LMV552MM

LMV551/LMV552/LMV554 3 MHz, Micropower RRO Amplifiers October 8, 2008 LMV551/LMV552/LMV554 3 MHz, Micropower RRO Amplifiers General Description The LMV551/LMV552/LMV554 are high performance, low power operational amplifiers implemented with National’s advanced VIP50 process. They feature 3 MHz of bandwidth while consuming only 37 μA of current per amplifier, which is an exceptional bandwidth to power ratio in this op amp class. These amplifiers are unity gain stable and provide an excellent solution for low power applications requiring a wide bandwidth. The LMV551/LMV552/LMV554 have a rail-to-rail output stage and an input common mode range that extends below ground. The LMV551/LMV552/LMV554 have an operating supply voltage range from 2.7V to 5.5V. These amplifiers can operate over a wide temperature range (−40°C to 125°C) making them a great choice for automotive applications, sensor applications as well as portable instrumentation applications. The LMV551 is offered in the ultra tiny 5-Pin SC70 and 5-Pin SOT-23 package. The LMV552 is offered in an 8-Pin MSOP package. The LMV554 is offered in the 14-Pin TSSOP. Features (Typical 5V supply, unless otherwise noted.) ■ Guaranteed 3V and 5.0V performance 3 MHz ■ High unity gain bandwidth 37 µA ■ Supply current (per amplifier) 93 dB ■ CMRR 90 dB ■ PSRR 1 V/µs ■ Slew rate 70 mV from rail ■ Output swing with 100 kΩ load 0.003% @ 1 kHz, 2 kΩ ■ Total harmonic distortion −40°C to 125°C ■ Temperature range Applications ■ ■ ■ ■ ■ Active filter Portable equipment Automotive Battery powered systems Sensors and Instrumentation Typical Application 20152601 20152613 Open Loop Gain and Phase vs. Frequency © 2008 National Semiconductor Corporation 201526 www.national.com LMV551/LMV552/LMV554 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 LMV551/LMV552/LMV554 Machine Model LMV551 LMV552/LMV554 VIN Differential (@ V+ = 5V) Supply Voltage (V+ - V−) Voltage at Input/Output pins Storage Temperature Range Junction Temperature (Note 3) Soldering Information Infrared or Convection (20 sec) Wave Soldering Lead Temp. (10 sec) 150°C 235°C 260°C Operating Ratings 2 KV 100V 250V ±2.5V 6V V+ +0.3V, V− −0.3V −65°C to 150°C Temperature Range (Note 3) Supply Voltage (V+ – V−) (Note 1) −40°C to 125°C 2.7V to 5.5V 456°C/W 234°C/W 235°C/W 160°C/W Package Thermal Resistance (θJA (Note 3)) 5-Pin SC70 5-Pin SOT-23 8-Pin MSOP 14-Pin TSSOP 3V Electrical Characteristics Unless otherwise specified, all limits are guaranteed for TA = 25°C, V+ = 3V, V− = 0V, VCM = V+/2 = VO. Boldface limits apply at the temperature extremes. (Note 4) Symbol VOS TC VOS IB IOS CMRR PSRR Parameter Input Offset Voltage Input Offset Average Drift Input Bias Current Input Offset Current Common Mode Rejection Ratio 0V ≤ VCM 2.0V Power Supply Rejection Ratio 3.0 ≤ V+ ≤ 5V, VCM = 0.5V LMV551/LMV552 LMV554 2.7 ≤ V+ ≤ 5.5V, VCM = 0.5V LMV551/LMV552 LMV554 CMVR AVOL Input Common-Mode Voltage Range Large Signal Voltage Gain CMRR ≥ 68 dB 0.4 ≤ VO ≤ 2.6, RL = 100 kΩ to V+/2 74 72 80 78 78 76 80 78 78 76 0 0 LMV551/LMV552 LMV554 81 78 79 77 71 68 (Note 7) Conditions Min (Note 6) Typ (Note 5) 1 3.3 20 1 92 38 20 Max (Note 6) 3 4.5 Units mV μV/°C nA nA dB 92 dB 92 CMRR ≥ 60 dB 2.1 2.1 V 90 dB 80 40 85 50 95 10 25 48 58 100 120 65 77 110 130 mA mV from rail 0.4 ≤ VO ≤ 2.6, RL = 10 kΩ to V+/2 VO Output Swing High RL = 100 kΩ to V+/2 RL = 10 kΩ to V+/2 Output Swing Low RL = 100 kΩ to V+/2 RL = 10 kΩ to V+/2 ISC Output Short Circuit Current Sourcing (Note 9) Sinking (Note 9) www.national.com 2 LMV551/LMV552/LMV554 Symbol IS SR Φm GBW en in THD Parameter Supply Current per Amplifier Slew Rate Phase Margin Gain Bandwidth Product Input-Referred Voltage Noise Input-Referred Current Noise Total Harmonic Distortion f = 100 kHz f = 1 kHz f = 100 kHz f = 1 kHz Conditions Min (Note 6) Typ (Note 5) 34 Max (Note 6) 42 52 Units μA V/μs Deg MHz nV/ pA/ % AV = +1, 10% to 90% (Note 8) RL = 10 kΩ, CL = 20 pF 1 75 3 70 70 0.1 0.15 0.003 f = 1 kHz, AV = 2, RL = 2 kΩ 5V Electrical Characteristics Unless otherwise specified, all limits are guaranteed for TA = 25°C, V+ = 5V, V− = 0V, VCM = V+/2 = VO. Boldface limits apply at the temperature extremes. Symbol VOS TC VOS IB IOS CMRR PSRR Parameter Input Offset Voltage Input Offset Average Drift Input Bias Current Input Offset Current Common Mode Rejection