 |
|
| If you can't view the Datasheet, Please click here to try to view without PDF Reader . |
|
|
|
| If you can't view the Datasheet, Please click here to try to view without PDF Reader . |
|
|
| Datasheet File OCR Text: |
| LM4940 6W Stereo Audio Power Amplifier April 2005 LM4940 6W Stereo Audio Power Amplifier General Description The LM4940 is a dual audio power amplifier primarily designed for demanding applications in flat panel monitors and TV's. It is capable of delivering 6 watts per channel to a 4 load with less than 10% THD+N while operating on a 14.4VDC power supply. Boomer audio power amplifiers were designed specifically to provide high quality output power with a minimal amount of external components. The LM4940 does not require bootstrap capacitors or snubber circuits. Therefore, it is ideally suited for display applications requiring high power and minimal size. The LM4940 features a low-power consumption active-low shutdown mode. Additionally, the LM4940 features an internal thermal shutdown protection mechanism along with short circuit protection. The LM4940 contains advanced pop & click circuitry that eliminates noises which would otherwise occur during turn-on and turn-off transitions. The LM4940 is a unity-gain stable and can be configured by external gain-setting resistors. Key Specifications j Quiscent Power Supply Current j POUT (SE) 40mA (max) 6W (typ) 40A (typ) VDD = 14.4V, RL = 4, 10% THD+N j Shutdown current Features n Pop & click circuitry eliminates noise during turn-on and turn-off transitions n Low current, active-low shutdown mode n Low quiescent current n Stereo 6W output, RL = 4 n Short circuit protection n Unity-gain stable n External gain configuration capability Applications n Flat Panel Monitors n Flat Panel TV's n Computer Sound Cards Typical Application 20075672 FIGURE 1. Typical Stereo Audio Amplifier Application Circuit Boomer (R) is a registered trademark of National Semiconductor Corporation. (c) 2005 National Semiconductor Corporation DS200756 www.national.com LM4940 Connection Diagram Plastic Package, TO-263 200756E7 Top View U = Wafer Fab Code Z = Assembly Plant Code XY = Date Code TT = Die Traceability Order Number LM4940TS See NS Package Number TS9A www.national.com 2 LM4940 Absolute Maximum Ratings (Notes 1, 2) If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications. Supply Voltage (pin 6, referenced to GND, pins 4 and 5) Storage Temperature Input Voltage pins 3 and 7 pins 1, 2, 8, and 9 Power Dissipation (Note 3) ESD Susceptibility (Note 4) ESD Susceptibility (Note 5) -0.3V to VDD + 0.3V -0.3V to 9.5V Internally limited 2000V 200V 18.0V -65C to +150C Junction Temperature Thermal Resistance JC (TS) JA (TS) (Note 3) JC (TA) JA (TA) (Note 3) 150C 4C/W 20C/W 4C/W 20C/W Operating Ratings Temperature Range TMIN TA TMAX Supply Voltage -40C T A 85C 10V VDD 16V Electrical Characteristics VDD = 12V (Notes 1, 2) The following specifications apply for VDD = 12V, AV = 10, RL = 4, f = 1kHz unless otherwise specified. Limits apply for TA = 25C. Symbol Parameter Conditions LM4940 Typical (Note 6) IDD ISD VSDIH VSDIL Quiescent Power Supply Current Shutdown Current Shutdown Voltage Input High Shutdown Voltage Input Low Single Channel PO Output Power THD+N = 1% THD+N = 10% VDD = 14.4V, THD+N = 10% THD+N eOS XTALK PSRR Total Harmomic Distortion + Noise Output Noise Channel Separation Power Supply Rejection Ratio PO = 1Wrms, AV = 10, f = 1kHz A-Weighted Filter, VIN = 0V, Input Referred PO = 1W VRIPPLE = 200mVp-p, fRIPPLE = 1kHz 3.1 4.2 6.0 0.15 10 70 56 % V dB dB 2.8 W (min) VIN = 0V, IO = 0A, No Load VSHUTDOWN = GND (Note 9) 16 40 Limit (Notes 7, 8) 40 100 2.0 VDD/2 0.4 Units (Limits) mA (max) A (max) V (min) V (max) V (max) Note 1: All voltages are measured with respect to the GND pin, unless otherwise specified. Note 2: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is functional, but do not guarantee specific performance limits. Electrical Characteristics state DC and AC electrical specifications under particular test conditions which guarantee specific performance limits. This assumes that the device is within the Operating Ratings. Specifications are not guaranteed for parameters where no limit is given, however, the typical value is a good indication of device performance. Note 3: The maximum power dissipation must be derated at elevated temperatures