LM7322MM

LM7321/LM7322 Rail-to-Rail Input/Output, ±15V, High Output Current and Unlimited Capacitive Load Operational Amplifier May 28, 2008 LM7321/LM7322 Rail-to-Rail Input/Output ±15V, High Output Current and Unlimited Capacitive Load Operational Amplifier General Description The LM7321/LM7322 are rail-to-rail input and output amplifiers with wide operating voltages and high output currents. The LM7321/LM7322 are efficient, achieving 18 V/µs slew rate and 20 MHz unity gain bandwidth while requiring only 1 mA of supply current per op amp. The LM7321/LM7322 performance is fully specified for operation at 2.7V, ±5V and ±15V. The LM7321/LM7322 are designed to drive unlimited capacitive loads without oscillations. All LM7321 and LM7322 parts are tested at −40°C, 125°C, and 25°C, with modern automatic test equipment. High performance from −40°C to 125°C, detailed specifications, and extensive testing makes them suitable for industrial, automotive, and communications applications. Greater than rail-to-rail input common mode voltage range with 50 dB of common mode rejection across this wide voltage range, allows both high side and low side sensing. Most device parameters are insensitive to power supply voltage, and this makes the parts easier to use where supply voltage may vary, such as automotive electrical systems and battery powered equipment. These amplifiers have true rail-to-rail output and can supply a respectable amount of current (15 mA) with minimal head- room from either rail (300 mV) at low distortion (0.05% THD+Noise). There are several package options for each part. Standard SOIC versions of both parts make upgrading existing designs easy. LM7322 is offered in a space saving 8-Pin MSOP package. The LM7321 is offered in small SOT23-5 package, which makes it easy to place this part close to sensors for better circuit performance. Features (VS = ±15, TA = 25°C, Typical values unless specified.) 2.5V to 32V ■ Wide supply voltage range +65 mA/−100 mA ■ Output current 20 MHz ■ Gain bandwidth product 18 V/µs ■ Slew rate Unlimited ■ Capacitive load tolerance 0.3V beyond rails ■ Input common mode voltage 15 nV/√Hz ■ Input voltage noise 1.3 pA/√Hz ■ Input current noise 1.1 mA ■ Supply current/channel −86 dB ■ Distortion THD+Noise −40°C to 125°C ■ Temperature range ■ Tested at −40°C, 25°C and 125°C at 2.7V, ±5V, ±15V. Applications ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ Driving MOSFETs and power transistors Capacitive proximity sensors Driving analog optocouplers High side sensing Below ground current sensing Photodiode biasing Driving varactor diodes in PLLs Wide voltage range power supplies Automotive International power supplies Typical Performance Characteristics Output Swing vs. Sourcing Current Large Signal Step Response 20205749 20205736 © 2008 National Semiconductor Corporation 202057 www.national.com LM7321/LM7322 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 Charge-Device Model VIN Differential Output Short Circuit Current Supply Voltage (VS = V+ - V−) Voltage at Input/Output pins Storage Temperature Range 2 kV 200V 1 kV ±10V (Note 3) 35V V+ +0.8V, V− −0.8V −65°C to 150°C Junction Temperature (Note 4) Soldering Information: 150°C 235°C 260°C  Infrared or Convection (20 sec.)  Wave Soldering (10 sec.) Operating Ratings Supply Voltage (VS = V+ - V−) Temperature Range (Note 4) 2.5V to 32V −40°C to 125°C 325°C/W 235°C/W 165°C/W Package Thermal Resistance, θJA,(Note 4) 5-Pin SOT-23 8-Pin MSOP 8-Pin SOIC (Note 5) Unless otherwise specified, all limits guaranteed for TA = 25°C, V+ = 2.7V, V− = 0V, VCM = 0.5V, VOUT = 1.35V, and RL > 1 MΩ to 1.35V. Boldface limits apply at the temperature extremes. Symbol VOS TC VOS IB Parameter Input Offset Voltage Condition VCM = 0.5V & VCM = 2.2V Min (Note 7) −5 −6 Typ (Note 6) ±0.7 ±2 −2.0 −2.5 −1.2 0.45 20 70 60 55 50 78 74 100 70 104 −0.3 2.8 2.7 AVOL Open Loop Voltage Gain 0.5V ≤ VO ≤ 2.2V RL = 10 kΩ to 1.35V 0.5V ≤ VO ≤ 2.2V RL = 2 kΩ to 