LM2940/LM2940C 1A Low Dropout Regulator General Description The LM2940/LM2940C positive voltage regulator features the ability to source 1A of output current with a dropout voltage of typically 0.5V and a maximum of 1V over the entire temperature range. Furthermore, a quiescent current reduction circuit has been included which reduces the ground current when the differential between the input voltage and the output voltage exceeds approximately 3V. The quiescent current with 1A of output current and an input-output differential of 5V is therefore only 30 mA. Higher quiescent currents only exist when the regulator is in the dropout mode (VIN - VOUT 3V). Designed also for vehicular applications, the LM2940/ LM2940C and all regulated circuitry are protected from reverse battery installations or 2-battery jumps. During line transients, such as load dump when the input voltage can momentarily exceed the specified maximum operating voltage, the regulator will automatically shut down to protect both the internal circuits and the load. The LM2940/ LM2940C cannot be harmed by temporary mirror-image insertion. Familiar regulator features such as short circuit and thermal overload protection are also provided. Features n n n n n n n Dropout voltage typically 0.5V @IO = 1A Output current in excess of 1A Output voltage trimmed before assembly Reverse battery protection Internal short circuit current limit Mirror image insertion protection P+ Product Enhancement tested Typical Application DS008822-3 *Required if regulator is located far from power supply filter. **COUT must be at least 22 F to maintain stability. May be increased without bound to maintain regulation during transients. Locate as close as possible to the regulator. This capacitor must be rated over the same operating temperature range as the regulator and the ESR is critical; see curve. Ordering Information Temperature Range 5.0 0C TJ 125C LM2940CT-5.0 LM2940CT-9.0 LM2940CT-12 LM2940CT-15 TO-220 LM2940CS-5.0 LM2940CS-9.0 LM2940CS-12 LM2940CS-15 TO-263 -40C TJ 125C -40C TJ 85C Output Voltage 8.0 9.0 10 12 Package 15 LM2940T-5.0 LM2940T-8.0 LM2940T-9.0 LM2940T-10 LM2940T-12 TO-220 LM2940S-5.0 LM2940S-8.0 LM2940S-9.0 LM2940S-10 LM2940S-12 TO-263 LM2940IMP-5.0 LM2940IMP-8.0 LM2940IMP-9.0 LM2940IMP-10 LM2940IMP-12 LM2940IMP-15 SOT-223 LM2940IMPX-5.0 LM2940IMPX-8.0 LM2940IMPX-9.0 LM2940IMPX-10 LM2940IMPX-12 LM2940IMPX-15 SOT-223 in Tape and Reel SOT-223 Package Marking L53B L54B L0EB L55B L56B L70B The physical size of the SOT-223 is too small to contain the full device part number. The package markings indicated are what will appear on the actual device. Temperature Output Voltage Package Range 5.0 8.0 12 15 -55C TJ 125C LM2940J-5.0/883 5962-8958701EA LM2940J-8.0/883 5962-9088301QEA LM2940J-12/883 5962-9088401QEA LM2940J-15/883 5962-9088501QEA J16A LM2940WG5.0/883 5962-8958701XA WG16A For information on military temperature range products, please go to the Mil/Aero Web Site at http://www.national.com/appinfo/milaero/index.html. (c) 2000 National Semiconductor Corporation DS008822 www.national.com LM2940/LM2940C 1A Low Dropout Regulator July 2000 LM2940/LM2940C Connection Diagrams (TO-220) Plastic Package 3-Lead SOT-223 DS008822-2 DS008822-42 Front View Order Number LM2940CT-5.0, LM2940CT-9.0, LM2940CT-12, LM2940CT-15, LM2940T-5.0, LM2940T-8.0, LM2940T-9.0, LM2940T-10 or LM2940T-12 See NS Package Number TO3B Front View Order Part Number LM2940IMP-5.0, LM2940IMP-8.0, LM2940IMP-9.0, LM2940IMP-10, LM2940IMP-12 or LM2940IMP-15 See NS Package Number MP04A 16-Lead Dual-in-Line Package (J) 16-Lead Ceramic Surface-Mount Package (WG) DS008822-43 DS008822-44 Top View Order Number LM2940J-5.0/883 (5962-8958701EA), LM2940J-8.0/883 (5962-9088301QEA), LM2940J-12/883 (5962-9088401QEA), LM2940J-15/883 (5962-9088501QEA) See NS Package Number J16A Top View Order Number LM2940WG5.0/883 (5962-8958701XA) See NS Package Number WG16A (TO-263) Surface-Mount Package DS008822-11 Top View DS008822-12 Side View Order Number LM2940CS-5.0, LM2940CS-9.0, LM2940CS-12, LM2940CS-15, LM2940S-5.0, LM2940S-8.0, LM2940S-9.0, LM2940S-10 or LM2940S-12 See NS Package Number TS3B www.national.com 2 TO-263 (S) Package SOT-223 (MP) Package ESD Susceptibility (Note 3) If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications. 260C, 4s 260C, 4s 2 kV Operating Conditions (Note 1) LM2940S, T, MP 100 ms 60V LM2940CS, T 1 ms 45V Internal Power Dissipation (Note 2) Internally Limited Maximum Junction Temperature 150C Storage Temperature Range -65C TJ +150C Lead Temperature, Time for Wave Soldering TO-220 (T) Package 260C, 10s Input Voltage Temperature Range LM2940T, LM2940S LM2940CT, LM2940CS LM2940IMP LM2940J, LM2940WG 26V -40C TJ 125C 0C TJ 125C -40C TJ 85C -55C TJ 125C Electrical Characteristics VIN = VO + 5V, IO = 1A, CO = 22 F, unless otherwise specified. Boldface limits apply over the entire operating temperature range of the indicated device. All other specifications apply for TA = TJ = 25C. Output Voltage (VO) Parameter Conditions 5V Typ 8V LM2940 LM2940/883 Limit Limit (Note 4) (Note 5) Typ 6.25V VIN 26V Output Voltage Line Regulation 5 mA IO 1A 4.85/4.75 4.85/4.75 5.15/5.25 5.15/5.25 20 50 40/50 LM2940, LM2940/883 35 50/80 50/100 LM2940C 35 50 VO + 2V VIN 26V, 5.00 LM2940 LM2940/883 Limit Limit (Note 4) (Note 5) Units 9.4V VIN 26V 8.00 7.76/7.60 7.76/7.60 VMIN 8.24/8.40 8.24/8.40 VMAX 20 80 50/80 mVMAX 55 80/130 80/130 mVMAX 55 80 1000/1000 m IO = 5 mA Load Regulation 50 mA IO 1A Output 100 mADC and Impedance 20 mArms, Quiescent VO +2V VIN 26V, Current IO = 5 mA 35 1000/1000 55 15/20 10 15/20 15/20 mAMAX 50/60 30 45/60 50/60 mAMAX 700/700 240 1000/1000 Vrms fO = 120 Hz LM2940, LM2940/883 10 15/20 LM2940C 10 15 VIN = VO + 5V, 30 45/60 IO = 1A Output Noise 10 Hz - 100 kHz, Voltage IO = 5 mA Ripple Rejection fO = 120 Hz, 1 Vrms, 150 IO = 100 mA LM2940 72 60/54 66 54/48 LM2940C 72 60 66 54 fO = 1 kHz, 1 Vrms, 60/50 dBMIN 54/48 dBMIN IO = 5 mA Long Term 20 32 mV/ Stability Dropout Voltage Short Circuit Current 1000 Hr IO = 1A 0.5 0.8/1.0 0.7/1.0 0.5 0.8/1.0 0.7/1.0 VMAX IO = 100 mA 110 150/200 150/200 110 150/200 150/200 mVMAX 1.9 1.6 1.5/1.3 1.9 1.6 1.6/1.3 AMIN (Note 6) 3 www.national.com LM2940/LM2940C Absolute Maximum Ratings (Note 1) LM2940/LM2940C Electrical Characteristics (Continued) VIN = VO + 5V, IO = 1A, CO = 22 F, unless otherwise specified. Boldface limits apply over the entire operating temperature range of the indicated device. All other specifications apply for TA = TJ = 25C. Output Voltage (VO) Parameter 5V Conditions Maximum Line Typ 8V LM2940 LM2940/883 Limit Limit (Note 4) (Note 5) Typ LM2940 LM2940/883 Limit Limit (Note 4) (Note 5) Units RO = 100 LM2940, T 100 ms Transient 75 60/60 75 LM2940/883, T 20 ms LM2940C, T 1 ms 55 45 LM2940, LM2940/883 -30 -15/-15 LM2940C -30 -15 -75 -50/-50 Reverse Polarity RO = 100 DC Input Voltage Reverse Polarity 60/60 40/40 -15/-15 40/40 55 45 -30 -15/-15 -30 -15 -75 -50/-50 -15/-15 VMIN VMIN RO = 100 Transient Input LM2940, T 100 ms Voltage LM2940/883, T 20 ms LM2940C, T 1 ms -45/-45 -55 VMIN -45/-45 -45/-45 Electrical Characteristics VIN = VO + 5V, IO = 1A, CO = 22 F, unless otherwise specified. Boldface limits apply over the entire operating temperature range of the indicated device. All other specifications apply for TA = TJ = 25C. Output Voltage (VO) 9V 10V LM2940 Parameter Conditions Typ Limit LM2940 Typ (Note 4) 10.5V VIN 26V Output Voltage 5 mA IO 1A 9.00 8.73/8.55 VO + 2V VIN 26V, Units (Note 4) 11.5V VIN 26V 10.00 9.27/9.45 Line Regulation Limit 9.70/9.50 VMIN 10.30/10.50 VMAX 20 90 20 100 mVMAX LM2940 60 90/150 65 100/165 mVMAX LM2940C 60 90 IO = 5 mA Load Regulation Output Impedance 50 mA IO 1A 100 mADC and 20 mArms, 60 65 m fO = 120 Hz Quiescent Current VO +2V VIN < 26V, IO = 5 mA LM2940 10 15/20 LM2940C 10 15 45/60 VIN = VO + 5V, IO = 1A 30 Output Noise 10 Hz - 100 kHz, 270 Voltage IO = 5 mA Ripple Rejection fO = 120 Hz, 1 Vrms, 10 15/20 mAMAX 30 45/60 mAMAX 300 Vrms IO = 100 mA LM2940 64 52/46 LM2940C 64 52 Long Term Stability Dropout Voltage www.national.com 34 63 51/45 36 dBMIN mV/ 1000 Hr IO = 1A 0.5 0.8/1.0 0.5 0.8/1.0 VMAX IO = 100 mA 110 150/200 110 150/200 mVMAX 4 (Continued) VIN = VO + 5V, IO = 1A, CO = 22 F, unless otherwise specified. Boldface limits apply over the entire operating temperature range of the indicated device. All other specifications apply for TA = TJ = 25C. Output Voltage (VO) 9V 10V LM2940 Parameter Conditions Typ Limit LM2940 Typ (Note 4) Short Circuit (Note 6) Units Limit (Note 4) 1.9 1.6 1.9 1.6 AMIN LM2940 75 60/60 75 60/60 VMIN LM2940C 55 45 -30 -15/-15 VMIN -75 -50/-50 VMIN Current Maximum Line RO = 100 Transient T 100 ms Reverse Polarity RO = 100 DC Input Voltage LM2940 -30 -15/-15 LM2940C -30 -15 Reverse Polarity RO = 100 Transient Input T 100 ms Voltage LM2940 -75 -50/-50 LM2940C -55 -45/-45 Electrical Characteristics VIN = VO + 5V, IO = 1A, CO = 22 F, unless otherwise specified. Boldface limits apply over the entire operating temperature range of the indicated device. All other specifications apply for TA = TJ = 25C. Output Voltage (VO) 12V LM2940 Parameter Conditions Typ 15V LM2940/833 Limit Limit (Note 4) (Note 5) LM2940 Typ 13.6V VIN 26V Output Voltage 5 mA IO 1A Line Regulation VO + 2V VIN 26V, 12.00 11.64/11.40 11.64/11.40 12.36/12.60 12.36/12.60 20 120 75/120 LM2940, LM2940/883 55 120/200 120/190 LM2940C 55 120 LM2940/833 Limit Limit (Note 4) (Note 5) Units 16.75V VIN 26V 15.00 14.55/14.25 14.55/14.25 VMIN 15.45/15.75 15.45/15.75 VMAX 20 150 95/150 mVMAX 150/240 mVMAX 70 150 1000/1000 m 15/20 mAMAX 50/60 mAMAX 1000/1000 Vrms IO = 5 mA Load Regulation Output Impedance 50 mA IO 1A 100 mADC and 20 mArms, 80 1000/1000 100 fO = 120 Hz Quiescent Current VO +2V VIN 26V, IO = 5 mA LM2940, LM2940/883 10 15/20 LM2940C 10 15 VIN = VO + 5V, IO = 1A 30 45/60 Output Noise 10 Hz - 100 kHz, 360 Voltage IO = 5 mA Ripple Rejection fO = 120 Hz, 1 Vrms, 15/20 10 15 50/60 30 45/60 1000/1000 450 IO = 100 mA LM2940 66 54/48 LM2940C 66 54 dBMIN 64 fO = 1 kHz, 1 Vrms, 52/46 IO = 5 mA 5 52 48/42 dBMIN www.national.com LM2940/LM2940C Electrical Characteristics LM2940/LM2940C Electrical Characteristics (Continued) VIN = VO + 5V, IO = 1A, CO = 22 F, unless otherwise specified. Boldface limits apply over the entire operating temperature range of the indicated device. All other specifications apply for TA = TJ = 25C. Output Voltage (VO) 12V LM2940 Parameter Conditions Long Term Short Circuit Limit Limit (Note 4) (Note 5) 48 Stability Dropout Voltage Typ 15V LM2940/833 LM2940 Typ LM2940/833 Limit Limit (Note 4) (Note 5) Units mV/ 60 1000 Hr IO = 1A 0.5 0.8/1.0 0.7/1.0 0.5 0.8/1.0 0.7/1.0 VMAX IO = 100 mA 110 150/200 150/200 110 150/200 150/200 mVMAX 1.9 1.6 1.6/1.3 1.9 1.6 1.6/1.3 AMIN 75 60/60 40/40 VMIN 55 45 55 45 -15/-15 VMIN -30 -15 -45/-45 VMIN (Note 6) Current Maximum Line RO = 100 Transient LM2940, T 100 ms LM2940/883, T 20 ms LM2940C, T 1 ms 40/40 Reverse Polarity RO = 100 DC Input LM2940, LM2940/883 -30 -15/-15 Voltage LM2940C -30 -15 Reverse Polarity RO = 100 -75 -50/-50 Transient Input LM2940, T 100 ms Voltage LM2940/883, T 20 ms LM2940C, T 1 ms -15/-15 -45/-45 -55 -45/-45 -55 -45/-45 Note 1: Absolute Maximum Ratings are limits