Product Folder Order Now Support & Community Tools & Software Technical Documents LM317A SNVSAC2A - MARCH 2015 - REVISED JUNE 2020 LM317A 1% Accurate 1.5A Adjustable Voltage Regulator 1 Features 3 Description * * * * * * * * * * The LM317A adjustable 3-terminal, positive-voltage regulators are capable of supplying current in excess of 1.5 A over a 1.25-V to 37-V output range and provide 1% output-voltage accuracy. Both line regulation and load regulation are better achieved with the LM317A device than with standard fixed regulators. 1 For a newer drop-in alternative, see the LM317 Typical 0.005%/V line regulation 1% output voltage tolerance 1.5-A output current Adjustable output down to 1.25 V Input-output differential up to 40 V Current limit constant with temperature No output capacitor required Short-circuit protected output -40C to 125C operating temperature range 2 Applications * * * * * Automotive LED lighting Battery chargers Post regulation for switching supplies Constant-current regulator Microprocessor supplies Typical Application *Needed if device is more than 6 inches from filter capacitors. Optional--improves transient response VOUT ae R2 o = 1.25 V c 1 + + I ADJ (R2 ) R1 /o e The LM317A offers full overload protection such as over current, thermal-overload protection, and safearea 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 and can be replaced with a ceramic and appropriate ESR. The adjustment terminal can be bypassed to achieve very high ripplerejection ratios that are difficult to achieve with standard 3-terminal regulators. Because the LM317A 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. Exceeding the maximum input-to-output deferential will result in short-circuiting the output. By connecting a fixed resistor between the adjustment pin and output, the LM317A can be also used as a precision current regulator. For applications requiring greater output current, see the LM150 series (3A) and LM138 series (5A) data sheets. For the negative complement, see the LM137 series data sheet. Device Information(1) PART NUMBER LM317A PACKAGE BODY SIZE (NOM) TO-220 (3) 14.986 mm x 10.16 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. LM317A SNVSAC2A - MARCH 2015 - REVISED JUNE 2020 www.ti.com Table of Contents 1 2 3 4 5 6 7 8 Features .................................................................. Applications ........................................................... Description ............................................................. Revision History..................................................... Device Comparison Table..................................... Pin Configuration and Functions ......................... Specifications......................................................... 1 1 1 2 3 4 5 7.1 7.2 7.3 7.4 7.5 7.6 5 5 5 5 6 7 Absolute Maximum Ratings ...................................... ESD Ratings.............................................................. Recommended Operating Conditions....................... Thermal Information .................................................. Electrical Characteristics........................................... Typical Characteristics .............................................. Detailed Description ............................................ 10 8.1 Overview ................................................................. 10 8.2 Functional Block Diagram ....................................... 11 8.3 Feature Description................................................. 12 8.4 Device Functional Modes........................................ 12 9 Application and Implementation ........................ 14 9.1 Application Information............................................ 14 9.2 Typical Applications ................................................ 14 10 Power Supply Recommendations ..................... 25 11 Layout................................................................... 25 11.1 Layout Guidelines ................................................. 25 11.2 Layout Examples................................................... 