1.35V VOUT Output Voltage Swing High RL = 10 kΩ to 1.35V VID = 100 mV RL = 2 kΩ to 1.35V VID = 100 mV Output Voltage Swing Low RL = 10 kΩ to 1.35V VID = −100 mV RL = 2 kΩ to 1.35V VID = −100 mV 65 62 59 55 3.0 72 66 50 100 20 40 150 160 250 280 120 150 120 150 dB −0.1 0.0 dB 1.0 1.5 200 300 µA Max (Note 7) +5 +6 Units 2.7V Electrical Characteristics mV µV/C Input Offset Voltage Temperature Drift VCM = 0.5V & VCM = 2.2V (Note 8) Input Bias Current VCM = 0.5V (Note 9) VCM = 2.2V (Note 9) IOS CMRR Input Offset Current Common Mode Rejection Ratio VCM = 0.5V and VCM = 2.2V 0V ≤ VCM ≤ 1.0V 0V ≤ VCM ≤ 2.7V nA PSRR CMVR Power Supply Rejection Ratio Common Mode Voltage Range 2.7V ≤ VS ≤ 30V CMRR > 50 dB dB V mV from either rail www.national.com 2 LM7321/LM7322 Symbol IOUT Parameter Output Current Condition Sourcing VID = 200 mV, VOUT = 0V (Note 3) Sinking VID = −200 mV, VOUT = 2.7V (Note 3) Min (Note 7) 30 20 40 30 Typ (Note 6) 48 65 0.95 2.0 8.5 7.5 16 11.9 0.5 −77 Max (Note 7) Units mA IS Supply Current LM7321 LM7322 1.3 1.9 2.5 3.8 mA SR fu GBW en in THD+N Slew Rate (Note 10) Unity Gain Frequency Gain Bandwidth Input Referred Current Noise Density Total Harmonic Distortion + Noise AV = +1, VI = 2V Step RL = 2 kΩ, CL = 20 pF f = 50 kHz f = 2 kHz V+ = 1.9V, V− = −0.8V f = 1 kHz, RL = 100 kΩ, AV = +2 VOUT = 210 mVPP V/µs MHz MHz nV/ pA/ dB Input Referred Voltage Noise Density f = 2 kHz CT Rej. Crosstalk Rejection f = 100 kHz, Driver RL = 10 kΩ 60 dB ±5V Electrical Characteristics Symbol VOS TC VOS IB Parameter Input Offset Voltage (Note 5) Unless otherwise specified, all limited guaranteed for TA = 25°C, V+ = 5V, V− = −5V, VCM = 0V, VOUT = 0V, and RL > 1 MΩ to 0V. Boldface limits apply at the temperature extremes. Condition VCM = −4.5V and VCM = 4.5V Min (Note 7) −5 −6 Typ (Note 6) ±0.7 ±2 −2.0 −2.5 −1.2 0.45 20 80 70 65 62 78 74 100 80 104 −5.3 5.1 5.0 AVOL Open Loop Voltage Gain −4V ≤ VO ≤ 4V RL = 10 kΩ to 0V −4V ≤ VO ≤ 4V RL = 2 kΩ to 0V 74 70 68 65 5.3 80 74 dB −5.1 −5.0 dB 1.0 1.5 200 300 µA Max (Note 7) +5 +6 Units mV µV/°C Input Offset Voltage Temperature Drift VCM = −4.5V and VCM = 4.5V (Note 8) Input Bias Current VCM = −4.5V (Note 9) VCM = 4.5V (Note 9) IOS CMRR Input Offset Current Common Mode Rejection Ratio VCM = −4.5V and VCM = 4.5V −5V ≤ VCM ≤ 3V −5V ≤ VCM ≤ 5V nA PSRR CMVR Power Supply Rejection Ratio Common Mode Voltage Range 2.7V ≤ VS ≤ 30V, VCM = −4.5V CMRR > 50 dB dB V 3 www.national.com LM7321/LM7322 Symbol VOUT Parameter Output Voltage Swing High Condition RL = 10 kΩ to 0V VID = 100 mV RL = 2 kΩ to 0V VID = 100 mV Min (Note 7) Typ (Note 6) 100 160 35 80 Max (Note 7) 250 280 350 450 200 250 200 250 Units Output Voltage Swing Low RL = 10 kΩ to 0V VID = −100 mV RL = 2 kΩ to 0V VID = −100 mV mV from either rail IOUT Output Current Sourcing VID = 200 mV, VOUT = −5V (Note 3) Sinking VID = −200 mV, VOUT = 5V (Note 3) 35 20 50 30 70 85 1.0 2.3 12.3 9 16 14.3 1.35 −79 60 1.3 2 2.8 3.8 mA IS Supply Current VCM = −4.5V LM7321 LM7322 mA SR fu GBW en in THD+N CT Rej. Slew Rate (Note 10) Unity Gain Frequency Gain Bandwidth Input Referred Voltage Noise Density Input Referred Current Noise Density Total Harmonic Distortion + Noise Crosstalk Rejection AV = +1, VI = 8V Step RL = 2 kΩ, CL = 20 pF f = 50 kHz f = 2 kHz f = 2 kHz f = 1 kHz, RL = 100 kΩ, AV = +2 VOUT = 8 VPP f = 100 kHz, Driver RL = 10 kΩ V/µs MHz MHz nV/ pA/ dB dB (Note 5) Unless otherwise specified, all limited guaranteed for TA = 25°C, V+ = 15V, V− = −15V, VCM = 0V, VOUT = 0V, and RL > 1MΩ to 15V. Boldface limits apply at the temperature extremes. Symbol VOS TC VOS IB Parameter Input Offset Voltage Condition VCM = −14.5V and VCM = 14.5V Min (Note 7) −6 −8 Typ (Note 6) ±0.7 ±2 −2 −2.5 −1.1 0.45 30 80 75 72 70 78 74 100 80 100 −15.3 15.1 15 www.national.com 4 ±15V Electrical Characteristics Max (Note 7) +6 +8 Units mV µV/°C Input Offset Voltage Temperature Drift VCM = −14.5V and VCM = 14.5V (Note 8) Input Bias Current VCM = −14.5V (Note 9) VCM = 14.5V (Note 9) 1.0 1.5 300 500 µA IOS CMRR Input Offset Current Common Mode Rejection Ratio VCM = −14.5V and VCM = 14.5V −15V ≤ VCM ≤ 12V −15V ≤ VCM ≤ 15V nA dB PSRR CMVR Power Supply Rejection Ratio Common Mode Voltage Range 2.7V ≤ VS ≤ 30V, VCM = −14.5V CMRR > 50 dB dB −15.1 −15 15.3 V LM7321/LM7322 Symbol AVOL Parameter Open Loop Voltage Gain Condition −13V ≤ VO ≤ 13V RL = 10 kΩ to 0V −13V ≤ VO ≤ 13V RL = 2 kΩ to 0V Min (Note 7) 75 70 70 65 Typ (Note 6) 85 78 150 250 60 130 Max (Note 7) Units dB VOUT Output Voltage Swing High RL = 10 kΩ to 0V VID = 100 mV RL = 2 kΩ to 0V VID = 100 mV 300 350 550 650 200 250 300 400 Output Voltage Swing Low RL = 10 kΩ to 0V VID = −100 mV RL = 2 kΩ to 0V VID = −100 mV mV from either rail IOUT Output Current Sourcing VID = 200 mV, VOUT = −15V (Note 3) Sinking VID = −200 mV, VOUT = 15V (Note 3) 40 60 65 100 1.1 2.5 18 11.3 20 15 1.3 −86 60 1.7 2.4 4 5.6 mA IS Supply Current VCM = −14.5V LM7321 LM7322 mA SR fu GBW en in THD+N CT Rej. Slew Rate (Note 10) Unity Gain Frequency Gain Bandwidth Input Referred Voltage Noise Density Input Referred Current Noise Density Total Harmonic Distortion +Noise Crosstalk Rejection AV = +1, VI = 20V Step RL = 2 kΩ, CL = 20 pF f = 50 kHz f = 2 kHz f = 2 kHz f = 1 kHz,RL 100 kΩ, AV = +2, VOUT = 23 VPP f = 100 kHz, Driver RL = 10 kΩ V/µs MHz MHz nV/ pA/ dB dB Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Rating 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, 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: 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. Short circuit test is a momentary test. Output short circuit duration is infinite for VS ≤ 6V at room temperature and below. For VS > 6V, allowable short circuit duration is 1.5 ms. Note 4: 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 5: 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 6: 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 7: All limits are guaranteed by testing or statistical analysis. Note 8: Offset voltage temperature drift determined by dividing the change in VOS at temperature extremes into the total temperature change. Note 9: Positive current corresponds to current flowing into the device. Note 10: Slew rate is the slower of the rising and falling slew rates. Connected as a Voltage Follower. 5 www.national.com LM7321/LM7322 Connection Diagrams 5-Pin SOT-23 8-Pin SOIC 8-Pin MSOP/SOIC 20205705 Top View 20205703 20205706 Top View Top View Ordering Information Package Part Number LM7321MF 5-Pin SOT-23 LM7321MFE LM7321MFX LM7322MM 8-Pin MSOP LM7322MME LM7322MMX LM7321MA 8-Pin SOIC LM7321MAX LM7322MA LM7322MAX LM7321MA LM7322MA AZ4A AU4A Package Marking Media Transport 1k Units Tape and Reel 250 Units Tape and Reel 3k Units Tape and Reel 1k Units Tape and Reel 250 Units Tape and Reel 3.5k Units Tape and Reel 95 Units/Rail 2.5k Units Tape and Reel 95 Units/Rail 2.5k Units Tape and Reel M08A MUA08A MF05A NSC Drawing www.national.com 6 LM7321/LM7322 Typical Performance Characteristics Output Swing vs. Sourcing Current Unless otherwise specified: TA = 25°C. Output Swing vs. Sinking Current 20205734 20205731 Output Swing vs. Sourcing Current Output Swing vs. Sinking Current 20205735 20205732 Output Swing vs. Sourcing Current Output Swing vs. Sinking Current 20205736 20205733 7 www.national.com LM7321/LM7322 VOS Distribution VOS vs. VCM (Unit 1) 20205730 20205707 VOS vs. VCM (Unit 2) VOS vs. VCM (Unit 3) 20205708 20205709 VOS vs. VCM (Unit 1) VOS vs. VCM (Unit 2) 20205710 20205711 www.national.com 8 LM7321/LM7322 VOS vs. VCM (Unit 2) VOS vs. VCM (Unit 1) 20205712 20205713 VOS vs. VCM (Unit 2) VOS vs. VCM (Unit 3) 20205714 20205715 VOS vs. VS (Unit 1) VOS vs. VS (Unit 2) 20205750 20205751 9 www.national.com LM7321/LM7322 VOS vs. VS (Unit 3) VOS vs. VS (Unit 1) 20205752 20205753 VOS vs. VS (Unit 2) VOS vs. VS (Unit 3) 20205754 20205755 IBIAS vs. VCM IBIAS vs. VCM 20205723 20205724 www.national.com 10 LM7321/LM7322 IBIAS vs. VCM IBIAS vs. VS 