and is dictated by TJMAX, JA, and the ambient temperature, TA. The maximum allowable power dissipation is P DMAX = (TJMAX - TA) / JA or the given in Absolute Maximum Ratings, whichever is lower. For the LM4940 typical application (shown in Figure 1) with VDD = 12V, RL = 4 stereo operation the total power dissipation is 3.65W. JA = 20C/W for both TO263 and TO220 packages mounted to 16in2 heatsink surface area. Note 4: Human body model, 100pF discharged through a 1.5 k resistor. Note 5: Machine Model, 220pF-240pF discharged through all pins. Note 6: Typicals are measured at 25C and represent the parametric norm. Note 7: Limits are guaranteed to National's AOQL (Average Outgoing Quality Level). Note 8: Datasheet min/max specification limits are guaranteed by design, test, or statistical analysis. Note 9: Shutdown current is measured in a normal room environment. The Shutdown pin should be driven as close as possible to GND for minimum shutdown current. 3 www.national.com LM4940 Typical Application 20075672 FIGURE 2. Typical Stereo Audio Amplifier Application Circuit External Components Description Components 1. RIN Refer to (Figure 1.) Functional Description This is the inverting input resistance that, along with RF, sets the closed-loop gain. Input resistance RIN and input capacitance CIN form a high pass filter. The filter's cutoff frequency is fC = 1/(2RINCIN). This is the input coupling capacitor. It blocks DC voltage at the amplifier's inverting input. CIN and RIN create a highpass filter. The filter's cutoff frequency is fC = 1/(2RINCIN). Refer to the SELECTING EXTERNAL COMPONENTS section for an explanation of determining CIN's value. This is the feedback resistance that, along with Ri, sets closed-loop gain. The supply bypass capacitor. Refer to the POWER SUPPLY BYPASSING section for information about properly placing, and selecting the value of, this capacitor. 2. 3. 4. CIN RF CS 5. 6. This capacitor filters the half-supply voltage present on the BYPASS pin. Refer to the Application CBYPASS section, SELECTING EXTERNAL COMPONENTS, for information about properly placing, and selecting the value of, this capacitor. COUT This is the output coupling capacitor. It blocks the nominal VDD/2 voltage present at the output and prevents it from reaching the load. COUT and RL form a high pass filter whose cutoff frequency is fC = 1/(2RLCOUT). Refer to the SELECTING EXTERNAL COMPONENTS section for an explanation of determining COUT's value. www.national.com 4 LM4940 Typical Performance Characteristics THD+N vs Frequency THD+N vs Frequency 20075699 200756A0 VDD = 12V, RL = 4, SE operation, both channels driven and loaded (average shown), POUT = 1W, AV = 1 THD+N vs Frequency VDD = 12V, RL = 4, SE operation, both channels driven and loaded (average shown), POUT = 2.5W, AV = 1 THD+N vs Output Power 200756A1 200756F3 VDD = 12V, RL = 8, SE operation, both channels driven and loaded (average shown), POUT = 1W, AV = 1 THD+N vs Output Power VDD = 14.4V, RL = 4, SE operation, AV = 1 single channel driven/single channel measured, fIN = 1kHz THD+N vs Output Power 200756D9 200756E0 VDD = 12V, RL = 4, SE operation, AV = 1 single channel driven/single channel measured, fIN = 1kHz VDD = 12V, RL = 8, SE operation, AV = 1 single channel driven/single channel measured, fIN = 1kHz 5 www.national.com LM4940 Typical Performance Characteristics THD+N vs Output Power (Continued) THD+N vs Output Power 200756E1 200756C7 VDD = 12V, RL = 16, SE operation, AV = 1 single channel driven/single channel measured, fIN = 1kHz THD+N vs Output Power VDD = 12V, RL = 4, SE operation, AV = 10 single channel driven/single channel measured, fIN = 1kHz THD+N vs Output Power 200756C6 20075666 VDD = 12V, RL = 8, SE operation, AV = 10 single channel driven/single channel measured, fIN = 1kHz Output Power vs Power Supply Voltage VDD = 12V, RL = 16, SE operation, AV = 10 single channel driven/single channel measured, fIN = 1kHz Output Power vs Power Supply Voltage 200756E8 200756E9 RL = 4, SE operation, fIN = 1kHz, both channels driven and loaded (average shown), at (from top to bottom at 12V): THD+N = 10%, THD+N = 1% RL = 8, SE operation, fIN = 1kHz, both channels driven and loaded (average shown), at (from top to bottom at 12V): THD+N = 10%, THD+N = 1% www.national.com 6 LM4940 Typical Performance Characteristics Output Power vs Power Supply Voltage (Continued) Power