30 12 Device and Documentation Support ................. 32 12.1 12.2 12.3 12.4 12.5 12.6 Documentation Support ........................................ Receiving Notification of Documentation Updates Support Resources ............................................... Trademarks ........................................................... Electrostatic Discharge Caution ............................ Glossary ................................................................ 32 32 32 32 32 32 13 Mechanical, Packaging, and Orderable Information ........................................................... 32 4 Revision History NOTE: Page numbers for previous revisions may differ from page numbers in the current version. Changes from Original (October 2015) to Revision A Page * Added alternative device Features bullet ............................................................................................................................... 1 * Changed Device Comparison Table ...................................................................................................................................... 3 * Changed Related Documentation section ............................................................................................................................ 32 2 Submit Documentation Feedback Copyright (c) 2015-2020, Texas Instruments Incorporated Product Folder Links: LM317A LM317A www.ti.com SNVSAC2A - MARCH 2015 - REVISED JUNE 2020 5 Device Comparison Table IOUT 1.5 A PARAMETER LM317 LM317-N LM317A LM317HV Input voltage range 4.25 - 40 4.25 - 40 4.25 - 40 4.25 - 60 UNIT V Load regulation accuracy 1.5 1.5 1 1.5 % dB PSRR (120 Hz) 64 80 80 65 Recommended operating temperature 0 to 125 0 to 125 -40 to 125 0 to 125 C TO-220 (NDE) TJA 23.5 23.2 23.3 23 C/W TO-200 (KCT) TJA 37.9 N/A N/A N/A C/W TO-252 TJA N/A 54 54 N/A C/W TO-263 TJA 38 41 N/A N/A C/W SOT-223 TJA 66.8 59.6 59.6 N/A C/W N/A 186 186 N/A C/W TO-92 TJA LM317M 0.5 A Input voltage range 3.75 - 40 Load regulation accuracy 1.5 % PSRR (120 Hz) 80 dB Recommended operating temperature -40 - 125 C SOT-223 TJA 60.2 C/W TO-252 TJA 56.9 C/W LM317L LM317L-N 3.75 - 40 4.25 - 40 Load regulation accuracy 1 1.5 % PSRR (120 Hz) 62 80 dB Recommended operating temperature -40 to 125 -40 to 125 C SOT-23 TJA 167.8 N/A C/W SO-8 TJA N/A 165 C/W DSBGA TJA N/A 290 C/W TO-92 TJA N/A 180 C/W Input voltage range 0.1 A V V Submit Documentation Feedback Copyright (c) 2015-2020, Texas Instruments Incorporated Product Folder Links: LM317A 3 LM317A SNVSAC2A - MARCH 2015 - REVISED JUNE 2020 www.ti.com 6 Pin Configuration and Functions Metal Can NDT Package 3-Pin TO Bottom View Surface-Mount DCY Package 4-Pin SOT-223 Top View CASE IS OUTPUT Surface-Mount NDP Package 4-Pin TO-252 Front View Plastic NDE Package 3-Pin TO-220 Front View Pin Functions PIN NAME I/O DESCRIPTION TO-220 SOT-223 TO-252 TO ADJ 1 1 1 2 -- VIN 3 3 3 1 I Input voltage pin for the regulator 2, TAB 2, 4 2, TAB 3, CASE O Output voltage pin for the regulator VOUT 4 Adjust pin Submit Documentation Feedback Copyright (c) 2015-2020, Texas Instruments Incorporated Product Folder Links: LM317A LM317A www.ti.com SNVSAC2A - MARCH 2015 - REVISED JUNE 2020 7 Specifications 7.1 Absolute Maximum Ratings over operating free-air temperature range (unless otherwise noted) (1) (2) MIN MAX Power dissipation UNIT Internally Limited Input-output voltage differential -0.3 40 V Storage temperature, Tstg -65 150 C (1) (2) 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. 7.2 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. 7.3 Recommended Operating Conditions over operating free-air temperature range (unless otherwise noted) Operating temperature MIN MAX UNIT -40 125 C 7.4 Thermal Information LM317A THERMAL METRIC (1) (2) NDE (TO-220) DCY (SOT-223) NDT (TO) NDP (TO-252) UNIT 3 PINS 4 PINS 3 PINS 3 PINS RJA Junction-to-ambient thermal resistance 23.3 59.6 186 (3) 54.0 C/W RJC(top) Junction-to-case (top) thermal resistance 16.2 39.3 21 51.3 C/W RJB Junction-to-board thermal resistance 4.9 8.4 -- 28.6 C/W JT Junction-to-top characterization parameter 2.7 1.8 -- 3.9 C/W JB Junction-to-board characterization parameter 4.9 8.3 -- 28.1 C/W RJC(bot) Junction-to-case (bottom) thermal resistance 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. 