LM1117

LM1117/LM1117I 800mA Low-Dropout Linear Regulator General Description The LM1117 is a series of low dropout voltage regulators with a dropout of 1.2V at 800mA of load current. It has the same pin-out as National Semiconductor’s industry standard LM317. The LM1117 is available in an adjustable version, which can set the output voltage from 1.25V to 13.8V with only two external resistors. In addition, it is also available in five fixed voltages, 1.8V, 2.5V, 2.85V, 3.3V, and 5V. The LM1117 offers current limiting and thermal shutdown. Its circuit includes a zener trimmed bandgap reference to as- sure output voltage accuracy to within ±1%. The LM1117 series is available in LLP, TO-263, SOT-223, TO-220, and TO-252 D-PAK packages. A minimum of 10µF tantalum capacitor is required at the output to improve the transient response and stability. Features n Available in 1.8V, 2.5V, 2.85V, 3.3V, 5V, and Adjustable Versions n Space Saving SOT-223 and LLP Packages n Current Limiting and Thermal Protection n Output Current 800mA n Line Regulation 0.2% (Max) n Load Regulation 0.4% (Max) n Temperature Range — LM1117 0˚C to 125˚C — LM1117I −40˚C to 125˚C Applications n 2.85V Model for SCSI-2 Active Termination n Post Regulator for Switching DC/DC Converter n High Efficiency Linear Regulators n Battery Charger n Battery Powered Instrumentation Typical Application Active Terminator for SCSI-2 Bus 10091905 Fixed Output Regulator 10091928 October 2002 LM 1117/LM 1117I800m A Low -DropoutLinearRegulator © 2002 National Semiconductor Corporation DS100919 www.national.com Ordering Information Package Temperature Range Part Number Packaging Marking Transport Media NSC Drawing 3-lead SOT-223 0˚C to +125˚C LM1117MPX-ADJ N03A Tape and Reel MP04A LM1117MPX-1.8 N12A Tape and Reel LM1117MPX-2.5 N13A Tape and Reel LM1117MPX-2.85 N04A Tape and Reel LM1117MPX-3.3 N05A Tape and Reel LM1117MPX-5.0 N06A Tape and Reel −40˚C to +125˚C LM1117IMPX-ADJ N03B Tape and Reel LM1117IMPX-3.3 N05B Tape and Reel LM1117IMPX-5.0 N06B Tape and Reel 3-lead TO-220 0˚C to +125˚C LM1117T-ADJ LM1117T-ADJ Rails T03B LM1117T-1.8 LM1117T-1.8 Rails LM1117T-2.5 LM1117T-2.5 Rails LM1117T-2.85 LM1117T-2.85 Rails LM1117T-3.3 LM1117T-3.3 Rails LM1117T-5.0 LM1117T-5.0 Rails 3-lead TO-252 0˚C to +125˚C LM1117DTX-ADJ LM1117DT-ADJ Tape and Reel TD03B LM1117DTX-1.8 LM1117DT-1.8 Tape and Reel LM1117DTX-2.5 LM1117DT-2.5 Tape and Reel LM1117DTX-2.85 LM1117DT-2.85 Tape and Reel LM1117DTX-3.3 LM1117DT-3.3 Tape and Reel LM1117DTX-5.0 LM1117DT-5.0 Tape and Reel −40˚C to +125˚C LM1117IDTX-ADJ LM1117IDT-ADJ Tape and Reel LM1117IDTX-3.3 LM1117IDT-3.3 Tape and Reel LM1117IDTX-5.0 LM1117IDT-5.0 Tape and Reel 8-lead LLP 0˚C to +125˚C LM1117LDX-ADJ 1117ADJ Tape and Reel LDC08A LM1117LDX-1.8 1117-18 Tape and Reel LM1117LDX-2.5 1117-25 Tape and Reel LM1117LDX-2.85 1117-28 Tape and Reel LM1117LDX-3.3 1117-33 Tape and Reel LM1117LDX-5.0 1117-50 Tape and Reel −40˚C to 125˚C LM1117ILDX-ADJ 1117IAD Tape and Reel LM1117ILDX-3.3 1117I33 Tape and Reel LM1117ILDX-5.0 1117I50 Tape and Reel TO-263 0˚C to +125˚C LM1117SX-ADJ LM1117SADJ Tape and Reel TS3B LM1117SX-2.85 LM1117S2.85 Tape and Reel LM1117SX-3.3 LM1117S3.3 Tape and Reel LM1117SX-5.0 LM1117S5.0 Tape and Reel LM 11 17 /L M 11 17 I