Supply Rejection vs Frequency 20075667 200756B8 RL = 16, SE operation, fIN = 1kHz, both channels driven and loaded (average shown), at (from top to bottom at 12V): THD+N = 10%, THD+N = 1% Power Supply Rejection vs Frequency VDD = 12V, RL = 8, SE operation, VRIPPLE = 200mVp-p, at (from top to bottom at 60Hz): CBYPASS = 1F, CBYPASS = 4.7F, CBYPASS = 10F, Total Power Dissipation vs Load Dissipation 200756D8 20075681 VDD = 12V, RL = 8, SE operation, VRIPPLE = 200mVp-p, AV = 10, at (from top to bottom at 60Hz): CBYPASS = 1F, CBYPASS = 4.7F, CBYPASS = 10F Output Power vs Load Resistance VDD = 12V, SE operation, fIN = 1kHz, at (from top to bottom at 1W): RL = 4, RL = 8 Channel-to-Channel Crosstalk vs Frequency 20075691 VDD = 12V, SE operation, fIN = 1kHz, both channels driven and loaded, at (from top to bottom at 15): THD+N = 10%, THD+N = 1% 20075698 VDD = 12V, RL = 4, POUT = 1W, SE operation, at (from top to bottom at 1kHz): VINB driven, VOUTA measured; VINA driven, VOUTB measured 7 www.national.com LM4940 Typical Performance Characteristics Channel-to-Channel Crosstalk vs Frequency (Continued) Power Supply Current vs Power Supply Voltage 200756A3 200756F0 VDD = 12V, RL = 8, POUT = 1W, SE operation, at (from top to bottom at 1kHz): VINB driven, VOUTA measured; VINA driven, VOUTB measured Clipping Voltage vs Power Supply Voltage RL = 4, SE operation VIN = 0V, RSOURCE = 50 Clipping Voltage vs Power Supply Voltage 200756F1 200756F2 RL = 4, SE operation, fIN = 1kHz both channels driven and loaded, at (from top to bottom at 13V): negative signal swing, positive signal swing Power Dissipation vs Ambient Temperature RL = 8, SE operation, fIN = 1kHz both channels driven and loaded, at (from top to bottom at 13V): negative signal swing, positive signal swing 200756E4 VDD = 12V, RL = 8 (SE), fIN = 1kHz, (from top to bottom at 120C): 16in2 copper plane heatsink area, 8in2 copper plane heatsink area www.national.com 8 LM4940 Application Information 20075672 FIGURE 3. Typical LM4940 Stereo Amplifier Application Circuit HIGH VOLTAGE BOOMER WITH INCREASED OUTPUT POWER Unlike previous 5V Boomer (R) amplifiers, the LM4940 is designed to operate over a power supply voltages range of 10V to 15V. Operating on a 12V power supply, the LM4940 will deliver 3.1W per channel into 4 loads with no more than 1% THD+N. POWER DISSIPATION Power dissipation is a major concern when designing a successful single-ended amplifier. Equation (2) states the maximum power dissipation point for a single-ended amplifier operating at a given supply voltage and driving a specified output load. PDMAX-SE = (VDD) 2 nect the two layers together under the tab with a 5x5 array of vias. For the TA package, use an external heatsink with a thermal impedance that is less than 20C/W. At any given ambient temperature TA, use Equation (4) to find the maximum internal power dissipation supported by the IC packaging. Rearranging Equation (4) and substituting PDMAX for PDMAX' results in Equation (5). This equation gives the maximum ambient temperature that still allows maximum stereo power dissipation without violating the LM4940's maximum junction temperature. TA = TJMAX - PDMAX-SEJA (3) / (22RL): Single Ended (1) The LM4940's dissipation is twice the value given by Equation (2) when driving two SE loads. For a 12V supply and two 8 SE loads, the LM4940's dissipation is 1.82W. The maximum power dissipation point (twice the value given by Equation (2)) must not exceed the power dissipation given by Equation (4): PDMAX' = (TJMAX - TA) / JA (2) For a typical application with a 12V power supply and two 4 SE loads, the maximum ambient temperature that allows maximum stereo power dissipation without exceeding the maximum junction temperature is approximately 113C for the TS package. TJMAX = PDMAX-SEJA + TA (4) The LM4940's TJMAX = 150C. In the TS package, the LM4940's JA is 20C/W when the metal tab is soldered to a copper plane of at least 16in2. This plane can be split between the top and bottom layers of a two-sided PCB. Con9 Equation (6) gives the maximum junction temperature TJMAX. If the result violates the LM4940's 150C, reduce the maximum junction temperature by reducing the power supply voltage or increasing the load resistance. Further allowance should be made for increased ambient temperatures. The above examples assume that a device is operating around the