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) 2015-2020, Texas Instruments Incorporated Product Folder Links: LM317A 5 LM317A SNVSAC2A - MARCH 2015 - REVISED JUNE 2020 www.ti.com 7.5 Electrical Characteristics Some specifications apply over full operating temperature range as noted. Unless otherwise specified, TJ = 25C, VIN - VOUT = 5 V, and IOUT = 10 mA. (1) PARAMETER MIN TYP MAX UNIT TJ = 25C TEST CONDITIONS 1.238 1.250 1.262 V Reference voltage 3 V (VIN - VOUT) 40 V, 10 mA IOUT IMAX (1) over full operating temperature range 1.225 1.250 1.270 V 0.005 0.01 Line regulation 3 V (VIN - VOUT) 40 V (2) 0.01 0.02 TJ = 25C 0.1% 0.5% Load regulation 10 mA IOUT IMAX (1) over full operating temperature range 0.3% 1% Thermal regulation 20-ms pulse 0.04 0.07 %/W Adjustment pin current over full operating temperature range 50 100 A 5 A mA TJ = 25C (2) over full operating temperature range %/V (1) Adjustment pin current change 10 mA IOUT IMAX 3 V (VIN - VOUT) 40 V (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 2.2 3.4 (VIN - VOUT) 15 V Current limit (VIN - VOUT) = 40 V SOT-223, TO-220 Packages, over full operating temperature range 1.5 TO, TO-252 Packages, over full operating temperature range 0.5 0.8 0.15 0.40 0.075 0.20 SOT-223, TO-220 Packages TO, TO-252 Packages RMS output noise, % of VOUT Ripple rejection ratio Long-term stability (1) (2) 6 A 10 Hz f 10 kHz TJ = 125C, 1000 hrs A 0.003% VOUT = 10 V, f = 120 Hz, CADJ = 0 F over full operating temperature range VOUT = 10 V, f = 120 Hz, CADJ = 10 F over full operating temperature range 1.8 66 65 dB 80 dB 0.3% 1% IMAX = 1.5 A for the NDE (TO-220). 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 minimum and maximum 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) 2015-2020, Texas Instruments Incorporated Product Folder Links: LM317A LM317A www.ti.com SNVSAC2A - MARCH 2015 - REVISED JUNE 2020 7.6 Typical Characteristics output capacitor = 0 F (unless otherwise noted) NDE PACKAGE DEVICE 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 = 5V Submit Documentation Feedback Copyright (c) 2015-2020, Texas Instruments Incorporated Product Folder Links: LM317A 7 LM317A SNVSAC2A - MARCH 2015 - REVISED JUNE 2020 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) 2015-2020, Texas Instruments Incorporated Product Folder Links: LM317A LM317A www.ti.com SNVSAC2A - MARCH 2015 - REVISED JUNE 2020 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) 2015-2020, Texas Instruments Incorporated Product Folder Links: LM317A 9 LM317A SNVSAC2A - MARCH 2015 - REVISED JUNE 2020 www.ti.com 8 Detailed Description 8.1 Overview In operation, the LM317A 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 LM317A 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) 2015-2020, Texas Instruments Incorporated Product Folder Links: LM317A LM317A www.ti.com SNVSAC2A - MARCH 2015 - REVISED JUNE 2020 8.2 Functional Block Diagram Submit Documentation Feedback Copyright (c) 2015-2020, Texas Instruments Incorporated Product Folder Links: LM317A 11 LM317A SNVSAC2A - MARCH 2015 - REVISED JUNE 2020 www.ti.com 8.3 Feature Description 8.3.1 Load Regulation The LM317A is capable of providing extremely good load regulation but a few precautions are needed to obtain maximum performance. The current set resistor, R1, should 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 should 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 package, care should 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. 