| LT1SOA/LT350A LM150/LM350 TECHNOLOGY 3 Amp Positive Adjustable Regulator FEATURES DESCRIPTION = Guaranteed 1% Initial Voltage Tolerance The LT150A Series are 3-terminal positive adjustable = Guaranteed 3A Output Current voltage regulators which offer improved performance = Guaranteed 0.3% Load Regulation over earlier devices. A major feature of the LT150A/ = Guaranteed 0.01%/V Line Regulation 350A is the output voltage tolerance is guaranteed at a = 100% Thermal Limit Burn-in maximum of + 1%, allowing an overall power supply tolerance to be better than 3% using inexpensive 1% resistors. Line and load regulation performance has been improved as well. Additionally, the LT150A/ APPLICATIONS 350A reference voltage is guaranteed not to exceed 2% when operating over the full load, line and power = Improved Linear Regulators dissipation conditions. The LT150A/350A adjustable = Adjustable Power Supplies regulators offer an improved solution for all positive Constant Current Regulation voltage regulator requirements with load currents up =. Battery Chargers to 3 amps. Regulator With Reference Output Voltage Error 12 vn LTas0aT 5y = " Vi Vout zg 10 Pw - < T $ 1212 & 8 LM350 p> & ? = oc $ 010 3 U0, > a5 LT350A 2.5V Oo 4 > = 23 LT350A 171009 5 2 Oo 1 i 0 2 4 6810 20 40 100 QUTPUT VOLTAGE LI Ure 4-177LT150A/LT350A LM150/LM350 ABSOLUTE MAXIMUM RATINGS PACKAGE /ORDER INFORMATION Power Dissipation ....... he eeae Internally Limited BOTTOM VW Input to Output Voltage Differential .......... 35V soustuent , ORDER PART NUMBER Operating Junction Temperature Range LT150AK LT150A/LM150........... 55C to 150C cise LT350AK LT350A/LM350................ 0C to 125C Sn LM150K Storage Temperature Range ch none, LM350K LT150A/LM150........... 65C to 150C (STEEL) LT350A/LM350........... 65C to 150C Vor a Lead Temperature (Soldering, 10 sec.)...... 300C | : | i) LTS50AT OC) > LM350T PRECONDITIONING: | ee 10-221 100% THERMAL LIMIT BURN-IN ELECTRICAL CHARACTERISTICS (See Note 1) LTI5OA LM150 SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS Veer Reference Voltage lour = 10mA, T, = 25C Vv < (Vin Vour) < 35V 120. 125 = (1.30 V Oma < Ipyr < 3A, P < 30W AVoy Line Regulation < (Vin Vour) < 35V, (See Ve Note 2) " oun) 0.005 0.04 0.005 0.01 HIV e 0.02 0.05 0.02 0.05 %/V AVout Load Regulation 10mA < lIgyr < 3A, (See Note 2) Alour Ta = 25C Vour < 5V be) 1 5 15 mV Vour = 5V 0.1 0.3 0.1 0.3 % your < oy 6 15 50 2 50 mV ouT = e 0.3 1 3 1 % Thermal Regulation Ta = 25C, 20msec Pulse 0.002 0.01 0.002 0.01 %/W Ripple Rejection Vour = 10V, f = 120Hz Cany = 0 65 65 dB Capp = 10uF @;| 6 86 66 86 dB laps Adjust Pin Current e 50 100 50 100 pA Alans Adjust Pin Current Change 10mA <I < 3A 3V < (Vin Vour) < 35V e 0.2 5 0.2 5 pA Minimum Load Current (Vin Vour) = 35V e 3.5 5 3.5 5 mA Current Limit (Vin Vout) < 10V @| 3 45 3.0 45 A (Viw Vour) = 30V | 03 1 A AVout Temperature Stability 55C < T; < + 150C 2 - 1 % ATemp Sout Long Term Stability Ty = 125C 1 0.3 1 % ime en RMS Output Noise Ty = 25C, 10Hz2 < f < 10kHz 0.001 0.001 % (% of Vout) jc Thermat Resistance K Package 1.5 15 C/W Junction to CaseLT150A/LT350A LM150/LM350 . ELECTRICAL CHARACTERISTICS (See Note 1) LT350A LM350 SYMBOL PARAMETER CONDITIONS MIN TYP _*MAX MIN Tye MAX UNITS Vper Reference Voltage lout = 10mA, Tj = 25C V 3V < (Vin Vout) < 35V e 4.20 125 = =1.30 V 10mA < Igy < 3A, P < 30W AVout Line Regulation 3V < (Vin Vout) < 35V, (See AV Note 2 " Ta 2 25C 0.005 0.03 %/V e 0.02 0.07 %/V AVour Load Regulation 10MA < Ioyr < 3A, (See Note 2) Alor Ty = 25C OUT Vou, =< 5V 5 25 mV Vout 2 5V 0.1 0.5 % Vour < 5V e 20 70 mV Vout > 5V e 0.3 1.5 % Thermal Regulation Ty = 25C, 20msec Pulse 0.002 0.03 %/W Ripple Rejection Vout == 10V, f = 120Hz Can = 0 e 65 65 dB Cans = 10pF @;| 66 86 66 86 dB las Adjust Pin Current e 50 100 50 100 BA Alans Adjust Pin Current Change 10mMA < lout < 3A 3V_ < (Vy Vour) < 35V 0.2 5 0.2 5 Minimum Load Current (Vin Your) < 35V e 3.5 10 3.5 10 Current Limit (Vin Vout) = 10V ee; 3 45 3 45 (Vin Vour) = 30V, T; = 25C 0.25 1 0.25 1 A AVout Temperature Stability 1 % ATemp AVout Long Term Stability Ta = 125C 0.3 1 % ATime ey RMS Output Noise Ty = 25C, 10Hz < f < 10kHz 0.001 0.001 % (% of Vour) ic Thermal Resistance K Package 1.2 1.5 1.2 15 C/W Junction to Case T Package 3 4 3 4 C/W The @ denotes the specifications which apply over the full operating temperature range. Note 1: Unless otherwise specified, these specifications apply for VinVour = 5V and Ioyr = 1.5A. These specifications are applicable for power dissipations up to 30W for the K package and up to 25W for the T package. Power dissipation is guaranteed at these values up to 15 Volts input-output differential. Above 15 Volts input-output differential power dissipation is limited by device internal protection circuitry. Note 2: Regulation is measured at a constant T;. Changes in output due to heating must be taken into account separately. Pulse testing with low duty cycle is used. LI Wntre 4-179LT150A/LT350A LM150/LM350 TYPICAL PERFORMANCE CHARACTERISTICS INPUT-OUTPUT DIFFERENTIAL (V) VOLTAGE CHANGE (PERCENT) RIPPLE REJECTION (dB) Load Regulation 0.1 0 01 0.2 03 0.4 0.5 ~75-50-25 0 25 SO 75 100 125 150 TEMPERATURE (C) Dropout Voltage 3 T T T Aout = 100 mv | | | 25 4 | 1 | louT = 3A fi 2 Pt t lqut = 2A ne | i | 15 /+ ao + lout - 20 mA | 1 | 0.5 -75 -25 5 75 125 TEMPERATURE (C) Ripple Rejection 100 J Cans = 10 BF 80 N PS =0 60 40 Vw Vout = 5V lout = 500 mA 20 [ f= 120Hz Tj = 25C 0 Li 0 5 10 15 2 25 30 35 OUTPUT VOLTAGE (V) REFERENCE VOLTAGE (V) Current Limit OUTPUT CURRENT (A) 35 0 0 5 10 15 20 26 30 INPUT-OUTPUT OIFFERENTIAL (V) Temperature Stability 1.270 1.260 | 1.250 mani Lo a 1.240 1.230 50-25 0 25 60 75 100 125 150 TEMPERATURE (C) Ripple Rejection RIPPLE REJECTION (dB) Vin = 15V Vout = 10V fouT = 500 mA 10 100 1k 10k 100k FREQUENCY (Hz) 1M Adjustment Current 65 60 + 3 55 | 5 a | 3 r Z 45 + wa, | 2 40 2 | ~ : 35 [i | I 30 ~__ 75 25 25 75 125 TEMPERATURE (C) Minimum Operating Current - | Pd TW WO ec { S Ty = 25C. | s Or So 3 FT 2 3 T T= -55C = = 1 0 I 0 5 1 1 2 25 30 35 40 INPUT-OUTPUT DIFFERENTIAL (V} Ripple Rejection Vw = 15V Vout = 10V f = 120Hz Tease = 25C RIPPLE REJECTION (dB) 0.1 1 10 OUTPUT CURRENT (A) LY WeLT150A/LT350A LM150/LM350 TYPICAL PERFORMANCE CHARACTERISTICS Output Impedance Line Transient Response Load Transient Response 1. 15 . | wy = 10V 3 S Cout - 0, Cand = 6 Caps = 0 2 Ss 1 = 50 3 Zz a 1 + =F CouT=0,Caoy-0 jt) = 25C = 05 -Cout~ 1uF, Caps = 10 oF 2 Cout =0 ne 0S = 3 5 ze 3 L, g o4 a> (0 05 Vag = 10 e o5 |Cout= taf, Caps = 104F ~1 PRELOAD = = 0.01 Cans = 10 nF J 15 T, = 25C = -1 2 A Cour = 10 uF | =" 2 3 o001 _ Vw = 15V | ge | os | lout = 500 mA 52 5 0.0001 BS 9 0 10 100 tk 10k) 100k M Q 10 20 30 40 FREQUENCY (Hz) TIME (us) TIME (us) aD General The LT150A develops a 1.25V reference voltage be- tween the output and the adjustable terminal (see Fig- ure 1). By placing a resistor, R1, between these two terminals, a constant current is caused to flow through R1 and down through R2 to set the overail output voltage. Normally this current is the specified minimum load current of 5mA or 10mA. R Vout = VREF (1 + 