Product Folder Order Now Technical Documents Support & Community Tools & Software LM317-N-MIL SNVSAY0 - JUNE 2017 LM317-N-MIL Wide Temperature Three-Pin Adjustable Regulator 1 Features 3 Description * * * * * * * The LM317-N-MIL adjustable 3-pin positive voltage regulator is capable of supplying in excess of 1.5 A over a 1.25-V to 37-V output range and a wide temperature range. The LM317-N-MIL is easy to use and requires only two external resistors to set the output voltage. Further, both line and load regulation are better than standard fixed regulators. 1 Typ. 0.1% Load Regulation Typ. 0.01%/V Line Regulation 1.5-A Output Current Adjustable Output Down to 1.25 V Current Limit Constant With Temperature 80-dB Ripple Rejection Short-Circuit Protected Output 2 Applications * * * * * Automotive LED Lighting Battery Chargers Post Regulation for Switching Supplies Constant Current Regulators Microprocessor Supplies Typical Application The LM317-N-MIL offers full overload protection, such as current limit, thermal overload protection, and safe area protection. All overload protection circuitry remains fully functional even if the adjustment terminal is disconnected. Typically, no capacitors are needed unless the device is situated more than 6 inches from the input filter capacitors, in which case an input bypass is needed. An optional output capacitor can be added to improve transient response. The adjustment terminal can be bypassed to achieve very high ripple rejection ratios that are difficult to achieve with standard 3-terminal regulators. Because the regulator is floating and detects only the input-to-output differential voltage, supplies of several hundred volts can be regulated as long as the maximum input-to-output differential is not exceeded. That is, avoid short-circuiting the output. By connecting a fixed resistor between the adjustment pin and output, the LM317-N-MIL can be also used as a precision current regulator. Supplies with electronic shutdown can be achieved by clamping the adjustment terminal to ground, which programs the output to 1.25 V where most loads draw little current. *Needed if device is more than 6 inches from filter capacitors. Optional--improves transient response ae R2 o V = 1.25 V c 1 + + I ADJ (R2 ) OUT R1 /o e For applications requiring greater output current, see data sheets for LM150 series (3 A), SNVS772, and LM138 series (5 A), SNVS771. For the negative complement, see LM137 (SNVS778) series data sheet. Device Information(1) PART NUMBER LM317-N-MIL PACKAGE BODY SIZE (NOM) TO-3 (2) 38.94 mm x 25.40 mm TO-220 (3) 14.986 mm x 10.16 mm TO-263 (3) 10.18 mm x 8.41 mm SOT-223 (4) 6.50 mm x 3.50 mm TO (3) 8.255 mm x 8.255 mm TO-252 (3) 6.58 mm x 6.10 mm (1) For all available packages, see the orderable addendum at the end of the data sheet. 1 An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications, intellectual property matters and other important disclaimers. PRODUCTION DATA. LM317-N-MIL SNVSAY0 - JUNE 2017 www.ti.com Table of Contents 1 2 3 4 5 6 7 Features .................................................................. Applications ........................................................... Description ............................................................. Revision History..................................................... Pin Configuration and Functions ......................... Specifications......................................................... 1 1 1 2 2 4 6.1 6.2 6.3 6.4 6.5 6.6 4 4 4 5 6 7 Absolute Maximum Ratings ...................................... ESD Ratings.............................................................. Recommended Operating Conditions....................... Thermal Information .................................................. Electrical Characteristics........................................... Typical Characteristics .............................................. 8 8.1 Application Information............................................ 14 8.2 Typical Applications ................................................ 14 9 Power Supply Recommendations...................... 26 10 Layout................................................................... 26 10.1 Layout Guidelines ................................................. 26 10.2 Layout Example .................................................... 26 10.3 Thermal Considerations ........................................ 27 11 Device and Documentation Support ................. 34 11.1 11.2 11.3 11.4 11.5 11.6 Detailed Description ............................................ 10 7.1 7.2 7.3 7.4 Overview ................................................................. Functional Block Diagram ....................................... Feature Description................................................. Device Functional Modes........................................ Application and Implementation ........................ 14 10 11 12 12 Documentation Support ........................................ Related Links ........................................................ Community Resources.......................................... Trademarks ........................................................... Electrostatic Discharge Caution ............................ Glossary ................................................................ 34 34 34 34 34 34 12 Mechanical, Packaging, and Orderable Information ........................................................... 