8.4 Device Functional Modes 8.4.1 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 LM317A 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 capacitor 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 LM317A 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) 2015-2020, Texas Instruments Incorporated Product Folder Links: LM317A LM317A www.ti.com SNVSAC2A - MARCH 2015 - REVISED JUNE 2020 Device Functional Modes (continued) 8.4.2 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 LM317A, 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 LM317A 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 LM317A 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) 2015-2020, Texas Instruments Incorporated Product Folder Links: LM317A 13 LM317A SNVSAC2A - MARCH 2015 - REVISED JUNE 2020 www.ti.com 9 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 should validate and test their design implementation to confirm system functionality. 9.1 Application Information The LM317A is a versatile, high-performance, linear regulator with 1% output-voltage accuracy. 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. 9.2 Typical Applications 9.2.1 1.25-V to 25-V Adjustable Regulator The LM317A 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 9.2.1.1 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. 9.2.1.2 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) 2015-2020, Texas Instruments Incorporated Product Folder Links: LM317A LM317A www.ti.com SNVSAC2A - MARCH 2015 - REVISED JUNE 2020 Typical Applications (continued) 9.2.1.3 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 = 5 V 9.2.2 5-V Logic Regulator With Electronic Shutdown Figure 20 shows a variation of the 5-V output regulator application uses the LM317A, 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 LM317A 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 1.25 V Figure 20. 5-V Logic Regulator With Electronic Shutdown Submit Documentation Feedback Copyright (c) 2015-2020, Texas Instruments Incorporated Product Folder Links: LM317A 15 LM317A SNVSAC2A - MARCH 2015 - REVISED JUNE 2020 www.ti.com Typical Applications (continued) 9.2.3 Slow Turnon 15-V Regulator An application of LM317A 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 9.2.4 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 16 Submit Documentation Feedback Copyright (c) 2015-2020, Texas Instruments Incorporated Product Folder Links: LM317A LM317A www.ti.com SNVSAC2A - MARCH 2015 - REVISED JUNE 2020 Typical Applications (continued) 9.2.5 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). LM317A 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 9.2.6 High-Current Adjustable Regulator Using the LM195 power transistor in parallel with the LM317A 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 LM317A NOTE: Optional--improves ripple rejection Solid tantalum *Minimum load current = 30 mA Figure 24. High-Current Adjustable Regulator Submit Documentation Feedback Copyright (c) 2015-2020, Texas Instruments Incorporated Product Folder Links: LM317A 17 LM317A SNVSAC2A - MARCH 2015 - REVISED JUNE 2020 www.ti.com Typical Applications (continued) 9.2.7 Emitter-Follower Current Amplifier The LM317A 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 LM317A provides a more stable current bias than a current bias from a system using only a resistor. Figure 25. Emitter-Follower Current Amplifier 18 Submit Documentation Feedback Copyright (c) 2015-2020, Texas Instruments Incorporated Product Folder Links: LM317A LM317A www.ti.com SNVSAC2A - MARCH 2015 - REVISED JUNE 2020 Typical Applications (continued) 9.2.8 1-A Current Regulator A simple, fixed-current regulator can be made by placing a resistor between the VOUT and ADJ pins of the LM317A (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 9.2.9 Common-Emitter Amplifier Sometimes it is necessary to use a power transistor for high current gain. In this case, the LM317A 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 Submit Documentation Feedback Copyright (c) 2015-2020, Texas Instruments Incorporated Product Folder Links: LM317A 19 LM317A SNVSAC2A - MARCH 2015 - REVISED JUNE 2020 www.ti.com Typical Applications (continued) 9.2.10 Low-Cost 3-A Switching Regulator The LM317A 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 LM317A. NOTE: Solid tantalum *Core--Arnold