www.national.com 2 Block Diagram 10091901 Connection Diagrams SOT-223 10091904 Top View TO-220 10091902 Top View TO-252 10091938 Top View TO-263 10091944 Top View 10091945 Side View LLP 10091946 When using the LLP package Pins 2, 3 & 4 must be connected together and Pins 5, 6 & 7 must be connected together Top View LM 1117/LM 1117I www.national.com3 Absolute Maximum Ratings (Note 1) If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications. Maximum Input Voltage (VIN to GND) 20V Power Dissipation (Note 2) Internally Limited Junction Temperature (TJ) (Note 2) 150˚C Storage Temperature Range -65˚C to 150˚C Lead Temperature TO-220 (T) Package 260˚C, 10 sec SOT-223 (IMP) Package 260˚C, 4 sec ESD Tolerance (Note 3) 2000V Operating Ratings (Note 1) Input Voltage (VIN to GND) 15V Junction Temperature Range (TJ)(Note 2) LM1117 0˚C to 125˚C LM1117I −40˚C to 125˚C LM1117 Electrical Characteristics Typicals and limits appearing in normal type apply for TJ = 25˚C. Limits appearing in Boldface type apply over the entire junc- tion temperature range for operation, 0˚C to 125˚C. Symbol Parameter Conditions Min(Note 5) Typ (Note 4) Max (Note 5) Units VREF Reference Voltage LM1117-ADJ IOUT = 10mA, VIN-VOUT = 2V, TJ = 25˚C 10mA ≤ IOUT ≤ 800mA, 1.4V ≤ VIN-VOUT ≤ 10V 1.238 1.225 1.250 1.250 1.262 1.270 V V VOUT Output Voltage LM1117-1.8 IOUT = 10mA, VIN = 3.8V, TJ = 25˚C 0 ≤ IOUT ≤ 800mA, 3.2V ≤ VIN ≤ 10V 1.782 1.746 1.800 1.800 1.818 1.854 V V LM1117-2.5 IOUT = 10mA, VIN = 4.5V, TJ = 25˚C 0 ≤ IOUT ≤ 800mA, 3.9V ≤ VIN ≤ 10V 2.475 2.450 2.500 2.500 2.525 2.550 V V LM1117-2.85 IOUT = 10mA, VIN = 4.85V, TJ = 25˚C 0 ≤ IOUT ≤ 800mA, 4.25V ≤ VIN ≤ 10V 0 ≤ IOUT ≤ 500mA, VIN = 4.10V 2.820 2.790 2.790 2.850 2.850 2.850 2.880 2.910 2.910 V V V LM1117-3.3 IOUT = 10mA, VIN = 5V TJ = 25˚C 0 ≤ IOUT ≤ 800mA, 4.75V≤ VIN ≤ 10V 3.267 3.235 3.300 3.300 3.333 3.365 V V LM1117-5.0 IOUT = 10mA, VIN = 7V, TJ = 25˚C 0 ≤ IOUT ≤ 800mA, 6.5V ≤ VIN ≤ 12V 4.950 4.900 5.000 5.000 5.050 5.100 V V ∆VOUT Line Regulation (Note 6) LM1117-ADJ IOUT = 10mA, 1.5V ≤ VIN-VOUT ≤ 13.75V 0.035 0.2 % LM1117-1.8 IOUT = 0mA, 3.2V ≤ VIN ≤ 10V 1 6 mV LM1117-2.5 IOUT = 0mA, 3.9V ≤ VIN ≤ 10V 1 6 mV LM1117-2.85 IOUT = 0mA, 4.25V ≤ VIN ≤ 10V 1 6 mV LM1117-3.3 IOUT = 0mA, 4.75V ≤ VIN ≤ 15V 1 6 mV LM1117-5.0 IOUT = 0mA, 6.5V ≤ VIN ≤ 15V 1 10 mV LM 11 17 /L M 11 17 I www.national.com 4 LM1117 Electrical Characteristics (Continued) Typicals and limits appearing in normal type apply for TJ = 25˚C. Limits appearing in Boldface type apply over the entire junc- tion temperature range for operation, 0˚C to 125˚C. Symbol Parameter Conditions Min(Note 5) Typ (Note 4) Max (Note 5) Units ∆VOUT Load Regulation (Note 6) LM1117-ADJ VIN-VOUT = 3V, 10 ≤ IOUT ≤ 800mA 0.2 0.4 % LM1117-1.8 VIN = 3.2V, 0 ≤ IOUT ≤ 800mA 1 10 mV LM1117-2.5 VIN = 3.9V, 0 ≤ IOUT ≤ 800mA 1 10 mV LM1117-2.85 VIN = 4.25V, 0 ≤ IOUT ≤ 800mA 1 10 mV LM1117-3.3 VIN = 4.75V, 0 ≤ IOUT ≤ 800mA 1 10 mV LM1117-5.0 VIN = 6.5V, 0 ≤ IOUT ≤ 800mA 1 15 mV VIN-V OUT Dropout Voltage (Note 7) IOUT = 100mA 1.10 1.20 V IOUT = 500mA 1.15 1.25 V IOUT = 800mA 1.20 1.30 V ILIMIT Current Limit VIN-VOUT = 5V, TJ = 25˚C 800 1200 1500 mA Minimum Load Current (Note 8) LM1117-ADJ VIN = 15V 1.7 5 mA Quiescent Current LM1117-1.8 VIN ≤ 15V 5 10 