Sallen-Key topology, in particular, can be used to attain a wide range of Q, by using positive feedback to reject the undesired frequency range. Typical Applications HIGH GAIN LOW POWER AMPLIFIERS With a low supply current, low power operation, and low harmonic distortion, the LMV651/LMV652/LMV654 are ideal for wide-bandwidth, high gain amplification. The wide unity gain bandwidth allows these parts to provide large gain over a wide frequency range, while driving loads as low as 2 kΩ with less www.national.com 12 LMV651/LMV652/LMV654 In the circuit shown in Figure 6, the two capacitors appear as open circuits at lower frequencies and the signal is simply buffered to the output. At high frequencies the capacitors appear as short circuits and the signal is shunted to ground by one of the capacitors before it can be amplified. Near the cutoff frequency, where the impedance of the capacitances is on the same order as Rg and Rf, positive feedback through the other capacitor allows the circuit to attain the desired Q. The ratio of the two resistors, m2, provides a knob to control the value of Q obtained. 20123820 FIGURE 6. 13 www.national.com LMV651/LMV652/LMV654 Physical Dimensions inches (millimeters) unless otherwise noted 5-Pin SC70 NS Package Number MAA05A 8-Pin MSOP NS Package Number MUA08A www.national.com 14 LMV651/LMV652/LMV654 14-Pin TSSOP NS Package Number MTC14 15 www.national.com LMV651/LMV652/LMV654 12 MHz, Low Voltage, Low Power Amplifier Notes THE CONTENTS OF THIS DOCUMENT ARE PROVIDED IN CONNECTION WITH NATIONAL SEMICONDUCTOR CORPORATION (“NATIONAL”) PRODUCTS. NATIONAL MAKES NO REPRESENTATIONS OR WARRANTIES WITH RESPECT TO THE ACCURACY OR COMPLETENESS OF THE CONTENTS OF THIS PUBLICATION AND RESERVES THE RIGHT TO MAKE CHANGES TO SPECIFICATIONS AND PRODUCT DESCRIPTIONS AT ANY TIME WITHOUT NOTICE. NO LICENSE, WHETHER EXPRESS, IMPLIED, ARISING BY ESTOPPEL OR OTHERWISE, TO ANY INTELLECTUAL PROPERTY RIGHTS IS GRANTED BY THIS DOCUMENT. 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