A-254168-2 60 turns Figure 28. Low-Cost 3-A Switching Regulator 20 Submit Documentation Feedback Copyright (c) 2015-2020, Texas Instruments Incorporated Product Folder Links: LM317A LM317A www.ti.com SNVSAC2A - MARCH 2015 - REVISED JUNE 2020 Typical Applications (continued) 9.2.11 Current-Limited Voltage Regulator A maximum limit on output current can be set using 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 LM117's higher current limit) --At 50 mA output only 3/4 volt of drop occurs in R3 and R4 Figure 29. Current-Limited Voltage Regulator 9.2.12 Adjusting Multiple On-Card Regulators With Single Control Figure 30 shows how multiple LM317A 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 will affect all regulators. NOTE: *All outputs within 100 mV Minimum load--10 mA Figure 30. Adjusting Multiple On-Card Regulators With Single Control Submit Documentation Feedback Copyright (c) 2015-2020, Texas Instruments Incorporated Product Folder Links: LM317A 21 LM317A SNVSAC2A - MARCH 2015 - REVISED JUNE 2020 www.ti.com Typical Applications (continued) 9.2.13 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 LM317A regulates 6 V at the output. When the input falls below -6 V minus the dropout voltage, only the bottom LM317A 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. LM317A LM317A Figure 31. AC Voltage Regulator 9.2.14 12-V Battery Charger The LM317A 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. LM317A Use of RS allows low charging rates with fully charged battery. Figure 32. 12-V Battery Charger 22 Submit Documentation Feedback Copyright (c) 2015-2020, Texas Instruments Incorporated Product Folder Links: LM317A LM317A www.ti.com SNVSAC2A - MARCH 2015 - REVISED JUNE 2020 Typical Applications (continued) 9.2.15 Adjustable 4-A Regulator Using three LM317A devices in parallel increases load-current capability (see Figure 33). Output voltage is set by the variable resistor tied to the noninverting 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. LM317A LM317A LM317A Figure 33. Adjustable 4-A Regulator Submit Documentation Feedback Copyright (c) 2015-2020, Texas Instruments Incorporated Product Folder Links: LM317A 23 LM317A SNVSAC2A - MARCH 2015 - REVISED JUNE 2020 www.ti.com Typical Applications (continued) 9.2.16 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. LM317A NOTE: *Sets peak current (0.6A for 1) **The 1000-F is recommended to filter out input transients Figure 34. Current-Limited 6-V Charger 9.2.17 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. NOTE: *Sets maximum VOUT Figure 35. Digitally-Selected Outputs 24 Submit Documentation Feedback Copyright (c) 2015-2020, Texas Instruments Incorporated Product Folder Links: LM317A LM317A www.ti.com SNVSAC2A - MARCH 2015 - REVISED JUNE 2020 10 Power Supply Recommendations The input supply to the LM317A should be kept at a voltage level lower than the maximum input-to-output differential voltage of 40 V. When possible, the minimum dropout voltage should also be met with extra headroom to keep the LM317A in regulation. TI recommends the use of an input capacitor, 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. 11 Layout 11.1 Layout Guidelines Some layout guidelines should be followed to ensure proper regulation of the output voltage with minimum noise. Traces carrying the load current should be wide to reduce the amount of parasitic trace inductance and the feedback loop from VOUT to ADJ should be kept as short as possible. To improve PSRR, a bypass capacitor can be placed at the ADJ pin and should be located as close as possible to the IC. In cases when VIN shorts to ground, an external diode should 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 should be placed from ADJ to VOUT to provide a path for the bypass capacitor to discharge. These diodes should be placed close to the corresponding IC pins to increase their effectiveness. 