mA LM1117-2.5 VIN ≤ 15V 5 10 mA LM1117-2.85 VIN ≤ 10V 5 10 mA LM1117-3.3 VIN ≤ 15V 5 10 mA LM1117-5.0 VIN ≤ 15V 5 10 mA Thermal Regulation TA = 25˚C, 30ms Pulse 0.01 0.1 %/W Ripple Regulation fRIPPLE =1 20Hz, VIN-VOUT = 3V VRIPPLE = 1VPP 60 75 dB Adjust Pin Current 60 120 µA Adjust Pin Current Change 10 ≤ IOUT≤ 800mA, 1.4V ≤ VIN-VOUT ≤ 10V 0.2 5 µA Temperature Stability 0.5 % Long Term Stability TA = 125˚C, 1000Hrs 0.3 % RMS Output Noise (% of VOUT), 10Hz ≤ f ≤10kHz 0.003 % Thermal Resistance Junction-to-Case 3-Lead SOT-223 15.0 ˚C/W 3-Lead TO-220 3.0 ˚C/W 3-Lead TO-252 10 ˚C/W Thermal Resistance Junction-to-Ambient (No air flow) 3-Lead SOT-223 (No heat sink) 136 ˚C/W 3-Lead TO-220 (No heat sink) 79 ˚C/W 3-Lead TO-252 (Note 9) (No heat sink) 92 ˚C/W 3-Lead TO-263 55 ˚C/W 8-Lead LLP(Note 10) 40 ˚C/W LM 1117/LM 1117I www.national.com5 LM1117I Electrical Characteristics Typicals and limits appearing in normal type apply for TJ = 25˚C. Limits appearing in Boldface type apply over the entire junc- tion temperature range for operation, −40˚C to 125˚C. Symbol Parameter Conditions Min(Note 5) Typ (Note 4) Max (Note 5) Units VREF Reference Voltage LM1117I-ADJ IOUT = 10mA, VIN-VOUT = 2V, TJ = 25˚C 10mA ≤ IOUT ≤ 800mA, 1.4V ≤ VIN-VOUT ≤ 10V 1.238 1.200 1.250 1.250 1.262 1.290 V V VOUT Output Voltage LM1117I-3.3 IOUT = 10mA, VIN = 5V, TJ = 25˚C 0 ≤ IOUT ≤ 800mA, 4.75V ≤ VIN ≤ 10V 3.267 3.168 3.300 3.300 3.333 3.432 V V LM1117I-5.0 IOUT = 10mA, VIN = 7V, TJ = 25˚C 0 ≤ IOUT ≤ 800mA, 6.5V ≤ VIN ≤ 12V 4.950 4.800 5.000 5.000 5.050 5.200 V V ∆VOUT Line Regulation (Note 6) LM1117I-ADJ IOUT = 10mA, 1.5V ≤ VIN-VOUT ≤ 13.75V 0.035 0.3 % LM1117I-3.3 IOUT = 0mA, 4.75V ≤ VIN ≤ 15V 1 10 mV LM1117I-5.0 IOUT = 0mA, 6.5V ≤ VIN ≤ 15V 1 15 mV ∆VOUT Load Regulation (Note 6) LM1117I-ADJ VIN-VOUT = 3V, 10 ≤ IOUT ≤ 800mA 0.2 0.5 % LM1117I-3.3 VIN = 4.75V, 0 ≤ IOUT ≤ 800mA 1 15 mV LM1117I-5.0 VIN = 6.5V, 0 ≤ IOUT ≤ 800mA 1 20 mV VIN-V OUT Dropout Voltage (Note 7) IOUT = 100mA 1.10 1.30 V IOUT = 500mA 1.15 1.35 V IOUT = 800mA 1.20 1.40 V ILIMIT Current Limit VIN-VOUT = 5V, TJ = 25˚C 800 1200 1500 mA Minimum Load Current (Note 8) LM1117I-ADJ VIN = 15V 1.7 5 mA Quiescent Current LM1117I-3.3 VIN ≤ 15V 5 15 mA LM1117I-5.0 VIN ≤ 15V 5 15 mA Thermal Regulation TA = 25˚C, 30ms Pulse 0.01 0.1 %/W Ripple Regulation fRIPPLE =1 20Hz, VIN-VOUT = 3V VRIPPLE = 1VPP 60 75 dB Adjust Pin Current 60 120 µA Adjust Pin Current Change 10 ≤ IOUT≤ 800mA, 1.4V ≤ VIN-VOUT ≤ 10V 0.2 10 µA Temperature Stability 0.5 % Long Term Stability TA = 125˚C, 1000Hrs 0.3 % RMS Output Noise (% of VOUT), 10Hz ≤ f ≤10kHz 0.003 % Thermal Resistance Junction-to-Case 3-Lead SOT-223 15.0 ˚C/W 3-Lead TO-252 10 ˚C/W Thermal Resistance Junction-to-Ambient No air flow) 3-Lead SOT-223 (No heat sink) 136 ˚C/W 3-Lead TO-252 (No heat sink)(Note 9) 92 ˚C/W 8-Lead LLP(Note 10) 40 ˚C/W Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is intended to be functional, but specific performance is not guaranteed. For guaranteed specifications and the test conditions, see the Electrical Characteristics. LM 11 17 /L M 11 17 I www.national.com 6 Note 2: The maximum power dissipation is a function of TJ(max) , θJA, and TA. The maximum allowable power dissipation at any ambient temperature is PD = (TJ(max)–TA)/θJA. All numbers apply for packages soldered directly into a PC board. Note 3: For testing purposes, ESD was applied using human body model, 1.5kΩ in series with 100pF. Note 4: Typical Values represent the most likely parametric norm. Note 5: All limits are guaranteed by testing or statistical analysis. Note 6: Load and line regulation are measured at constant junction room temperature. Note 7: The dropout voltage is the input/output differential at which the circuit ceases to regulate against further reduction in input voltage. It is measured when the output voltage has dropped 100mV from the nominal value obtained at VIN = VOUT +1.5V. Note 8: The minimum output current required to maintain regulation. Note 9: Minimum pad size of 0.038in2 Note 10: Thermal Performance for the LLP was obtained using JESD51-7 board with six vias and an ambient temperature of 22˚C. For information about improved thermal performance and power dissipation for the LLP, refer to Application Note AN-1187. Typical Performance Characteristics Dropout Voltage (VIN-V OUT) Short-Circuit Current 10091922 10091923 Load Regulation LM1117-ADJ Ripple Rejection 10091943 10091906 LM 1117/LM 1117I www.national.com7 Typical Performance Characteristics (Continued) LM1117-ADJ Ripple Rejection vs. Current Temperature Stability 10091907 10091925 Adjust Pin Current LM1117-2.85 Load Transient Response 10091926 10091908 LM1117-5.0 Load Transient Response LM1117-2.85 Line Transient Response 10091909 10091910 LM 11 17 /L M 11 17 I www.national.com 8 Typical Performance Characteristics (Continued) LM1117-5.0 Line Transient Response 10091911 Application Note 1.0 External Capacitors/Stability 1.1 Input Bypass Capacitor An input capacitor is recommended. A 10µF tantalum on the input is a suitable input bypassing for almost all applications. 1.2 Adjust Terminal Bypass Capacitor The adjust terminal can be bypassed to ground with a by- pass capacitor (CADJ) to improve ripple rejection. This by- pass capacitor prevents ripple from being amplified as the output voltage is increased. At any ripple frequency, the impedance of the CADJ should be less than R1 to prevent the ripple from being amplified: 1/(2π*fRIPPLE*CADJ) < R1 The R1 is the resistor between the output and the adjust pin. Its value is normally in the range of 100-200Ω. For example, with R1 = 124Ω and fRIPPLE = 120Hz, the CADJ should be > 11µF. 1.3 Output Capacitor The output capacitor is critical in maintaining regulator sta- bility, and must meet the required conditions for both mini- mum amount of capacitance and ESR (Equivalent Series Resistance). The minimum output capacitance required by the LM1117 is 10µF, if a tantalum capacitor is used. Any increase of the output capacitance will merely improve the loop stability and transient response. The ESR of the output capacitor should range between 0.3Ω - 22Ω. In the case of the adjustable regulator, when the CADJ is used, a larger output capacitance (22µf tantalum) is required. 