2) + lapy Re Basic Adjustable Regulator Figure 1 Because lap, is very small and constant when com- pared with the current through R1, it represents a small error and can usually be ignored. It is easily seen from the above equation, that even if the resistors were of exact value, the accuracy of the output is limit- ed by the accuracy of Veer. Earlier adjustable regula- tors had a reference tolerance of +4% which is LY Whe dangerously close to the +5% supply tolerance re- quired in many logic and analog systems. Further, even 1% resistors can drift 0.01%/C, adding addi- tional error to the output voltage tolerance. For example, using 2% resistors and + 4% tolerance for Veer, calculations will show that the expected range of a 5V regulator design would be 4.66V < Voyr < 5.36V or approximately + 7%. If the same example were used for a 15V regulator, the expected tolerance would be + 8%. With these results most applications required some method of trimming, usually a trim pot. This solution is both expensive and not conducive to volume production. One of the enhancements of Linear Technologys ad- justable regulators over existing devices is the tight- ened initial tolerance of Vper. This allows relatively inexpensive 1% or 2% film resistors to be used for R1 and R2 to set the output voltage within an acceptable tolerance. With a guaranteed 1% reference, a 5V power supply design, using +2% resistors, would have a worst case manufacturing tolerance of + 4%. If 1% resistors were used, the tolerance would drop to + 2.5%. A plot of the worst case output voltage tolerance as a func- tion of resistor tolerance is shown on the front page. #77 ~~ 4-181LT150A/LT350A LM150/LM350 For convenience, a table of standard 1% resistor val- ues is shown below. Table of 2% and 1% Standard Resistance Values 1.00 1.47 2.15 3.16 4.64 6.81 1.02 1.50 2.21 3.24 4.75 6.98 1.05 1.54 2.26 3.32 4.87 7.18 1.07 1.58 2.32 3.40 4.99 7.32 1.10 1.62 2.37 3.48 5.11 7.50 1.13 1.65 2.43 3.57 5.23 7.68 1.15 1.69 2.49 3.65 5.36 7.87 1.18 1.74 2.55 3.74 5.49 8.06 1.21 1.78 2.61 3.83 5.62 8.25 1.24 1.82 2.67 3.92 5.76 8.45 1.27 1.87 2.74 4.02 5.90 8.66 1.30 1.91 2.80 4.12 6.04 8.87 1.33 1.96 2.87 4.22 6.19 9.09 1.37 2.00 2.94 4.32 6.34 9.31 1.40 2.05 3.01 4.42 6.49 9.53 1.43 2.10 3.09 4.53 6.65 9.76 Standard Resistance Values are obtained from the Decade Table by multiplying by multiples of 10. As an example, 1.21 can repre- sent 1.210, 12.10, 1210, 1.21KQ etc. Bypass Capacitors Input bypassing using a 1uF tantalum or 25yF electro- lytic is recommended when the input filter capacitors are more than 5 inches from the device. Improved rip- ple rejection (80 dB) can be accomplished by adding a 10,.F capacitor from the adjust pin to ground. Increas- ing the size of the capacitor to 20uF will help ripple rejection at low output voltage since the reactance of this capacitor should be small compared to the voltage setting resistor, R2. For improved AC transient re- sponse and to prevent the possibility of oscillation due to unknown reactive load, a 14F capacitor is also rec- ommended at the output. Because of their low imped- ance at high frequencies, the best type of capacitor to use is solid tantalum. Protection Diodes The LT150A/350A do not require a protection diode from the adjustment terminal to the output (see Figure 2). Improved internal circuitry eliminates the need for this diode when the adjustment pin is bypassed with a Capacitor to improve ripple rejection. D1 IN4002 A + 100K NOT NEEDED FOR LT150A/350A Figure 2 lf a very large output capacitor is