LM317T

LM317T Integrated Circuit 3−Terminal Adjustable Positive Voltage Regulator Description: The LM317T is an adjustable 3−terminal positive voltage regulator in a TO220 type package capable of supplying in excess of 1.5A over a 1.2V to 37V output range. This device is exceptionally easy to use and both line and load regulation are better than standard fixed regulators. In addition to higher performance than fixed regulators, the LM317T offers full overload protection available only in IC’s. Included on the chip are current limit, thermal overload protection and safe area protection. All overload protection circuitry remains fully functional even if the adjustment terminal is disconnected. Normally, no capacitors are needed unless the device is situated far 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 which are difficult to achieve with standard 3−terminal regulators. Besides replacing fixed regulators, the LM317T is useful in a wide variety of other applications. Since the regulator is “floating” and sees 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. Also, it makes an especially simple adjustable switching regulator, a programmable output regulator, or by connecting a fixed resistor between the adjustment and output, the LM317T can be used as a precision current regulator. Supplies with electronic shutdown can be achieved by clamping the adjustment terminal to GND which programs the output to 1.2V where most loads draw little current. Features: D Adjustable Output Down to 1.2V D Guaranteed 1.5A Output Current D Line Regulation Typically 0.01%/V D Load Regulation Typically 0.1% D Current Limit Constant with Temperature D 100% Electrical Burn−In D Eliminates the Need to Stock Many Voltages D 80dB Ripple Rejection Absolute Maximum Ratings: Power Dissipation, PD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Internally Limited Input−Output Voltage Differential, VI−VO . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40V Operating Junction Temperature Range, TJ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 05 to +1255C Storage Temperature Range, Tstg . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . −655 to +1505C Typical Thermal Resistance, Junction−to−Case, RthJC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45C/W Lead Temperature (During Soldering, 10sec), TL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +3005C Electrical Characteristics: (05 3 TJ 3 +1255C, VIN−VOUT = 5V, IO = 500mA, IMAX = 1.5A, Note 1 unless otherwise specified) Parameter Line Regulation Load Regulation Symbol Test Conditions Min Typ Max Unit Regline TA = +255C, 3V 3 (VIN−VOUT) 3 40V, Note 2 − 0.01 0.04 %/V 3V 3 (VIN−VOUT) 3 40V − 0.02 0.07 %/V Regload Thermal Regulation TA = +255C, 10mA 3 IO 3 1MAX, Note 2 VOUT 3 5V − 5 25 mV VOUT . 5V − 0.1 0.5 % 10mA 3 IO 3 1MAX, Note 2 VOUT 3 5V − 20 70 mV VOUT . 5V − 0.3 1.5 % − 0.04 0.07 %/W − 50 100 3A TA = +255C, 20ms Pulse Adjustment Pin Current IAdj Adjustment Pin Current Change .IAdj 10mA 3 IL 3 IMAX, 2.5V 3 (VIN−VOUT) 3 40V − 0.2 5.0 3A Reference Voltage Vref 3V 3 (VIN−VOUT) 3 40V, 10mA 3 IO 3 1MAX, P 3 PMAX 1.20 1.25 1.30 V Temperature Stability TS 05 3 TJ 3 +1255C − 1 − % Minimum Load Current ILmin (VIN−VOUT) 3 40V − 3.5 10 mA Maximum Output Current Limit Imax VIN−VOUT 3 15V 1.5 2.2 − A VIN−VOUT = 40V − 0.4 − A TA = +255C, 10Hz 3 f 3 10kHz − 0.003 − % VOUT = 10V, f = 120Hz − 65 − dB 66 80 − dB − 0.3 1.0 % RMS Output Noise, % of VOUT Ripple Rejection Ratio N RR CADJ = 103F Long Term Stability S TA = +1255C, 1000 Hours Note 1. Although power dissipation is internally limited, these specifications are applicable for power dissipations of 20W. Note 2. Regulation is measured at constant junction temperature, using pulse testing with a low duty cycle. Changes in output voltage due to heating effects are covered under the specification for thermal regulation. .420 (10.67) Max .110 (2.79) .500 (12.7) Max .147 (3.75) Dia Max .250 (6.35) Max .500 (12.7) Min .070 (1.78) Max Adj .100 (2.54) VIN VOUT/Tab