CYStech Electronics Corp. Spec. No. : C513L3 Issued Date : 2003.04.09 Revised Date :2005.05.03 Page No. : 1/9 Three Terminal Adjustable Output Positive Voltage Regulators LM317L3 The LM317L3 is an adjustable 3–terminal positive voltage regulator capable of supplying in excess of 1.5A over an output voltage range of 1.2 V to 37 V. This voltage regulator is exceptionally easy to use and requires only two external resistors to set the output voltage. Further, it employs internal current limiting, thermal shutdown and safe area compensation, making it essentially blow–out proof. The LM317L3 serves a wide variety of applications including local, on-card regulation. This device can also be used to make a programmable output regulator, or by connecting a fixed resistor between the adjustment and output, the LM317L3 can be used as a precision current regulator. ● Output Current in Excess of 1.5 A ● Output Adjustable between 1.2 V and 37 V ● Internal Thermal Overload Protection ● Internal Short Circuit Current Limiting Constant with Temperature ● Output Transistor Safe–Area Compensation ● Floating Operation for High Voltage Applications ● Eliminates Stocking many Fixed Voltages Standard Application Vin Vout LM317 PL317 Cin + ＊Cin is required if regulator is located an appreciate distance from power supply filter. ＊＊Cout is not needed for stability, however, it does improve transient response. R1 IAdj + 0.1µF Cout 1.0µF R2 Vout=1.25(1+R2/R1)+IAdjR2 Since IAdj is controlled to less than 100 µA, the error associated with this term is negligible in most applications. Package Information 1 2 3 Pin 1 2 3 Function ADJ OUTPUT INPUT SOT-223 LM317L3 CYStek Product Specification Spec. No. : C513L3 Issued Date : 2003.04.09 Revised Date :2005.05.03 Page No. : 2/9 CYStech Electronics Corp. Maximum Ratings Rating Input-Output Voltage Differential Power Dissipation TA=25℃ Operating Junction Temperature Range Storage Temperature Range Symbol VI-VO Value 40 Unit V PD Internally Limited W TJ Tstg -40 to +125 -65 to +150 ℃ ℃ Electrical Characteristics(VI-VO=5V,IO=0.5A,TJ=0 to 125℃, unless otherwise noted) Characteristics Line Regulation(Note 1) Load Regulation(Note 1) Symbol Conditions Reg line TA=25℃,3.0V≤VI-VO≤40V Reg load TA=25℃,10mA≤IO≤1.5A VO≤5.0V VO≥5.0V Thermal Regulation(Note 4) Reg therm TA=25℃, 20ms pulse Adjust Pin Current IAdj 2.5V≤VI-VO≤40V,10mA≤IL≤1.5A Adjust Pin Current Change ∆IAdj PD≤5W 3.0V≤VI-VO≤40V,10mA≤IO≤1.5A Reference Voltage Vref PD≤5W Temperature Stability Ts 0≤TJ≤125℃ Minimum Load Current to ILmin VI-VO=40V maintain Regulation Maximum Output Current Imax VI-VO≤15V,PD≤5W VI-VO≤40V,PD≤5W,TA=25℃ % of VO,TA=25℃,10Hz≤f≤10kHz RMS Noise N Ripple Rejection(Note 2) RR VO=10V,f=120Hz Without CAdj CAdj=10µF Long-Term Stability(Note 3) S TJ=125℃,TA=25℃ for endpoint measurements Min - Typ 0.01 Max 0.04 Unit %/V - 5.0 0.1 0.03 50 0.2 25 0.5 0.07 100 5.0 mV %VO %VO/W µA µA 1.2 1.25 1.3 V - 0.7 3.5 10 %VO mA 1. 5 0.15 - 2.2 0.4 0.003 - A 66 - 65 80 0.3 1.0 %VO dB %/1.0k Hrs Notes:1.Load and line regulation are specified at constant junction temperature. Changes in VO due to heating effects must be taken into account separately. Pulse testing with low duty cycle is used. 2.CAdj, when used, is connected between the adjustment pin and ground. 3.Since long-term stability cannot be measured on each device before shipment, this specification is an engineering estimate of average stability from lot to lot. 4.Power dissipation within an IC voltage regulator produces a temperature gradient on the die, affecting individual IC components on the die. These effects can be minimized by proper integrated circuit design and layout techniques. Thermal regulation is the effect of these temperature gradients on the output voltage and is expressed in percentage of output change per watt of power change in a specified time. LM317L3 CYStek Product Specification CYStech Electronics Corp. Spec. No. : C513L3 Issued Date : 2003.04.09 Revised Date :2005.05.03 Page No. : 3/9 Representative Schematic Diagram Vin Vout Adjust ∣VOH-VOL∣ Line Regulation(%/V)= ×100 ∣VOL∣ Pulse testing required 1% Duty Cycle is suggested Fig 1. Line Regulation and ∆IAdj/Line test circuit LM317L3 CYStek Product Specification CYStech Electronics Corp. Spec. No. : C513L3 Issued Date : 2003.04.09 Revised Date :2005.05.03 Page No. : 4/9 Vo(min load)-Vo(max load) Load Regulation(mV)=Vo(min load)-Vo(max load) Load Regulation(%Vo)= ×100 Vo(min load) Fig 2. Load Regulation and ∆IAdj/Load test circuit ＊ Pulse testing required. 