Ratio Power Supply Rejection Ratio 0 ≤ VCM ≤ 4.0V 3V ≤ V+ ≤ 5V to VCM = 0.5V 2.7V ≤ V+ ≤ 5.5V to VCM = 0.5V CMVR AVOL Input Common-Mode Voltage Range Large Signal Voltage Gain CMRR ≥ 68 dB CMRR ≥ 60 dB 0.4 ≤ VO ≤ 4.6, RL = 100 kΩ to V+/2 0.4 ≤ VO ≤ 4.6, RL = 10 kΩ to V+/2 VO Output Swing High RL = 100 kΩ to V+/2 RL = 10 kΩ to V+/2 Output Swing Low RL = 100 kΩ to V+/2 RL = 10 kΩ to V+/2 ISC IS SR Φm GBW Output Short Circuit Current Supply Current Per Amplifier Slew Rate Phase Margin Gain Bandwidth Product AV = +1, VO = 1 VPP 10% to 90% (Note 8) RL = 10 kΩ, CL = 20 pF Sourcing (Note 9) Sinking (Note 9) 76 74 78 75 78 75 0 0 78 75 75 72 90 80 70 125 60 110 10 25 37 1 75 3 46 54 92 122 155 210 70 82 130 155 mA μA V/μs Deg MHz mV from rail dB (Note 7) Conditions Min (Note 6) Typ (Note 5) 1 3.3 20 1 93 90 90 4.1 4.1 dB 38 20 Max (Note 6) 3.0 4.5 Units mV μV/°C nA nA dB V 3 www.national.com LMV551/LMV552/LMV554 Symbol en in THD Parameter Input-Referred Voltage Noise Input-Referred Current Noise Total Harmonic Distortion f = 100 kHz f = 1 kHz f = 100 kHz f = 1 kHz Conditions Min (Note 6) Typ (Note 5) 70 70 0.1 0.15 0.003 Max (Note 6) Units nV/ pA/ % f = 1 kHz, AV = 2, RL = 2 kΩ 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. 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: Electrical Table values apply only for factory testing conditions at the temperature indicated. Factory testing conditions result in very limited self-heating of the device such that TJ = TA. No guarantee of parametric performance is indicated in the electrical tables under conditions of internal self-heating where TJ > TA. Note 5: 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 6: 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 7: Positive current corresponds to current flowing into the device. Note 8: Slew rate is the average of the rising and falling slew rates. Note 9: The part is not short circuit protected and is not recommended for operation with heavy resistive loads. Connection Diagrams 5-Pin SC70/ SOT-23 8-Pin MSOP 14-Pin TSSOP 20152602 Top View 20152611 Top View Top View 20152610 Ordering Information Package 5-Pin SC70 5-Pin SOT-23 8-Pin MSOP 14-Pin TSSOP Part Number LMV551MG LMV551MGX LMV551MF LMV551MFX LMV552MM LMV552MMX LMV554MT LMV554MTX Package Marking A94 AF3A AH3A LMV554MT Transport Media 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 94 Units/Rail 2.5k Units Tape and Reel NSC Drawing MAA05A MF05A MUA08A MTC14 www.national.com 4 LMV551/LMV552/LMV554 Typical Performance Characteristics Open Loop Gain and Phase with Capacitive Load Open Loop Gain and Phase with Resistive Load 20152614 20152615 Open Loop Gain and Phase with Resistive Load Open Loop Gain and Phase with Resistive Load 20152616 20152617 Open Loop Gain and Phase with Resistive Load Slew Rate vs. Supply voltage 20152618 20152619 5 www.national.com LMV551/LMV552/LMV554 Small Signal Transient Response Large Signal Transient Response 20152620 20152621 Small Signal Transient Response Input Referred Noise vs. Frequency 20152622 20152623 THD+N vs. Amplitude @ 3V THD+N vs. Amplitude @ 5V 20152624 20152625 www.national.com 6 LMV551/LMV552/LMV554 THD+N vs. Amplitude THD+N vs. Amplitude 20152626 20152627 Supply Current vs. Supply Voltage VOS vs. VCM 20152628 20152629 VOS vs. VCM VOS vs. Supply Voltage 20152630 20152631 7 www.national.com LMV551/LMV552/LMV554 IBIAS vs. VCM IBIAS vs. VCM 20152632 20152633 IBIAS vs. Supply Voltage Positive Output Swing vs. Supply Voltage 20152634 20152635 Negative Output Swing vs. Supply Voltage Positive Output Swing vs. Supply Voltage 20152636 20152637 www.national.com 8 LMV551/LMV552/LMV554 Negative Output Swing vs. Supply Voltage 20152638 Applications Information ADVANTAGES OF THE LMV551/LMV552/LMV554 Low Voltage and Low Power Operation The LMV551/LMV552/LMV554 have performance guaranteed at supply voltages of 3V and 5V and are guaranteed to be operational at all supply voltages between 2.7V and 5.5V. For this supply voltage range, the LMV551/LMV552/LMV554 draw the extremely low supply current of less than 37 μA per amp. Wide Bandwidth The bandwidth to power ratio of 3 MHz to 37 μA per amplifier is one of the best bandwidth to power ratios ever achieved. This makes these devices ideal for low power signal processing applications such as portable media players and