2.0 Output Voltage The LM1117 adjustable version develops a 1.25V reference voltage, VREF, between the output and the adjust terminal. As shown in Figure 1, this voltage is applied across resistor R1 to generate a constant current I1. The current IADJ from the adjust terminal could introduce error to the output. But since it is very small (60µA) compared with the I1 and very constant with line and load changes, the error can be ig- nored. The constant current I1 then flows through the output set resistor R2 and sets the output voltage to the desired level. For fixed voltage devices, R1 and R2 are integrated inside the devices. 3.0 Load Regulation The LM1117 regulates the voltage that appears between its output and ground pins, or between its output and adjust pins. In some cases, line resistances can introduce errors to the voltage across the load. To obtain the best load regula- tion, a few precautions are needed. Figure 2, shows a typical application using a fixed output regulator. The Rt1 and Rt2 are the line resistances. It is obvious that the VLOAD is less than the VOUT by the sum of the voltage drops along the line resistances. In this case, the load regulation seen at the RLOAD would be degraded from the data sheet specification. To improve this, the load should be tied directly to the output terminal on the positive side and directly tied to the ground terminal on the negative side. 10091917 FIGURE 1. Basic Adjustable Regulator LM 1117/LM 1117I www.national.com9 Application Note (Continued) When the adjustable regulator is used (Figure 3), the best performance is obtained with the positive side of the resistor R1 tied directly to the output terminal of the regulator rather than near the load. This eliminates line drops from appearing effectively in series with the reference and degrading regu- lation. For example, a 5V regulator with 0.05Ω resistance between the regulator and load will have a load regulation due to line resistance of 0.05Ω x IL. If R1 (=125Ω) is con- nected near the load, the effective line resistance will be 0.05Ω (1+R2/R1) or in this case, it is 4 times worse. In addition, the ground side of the resistor R2 can be returned near the ground of the load to provide remote ground sens- ing and improve load regulation. 4.0 Protection Diodes Under normal operation, the LM1117 regulators do not need any protection diode. With the adjustable device, the internal resistance between the adjust and output terminals limits the current. No diode is needed to divert the current around the regulator even with capacitor on the adjust terminal. The adjust pin can take a transient signal of ±25V with respect to the output voltage without damaging the device. When a output capacitor is connected to a regulator and the input is shorted to ground, the output capacitor will discharge into the output of the regulator. The discharge current de- pends on the value of the capacitor, the output voltage of the regulator, and rate of decrease of VIN. In the LM1117 regu- lators, the internal diode between the output and input pins can withstand microsecond surge currents of 10A to 20A. With an extremely large output capacitor (≥1000 µF), and with input instantaneously shorted to ground, the regulator could be damaged. In this case, an external diode is recommended between the output and input pins to protect the regulator, as shown in Figure 4. 