34 4 Revision History DATE REVISION NOTES June 2017 * Initial Release 5 Pin Configuration and Functions NDS Metal Can Package 2-Pin TO-3 Bottom View NDT Metal Can Package 3-Pin TO Bottom View Case is Output Case is Output Pin Functions, Metal Can Packages PIN NAME I/O DESCRIPTION TO-3 TO ADJ 1 2 -- Adjust pin VOUT CASE 3, CASE O Output voltage pin for the regulator 2 1 I Input voltage pin for the regulator VIN 2 Submit Documentation Feedback Copyright (c) 2017, Texas Instruments Incorporated Product Folder Links: LM317-N-MIL LM317-N-MIL www.ti.com SNVSAY0 - JUNE 2017 KTT Surface-Mount Package 3-Pin DDPAK/TO-263 Top View DCY Surface-Mount Package 4-Pin SOT-223 Top View NDP Surface-Mount Package 3-Pin TO-252 Front View NDE Plastic Package 3-Pin TO-220 Front View Pin Functions PIN NAME I/O DESCRIPTION TO-263 TO-220 SOT-223 TO-252 ADJ 1 1 1 1 -- Adjust pin VOUT 2, TAB 2, TAB 2, 4 2, TAB O Output voltage pin for the regulator 3 3 3 3 I Input voltage pin for the regulator VIN Submit Documentation Feedback Copyright (c) 2017, Texas Instruments Incorporated Product Folder Links: LM317-N-MIL 3 LM317-N-MIL SNVSAY0 - JUNE 2017 www.ti.com 6 Specifications 6.1 Absolute Maximum Ratings over operating free-air temperature range (unless otherwise noted) (1) (2) MIN Power dissipation -0.3 Input-output voltage differential Lead temperature (2) UNIT 40 V Metal package (soldering, 10 seconds) 300 C Plastic package (soldering, 4 seconds) 260 C 150 C -65 Storage temperature, Tstg (1) MAX Internally Limited Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings only, which do not imply functional operation of the device at these or any other conditions beyond those indicated under Recommended Operating Conditions. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability. If Military/Aerospace specified devices are required, please contact the Texas Instruments Sales Office/Distributors for availability and specifications. 6.2 ESD Ratings V(ESD) (1) Electrostatic discharge Human-body model (HBM) (1) VALUE UNIT 3000 V Manufacturing with less than 500-V HBM is possible with the necessary precautions. Pins listed as 3000 V may actually have higher performance. 6.3 Recommended Operating Conditions over operating free-air temperature range (unless otherwise noted) Operating temperature (LM117) Operating temperature (LM317-N) 4 Submit Documentation Feedback MIN MAX UNIT -55 150 C 0 125 C Copyright (c) 2017, Texas Instruments Incorporated Product Folder Links: LM317-N-MIL LM317-N-MIL www.ti.com SNVSAY0 - JUNE 2017 6.4 Thermal Information LM317-N THERMAL METRIC (1) (2) KTT (TO-263) NDE (TO-220) DCY (SOT-223) NDT (TO) NDP (TO-252) 3 PINS 3 PINS 4 PINS 3 PINS 3 PINS (3) UNIT RJA Junction-to-ambient thermal resistance 41.0 23.3 59.6 186 54 C/W RJC(top) Junction-to-case (top) thermal resistance 43.6 16.2 39.3 21 51.3 C/W RJB Junction-to-board thermal resistance 23.6 4.9 8.4 -- 28.6 C/W JT Junction-to-top characterization parameter 10.4 2.7 1.8 -- 3.9 C/W JB Junction-to-board characterization parameter 22.6 4.9 8.3 -- 28.1 C/W RJC(bot) Junction-to-case (bottom) thermal resistance 0.9 1.1 -- -- 0.9 C/W (1) (2) (3) For more information about traditional and new thermal metrics, see the Semiconductor and IC Package Thermal Metrics application report, SPRA953. When surface mount packages are used (SOT-223, TO-252), the junction to ambient thermal resistance can be reduced by increasing the PCB copper area that is thermally connected to the package. See Heatsink Requirements for heatsink techniques. No heatsink Submit Documentation Feedback Copyright (c) 2017, Texas Instruments Incorporated Product Folder Links: LM317-N-MIL 5 LM317-N-MIL SNVSAY0 - JUNE 2017 www.ti.com 6.5 Electrical Characteristics (1) Some specifications apply over full Operating Temperature Range as noted. Unless otherwise specified, TJ = 25C, VIN - VOUT = 5 V, and IOUT = 10 mA. PARAMETER TEST CONDITIONS MIN TJ = 25C TYP MAX 1.25 Reference voltage 3 V (VIN - VOUT) 40 V, 10 mA IOUT IMAX (1) (over Full Operating Temperature Range) Line regulation 3V (VIN - VOUT) 40 V (2) Load regulation 10 mA IOUT IMAX (1) (2) Thermal regulation 20-ms pulse Adjustment pin current (over full operating temperature range) (1) 1.2 V 1.25 1.3 TJ = 25C 0.01 0.04 (over full operating temperature range) 0.02 0.07 TJ = 25C 0.1% 0.5% (over full operating temperature range) 0.3% 1.5% 0.04 0.07 %/W 50 100 A 5 A mA Adjustment pin current change 10 mA IOUT IMAX 3V (VIN - VOUT) 40V (over full operating temperature range) 0.2 Temperature stability TMIN TJ TMAX (over full operating temperature range) 1% Minimum load current (VIN - VOUT) = 40 V (over full operating temperature range) 3.5 10 (VIN - VOUT) 15 V Current limit (VIN - VOUT) = 40 V TO-3, TO-263 Packages (over full operating temperature range) 1.5 2.2 3.4 SOT-223, TO-220 Packages (over full operating temperature range) 1.5 2.2 3.4 TO, TO-252 Package (over full operating temperature range) 0.5 0.8 1.8 TO-3, TO-263 packages 0.15 0.4 SOT-223, TO-220 packages 0.15 0.4 TO, TO-252 package RMS output noise, % of VOUT Ripple rejection ratio Long-term stability (1) (2) 6 UNIT 0.075 10 Hz f 10 kHz TJ = 125C, 1000 hrs %/V A A 0.2 0.003% VOUT = 10 V, f = 120 Hz, CADJ = 0 F (over full operating temperature range) VOUT = 10V, f = 120 Hz, CADJ = 10 F (over full operating temperature range) V 66 65 dB 80 dB 0.3% 1% IMAX = 1.5 A for the NDS (TO-3), NDE (TO-220), and KTT (TO-263) packages. IMAX = 1.0 A for the DCY (SOT-223) package. IMAX = 0.5 A for the NDT (TO) and NDP (TO-252) packages. Device power dissipation (PD) is limited by ambient temperature (TA), device maximum junction temperature (TJ), and package thermal resistance (JA). The maximum allowable power dissipation at any temperature is : PD(MAX) = ((TJ(MAX) - TA) / JA). All Min. and Max. limits are ensured to TI's Average Outgoing Quality Level (AOQL). Regulation is measured at a constant junction temperature, using pulse testing with a low duty cycle. Changes in output voltage due to heating effects are covered under the specifications for thermal regulation. Submit Documentation Feedback Copyright (c) 2017, Texas Instruments Incorporated Product Folder Links: LM317-N-MIL LM317-N-MIL www.ti.com SNVSAY0 - JUNE 2017 6.6 Typical Characteristics Output Capacitor = 0 F, unless otherwise noted. Figure 1. Load Regulation Figure 2. Current Limit Figure 3. Adjustment Current Figure 4. Dropout Voltage Figure 5. VOUT vs VIN, VOUT = VREF Figure 6. VOUT vs VIN, VOUT = 5 V Submit Documentation Feedback Copyright (c) 2017, Texas Instruments Incorporated Product Folder Links: LM317-N-MIL 7 LM317-N-MIL SNVSAY0 - JUNE 2017 www.ti.com Typical Characteristics (continued) Output Capacitor = 0 F, unless otherwise noted. 