1% Duty Cycle is suggested. To calculate R2: Vout=ISETR2+1.250V Assume ISET=5.25mA Fig 3. Standard Test Circuit LM317L3 CYStek Product Specification CYStech Electronics Corp. Spec. No. : C513L3 Issued Date : 2003.04.09 Revised Date :2005.05.03 Page No. : 5/9 Fig 4. Ripple Rejection Test Circuit Application Information Basic Circuit Operation The LM317 is a 3-terminal floating regulator. In operation, the LM317 develops and maintains a nominal 1.25V reference (Vref) between its output and adjustment terminals. This reference voltage is converted to a programming current (Iprog) by R1(see Fig 5), and this constant current flows through R2 to ground. The regulated output voltage is given by: Vout=Vref(1+R2/R1)+IAdjR2 Since the current from the adjustment terminal (IAdj) represents an error term in the equation, the LM317 was designed to control IAdj to less than 100 µA and keep it constant. To do this, all quiescent operating current is returned to the output terminal. This imposes the requirement for a minimum load current. If the load current is less than this minimum, the output voltage will rise. Since the LM317 is a floating regulator, it is only the voltage differential across the circuit which is important to performance, and operation at high voltages with respect to ground is possible. Fig 5. Basic Circuit Configuration LM317L3 CYStek Product Specification CYStech Electronics Corp. Spec. No. : C513L3 Issued Date : 2003.04.09 Revised Date :2005.05.03 Page No. : 6/9 Load Regulation The LM317 is capable of providing extremely good load regulation, but a few precautions are needed to obtain maximum performance. For best performance, the programming resistor (R1) should be connected as close to the regulator as possible to minimize line drops which effectively appear in series with the reference, thereby degrading regulation. The ground end of R2 can be returned near the load ground to provide remote ground sensing and improve load regulation. External Capacitors A 0.1µF disc or 1.0µF tantalum input bypass capacitor (Cin) is recommended to reduce the sensitivity to input line impedance. The adjustment terminal may be bypassed to ground to improve ripple rejection. This capacitor (CAdj) prevents ripple from being amplified as the output voltage is increased. A 10µF capacitor should improve ripple rejection about 15 dB at 120 Hz in a 10V application. Although the LM317 is stable with no output capacitance, like any feedback circuit, certain values of external capacitance can cause excessive ringing. An output capacitance (Co) in the form of a 1.0µF tantalum or 25µF aluminum electrolytic capacitor on the output swamps this effect and insures stability. 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. Fig 6 shows the LM317 with the recommended protection diodes for output voltages in excess of 25V or high capacitance values (Co>25µF,CAdj>10µF). Diode D1 prevents Co from discharging thru the IC during an input short circuit. Diode D2 protects against capacitor CAdj discharging through the IC during an output short circuit. The combination of diodes D1 and D2 prevents CAdj from discharging through the IC during an input short circuit. Fig 6. Voltage Regulator with Protection Diodes LM317L3 CYStek Product Specification CYStech Electronics Corp. Spec. No. : C513L3 Issued Date : 2003.04.09 Revised Date :2005.05.03 Page No. : 7/9 Application Circuits Fig 7. “Laboratory” Power Supply with Adjustable Current Limit and Output Voltage R1=Vref/(Iomax+IDSS) R2≤Vref/IDSS Vo<BVDSS+1.25V+Vss ILmin-IDSS<Io<1.5A As shown 0<Io<1.0A Fig 8. Adjustable Current Limiter LM317L3 Fig 9. 5.0V Electronic Shutdown Regulator CYStek Product Specification CYStech Electronics Corp. Fig 10. Slow Turn-on Regulator LM317L3 Spec. No. : C513L3 Issued Date : 2003.04.09 Revised Date :2005.05.03 Page No. : 8/9 Fig 11. Current Regulator CYStek Product Specification Spec. No. : C513L3 Issued Date : 2003.04.09 Revised Date :2005.05.03 Page No. : 9/9 CYStech Electronics Corp. SOT-223 Dimension A Marking: B 317 C 1 2 3 D E Style: Pin 1.Adj 2.Output 3.Input F H G a1 I a2 3-Lead SOT-223 Plastic Surface Mounted Package CYStek Package Code: L3 *: Typical Inches Min. Max. 0.1142 0.1220 0.2638 0.2874 0.1299 0.1457 0.0236 0.0315 *0.0906 0.2480 0.2638 DIM A B C D E F Millimeters Min. Max. 2.90 3.10 6.70 7.30 3.30 3.70 0.60 0.80 *2.30 6.30 6.70 DIM G H I a1 a2 Inches Min. Max. 0.0551 0.0709 0.0098 0.0138 0.0008 0.0039 *13o 0o 10 o Millimeters Min. Max. 1.40 1.80 0.25 0.35 0.02 0.10 *13o 0o 10 o Notes: 1.Controlling dimension: millimeters. 2.Maximum lead thickness includes lead finish thickness, and minimum lead thickness is the minimum thickness of base material. 3.If there is any question with packing specification or packing method, please contact your local CYStek sales office. Material: • Lead: 42 Alloy; solder plating • Mold Compound: Epoxy resin family, flammability solid burning class: UL94V-0 Important Notice: • All rights are reserved. Reproduction in whole or in part is prohibited without the prior written approval of CYStek. • CYStek reserves the right to make changes to its products without notice. • CYStek semiconductor products are not warranted to be suitable for use in Life-Support Applications, or systems. • CYStek assumes no liability for any consequence of customer product design, infringement of patents, or application assistance. LM317L3 CYStek Product Specification