11.1.1 Thermal Considerations 11.1.1.1 Heatsink Requirements The LM317A regulators have internal thermal shutdown to protect the device from over-heating. Under all operating conditions, the junction temperature of the LM317A should 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 calculated by Equation 2: PD = ((VIN - VOUT) x IL) + (VIN x IG) (2) Figure 36 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 3: TR(MAX) = TJ(MAX) - TA(MAX) where * * TJ(MAX) is the maximum allowable junction temperature (125C for the LM317A), and TA(MAX) is the maximum ambient temperature that will be encountered in the application. (3) Using the calculated values for TR(MAX) and PD, the maximum allowable value for the junction-to-ambient thermal resistance (JA) can be calculated by Equation 4: JA = (TR(MAX) / PD) (4) Figure 36. Power Dissipation Diagram Submit Documentation Feedback Copyright (c) 2015-2020, Texas Instruments Incorporated Product Folder Links: LM317A 25 LM317A SNVSAC2A - MARCH 2015 - REVISED JUNE 2020 www.ti.com Layout Guidelines (continued) 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 measures should be implemented. If a heatsink is needed, the value can be calculated from Equation 5: 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 (5) 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. 11.1.1.2 Heatsinking Surface Mount Packages The 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. 11.1.1.2.1 Heatsinking the SOT-223 (DCY) Package Figure 37 and Figure 38 show the information for the SOT-223 package. Figure 38 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 the AN-1028 Maximum Power Enhancement Techniques for Power Packages application note for thermal enhancement techniques to be used with SOT-223 and TO-252 packages. Figure 37. JA vs Copper (2-oz.) Area for the SOT-223 Package Figure 38. Maximum Power Dissipation vs TAMB for the SOT-223 Package 11.1.1.2.2 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 43. Figure 39 reflects the same test results as what are in Table 1. 26 Submit Documentation Feedback Copyright (c) 2015-2020, Texas Instruments Incorporated Product Folder Links: LM317A LM317A www.ti.com SNVSAC2A - MARCH 2015 - REVISED JUNE 2020 Layout Guidelines (continued) Figure 40 shows the maximum allowable power dissipation versus ambient temperature for the TO-252 device. Figure 41 shows the maximum allowable power dissipation versus copper area (in2) for the TO-252 device. See the AN-1028 Maximum Power Enhancement Techniques for Power Packages application note for thermal enhancement techniques to be used with SOT-223 and TO-252 packages. 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 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 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 39. JA vs 2-oz. Copper Area for TO-252 Figure 40. Maximum Allowable Power Dissipation vs Ambient Temperature for TO-252 Submit Documentation Feedback Copyright (c) 2015-2020, Texas Instruments Incorporated Product Folder Links: LM317A 27 LM317A SNVSAC2A - MARCH 2015 - REVISED JUNE 2020 www.ti.com Figure 41. Maximum Allowable Power Dissipation vs 2-oz. Copper Area for TO-252 Figure 42. Top View of the Thermal Test Pattern in Actual Scale 28 Submit Documentation Feedback Copyright (c) 2015-2020, Texas Instruments Incorporated Product Folder Links: LM317A LM317A www.ti.com SNVSAC2A - MARCH 2015 - REVISED JUNE 2020 Figure 43. Bottom View of the Thermal Test Pattern in Actual Scale Submit Documentation Feedback Copyright (c) 2015-2020, Texas Instruments Incorporated Product Folder Links: LM317A 29 LM317A SNVSAC2A - MARCH 2015 - REVISED JUNE 2020 www.ti.com 11.2 Layout Examples Figure 44. Layout Example (SOT-223) 30 Submit Documentation Feedback Copyright (c) 2015-2020, Texas Instruments Incorporated Product Folder Links: LM317A LM317A www.ti.com SNVSAC2A - MARCH 2015 - REVISED JUNE 2020 Layout Examples (continued) Figure 45. Layout Example (TO-220) Submit Documentation Feedback Copyright (c) 2015-2020, Texas Instruments Incorporated Product Folder Links: LM317A 31 LM317A SNVSAC2A - MARCH 2015 - REVISED JUNE 2020 www.ti.com 12 Device and Documentation Support 12.1 Documentation Support 12.1.1 Related Documentation