8 Figure 7. Temperature Stability Figure 8. Minimum Operating Current Figure 9. Ripple Rejection Figure 10. Ripple Rejection Figure 11. Ripple Rejection Figure 12. Output Impedance Submit Documentation Feedback Copyright (c) 2017, Texas Instruments Incorporated Product Folder Links: LM317-N-MIL LM317-N-MIL www.ti.com SNVSAY0 - JUNE 2017 Typical Characteristics (continued) Output Capacitor = 0 F, unless otherwise noted. Figure 13. Line Transient Response Figure 14. Load Transient Response Submit Documentation Feedback Copyright (c) 2017, Texas Instruments Incorporated Product Folder Links: LM317-N-MIL 9 LM317-N-MIL SNVSAY0 - JUNE 2017 www.ti.com 7 Detailed Description 7.1 Overview In operation, the LM317-N-MIL develops a nominal 1.25-V reference voltage, VREF, between the output and adjustment terminal. The reference voltage is impressed across program resistor R1 and, because the voltage is constant, a constant current I1 then flows through the output set resistor R2, giving an output voltage calculated by Equation 1: ae R2 o VOUT = 1.25 V c 1 + + I ADJ (R2 ) R1 /o e (1) Figure 15. Setting the VOUT Voltage Because the 100-A current from the adjustment terminal represents an error term, the LM317-N-MIL was designed to minimize IADJ and make it very constant with line and load changes. To do this, all quiescent operating current is returned to the output establishing a minimum load current requirement. If there is insufficient load on the output, the output will rise. 10 Submit Documentation Feedback Copyright (c) 2017, Texas Instruments Incorporated Product Folder Links: LM317-N-MIL LM317-N-MIL www.ti.com SNVSAY0 - JUNE 2017 7.2 Functional Block Diagram Submit Documentation Feedback Copyright (c) 2017, Texas Instruments Incorporated Product Folder Links: LM317-N-MIL 11 LM317-N-MIL SNVSAY0 - JUNE 2017 www.ti.com 7.3 Feature Description 7.3.1 Load Regulation The LM317-N-MIL is capable of providing extremely good load regulation but a few precautions are needed to obtain maximum performance. The current set resistor, R1, must be connected near the output terminal of the regulator rather than near the load. If R1 is placed too far from the output terminal, then the increased trace resistance, RS, will cause an error voltage drop in the adjustment loop and degrade load regulation performance. Therefore, R1 must be placed as close as possible to the output terminal to minimize RS and maximize load regulation performance. Figure 16 shows the effect of the trace resistance, RS, when R1 is placed far from the output terminal of the regulator. It is clear that RS will cause an error voltage drop especially during higher current loads, so it is important to minimize the RS trace resistance by keeping R1 close to the regulator output terminal. Figure 16. Regulator With Line Resistance in Output Lead With the TO-3 package, it is easy to minimize the resistance from the case to the set resistor, by using two separate leads to the case. However, with the TO package, care must be taken to minimize the wire length of the output lead. The ground of R2 can be returned near the ground of the load to provide remote ground sensing and improve load regulation. 7.4 Device Functional Modes 7.4.1 External Capacitors An input bypass capacitor is recommended. A 0.1-F disc or 1-F solid tantalum on the input is suitable input bypassing for almost all applications. The device is more sensitive to the absence of input bypassing when adjustment or output capacitors are used, but the above values will eliminate the possibility of problems. The adjustment terminal can be bypassed to ground on the LM317-N-MIL to improve ripple rejection. This bypass capacitor prevents ripple from being amplified as the output voltage is increased. With a 10-F bypass capacitor, 80-dB ripple rejection is obtainable at any output level. Increases over 10 F do not appreciably improve the ripple rejection at frequencies above 120 Hz. If the bypass capacitor is used, it is sometimes necessary to include protection diodes to prevent the capacitor from discharging through internal low current paths and damaging the device. In general, the best type of capacitors to use is solid tantalum. Solid tantalum capacitors have low impedance even at high frequencies. Depending upon capacitor construction, it takes about 25 F in aluminum electrolytic to equal 1-F solid tantalum at high frequencies. Ceramic capacitors are also good at high frequencies. However, some types have a large decrease in capacitance at frequencies around 0.5 MHz. For this reason, 0.01-F disc may seem to work better than a 0.1-F disc as a bypass. Although the LM317-N-MIL is stable with no output capacitors, like any feedback circuit, certain values of external capacitance can cause excessive ringing. This occurs with values between 500 pF and 5000 pF. A 1-F solid tantalum (or 25-F aluminum electrolytic) on the output swamps this effect and insures stability. Any increase of the load capacitance larger than 10 F will merely improve the loop stability and output impedance. 