20205725 20205722 IBIAS vs. VS IS vs. VCM (LM7321) 20205721 20205718 IS vs. VCM (LM7322) IS vs. VCM (LM7321) 20205775 20205719 11 www.national.com LM7321/LM7322 IS vs. VCM (LM7322) IS vs. VCM (LM7321) 20205776 20205720 IS vs. VCM (LM7322) IS vs. VS (LM7321) 20205777 20205717 IS vs. VS (LM7322) IS vs. VS (LM7321) 20205779 20205716 www.national.com 12 LM7321/LM7322 IS vs. VS (LM7322) Positive Output Swing vs. Supply Voltage 20205778 20205727 Positive Output Swing vs. Supply Voltage Negative Output Swing vs. Supply Voltage 20205726 20205728 Negative Output Swing vs. Supply Voltage Open Loop Frequency Response with Various Capacitive Load 20205729 20205782 13 www.national.com LM7321/LM7322 Open Loop Frequency Response with Various Resistive Load Open Loop Frequency Response with Various Supply Voltage 20205783 20205784 Phase Margin vs. Capacitive Load CMRR vs. Frequency 20205738 20205739 +PSRR vs. Frequency −PSRR vs. Frequency 20205740 20205741 www.national.com 14 LM7321/LM7322 Small Signal Step Response Large Signal Step Response 20205737 20205749 Input Referred Noise Density vs. Frequency Input Referred Noise Density vs. Frequency 20205742 20205743 Input Referred Noise Density vs. Frequency THD+N vs. Frequency 20205744 20205745 15 www.national.com LM7321/LM7322 THD+N vs. Output Amplitude THD+N vs. Output Amplitude 20205746 20205747 THD+N vs. Output Amplitude Crosstalk Rejection vs. Frequency 20205748 20205768 www.national.com 16 LM7321/LM7322 Application Information DRIVING CAPACITIVE LOADS The LM7321/LM7322 are specifically designed to drive unlimited capacitive loads without oscillations as shown in Figure 1. 20205771 FIGURE 3. −SR vs. Capacitive Load The combination of these features is ideal for applications such as TFT flat panel buffers, A/D converter input amplifiers, etc. However, as in most op amps, addition of a series isolation resistor between the op amp and the capacitive load improves the settling and overshoot performance. Output current drive is an important parameter when driving capacitive loads. This parameter will determine how fast the output voltage can change. Referring to the Slew Rate vs. Capacitive Load Plots (typical performance characteristics section), two distinct regions can be identified. Below about 10,000 pF, the output Slew Rate is solely determined by the op amp’s compensation capacitor value and available current into that capacitor. Beyond 10 nF, the Slew Rate is determined by the op amp’s available output current. Note that because of the lower output sourcing current compared to the sinking one, the Slew Rate limit under heavy capacitive loading is determined by the positive transitions. An estimate of positive and negative slew rates for loads larger than 100 nF can be made by dividing the short circuit current value by the capacitor. For the LM7321/LM7322, the available output current increases with the input overdrive. Referring to Figure 4 and Figure 5 , Output Short Circuit Current vs. Input Overdrive, it can be seen that both sourcing and sinking short circuit current increase as input overdrive increases. In a closed loop amplifier configuration, during transient conditions while the fed back output has not quite caught up with the input, there will be an overdrive imposed on the input allowing more output current than would normally be available under steady state condition. Because of this feature, the op amp’s output stage quiescent current can be kept to a minimum, thereby reducing power consumption, while enabling the device to deliver large output current when the need arises (such as during transients). 20205769 FIGURE 1. ±5% Settling Time vs. Capacitive Load In addition, the output current handling capability of the device allows for good slewing characteristics even with large capacitive loads as shown in Figure 2 and Figure 3. 