For related documentation see the following: * Texas Instruments, LM150/LM350A/LM350 3-Amp Adjustable Regulators data sheet * Texas Instruments, LM138 and LM338 5-Amp Adjustable Regulators data sheet * Texas Instruments, LM137, LM337-N 3-Terminal Adjustable Negative Regulators data sheet * Texas Instruments, AN-1028 Maximum Power Enhancement Techniques for Power Packages application note 12.2 Receiving Notification of Documentation Updates To receive notification of documentation updates, navigate to the device product folder on ti.com. In the upper right corner, click on Alert me to register and receive a weekly digest of any product information that has changed. For change details, review the revision history included in any revised document. 12.3 Support Resources TI E2ETM support forums are an engineer's go-to source for fast, verified answers and design help -- straight from the experts. Search existing answers or ask your own question to get the quick design help you need. Linked content is 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. 12.4 Trademarks E2E is a trademark of Texas Instruments. All other trademarks are the property of their respective owners. 12.5 Electrostatic Discharge Caution This integrated circuit can be damaged by ESD. Texas Instruments recommends that all integrated circuits be handled with appropriate precautions. Failure to observe proper handling and installation procedures can cause damage. ESD damage can range from subtle performance degradation to complete device failure. Precision integrated circuits may be more susceptible to damage because very small parametric changes could cause the device not to meet its published specifications. 12.6 Glossary SLYZ022 -- TI Glossary. This glossary lists and explains terms, acronyms, and definitions. 13 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. 32 Submit Documentation Feedback Copyright (c) 2015-2020, Texas Instruments Incorporated Product Folder Links: LM317A PACKAGE OPTION ADDENDUM www.ti.com 11-Jan-2021 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) LM317AEMP NRND SOT-223 DCY 4 1000 Non-RoHS & Green Call TI Call TI -40 to 125 N07A LM317AEMP/NOPB ACTIVE SOT-223 DCY 4 1000 RoHS & Green SN Level-1-260C-UNLIM -40 to 125 N07A LM317AEMPX NRND SOT-223 DCY 4 2000 Non-RoHS & Green Call TI Call TI LM317AEMPX/NOPB ACTIVE SOT-223 DCY 4 2000 RoHS & Green SN Level-1-260C-UNLIM -40 to 125 N07A LM317AH ACTIVE TO NDT 3 500 RoHS & Green AU Level-1-NA-UNLIM -40 to 125 ( LM317AHP+, LM317 AHP+) LM317AH/NOPB ACTIVE TO NDT 3 500 RoHS & Green AU Level-1-NA-UNLIM -40 to 125 ( LM317AHP+, LM317 AHP+) LM317AMDT NRND TO-252 NDP 3 75 Non-RoHS & Green Call TI Call TI -40 to 125 LM317 AMDT LM317AMDT/NOPB ACTIVE TO-252 NDP 3 75 RoHS & Green SN Level-2-260C-1 YEAR -40 to 125 LM317 AMDT LM317AMDTX NRND TO-252 NDP 3 2500 Non-RoHS & Green Call TI Call TI -40 to 125 LM317 AMDT LM317AMDTX/NOPB ACTIVE TO-252 NDP 3 2500 RoHS & Green SN Level-2-260C-1 YEAR -40 to 125 LM317 AMDT LM317AT NRND TO-220 NDE 3 45 Non-RoHS & Green Call TI Call TI -40 to 125 LM317AT P+ LM317AT/NOPB ACTIVE TO-220 NDE 3 45 RoHS-Exempt & Green SN Level-1-NA-UNLIM -40 to 125 LM317AT P+ N07A (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". Addendum-Page 1 Samples PACKAGE OPTION ADDENDUM www.ti.com 11-Jan-2021 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. Addendum-Page 2 PACKAGE MATERIALS INFORMATION www.ti.com 9-Jun-2020 TAPE AND REEL INFORMATION *All dimensions are nominal Device Package Package Pins Type Drawing SPQ Reel Reel A0 Diameter Width (mm) (mm) W1 (mm) B0 (mm) K0 (mm) P1 (mm) W Pin1 (mm) Quadrant LM317AEMP SOT-223 DCY 4 1000 330.0 16.4 7.0 7.5 2.2 12.0 16.0 Q3 LM317AEMP/NOPB SOT-223 DCY 4 1000 330.0 LM317AEMPX SOT-223 DCY 4 2000 330.0 16.4 7.0 7.5 2.2 12.0 16.0 Q3 16.4 7.0 7.5 2.2 12.0 16.0 LM317AEMPX/NOPB SOT-223 DCY 4 2000 Q3 330.0 16.4 7.0 7.5 2.2 12.0 16.0 LM317AMDTX TO-252 NDP 3 Q3 2500 330.0 16.4 6.9 10.5 2.7 8.0 16.0 Q2 LM317AMDTX/NOPB TO-252 NDP 3 2500 330.0 16.4 6.9 10.5 2.7 8.0 16.0 Q2 Pack Materials-Page 1 PACKAGE MATERIALS