12 Submit Documentation Feedback Copyright (c) 2017, Texas Instruments Incorporated Product Folder Links: LM317-N-MIL LM317-N-MIL www.ti.com SNVSAY0 - JUNE 2017 Device Functional Modes (continued) 7.4.2 Protection Diodes When external capacitors are used with any IC regulator, it is sometimes necessary to add protection diodes to prevent the capacitors from discharging through low current points into the regulator. Most 10-F capacitors have low enough internal series resistance to deliver 20-A spikes when shorted. Although the surge is short, there is enough energy to damage parts of the IC. When an output capacitor is connected to a regulator and the input is shorted, the output capacitor will discharge into the output of the regulator. The discharge current depends on the value of the capacitor, the output voltage of the regulator, and the rate of decrease of VIN. In the LM317-N-MIL, this discharge path is through a large junction that is able to sustain 15-A surge with no problem. This is not true of other types of positive regulators. For output capacitors of 25 F or less, there is no need to use diodes. The bypass capacitor on the adjustment terminal can discharge through a low current junction. Discharge occurs when either the input, or the output, is shorted. Internal to the LM317-N-MIL is a 50- resistor which limits the peak discharge current. No protection is needed for output voltages of 25 V or less and 10-F capacitance. Figure 17 shows an LM317-N-MIL with protection diodes included for use with outputs greater than 25 V and high values of output capacitance. ae R2 o VOUT = 1.25 V c 1 + + I ADJ (R2 ) R1 /o e D1 protects against C1 D2 protects against C2 Figure 17. Regulator With Protection Diodes Submit Documentation Feedback Copyright (c) 2017, Texas Instruments Incorporated Product Folder Links: LM317-N-MIL 13 LM317-N-MIL SNVSAY0 - JUNE 2017 www.ti.com 8 Application and Implementation NOTE Information in the following applications sections is not part of the TI component specification, and TI does not warrant its accuracy or completeness. TI's customers are responsible for determining suitability of components for their purposes. Customers must validate and test their design implementation to confirm system functionality. 8.1 Application Information The LM317-N-MIL is a versatile, high performance, linear regulator with high accuracy and a wide temperature range. An output capacitor can be added to further improve transient response, and the ADJ pin can be bypassed to achieve very high ripple-rejection ratios. Its functionality can be utilized in many different applications that require high performance regulation, such as battery chargers, constant current regulators, and microprocessor supplies. 8.2 Typical Applications 8.2.1 1.25-V to 25-V Adjustable Regulator The device can be used as a simple, low-dropout regulator to enable a variety of output voltages needed for demanding applications. By using an adjustable R2 resistor, a variety of output voltages can be made possible as shown in Figure 18. NOTE: Full output current not available at high input-output voltages *Needed if device is more than 6 inches from filter capacitors. Optional--improves transient response. Output capacitors in the range of 1 F to 1000 F of aluminum or tantalum electrolytic are commonly used to provide improved output impedance and rejection of transients. Figure 18. 1.25-V to 25-V Adjustable Regulator 8.2.1.1 Design Requirements The device component count is very minimal, employing two resistors as part of a voltage divider circuit and an output capacitor for load regulation. An input capacitor is needed if the device is more than 6 inches from filter capacitors. An optional bypass capacitor across R2 can also be used to improve PSRR. 8.2.1.2 Detailed Design Procedure The output voltage is set based on the selection of the two resistors, R1 and R2, as shown in Figure 18. For details on capacitor selection, refer to External Capacitors. 14 Submit Documentation Feedback Copyright (c) 2017, Texas Instruments Incorporated Product Folder Links: LM317-N-MIL LM317-N-MIL www.ti.com SNVSAY0 - JUNE 2017 Typical Applications (continued) 8.2.1.3 Application Curve As shown in Figure 19, VOUT will rise with VIN minus some dropout voltage. This dropout voltage during startup will vary with ROUT. Figure 19. VOUT vs VIN, VOUT = 5V 8.2.2 5-V Logic Regulator With Electronic Shutdown Figure 20 shows a variation of the 5-V output regulator application uses the device along with an NPN transistor to provide shutdown control. The NPN will either block or sink the current from the ADJ pin by responding to the TTL pin logic. When TTL is pulled high, the NPN is on and pulls the ADJ pin to GND, and the LM117 outputs about 1.25 V. When TTL is pulled low, the NPN is off and the regulator outputs according to the programmed adjustable voltage. NOTE: Min. output 1.2 V Figure 20. 