beyond which damage to the device may occur. Operating Conditions are conditions under which the device functions but the specifications might not be guaranteed. For guaranteed specifications and test conditions see the Electrical Characteristics. Note 2: The maximum allowable power dissipation is a function of the maximum junction temperature, TJ, the junction-to-ambient thermal resistance, J-A, and the ambient temperature, TA. Exceeding the maximum allowable power dissipation will cause excessive die temperature, and the regulator will go into thermal shutdown. The value of J-A (for devices in still air with no heatsink) is 60C/W for the TO-220 package, 80C/W for the TO-263 package, and 174C/W for the SOT-223 package. The effective value of J-A can be reduced by using a heatsink (see Application Hints for specific information on heatsinking). The values of J-A and J-Cfor the K02A package are 39C/W and 4C/W respectively. Note 3: ESD rating is based on the human body model, 100 pF discharged through 1.5 k. Note 4: All limits are guaranteed at TA = TJ = 25C only (standard typeface) or over the entire operating temperature range of the indicated device (boldface type). All limits at TA = TJ = 25C are 100% production tested. All limits at temperature extremes are guaranteed via correlation using standard Statistical Quality Control methods. Note 5: All limits are guaranteed at TA = TJ = 25C only (standard typeface) or over the entire operating temperature range of the indicated device (boldface type). All limits are 100% production tested and are used to calculate Outgoing Quality Levels. Note 6: Output current will decrease with increasing temperature but will not drop below 1A at the maximum specified temperature. Typical Performance Characteristics Dropout Voltage Dropout Voltage vs Temperature Output Voltage vs Temperature DS008822-13 DS008822-14 www.national.com 6 DS008822-15 Quiescent Current vs Temperature LM2940/LM2940C Typical Performance Characteristics (Continued) Quiescent Current Quiescent Current DS008822-18 DS008822-17 DS008822-16 Line Transient Response Load Transient Response Low Voltage Behavior DS008822-25 Low Voltage Behavior DS008822-21 DS008822-20 DS008822-19 Low Voltage Behavior Ripple Rejection Low Voltage Behavior DS008822-27 DS008822-26 Low Voltage Behavior DS008822-28 Low Voltage Behavior DS008822-29 7 DS008822-30 www.national.com LM2940/LM2940C Typical Performance Characteristics Output at Voltage Extremes (Continued) Output at Voltage Extremes DS008822-31 Output at Voltage Extremes DS008822-32 Output at Voltage Extremes DS008822-34 DS008822-33 Output at Voltage Extremes DS008822-35 Output Capacitor ESR DS008822-36 Peak Output Current DS008822-8 DS008822-6 www.national.com Output at Voltage Extremes 8 Output Impedance LM2940/LM2940C Typical Performance Characteristics (Continued) Maximum Power Dissipation (TO-220) Maximum Power Dissipation (TO-3) DS008822-22 DS008822-23 DS008822-24 Maximum Power Dissipation (TO-263) See (Note 2) DS008822-10 9 www.national.com LM2940/LM2940C Equivalent Schematic Diagram DS008822-1 Application Hints EXTERNAL CAPACITORS The output capacitor is critical to maintaining regulator stability, and must meet the required conditions for both ESR (Equivalent Series Resistance) and minimum amount of capacitance. MINIMUM CAPACITANCE: The minimum output capacitance required to maintain stability is 22 F (this value may be increased without limit). Larger values of output capacitance will give improved transient response. ESR LIMITS: The ESR of the output capacitor will cause loop instability if it is too high or too low. The acceptable range of ESR plotted versus load current is shown in the graph below. It is essential that the output