20205770 FIGURE 2. +SR vs. Capacitive Load 17 www.national.com LM7321/LM7322 20205774 FIGURE 6. Buffer Amplifier Scope Photo 20205772 FIGURE 4. Output Short Circuit Sourcing Current vs. Input Overdrive ESTIMATING THE OUTPUT VOLTAGE SWING It is important to keep in mind that the steady state output current will be less than the current available when there is an input overdrive present. For steady state conditions, the Output Voltage vs. Output Current plot (Typical Performance Characteristics section) can be used to predict the output swing. Figure 7 and Figure 8 show this performance along with several load lines corresponding to loads tied between the output and ground. In each cases, the intersection of the device plot at the appropriate temperature with the load line would be the typical output swing possible for that load. For example, a 1 kΩ load can accommodate an output swing to within 250 mV of V− and to 330 mV of V+ (VS = ±15V) corresponding to a typical 29.3 VPP unclipped swing. 20205773 FIGURE 5. Output Short Circuit Sinking Current vs. Input Overdrive Figure 6 shows the output voltage, output current, and the resulting input overdrive with the device set for AV = +1 and the input tied to a 1 VPP step function driving a 47 nF capacitor. As can be seen, during the output transition, the input overdrive reaches 1V peak and is more than enough to cause the output current to increase to its maximum value (see Figure 4 and Figure 5 plots). Note that because of the larger output sinking current compared to the sourcing one, the output negative transition is faster than the positive one. 20205756 FIGURE 7. Output Sourcing Characteristics with Load Lines www.national.com 18 LM7321/LM7322 20205759 20205757 FIGURE 10. VCOM Driver Performance Scope Photo OUTPUT SHORT CIRCUIT CURRENT AND DISSIPATION ISSUES The LM7321/LM7322 output stage is designed for maximum output current capability. Even though momentary output shorts to ground and either supply can be tolerated at all operating voltages, longer lasting short conditions can cause the junction temperature to rise beyond the absolute maximum rating of the device, especially at higher supply voltage conditions. Below supply voltage of 6V, the output short circuit condition can be tolerated indefinitely. With the op amp tied to a load, the device power dissipation consists of the quiescent power due to the supply current flow into the device, in addition to power dissipation due to the load current. The load portion of the power itself could include an average value (due to a DC load current) and an AC component. DC load current would flow if there is an output voltage offset, or the output AC average current is non-zero, or if the op amp operates in a single supply application where the output is maintained somewhere in the range of linear operation. Therefore: PTOTAL = PQ + PDC + PAC PQ = IS · VS PDC = IO · (Vr - Vo) PAC = See Table 1 below Op Amp Quiescent Power Dissipation DC Load Power AC Load Power FIGURE 8. Output Sinking Characteristics with Load Lines SETTLING TIME WITH LARGE CAPACITIVE LOADS Figure 9 below, shows a typical application where the LM7321/LM7322 is used as a buffer amplifier for the VCOM signal employed in a TFT LCD flat panel: 20205758 FIGURE 9. VCOM Driver Application Schematic Figure 10 shows the time domain response of the amplifier when used as a VCOM buffer/driver with VREF at ground. In this application, the op amp loop will try and maintain its output voltage based on the voltage on its non-inverting input (VREF) despite the current injected into the TFT simulated load. As long as this load current is within the range tolerable by the LM7321/LM7322 (45 mA sourcing and 65 mA sinking for ±5V supplies), the output will settle to its final value within less than 2 μs. where: IS: Supply Current VS: Total Supply Voltage (V+ − V−) VO: Average Output Voltage Vr: V+ for sourcing and V− for sinking current 19 www.national.com LM7321/LM7322 Table 1 below shows the maximum AC component of the load power dissipated by the op amp for standard Sinusoidal, Triangular, and Square Waveforms: TABLE 1. Normalized AC Power Dissipated in the Output Stage for Standard Waveforms PAC (W.