5-V Logic Regulator With Electronic Shutdown Submit Documentation Feedback Copyright (c) 2017, Texas Instruments Incorporated Product Folder Links: LM317-N-MIL 15 LM317-N-MIL SNVSAY0 - JUNE 2017 www.ti.com Typical Applications (continued) 8.2.3 Slow Turnon 15-V Regulator An application of the device includes a PNP transistor with a capacitor to implement slow turnon functionality (see Figure 21). As VIN rises, the PNP sinks current from the ADJ rail. The output voltage at start up is the addition of the 1.25-V reference plus the drop across the base to emitter. While this is happening, the capacitor begins to charge and eventually opens the PNP. At this point, the device functions normally, regulating the output at 15 V. A diode is placed between C1 and VOUT to provide a path for the capacitor to discharge. Such controlled turnon is useful for limiting the in-rush current. Figure 21. Slow Turnon 15-V Regulator 16 Submit Documentation Feedback Copyright (c) 2017, Texas Instruments Incorporated Product Folder Links: LM317-N-MIL LM317-N-MIL www.ti.com SNVSAY0 - JUNE 2017 Typical Applications (continued) 8.2.4 Adjustable Regulator With Improved Ripple Rejection To improve ripple rejection, a capacitor is used to bypass the ADJ pin to GND (see Figure 22). This is used to smooth output ripple by cleaning the feedback path and stopping unnecessary noise from being fed back into the device, propagating the noise. NOTE: Solid tantalum *Discharges C1 if output is shorted to ground Figure 22. Adjustable Regulator With Improved Ripple Rejection 8.2.5 High Stability 10-V Regulator Using a high stability shunt voltage reference in the feedback path, such as the LM329, provides damping necessary for a stable, low noise output (see Figure 23). VIN 15 V VIN VOUT ADJ C1 0.1 F R1 2k 5% VOUT 10 V R2 1.5 k 1% LM329 R3 267 1% Figure 23. High Stability 10-V Regulator Submit Documentation Feedback Copyright (c) 2017, Texas Instruments Incorporated Product Folder Links: LM317-N-MIL 17 LM317-N-MIL SNVSAY0 - JUNE 2017 www.ti.com Typical Applications (continued) 8.2.6 High-Current Adjustable Regulator Using the LM195 power transistor in parallel with the device can increase the maximum possible output load current (see Figure 24). Sense resistor R1 provides the 0.6 V across base to emitter to turn on the PNP. This on switch allows current to flow, and the voltage drop across R3 drives three LM195 power transistors designed to carry an excess of 1 A each. NOTE The selection of R1 determines a minimum load current for the PNP to turn on. The higher the resistor value, the lower the load current must be before the transistors turn on. three LM195 devices in parallel NOTE: Optional--improves ripple rejection Solid tantalum *Minimum load current = 30 mA Figure 24. High-Current Adjustable Regulator 18 Submit Documentation Feedback Copyright (c) 2017, Texas Instruments Incorporated Product Folder Links: LM317-N-MIL LM317-N-MIL www.ti.com SNVSAY0 - JUNE 2017 Typical Applications (continued) 8.2.7 Emitter-Follower Current Amplifier The device is used as a constant current source in the emitter follower circuit (see Figure 25). The LM195 power transistor is being used as a current gain amplifier, boosting the INPUT current. The device provides a stable current bias than just using a resistor. Figure 25. Emitter-Follower Current Amplifier 8.2.8 1-A Current Regulator A simple, fixed current regulator can be made by placing a resistor between the VOUT and ADJ pins of the device (see Figure 26). By regulating a constant 1.25 V between these two terminals, a constant current is delivered to the load. Figure 26. 1-A Current Regulator Submit Documentation Feedback Copyright (c) 2017, Texas Instruments Incorporated Product Folder Links: LM317-N-MIL 19 LM317-N-MIL SNVSAY0 - JUNE 2017 www.ti.com Typical Applications (continued) 8.2.9 Common-Emitter Amplifier Sometimes it is necessary to use a power transistor for high current gain. In this case, the device provides constant current at the collector of the LM195 in this common emitter application (see Figure 27). The 1.25-V reference between VOUT and ADJ is maintained across the 2.4- resistor, providing about 500-mA constant bias current into the collector of the LM195. Figure 27. Common-Emitter Amplifier 20 Submit Documentation Feedback Copyright (c) 2017, Texas Instruments Incorporated Product Folder Links: LM317-N-MIL LM317-N-MIL www.ti.com SNVSAY0 - JUNE 2017 Typical Applications (continued) 8.2.10 Low-Cost 3-A Switching Regulator The LM317-N-MIL can be used in a switching buck regulator application in cost sensitive applications that require high efficiency. The switch node above D1 oscillates between ground and VIN, as the voltage across sense resistor R1 drives the power transistor on and off. Figure 28 exhibits self-oscillating behavior by negative feedback through R6 and C3 to the ADJ pin of the LM317-N-MIL. NOTE: Solid tantalum *Core--Arnold A-254168-2 60 turns Figure 28. Low-Cost 3-A Switching Regulator Submit Documentation Feedback Copyright (c) 2017, Texas Instruments Incorporated Product Folder Links: LM317-N-MIL 21 LM317-N-MIL SNVSAY0 - JUNE 2017 www.ti.com Typical Applications (continued) 8.2.11 Current-Limited Voltage Regulator A maximum limit on output current can be set using the circuit shown in Figure 29. The load current travels through R3 and R4. As the load current increases, the voltage drop across R3 increases until the NPN transistor is driven, during which the ADJ pin is pulled down to ground and the output voltage is pulled down to the reference voltage of 1.25 V. -Short circuit current is approximately 600 mV , or 210 mA R3 (Compared to the higher current limit of the device) --At 50 mA output only 3/4 volt of drop occurs in R3 and R4 Figure 29. Current-Limited Voltage Regulator 8.2.12 Adjusting Multiple On-Card Regulators With Single Control Figure 30 shows how multiple LM317-N-MIL regulators can be controlled by setting one resistor. Because each device maintains the reference voltage of about 1.25 V between its VOUT and ADJ pins, we can connect each ADJ rail to a single resistor, setting the same output voltage across all devices. This allows for independent outputs, each responding to its corresponding input only. Designers must also consider that by the nature of the circuit, changes to R1 and R2 affect all regulators. NOTE: *All outputs within 100 mV Minimum load--10 mA Figure 30. Adjusting Multiple On-Card Regulators With Single Control 22 Submit Documentation Feedback Copyright (c) 2017, Texas Instruments Incorporated Product Folder