instrumentation. Low Input Referred Noise The LMV551/LMV552/LMV554 provide a flatband input re, which is signififerred voltage noise density of 70 nV/ cantly better than the noise performance expected from an ultra low power op amp. They also feature the exceptionally low 1/f noise corner frequency of 4 Hz. This noise specification makes the LMV551/LMV552/LMV554 ideal for low power applications such as PDAs and portable sensors. Ground Sensing and Rail-to-Rail Output The LMV551/LMV552/LMV554 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 includes the negative supply rail which allows direct sensing at ground in a single supply operation. Small Size The small footprints of the LMV551/LMV552/LMV554 packages save space on printed circuit boards, and enable 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, the amplifiers can be placed closer to the signal source, reducing noise pickup and enhancing signal integrity STABILITY OF OP AMP CIRCUITS Stability and Capacitive Loading As seen in the Phase Margin vs. Capacitive Load graph, the phase margin reduces significantly for CL greater than 100 pF. This is because the op amp is designed to provide the maximum bandwidth possible for a low supply current. Stabilizing them 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 the LMV551/LMV552/ LMV554 are to be used for driving higher capacitive loads, they will have to be externally compensated. 20152603 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. 9 www.national.com LMV551/LMV552/LMV554 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. 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. 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 less ringing and overshoot, but will also limit the output swing and the short circuit current of the circuit. 20152612 FIGURE 3. Compensation by Isolation Resistor Typical Application 20152604 FIGURE 2. In the Loop Compensation 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, RIN, and RL are to be 10 kΩ, while ROUT is 340Ω. ACTIVE FILTERS With a wide unity gain bandwidth of 3 MHz, low input referred noise density and a low power supply current, the LMV551/ LMV552/LMV554 are well suited for low-power filtering applications. Active filter topologies, such as the Sallen-Key low pass filter shown in Figure 4, 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. In the circuit shown in Figure 4, 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. (1) TABLE 1. CL (pF) 50 100 150 RS (Ω) 340 340 340 CF (pF) 8 15 22 Phase Margin (°) 47 42 40 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 FIGURE 4. Sallen-Key Filter 20152609 www.national.com 10 LMV551/LMV552/LMV554 Physical Dimensions inches (millimeters) unless otherwise noted 5-Pin SC70 NS Package Number MAA05A 5-Pin SOT-23 NS Package Number MF05A 11 www.national.com LMV551/LMV552/LMV554 8-Pin MSOP NS Package Number MUA08A 14-Pin TSSOP NS Package Number MTC14 www.national.com 12 LMV551/LMV552/LMV554 Notes 13 www.national.com LMV551/LMV552/LMV554 3 MHz, Micropower RRO Amplifiers Notes For more National Semiconductor product information and proven design tools, visit the following Web sites at: Products Amplifiers Audio Clock Conditioners Data Converters Displays Ethernet Interface LVDS Power Management Switching Regulators LDOs LED Lighting PowerWise Serial Digital Interface (SDI) Temperature Sensors Wireless (PLL/VCO) www.national.com/amplifiers www.national.com/audio www.national.com/timing www.national.com/adc www.national.com/displays www.national.com/ethernet www.national.com/interface www.national.com/lvds www.national.com/power www.national.com/switchers www.national.com/ldo www.national.com/led www.national.com/powerwise www.national.com/sdi www.national.com/tempsensors www.national.com/wireless WEBENCH Analog University App Notes Distributors Green Compliance Packaging Design Support www.national.com/webench www.national.com/AU www.national.com/appnotes www.national.com/contacts www.national.com/quality/green www.national.com/packaging www.national.com/quality www.national.com/refdesigns www.national.com/feedback Quality and Reliability Reference Designs Feedback THE CONTENTS OF THIS DOCUMENT ARE PROVIDED IN CONNECTION WITH NATIONAL SEMICONDUCTOR CORPORATION (“NATIONAL”) PRODUCTS. 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