INFORMATION www.ti.com 9-Jun-2020 *All dimensions are nominal Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) LM317AEMP SOT-223 DCY 4 1000 367.0 367.0 35.0 LM317AEMP/NOPB SOT-223 DCY 4 1000 367.0 367.0 35.0 LM317AEMPX SOT-223 DCY 4 2000 367.0 367.0 35.0 LM317AEMPX/NOPB SOT-223 DCY 4 2000 367.0 367.0 35.0 LM317AMDTX TO-252 NDP 3 2500 367.0 367.0 35.0 LM317AMDTX/NOPB TO-252 NDP 3 2500 367.0 367.0 38.0 Pack Materials-Page 2 MECHANICAL DATA NDE0003B www.ti.com MECHANICAL DATA MPDS094A - APRIL 2001 - REVISED JUNE 2002 DCY (R-PDSO-G4) PLASTIC SMALL-OUTLINE 6,70 (0.264) 6,30 (0.248) 3,10 (0.122) 2,90 (0.114) 4 0,10 (0.004) M 3,70 (0.146) 3,30 (0.130) 7,30 (0.287) 6,70 (0.264) Gauge Plane 1 2 0,84 (0.033) 0,66 (0.026) 2,30 (0.091) 4,60 (0.181) 1,80 (0.071) MAX 3 0-10 0,10 (0.004) M 0,25 (0.010) 0,75 (0.030) MIN 1,70 (0.067) 1,50 (0.059) 0,35 (0.014) 0,23 (0.009) Seating Plane 0,08 (0.003) 0,10 (0.0040) 0,02 (0.0008) 4202506/B 06/2002 NOTES: A. B. C. D. All linear dimensions are in millimeters (inches). This drawing is subject to change without notice. Body dimensions do not include mold flash or protrusion. Falls within JEDEC TO-261 Variation AA. POST OFFICE BOX 655303 * DALLAS, TEXAS 75265 PACKAGE OUTLINE NDP0003B TO-252 - 2.55 mm max height SCALE 1.500 TRANSISTOR OUTLINE 10.42 9.40 6.22 5.97 B 1.27 0.88 A 5.46 4.96 6.73 6.35 (2.345) 1 (2.5) 2.285 2 4.57 3 0.88 3X 0.64 0.25 C A B 1.02 0.64 PKG OPTIONAL 8 TOP & BOTTOM 8 1.14 0.89 C 2.55 MAX SEATING PLANE 0.17 0.88 0.46 0.60 0.46 0.51 MIN 4.32 MIN 3 2 4 1 4219870/A 03/2018 NOTES: 1. All linear dimensions are in millimeters. Any dimensions in parenthesis are for reference only. Dimensioning and tolerancing per ASME Y14.5M. 2. This drawing is subject to change without notice. 3. Reference JEDEC registration TO-252. www.ti.com EXAMPLE BOARD LAYOUT NDP0003B TO-252 - 2.55 mm max height TRANSISTOR OUTLINE SEE SOLDER MASK DETAIL 2X (2.15) (5.7) 2X (1.3) 1 4 (4.57) SYMM (5.5) 3 (R0.05) TYP (4.38) (2.285) PKG LAND PATTERN EXAMPLE EXPOSED METAL SHOWN SCALE: 8X 0.07 MAX ALL AROUND 0.07 MIN ALL AROUND METAL EDGE METAL UNDER SOLDER MASK EXPOSED METAL EXPOSED METAL SOLDER MASK OPENING NON SOLDER MASK DEFINED (PREFERRED) SOLDER MASK OPENING SOLDER MASK DEFINED SOLDER MASK DETAIL 4219870/A 03/2018 NOTES: (continued) 4. This package is designed to be soldered to a thermal pad on the board. For more information, see Texas Instruments literature numbers SLMA002(www.ti.com/lit/slm002) and SLMA004 (www.ti.com/lit/slma004). 5. Vias are optional depending on application, refer to device data sheet. It is recommended that vias under paste be filled, plugged or tented. www.ti.com EXAMPLE STENCIL DESIGN NDP0003B TO-252 - 2.55 mm max height TRANSISTOR OUTLINE (1.35) TYP 2X (2.15) 2X (1.3) (0.26) (R0.05) TYP (1.32) TYP (4.57) 16X (1.12) 16X (1.15) (4.38) PKG SOLDER PASTE EXAMPLE BASED ON 0.125 MM THICK STENCIL SCALE: 8X 4219870/A 03/2018 NOTES: (continued) 6. Laser cutting apertures with trapezoidal walls and rounded corners may offer better paste release. IPC-7525 may have alternate design recommendations. 7. Board assembly site may have different recommendations for stencil design. www.ti.com MECHANICAL DATA NDT0003A H03A (Rev D) www.ti.com IMPORTANT NOTICE AND DISCLAIMER TI PROVIDES TECHNICAL AND RELIABILITY DATA (INCLUDING DATASHEETS), DESIGN RESOURCES (INCLUDING REFERENCE DESIGNS), APPLICATION OR OTHER DESIGN ADVICE, WEB TOOLS, SAFETY INFORMATION, AND OTHER RESOURCES "AS IS" AND WITH ALL FAULTS, AND DISCLAIMS ALL WARRANTIES, EXPRESS AND IMPLIED, INCLUDING WITHOUT LIMITATION ANY IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT OF THIRD PARTY INTELLECTUAL PROPERTY RIGHTS. These resources are intended for skilled developers designing with TI products. You are solely responsible for (1) selecting the appropriate TI products for your application, (2) designing, validating and testing your application, and (3) ensuring your application meets applicable standards, and any other safety, security, or other requirements. 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