Links: LM317-N-MIL LM317-N-MIL www.ti.com SNVSAY0 - JUNE 2017 Typical Applications (continued) 8.2.13 AC Voltage Regulator In Figure 31, the top regulator is +6 V above the bottom regulator. It is clear that when the input rises above +6 V plus the dropout voltage, only the top LM317-N-MIL regulates +6 V at the output. When the input falls below -6 V minus the dropout voltage, only the bottom LM317-N-MIL regulates -6 V at the output. For regions where the output is not clipped, there is no regulation taking place, so the output follows the input. Figure 31. AC Voltage Regulator 8.2.14 12-V Battery Charger The LM317-N-MIL can be used in a battery charger application shown in Figure 32, where the device maintains either constant voltage or constant current mode depending on the current charge of the battery. To do this, the part senses the voltage drop across the battery and delivers the maximum charging current necessary to charge the battery. When the battery charge is low, there exists a voltage drop across the sense resistor RS, providing constant current to the battery at that instant. As the battery approaches full charge, the potential drop across RS approaches zero, reducing the current and maintaining the fixed voltage of the battery. Use of RS allows low charging rates with fully charged battery. Figure 32. 12-V Battery Charger Submit Documentation Feedback Copyright (c) 2017, Texas Instruments Incorporated Product Folder Links: LM317-N-MIL 23 LM317-N-MIL SNVSAY0 - JUNE 2017 www.ti.com Typical Applications (continued) 8.2.15 Adjustable 4-A Regulator Using three LM317-N-MIL devices in parallel increases load current capability (Figure 33). Output voltage is set by the variable resistor tied to the non-inverting terminal of the operational amplifier, and reference current to the transistor is developed across the 100- resistor. When output voltage rises, the operational amplifier corrects by drawing current from the base, closing the transistor. This effectively pulls ADJ down and lowers the output voltage through negative feedback. Figure 33. Adjustable 4-A Regulator 24 Submit Documentation Feedback Copyright (c) 2017, Texas Instruments Incorporated Product Folder Links: LM317-N-MIL LM317-N-MIL www.ti.com SNVSAY0 - JUNE 2017 Typical Applications (continued) 8.2.16 Current-Limited 6-V Charger The current in a battery charger application is limited by switching between constant current and constant voltage states (see Figure 34). When the battery pulls low current, the drop across the 1- resistor is not substantial and the NPN remains off. A constant voltage is seen across the battery, as regulated by the resistor divider. When current through the battery rises past peak current, the 1 provides enough voltage to turn the transistor on, pulling ADJ close to ground. This results in limiting the maximum current to the battery. *Sets peak current (0.6A for 1) **The 1000-F is recommended to filter out input transients Figure 34. Current-Limited 6-V Charger 8.2.17 Digitally Selected Outputs Figure 35 demonstrates a digitally selectable output voltage. In its default state, all transistors are off and the output voltage is set based on R1 and R2. By driving certain transistors, the associated resistor is connected in parallel to R2, modifying the output voltage of the regulator. *Sets maximum VOUT Figure 35. Digitally Selected Outputs (2) Submit Documentation Feedback Copyright (c) 2017, Texas Instruments Incorporated Product Folder Links: LM317-N-MIL 25 LM317-N-MIL SNVSAY0 - JUNE 2017 www.ti.com 9 Power Supply Recommendations The input supply to the LM317-N-MIL must be kept at a voltage level such that its maximum input to output differential voltage is not exceeded. The minimum dropout voltage must also be met with extra headroom when possible to keep the LM317-N-MIL in regulation. An input capacitor is recommended, especially when the input pin is located more than 6 inches away from the power supply source. For more information regarding capacitor selection, refer to External Capacitors. 10 Layout 10.1 Layout Guidelines Some layout guidelines must be followed to ensure proper regulation of the output voltage with minimum noise. Traces carrying the load current must be wide to reduce the amount of parasitic trace inductance and the feedback loop from VOUT to ADJ must be kept as short as possible. To improve PSRR, a bypass capacitor can be placed at the ADJ pin and must be located as close as possible to the IC. In cases when VIN shorts to ground, an external diode must be placed from VOUT to VIN to divert the surge current from the output capacitor and protect the IC. Similarly, in cases when a large bypass capacitor is placed at the ADJ pin and VOUT shorts to ground, an external diode must be placed from ADJ to VOUT to provide a path for the bypass capacitor to discharge. These diodes must be placed close to the corresponding IC pins to increase their effectiveness. 