Ω/V2) Sinusoidal 50.7 x 10−3 Triangular 46.9 x 10−3 Square 62.5 x 10−3 The table entries are normalized to VS2/RL. To figure out the AC load current component of power dissipation, simply multiply the table entry corresponding to the output waveform by the factor VS2/RL. For example, with ±12V supplies, a 600Ω load, and triangular waveform power dissipation in the output stage is calculated as: PAC = (46.9 x 10−3) · [242/600] = 45.0 mW The maximum power dissipation allowed at a certain temperature is a function of maximum die junction temperature (TJ (MAX)) allowed, ambient temperature TA, and package thermal resistance from junction to ambient, θJA. 20205765 FIGURE 11. Power Capability vs. Temperature When high power is required and ambient temperature can't be reduced, providing air flow is an effective approach to reduce thermal resistance therefore to improve power capability. Other Application Hints For the LM7321/LM7322, the maximum junction temperature allowed is 150°C at which no power dissipation is allowed. The power capability at 25°C is given by the following calculations: For MSOP package: The use of supply decoupling is mandatory in most applications. As with most relatively high speed/high output current Op Amps, best results are achieved when each supply line is decoupled with two capacitors; a small value ceramic capacitor (∼0.01 μF) placed very close to the supply lead in addition to a large value Tantalum or Aluminum (> 4.7 μF). The large capacitor can be shared by more than one device if necessary. The small ceramic capacitor maintains low supply impedance at high frequencies while the large capacitor will act as the charge "bucket" for fast load current spikes at the op amp output. The combination of these capacitors will provide supply decoupling and will help keep the op amp oscillation free under any load. SIMILAR HIGH OUTPUT DEVICES The LM7332 is a dual rail-to-rail amplifier with a slightly lower GBW capable of sinking and sourcing 100 mA. It is available in SOIC and MSOP packages. The LM4562 is dual op amp with very low noise and 0.7 mV voltage offset. The LME49870 and LME49860 are single and dual low noise amplifiers that can work from ±22 volt supplies. OTHER HIGH PERFORMANCE SOT-23 AMPLIERS The LM7341 is a 4 MHz rail-to-rail input and output part that requires only 0.6 mA to operate, and can drive unlimited capacitive load. It has a voltage gain of 97 dB, a CMRR of 93 dB, and a PSRR of 104 dB. The LM6211 is a 20 MHz part with CMOS input, which runs on ±12 volt or 24 volt single supplies. It has rail-to-rail output and low noise. The LM7121 has a gain bandwidth of 235 MHz. Detailed information on these parts can be found at www.national.com. For SOIC package: Similarly, the power capability at 125°C is given by: For MSOP package: For SOIC package: Figure 11 shows the power capability vs. temperature for MSOP and SOIC packages. The area under the maximum thermal capability line is the operating area for the device. When the device works in the operating area where PTOTAL is less than PD(MAX), the device junction temperature will remain below 150°C. If the intersection of ambient temperature and package power is above the maximum thermal capability line, the junction temperature will exceed 150°C and this should be strictly prohibited. www.national.com 20 LM7321/LM7322 Physical Dimensions inches (millimeters) unless otherwise noted 5-Pin SOT-23 NS Package Number MF05A 8-Pin MSOP NS Package Number MUA08A 21 www.national.com LM7321/LM7322 8-Pin SOIC NS Package Number M08A www.national.com 22 LM7321/LM7322 Notes 23 www.national.com LM7321/LM7322 Rail-to-Rail Input/Output, ±15V, High Output Current and Unlimited Capacitive Load Operational Amplifier 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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