maximum power dissipation point. Since internal power dissipation is a function of output power, higher ambient temperatures are allowed as output power or duty cycle decreases. www.national.com LM4940 Application Information (Continued) SELECTING EXTERNAL COMPONENTS Input Capacitor Value Selection Two quantities determine the value of the input coupling capacitor: the lowest audio frequency that requires amplification and desired output transient suppression. As shown in Figure 3, the input resistor (RIN) and the input capacitor (CIN) produce a high pass filter cutoff frequency that is found using Equation (7). (5) fc = 1/2RiCi As an example when using a speaker with a low frequency limit of 50Hz, Ci, using Equation (7) is 0.159F. The 0.39F CINA shown in Figure 3allows the LM4940 to drive high efficiency, full range speaker whose response extends below 30Hz. Output Coupling Capacitor Value Selection The capacitors COUTA and COUTB that block the VDD/2 output DC bias voltage and couple the output AC signal to the amplifier loads also determine low frequency response. These capacitors, combined with their respective loads create a highpass filter cutoff frequency. The frequency is also given by Equation (6). Using the same conditions as above, with a 4 speaker, COUT is 820F (nearest common valve). Bypass Capacitor Value Besides minimizing the input capacitor size, careful consideration should be paid to value of CBYPASS, the capacitor connected to the BYPASS pin. Since CBYPASS determines how fast the LM4940 settles to quiescent operation, its value is critical when minimizing turn-on pops. The slower the LM4940's outputs ramp to their quiescent DC voltage (nominally VDD/2), the smaller the turn-on pop. Choosing CBYPASS equal to 10F along with a small value of CIN (in the range of 0.1F to 0.39F), produces a click-less and pop-less shutdown function. As discussed above, choosing CIN no larger than necessary for the desired bandwidth helps minimize clicks and pops. OPTIMIZING CLICK AND POP REDUCTION PERFORMANCE The LM4940 contains circuitry that eliminates turn-on and shutdown transients ("clicks and pops"). For this discussion, turn-on refers to either applying the power supply voltage or when the micro-power shutdown mode is deactivated. As the VDD/2 voltage present at the BYPASS pin ramps to its final value, the LM4940's internal amplifiers are configured as unity gain buffers and are disconnected from the AMPA and AMPB pins. An internal current source charges the capacitor connected between the BYPASS pin and GND in a controlled manner. Ideally, the input and outputs track the voltage applied to the BYPASS pin. The gain of the internal amplifiers remains unity until the voltage applied to the BYPASS pin. The gain of the internal amplifiers remains unity until the voltage on the bypass pin reaches VDD/2. As soon as the voltage on the bypass pin is stable, the device becomes fully operational and the amplifier outputs are reconnected to their respective output pins. Although the BYPASS pin current cannot be modified, changing the size of CBYPASS alters the device's turn-on time. Here are some typical turn-on times for various values of CBYPASS: If the result of Equation (3) is greater than that of Equation (4), then decrease the supply voltage, increase the load impedance, or reduce the ambient temperature. Further, ensure that speakers rated at a nominal 4 do not fall below 3. If these measures are insufficient, a heat sink can be added to reduce JA. The heat sink can be created using additional copper area around the package, with connections to the ground pins, supply pin and amplifier output pins. Refer to the Typical Performance Characteristics curves for power dissipation information at lower output power levels. POWER SUPPLY VOLTAGE LIMITS Continuous proper operation is ensured by never exceeding the voltage applied to any pin, with respect to ground, as listed in the Absolute Maximum Ratings section. POWER SUPPLY BYPASSING As with any power amplifier, proper supply bypassing is critical for low noise performance and high power supply rejection. Applications that employ a voltage regulator typically use a 10F in parallel with a 0.1F filter capacitors to stabilize the regulator's output, reduce noise on the supply line, and improve the supply's transient response. However, their presence does not eliminate