10.2 Layout Example Figure 36. Layout Example (SOT-223) 26 Submit Documentation Feedback Copyright (c) 2017, Texas Instruments Incorporated Product Folder Links: LM317-N-MIL LM317-N-MIL www.ti.com SNVSAY0 - JUNE 2017 Layout Example (continued) Figure 37. Layout Example (TO-220) 10.3 Thermal Considerations 10.3.1 Heatsink Requirements The LM317-N-MIL regulators have internal thermal shutdown to protect the device from over-heating. Under all operating conditions, the junction temperature of the LM317-N-MIL must not exceed the rated maximum junction temperature (TJ) of 125C. A heatsink may be required depending on the maximum device power dissipation and the maximum ambient temperature of the application. To determine if a heatsink is needed, the power dissipated by the regulator, PD, must be calculate with Equation 3: PD = ((VIN - VOUT) x IL) + (VIN x IG) (3) Figure 38 shows the voltage and currents which are present in the circuit. The next parameter which must be calculated is the maximum allowable temperature rise, TR(MAX) in Equation 4: TR(MAX) = TJ(MAX) - TA(MAX) (4) where TJ(MAX) is the maximum allowable junction temperature (125C for the LM317-N-MIL), and TA(MAX) is the maximum ambient temperature that 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 (JA) can be calculated with Equation 5: JA = (TR(MAX) / PD) (5) Submit Documentation Feedback Copyright (c) 2017, Texas Instruments Incorporated Product Folder Links: LM317-N-MIL 27 LM317-N-MIL SNVSAY0 - JUNE 2017 www.ti.com Thermal Considerations (continued) Figure 38. Power Dissipation Diagram If the calculated maximum allowable thermal resistance is higher than the actual package rating, then no additional work is needed. If the calculated maximum allowable thermal resistance is lower than the actual package rating either the power dissipation (PD) needs to be reduced, the maximum ambient temperature TA(MAX) needs to be reduced, the thermal resistance (JA) must be lowered by adding a heatsink, or some combination of these. If a heatsink is needed, the value can be calculated from Equation 6: HA (JA - (CH + JC)) where * * CH is the thermal resistance of the contact area between the device case and the heatsink surface JC is thermal resistance from the junction of the die to surface of the package case (6) When a value for HA is found using the equation shown, a heatsink must be selected that has a value that is less than, or equal to, this number. The HA rating 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. 10.3.2 Heatsinking Surface Mount Packages The TO-263 (KTT), SOT-223 (DCY) and TO-252 (NDP) 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. 10.3.2.1 Heatsinking the SOT-223 (DCY) Package Figure 39 and Figure 40 show the information for the SOT-223 package. Figure 40 assumes a JA of 74C/W for 1-oz. copper and 59.6C/W for 2-oz. copper and a maximum junction temperature of 125C. See AN-1028 (SNVA036) for thermal enhancement techniques to be used with SOT-223 and TO-252 packages. 28 Submit Documentation Feedback Copyright (c) 2017, Texas Instruments Incorporated Product Folder Links: LM317-N-MIL LM317-N-MIL www.ti.com SNVSAY0 - JUNE 2017 Thermal Considerations (continued) Figure 39. JA vs Copper (2-oz.) Area for the SOT-223 Package Figure 40. Maximum Power Dissipation vs TAMB for the SOT-223 Package 10.3.2.2 Heatsinking the TO-263 (KTT) Package Figure 41 shows for the TO-263 the measured values of JA for different copper area sizes using a typical PCB with 1-oz. copper and no solder mask over the copper area used for heatsinking. As shown in Figure 41, increasing the copper area beyond 1 square inch produces very little improvement. It must also be observed that the minimum value of JA for the TO-263 package mounted to a PCB is 32C/W. Figure 41. JA vs Copper (1-oz.) Area for the TO-263 Package As a design aid, Figure 42 shows the maximum allowable power dissipation compared to ambient temperature for the TO-263 device (assuming JA is 35C/W and the maximum junction temperature is 125C). Submit Documentation Feedback Copyright (c) 2017, Texas Instruments Incorporated Product Folder Links: LM317-N-MIL 29 LM317-N-MIL SNVSAY0 - JUNE 2017 www.ti.com Thermal Considerations (continued) Figure 42. Maximum Power Dissipation vs TAMB for the TO-263 Package 10.3.2.3 Heatsinking the TO-252 (NDP) Package If the maximum allowable value for JA is found to be 54C/W (typical rated value) for the TO-252 package, no heatsink is needed because the package alone will dissipate enough heat to satisfy these requirements. If the calculated value for JA falls below these limits, a heatsink is required. As a design aid, Table 1 shows the value of the JA of NDP the package for different heatsink area. The copper patterns that we used to measure these JAs are shown in Figure 47. Figure 43 reflects the same test results as what are in Table 1. Figure 44 shows the maximum allowable power dissipation versus ambient temperature for the TO-252 device. Figure 45 shows the maximum allowable power dissipation versus copper area (in2) for the TO-252 device. See AN-1028 (SNVA036) for thermal enhancement techniques to be used with SOT-223 and TO-252 packages. 30 Submit Documentation Feedback Copyright (c) 2017, Texas Instruments Incorporated Product Folder Links: LM317-N-MIL LM317-N-MIL www.ti.com SNVSAY0 - JUNE 2017 Thermal Considerations (continued) Table 1. JA Different Heatsink Area LAYOUT (1) COPPER AREA THERMAL RESISTANCE Top Side (in2) (1) Bottom Side (in2) (JAC/W) TO-252 1 0.0123 0 103 2 0.066 0 87 3 0.3 0 60 4 0.53 0 54 5 0.76 0 52 6 1.0 0 47 7 0.066 0.2 84 8 0.066 0.4 70 9 0.066 0.6 63 10 0.066 0.8 57 11 0.066 1.0 57 12 0.066 0.066 89 13 0.175 0.175 72 14 0.284 0.284 61 15 0.392 0.392 55 16 0.5 0.5 53 Tab of device attached to topside of copper. Figure 43. JA vs 2-oz. Copper Area for TO-252 Figure 44. Maximum Allowable Power Dissipation vs Ambient Temperature for TO-252 Submit Documentation Feedback Copyright (c) 2017, Texas Instruments Incorporated Product Folder Links: LM317-N-MIL 31 LM317-N-MIL SNVSAY0 - JUNE 2017 www.ti.com Figure 45. Maximum Allowable Power Dissipation vs 2-oz. Copper Area for TO-252 Figure 46. Top View of the Thermal Test Pattern in Actual Scale 32 Submit Documentation Feedback Copyright (c) 2017, Texas Instruments Incorporated Product Folder Links: LM317-N-MIL LM317-N-MIL www.ti.com SNVSAY0 - JUNE 2017 Figure 47. Bottom View of the Thermal Test Pattern in Actual Scale Submit Documentation Feedback Copyright (c) 2017, Texas Instruments Incorporated Product Folder Links: LM317-N-MIL 33 LM317-N-MIL SNVSAY0 - JUNE 2017 www.ti.com 11 Device and Documentation Support 11.1 Documentation Support 11.1.1 Related Documentation * For applications requiring greater output current, see LM150 series (3A) (SNVS772) and LM138 series (5A) (SNVS771) data sheets. * For the negative complement, see LM137 (SNVS778) series data sheet. * For specifications and availability for military and space grades of LM117/883, see the LM117QML data sheet (SNVS356). * Specifications and availability for military and space grades of LM117JAN can be found in the LM117 data sheet (SNVS365). * For thermal enhancement techniques to be used with SOT-223 and TO-252 packages, see AN-1028, Maximum Power Enhancement Techniques for Power Packages (SNVA036). 