capacitor meet these requirements, or oscillations can result. Output Capacitor ESR DS008822-6 FIGURE 1. ESR Limits It is important to note that for most capacitors, ESR is specified only at room temperature. However, the designer must ensure that the ESR will stay inside the limits shown over the entire operating temperature range for the design. For aluminum electrolytic capacitors, ESR will increase by about 30X as the temperature is reduced from 25C to -40C. This type of capacitor is not well-suited for low temperature operation. Solid tantalum capacitors have a more stable ESR over temperature, but are more expensive than aluminum electrolytics. A cost-effective approach sometimes used is to parallel www.national.com 10 If a manufactured heatsink is to be selected, the value of heatsink-to-ambient thermal resistance, (H-A), must first be calculated: (Continued) an aluminum electrolytic with a solid Tantalum, with the total capacitance split about 75/25% with the Aluminum being the larger value. (H-A) = (J-A) - (C-H) - (J-C) Where: (J-C) If two capacitors are paralleled, the effective ESR is the parallel of the two individual values. The "flatter" ESR of the Tantalum will keep the effective ESR from rising as quickly at low temperatures. is defined as the thermal resistance from the junction to the surface of the case. A value of 3C/W can be assumed for (J-C) for this calculation. (C-H) is defined as the thermal resistance between the case and the surface of the heatsink. The value of (C-H) will vary from about 1.5C/W to about 2.5C/W (depending on method of attachment, insulator, etc.). If the exact value is unknown, 2C/W should be assumed for (C-H). When a value for (H-A) is found using the equation shown, a heatsink must be selected that has a value that is less than or equal to this number. HEATSINKING A heatsink may be required depending on the maximum power dissipation and maximum ambient temperature of the application. Under all possible operating conditions, the junction temperature must be within the range specified under Absolute Maximum Ratings. To determine if a heatsink is required, the power dissipated by the regulator, PD, must be calculated. The figure below shows the voltages and currents which are present in the circuit, as well as the formula for calculating the power dissipated in the regulator: (H-A) is specified numerically by the heatsink manufacturer in the catalog, or shown in a curve that plots temperature rise vs power dissipation for the heatsink. HEATSINKING TO-263 AND SOT-223 PACKAGE PARTS Both the TO-263 ("S") and SOT-223 ("MP") packages use a copper plane on the PCB and the PCB itself as a heatsink. To optimize the heat sinking ability of the plane and PCB, solder the tab of the package to the plane. Figure 3 shows for the TO-263 the measured values of (J-A) for different copper area sizes using a typical PCB with 1 ounce copper and no solder mask over the copper area used for heatsinking. DS008822-37 IIN = IL / IG PD = (VIN - VOUT) IL + (VIN) IG FIGURE 2. Power Dissipation Diagram The next parameter which must be calculated is the maximum allowable temperature rise, TR (max). This is calculated by using the formula: TR (max) = TJ(max) - TA (max) where: TJ (max) is the maximum allowable junction temperature, which is 125C for commercial grade parts. TA (max) is the maximum ambient temperature which will be encountered in the application. Using the calculated values for TR(max) and PD, the maximum allowable value for the junction-to-ambient thermal resistance, (J-A), can now be found: (J-A) = TR (max)/PD DS008822-38 FIGURE 3. (J-A) vs Copper (1 ounce) Area for the TO-263 Package As shown in the figure, increasing the copper area beyond 1 