the need for a local 1.0F tantalum bypass capacitance connected between the LM4940's supply pins and ground. Do not substitute a ceramic capacitor for the tantalum. Doing so may cause oscillation. Keep the length of leads and traces that connect capacitors between the LM4940's power supply pin and ground as short as possible. Connecting a 10F capacitor, CBYPASS, between the BYPASS pin and ground improves the internal bias voltage's stability and improves the amplifier's PSRR. The PSRR improvements increase as the bypass pin capacitor value increases. Too large, however, increases turn-on time and can compromise the amplifier's click and pop performance. The selection of bypass capacitor values, especially CBYPASS, depends on desired PSRR requirements, click and pop performance (as explained in the section, SELECTING EXTERNAL COMPONENTS), system cost, and size constraints. MICRO-POWER SHUTDOWN The LM4940 features an active-low micro-power shutdown mode. When active, the LM4940's micro-power shutdown feature turns off the amplifier's bias circuitry, reducing the supply current. The low 40A typical shutdown current is achieved by applying a voltage to the SHUTDOWN pin that is as near to GND as possible. A voltage that is greater than GND may increase the shutdown current. There are a few methods to control the micro-power shutdown. These include using a single-pole, single-throw switch (SPST), a microprocessor, or a microcontroller. When using a switch, connect a 100k pull-up resistor between the SHUTDOWN pin and VDD and the SPST switch between the SHUTDOWN pin and GND. Select normal amplifier operation by opening the switch. Closing the switch applies GND to the SHUTDOWN pin, activating micro-power shutdown. The switch and resistor guarantee that the SHUTDOWN pin will not float. This prevents unwanted state changes. In a system with a microprocessor or a microcontroller, use a digital output to apply the active-state voltage to the SHUTDOWN pin. www.national.com 10 LM4940 Application Information CB (F) 1.0 2.2 4.7 10 (Continued) (8) Thus, a minimum gain of 11.6 allows the LM4940's to reach full output swing and maintain low noise and THD+N performance. For this example, let AV = 12. The amplifier's overall BTL gain is set using the input (RINA) and feedback (R) resistors of the first amplifier in the series BTL configuration. Additionaly, AV-BTL is twice the gain set by the first amplifier's RIN and Rf. With the desired input impedance set at 20k, the feedback resistor is found using Equation (11). Rf / RIN = AV (9) TON (ms) 120 120 200 440 In order eliminate "clicks and pops", all capacitors must be discharged before turn-on. Rapidly switching VDD may not allow the capacitors to fully discharge, which may cause "clicks and pops". There is a relationship between the value of CIN and CBYPASS that ensures minimum output transient when power is applied or the shutdown mode is deactivated. Best performance is achieved by setting the time constant created by CIN and Ri + Rf to a value less than the turn-on time for a given value of CBYPASS as shown in the table above. AUDIO POWER AMPLIFIER DESIGN Audio Amplifier Design: Driving 3W into a 4 load The following are the desired operational parameters: Power Output Load Impedance Input Level Input Impedance 3WRMS 4 0.3VRMS (max) 20k The value of Rf is 240k. The nominal output power is 3W. The last step in this design example is setting the amplifier's -3dB frequency bandwidth. To achieve the desired 0.25dB pass band magnitude variation limit, the low frequency response must extend to at least one-fifth the lower bandwidth limit and the high frequency response must extend to at least five times the upper bandwidth limit. The gain variation for both response limits is 0.17dB, well within the 0.25dBdesired limit. The results are an fL = 100Hz / 5 = 20Hz and an fL = 20kHz x 5 = 100kHz (11) (10) Bandwidth 100Hz-20kHz 0.25dB The design begins by specifying the minimum supply voltage necessary to obtain the specified output power. One way to find the minimum supply voltage is to use the Output Power vs Power Supply Voltage curve in the Typical Performance Characteristics section. Another way, using Equation (8), is to calculate the peak output voltage necessary to achieve the desired output power for a given load impedance. To account for the amplifier's dropout voltage, two