used, such as a 100,.F shown in Figure 2, the regulator could be dam- aged or destroyed if the input is accidentally shorted to ground or crowbarred, due to the output capacitor discharging into the output terminal of the regulator. To prevent this, a diode D1 as shown, is recommended to safely discharge the capacitor. Load Regulation Because the LT150A is a three-terminal device, it is not possible to provide true remote load sensing. Load regulation will be limited by the resistance of the wire connecting the regulator to the load. The data sheet specification for load regulation is measured at the bottom of the package. Negative side sensing is a true Kelvin connection, with the bottom of the output divid- er returned to the negative side of the load. Although it may not be immediately obvious, best load regulation is obtained when the top of the resistor divider (R1) is connected directly to the case not to the load. This is illustrated in Figure 3. lf R1 were connected to the load, the effective resistance between the regulator and the load would be Ry Xx (a oH ).Rp = Parasitic Line Resistance. Connected as shown, R, is not multiplied by the divid- er ratio. Rp is about 0.004 per foot using 16 gauge wire. This translates to 4mV/ft at 1A load current, so it 4-182 LI WeLT150A/LT350A LM150/LM350 is important to keep the positive lead between regula- an tor and load as short as possible, and use large wire or ra8GR | une reSisTANCE PC board traces. Ye WW? = CONNECT R1TO CASE 3 R1 q RL > Re EN L : CONNECT R2 = TO LOAD Connections for Best Load Regulation Figure 3 pee 1.2V-25V Adjustable Regulator Improving Ripple Rejection *Parallel Regulators for Higher Current Soe AT SGOASS | Anspon 52 LT 338A [ Wwe Now on We sv OS peggy OE Sai | Oy ee S$ 240 1 uF sin $1212 ci* +L C2+ T | 1% TF TT tut = + oy fe ners $ =O + > 5k 1% 10uf * L. * Needed if device is far from e a rg + ionalimprov transient response | Vout = 1.25V (1 + =r) 3650 * THS CIRCUIT WILL NOT WORK 1% Adjustable Current Limiter Automatic Light Control WITH LM VERSION DEVICES = = oer ~ BECAUSE OF WIDER eo ATBEOAS 0.52 ope ATSSOR REFERENCE VOLTAGE LIMITS Nc Nu 9 we Ne ** CURRENT SHARING RESISTORS 2 Sey iKQ 5000 a DEGRADE REGULATION TO 1% Precision High Current Reference ~ ~ Remote Sensing Vn LTS50A vay +40V Fe (MAX DROP 300mv) 5 VIN 7 _ 2 252 |g q LM301A = Re S210 ' 3 ko 5 8 4 3 3652 100pF p +* = wet RETURN en" LY Wiener 4-183LT150A/LT350A LM150/LM350 SCHEMATIC DIAGRAM LT150A/LT350A . - 1 ww | 2 2 $3100 310 $ 190 50 56k 3 3 20k Q23 024 300 a1 aig Kaze 02>} fo 15 o1 30k 18k 018 q 3k D2 Q16 Q20 O17 ct i 30 =. 1 PF 2.4k 8 ce 30! 9 pF < 3 160k $5.1k 3 ok mw | , 2 0.05 ] Your CJ PACKAGE DESCRIPTION Dimensions in inches (millimeters) unless otherwise noted. K Package TO-3 STEEL Metal Can T Package T0-220 Plastic 0760-0775, [warner | 0.116 a) 0.174 - 0.186 MAX (4.420 ~4.724} 0.320-~0.350 0.100.010 0.305-0.420 | (8 13-8.89} t (2.7944.0.254) * (10.03 10.68) 0.045 - 0.055 [ ] T ene (1-43-7397) 0.420 -0.480 f tN 0.1470.151 (10 67 12 19} { YJ (3.734 3.835) 0.0380 043 0.150 (0.9650 109) aa 1477 ~1 197 t {29.90 - 30.40) 1.020 40.015 0.067 0.077| (25.91 + 0.381) {1.70 1.96} 0.210 - 0 220 0.54020 015 (5 335.39) f 113.720.381) 0.152 ~0. 162 (3.86 4.11) 0 425-0.435 RTP (10.8011 08} ~ 0.167~0.177 0.013 0.030. at Somenas name RIVE | 0.000.125 ee (2.2853 175) 9.050 _, | ae 0.4900 510 (1.2?) 112-4512 95) TP o200.20.010 Tj max. Ga Gc (5.08 + 0.254) Ree | asec | 35crw | 1.5CAW Tj max. Sia Bic LT350A LT350A o 9 LM350 125C 35C/W | 1.5C/W LM350 125C S5ac/w | 2.5C/W 4-184 LY Wie