square inch produces very little improvement. It should also be observed that the minimum value of (J-A) for the TO-263 package mounted to a PCB is 32C/W. As a design aid, Figure 4 shows the maximum allowable power dissipation compared to ambient temperature for the TO-263 device (assuming (J-A) is 35C/W and the maximum junction temperature is 125C). IMPORTANT: If the maximum allowable value for (J-A) is found to be 53C/W for the TO-220 package, 80C/W for the TO-263 package, or 174C/W for the SOT-223 package, no heatsink is needed since the package alone will dissipate enough heat to satisfy these requirements. If the calculated value for (J-A)falls below these limits, a heatsink is required. HEATSINKING TO-220 PACKAGE PARTS The TO-220 can be attached to a typical heatsink, or secured to a copper plane on a PC board. If a copper plane is to be used, the values of (J-A) will be the same as shown in the next section for the TO-263. 11 www.national.com LM2940/LM2940C Application Hints LM2940/LM2940C Application Hints (Continued) DS008822-40 FIGURE 5. (J-A) vs Copper (2 ounce) Area for the SOT-223 Package DS008822-39 FIGURE 4. Maximum Power Dissipation vs TAMB for the TO-263 Package Figure 5 and Figure 6 show the information for the SOT-223 package. Figure 6 assumes a (J-A) of 74C/W for 1 ounce copper and 51C/W for 2 ounce copper and a maximum junction temperature of 125C. DS008822-41 FIGURE 6. Maximum Power Dissipation vs TAMB for the SOT-223 Package www.national.com 12 LM2940/LM2940C Physical Dimensions inches (millimeters) unless otherwise noted 3-Lead SOT-223 Package Order Part Number LM2940IMP-5.0 LM2940IMP-8.0 LM2940IMP-9.0 LM2940IMP-10 LM2940IMP-12 LM2940IMP-15 NS Package Number MP04A 13 www.national.com LM2940/LM2940C Physical Dimensions inches (millimeters) unless otherwise noted (Continued) 16 Lead Dual-in-Line Package (J) Order Number LM2940J-5.0/883 (5962-8958701EA), LM2940J-8.0/883 (5962-9088301QEA), LM2940J-12/883 (5962-9088401QEA), LM2940J-15/883 (5962-9088501QEA) See NS Package Number J16A www.national.com 14 LM2940/LM2940C Physical Dimensions inches (millimeters) unless otherwise noted (Continued) 16 Lead Surface Mount Package (WG) Order Number LM2940WG5.0/883 (5962-8958701XA) See NS Package Number WG16A 15 www.national.com LM2940/LM2940C Physical Dimensions inches (millimeters) unless otherwise noted (Continued) 3-Lead TO-220 Plastic Package (T) Order Number LM2940T-5.0, LM2940T-8.0, LM2940T-9.0, LM2940T-10, LM2940T-12, LM2940CT-5.0, LM2940CT-12 or LM2940CT-15 NS Package Number TO3B www.national.com 16 LM2940/LM2940C 1A Low Dropout Regulator Physical Dimensions inches (millimeters) unless otherwise noted (Continued) 3-Lead TO-263 Surface Mount Package (MP) Order Number LM2940S-5.0, LM2940S-8.0, LM2940S-9.0, LM2940S-10, LM2940S-12, LM2940CS-5.0, LM2940CS-12 or LM2940CS-15 NS Package Number TS3B 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) 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 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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National Semiconductor Company Design Purchasing Quality Company Jobs Products > Analog - Regulators > Linear Regulators - Low Dropout Voltage > Positive Voltage - Fixed > LM2940C Product Folder LM2940C 1A Low Dropout Regulator Generic P/N 2940C Contents l l l l General Description Features Datasheet Package Availability, Models, Samples & Pricing Parametric Table Multiple Output Capability No On/Off Pin No Error Flag No Input Voltage, max (Volt) 26 Output Current, max 1 Amp Dropout Voltage, typ (Volt) .50 Quiescent Current, typ (mA) 10 Output Voltage (Volt) 12,15,5,9 General Description The LM2940/LM2940C positive voltage regulator features the ability to source 1A