additional voltages, based on the Clipping Dropout Voltage vs Power Supply Voltage in the Typical Performance Characteristics curves, must be added to the result obtained by Equation (8). The result is Equation (9). As mentioned in the SELECTING EXTERNAL COMPONENTS section, RINA and CINA, as well as COUT and RL, create a highpass filter that sets the amplifier's lower bandpass frequency limit. Find the coupling capacitor's value using Equation (14). CIN = 1 / 2RINfL The result is (12) (6) and VDD = VOUTPEAK + VODTOP + VODBOT (7) 1 / (2x20kx20Hz) = 0.398F = CIN 1 / (2x4x20Hz) = 1989F = COUT The Output Power vs. Power Supply Voltage graph for an 8 load indicates a minimum supply voltage of 11.8V. The commonly used 12V supply voltage easily meets this. The additional voltage creates the benefit of headroom, allowing the LM4940 to produce an output power of 3W without clipping or other audible distortion. The choice of supply voltage must also not create a situation that violates of maximum power dissipation as explained above in the Power Dissipation section. After satisfying the LM4940's power dissipation requirements, the minimum differential gain needed to achieve 3W dissipation in a 4 BTL load is found using Equation (10). Use a 0.39F capacitor for CIN and a 2000F capacitor for COUT, the closest standard values. The product of the desired high frequency cutoff (100kHz in this example) and the differential gain AV, determines the upper passband response limit. With AV = 12 and fH = 100kHz, the closed-loop gain bandwidth product (GBWP) is 1.2mHz. This is less than the LM4940's 3.5MHz GBWP. With this margin, the amplifier can be used in designs that require more differential gain while avoiding performance restricting bandwidth limitations. 11 www.national.com LM4940 Application Information (Continued) RECOMMENDED PRINTED CIRCUIT BOARD LAYOUT Figure 5 through Figure 7 show the recommended two-layer PC board layout that is optimized for the TO263-packaged LM4940 and associated external components. This circuit board is designed for use with an external 12V supply and 4(min) speakers. This circuit board is easy to use. Apply 12V and ground to the board's VDD and GND pads, respectively. Connect a speaker between the board's OUTA and OUTB outputs and their respective GND terminals. Demonstration Board Layout 20075663 FIGURE 4. Recommended TS PCB Layout: Top Silkscreen 20075664 FIGURE 5. Recommended TS PCB Layout: Top Layer www.national.com 12 LM4940 Demonstration Board Layout (Continued) 20075665 FIGURE 6. Recommended TS PCB Layout: Bottom Layer 13 www.national.com LM4940 6W Stereo Audio Power Amplifier Physical Dimensions inches (millimeters) unless otherwise noted Plastic Package, Order Number LM4940TS NS Package Number TS9A National does not assume any responsibility for use of any circuitry described, no circuit patent licenses are implied and National reserves the right at any time without notice to change said circuitry and specifications. For the most current product information visit us at www.national.com. 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. BANNED SUBSTANCE COMPLIANCE National Semiconductor manufactures products and uses packing materials that meet the provisions of the Customer Products Stewardship Specification (CSP-9-111C2) and the Banned Substances and Materials of Interest Specification (CSP-9-111S2) and contain no ``Banned Substances'' as defined in CSP-9-111S2. National Semiconductor Americas Customer Support Center Email: new.feedback@nsc.com Tel: 1-800-272-9959 www.national.com National Semiconductor Europe Customer Support Center Fax: +49 (0) 180-530 85 86 Email: europe.support@nsc.com Deutsch Tel: +49 (0) 69 9508 6208 English Tel: +44 (0) 870 24 0 2171 Francais Tel: +33 (0) 1 41 91 8790 National Semiconductor Asia Pacific Customer Support Center Email: ap.support@nsc.com National Semiconductor Japan Customer Support Center Fax: 81-3-5639-7507 Email: jpn.feedback@nsc.com Tel: 81-3-5639-7560 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. |
Price & Availability of LM4940
 |
|
|
|
|
All Rights Reserved © IC-ON-LINE 2003 - 2022 |
| [Add Bookmark] [Contact Us] [Link exchange] [Privacy policy] |
|
Mirror Sites : [www.datasheet.hk]
[www.maxim4u.com] [www.ic-on-line.cn]
[www.ic-on-line.com] [www.ic-on-line.net]
[www.alldatasheet.com.cn]
[www.gdcy.com]
[www.gdcy.net] |