5.0 Heatsink Requirements When an integrated circuit operates with an appreciable current, its junction temperature is elevated. It is important to quantify its thermal limits in order to achieve acceptable performance and reliability. This limit is determined by sum- ming the individual parts consisting of a series of tempera- ture rises from the semiconductor junction to the operating environment. A one-dimensional steady-state model of con- duction heat transfer is demonstrated in Figure 5. The heat generated at the device junction flows through the die to the die attach pad, through the lead frame to the surrounding case material, to the printed circuit board, and eventually to the ambient environment. Below is a list of variables that may affect the thermal resistance and in turn the need for a heatsink. RθJC (Component Variables) Rθ CA (Application Variables) Leadframe Size & Material Mounting Pad Size, Material, & Location No. of Conduction Pins Placement of Mounting Pad Die Size PCB Size & Material Die Attach Material Traces Length & Width Molding Compound Size and Material Adjacent Heat Sources Volume of Air Ambient Temperatue Shape of Mounting Pad 10091918 FIGURE 2. Typical Application using Fixed Output Regulator 10091919 FIGURE 3. Best Load Regulation using Adjustable Output Regulator 10091915 FIGURE 4. Regulator with Protection Diode LM 11 17 /L M 11 17 I www.national.com 10 Application Note (Continued) The LM1117 regulators have internal thermal shutdown to protect the device from over-heating. Under all possible operating conditions, the junction temperature of the LM1117 must be within the range of 0˚C to 125˚C. A heatsink may be required depending on the maximum power dissipation and maximum ambient temperature of the application. To deter- mine if a heatsink is needed, the power dissipated by the regulator, PD , must be calculated: IIN = IL + IG PD = (VIN-VOUT)I L + VINIG Figure 6 shows the voltages and currents which are present in the circuit. The next parameter which must be calculated is the maxi- mum allowable temperature rise, TR(max): TR(max) = TJ(max)-TA(max) where TJ(max) is the maximum allowable junction tempera- ture (125˚C), and TA(max) is the maximum ambient tem- perature which will be encountered in the application. Using the calculated values for TR(max) and PD, the maxi- mum allowable value for the junction-to-ambient thermal resistance (θJA) can be calculated: θJA = TR(max)/PD If the maximum allowable value for θJA is found to be ≥136˚C/W for SOT-223 package or ≥79˚C/W for TO-220 package or ≥92˚C/W for TO-252 package, no heatsink is needed since the package alone will dissipate enough heat to satisfy these requirements. If the calculated value for θJA falls below these limits, a heatsink is required. As a design aid, Table 1 shows the value of the θJA of SOT-223 and TO-252 for different heatsink area. The copper patterns that we used to measure these θJAs are shown at the end of the Application Notes Section. Figure 7 and Figure 8 reflects the same test results as what are in the Table 1 Figure 9 and Figure 10 shows the maximum allowable power dissipation vs. ambient temperature for the SOT-223 and TO-252 device. Figures Figure 11 and Figure 12 shows the maximum allowable power dissipation vs. copper area (in2) for the SOT-223 and TO-252 devices. Please see AN1028 for power enhanc