11.2 Related Links The table below lists quick access links. Categories include technical documents, support and community resources, tools and software, and quick access to sample or buy. Table 2. Related Links PARTS PRODUCT FOLDER SAMPLE & BUY TECHNICAL DOCUMENTS TOOLS & SOFTWARE SUPPORT & COMMUNITY LM317-N-MIL Click here Click here Click here Click here Click here 11.3 Community Resources The following links connect to TI community resources. Linked contents are provided "AS IS" by the respective contributors. They do not constitute TI specifications and do not necessarily reflect TI's views; see TI's Terms of Use. TI E2ETM Online Community TI's Engineer-to-Engineer (E2E) Community. Created to foster collaboration among engineers. At e2e.ti.com, you can ask questions, share knowledge, explore ideas and help solve problems with fellow engineers. Design Support TI's Design Support Quickly find helpful E2E forums along with design support tools and contact information for technical support. 11.4 Trademarks E2E is a trademark of Texas Instruments. All other trademarks are the property of their respective owners. 11.5 Electrostatic Discharge Caution These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam during storage or handling to prevent electrostatic damage to the MOS gates. 11.6 Glossary SLYZ022 -- TI Glossary. This glossary lists and explains terms, acronyms, and definitions. 12 Mechanical, Packaging, and Orderable Information The following pages include mechanical, packaging, and orderable information. This information is the most current data available for the designated devices. This data is subject to change without notice and revision of this document. For browser-based versions of this data sheet, refer to the left-hand navigation. 34 Submit Documentation Feedback Copyright (c) 2017, Texas Instruments Incorporated Product Folder Links: LM317-N-MIL PACKAGE OPTION ADDENDUM www.ti.com 10-Dec-2020 PACKAGING INFORMATION Orderable Device Status (1) Package Type Package Pins Package Drawing Qty Eco Plan (2) Lead finish/ Ball material MSL Peak Temp Op Temp (C) Device Marking (3) (4/5) (6) LM317K STEEL ACTIVE TO-3 NDS 2 50 Non-RoHS & Non-Green Call TI Call TI 0 to 0 LM317K STEELP+ LM317K STEEL/NOPB ACTIVE TO-3 NDS 2 50 RoHS & Green Call TI Level-1-NA-UNLIM 0 to 0 LM317K STEELP+ (1) The marketing status values are defined as follows: ACTIVE: Product device recommended for new designs. LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect. NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design. PREVIEW: Device has been announced but is not in production. Samples may or may not be available. OBSOLETE: TI has discontinued the production of the device. (2) RoHS: TI defines "RoHS" to mean semiconductor products that are compliant with the current EU RoHS requirements for all 10 RoHS substances, including the requirement that RoHS substance do not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, "RoHS" products are suitable for use in specified lead-free processes. TI may reference these types of products as "Pb-Free". RoHS Exempt: TI defines "RoHS Exempt" to mean products that contain lead but are compliant with EU RoHS pursuant to a specific EU RoHS exemption. Green: TI defines "Green" to mean the content of Chlorine (Cl) and Bromine (Br) based flame retardants meet JS709B low halogen requirements of <=1000ppm threshold. Antimony trioxide based flame retardants must also meet the <=1000ppm threshold requirement. (3) MSL, Peak Temp. - The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder temperature. (4) There may be additional marking, which relates to the logo, the lot trace code information, or the environmental category on the device. (5) Multiple Device Markings will be inside parentheses. Only one Device Marking contained in parentheses and separated by a "~" will appear on a device. If a line is indented then it is a continuation of the previous line and the two combined represent the entire Device Marking for that device. (6) Lead finish/Ball material - Orderable Devices may have multiple material finish options. Finish options are separated by a vertical ruled line. Lead finish/Ball material values may wrap to two lines if the finish value exceeds the maximum column width. Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided. TI bases its knowledge and belief on information provided by third parties, and makes no representation or warranty as to the accuracy of such information. Efforts are underway to better integrate information from third parties. TI has taken and continues to take reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on incoming materials and chemicals. TI and TI suppliers consider certain information to be proprietary, and thus CAS numbers and other limited information may not be available for release. In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold by TI to Customer on an annual basis. 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