of output current with a dropout voltage of typically 0.5V and a maximum of 1V over the entire temperature range. Furthermore, a quiescent current reduction circuit has been included which reduces the ground current when the differential between the input voltage and the output voltage exceeds approximately 3V. The quiescent current with 1A of output current and an input-output differential of 5V is therefore only 30 mA. Higher quiescent currents only exist when the regulator is in the dropout mode (VIN - VOUT [Less_Than_Or_Equal] 3V). Designed also for vehicular applications, the LM2940/LM2940C and all regulated circuitry are protected from reverse battery installations or 2-battery jumps. During line transients, such as load dump when the input voltage can momentarily exceed the specified maximum operating voltage, the regulator will automatically shut down to protect both the internal circuits and the load. The LM2940/LM2940C cannot be harmed by temporary mirror-image insertion. Familiar regulator features such as short circuit and thermal overload protection are also provided. Features l Dropout voltage typically 0.5V @IO = 1A l Output current in excess of 1A Output voltage trimmed before assembly Reverse battery protection Internal short circuit current limit Mirror image insertion protection P+ Product Enhancement tested l l l l l Datasheet Title Size (in Kbytes) Date View Online Download Receive via Email LM2940/LM2940C 1A Low Dropout Regulator 409 Kbytes 21-Jul-00 View Online Download Receive via Email Please use Adobe Acrobat to view PDF file(s). If you have trouble printing, see Printing Problems. Package Availability, Models, Samples & Pricing Samples Budgetary Pricing Std Package & Status Pack Electronic Marking Type # pins SPICE IBIS Quantity $US each Size Orders tube [logo]UZ2T . TO-220 3 Full production N/A N/A 1K+ $0.6600 of LM2940CT 45 -12 P+ Package Part Number LM2940CT-12 Models Order Parts 1K+ tube [logo]UZ2T LM2940CT $0.6600 of 45 -15 P+ 1K+ tube [logo]UZ2T $0.6600 of LM2940CT 45 -5.0 P+ 1K+ $0.6600 1K+ tube [logo]UZ2T $0.8600 of LM2940CS 45 -12 P+ 1K+ $0.8600 tube [logo]UZ2T of LM2940CS 45 -15 P+ 1K+ $0.8600 tube [logo]UZ2T of LM2940CS 45 -5.0 P+ 1K+ tube [logo]UZ2T $0.8600 of LM2940CS 45 -9.0 P+ . LM2940CT-15 TO-220 3 Full production N/A N/A LM2940CT-5.0 TO-220 3 Full production N/A N/A LM2940CT-9.0 TO-220 3 Full production N/A N/A Order Parts . Order Parts . Order Parts Samples LM2940CS-12 TO 263 3 Full production N/A N/A LM2940CS-15 TO 263 3 Full production N/A N/A LM2940CS-5.0 TO 263 3 Full production N/A N/A Order Parts Samples Order Parts Samples Order Parts Samples tube [logo]UZ2T of LM2940CT 45 -9.0 P+ LM2940CS-9.0 TO 263 3 Full production N/A N/A LM2940CSX-12 TO 263 3 Full production N/A N/A . 1K+ $0.8900 reel [logo]UZ2T of LM2940CS 500 -12 P+ LM2940CSX-15 TO 263 3 Full production N/A N/A . 1K+ $0.8900 reel [logo]UZ2T of LM2940CS 500 -15 P+ LM2940CSX-5.0 TO 263 3 Full production N/A N/A 1K+ $0.8900 reel [logo]UZ2T of LM2940CS 500 -5.0 P+ LM2940CSX-9.0 TO 263 3 Full production N/A N/A 1K+ $0.8900 reel [logo]UZ2T of LM2940CS 500 -9.0 P+ Order Parts . Order Parts . Order Parts LM2940CT-12 MDC die Full production N/A N/A . N/A - LM2940CT-15 MDC die Full production N/A N/A . N/A - LM2940CT-12 MWC wafer Full production N/A N/A . N/A - LM2940CT-15 MWC wafer Full production N/A N/A . N/A - LM2940CT-5 MWC wafer Full production N/A N/A . N/A - LM2940-12 MW8 wafer Full production N/A N/A . N/A - [Information as of 2-Sep-2000] Quick Search Parametric Search System Diagrams Product Tree Home About Languages . About the Site . About "Cookies" National is QS 9000 Certified . Privacy/Security Copyright (c) National Semiconductor Corporation Preferences . Feedback