LT317

LT117A LINER | Alldatasheet

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TECHNOLOGY - Positive Adjustable Regulator FEATURES DESCRIPTION = Guaranteed 1% Output Voltage Tolerance The LT117A Series are 3-terminal positive adjustable = Guaranteed max. 0.01%/V Line Regulation voltage regulators which offer improved performance = Guaranteed max. 0.3% Load Regulation over earlier devices. A major feature of the LT117A is = Min. 1.5A Output Current the output voltage tolerance is guaranteed at a maxi- = 100% Burn-in in Thermal Overload mum of + 1%, allowing an overall power supply toler- ance to be better than 3% using inexpensive 1% resistors. Line and load regulation performance has been improved as well. Additionally, the LT 117A refer- APPLICATIONS ence voltage is guaranteed not to exceed 2% when op- erating over the full load, line and power dissipation = Wide Range Power Supplies Conditions. The LT117A adjustable regulators offer an = Constant Current Supplies improved solution for all positive voltage regulator re- = Voltage Programmable Supplies quirements with load currents up to 1.5 amps. SS Regulator with Reference Output Voltage Error [TTT TTT “ = Pe ae Aol 1219 8 ot TUM Ti re Be ssa = 1219 & i a anit RESISTORS) 14347 25v Bo | Zbbeiiresstons! os 5. (Ae i ce = 4 LOD Tr 2 4 6 810 20 40 100 OUTPUT VOLTAGE rr LT LINEAR 4-137

ABSOLUTE MAXIMUM RATINGS PACKAGE/ORDER INFORMATION Operating Junction Temperature Range ” LTA47K wer LT147AH Storage Temperature Range 10 Sete Ean we sprcnace LM317H [= LTS 17AT 100% THERMAL LIMIT BURN-IN ou ne ELECTRICAL CHARACTERISTICS (See Note 1) UT1T7A/AM117 4OMA < lout <Inax, P< Pmax i Je] oor ase | one ons | aw Vour > 5V 041 0.3 % Vour > 5V % [Thermal Regulation (Ta = 25°C, 20mseo Pulse |_| one _ ome | 0.03007 | aw Caps = 0 dB Sus = 104F lef so | os Sw] thos [AdjustPin Current | fC SYCSCSC*éSC*C uA 2.5V < (Vin — Vour) < 40V uA laun [Minimum Load Current (Vw —Vour) = 40V_ fe] 5S | SSS SYA Current Limit (Vin — Vour) < 15V K Package 15 22 15 2.2 A

4 Package sew laa | A

(Vin — Vout) = 40V, T; = 25°C K Package 0.3 05 03 04 A H Package 015 02 0.15 02 A a eee ATemp a a [AMS Output Noise (% of Vour) [Ta = 25°C, toe < t= torre | | oor | oom + % Junction to Case K Package 23 3 “c/w 4-138 LIT ne

€LECTRICAL CHARACTERISTICS (See Note 1) LT317A/LM317 SYMBOL PARAMETER: CONDITIONS MIN OTYP. MAX UNITS Vac Reference Voltage lor = 10mA 1; = 25°C |_| 1.238 1.250 1.262 | v BV < (Vn — Vo) < 400 1205 1250 1.270 jt 1510 | v 10MA_< lout <Imaxs P< Prax Vout. Line Regulation 3V < (Vin — Vour) < 40V, (See a Noe?) [| om oor | aor one | iid . - lef oro | oe oor | ov Wout Load Regulation 10MA < loyy < Inax, (See Note 2) Mout Vo = SV av Vo > 5V % Vo < SV 20 50 20 70 mV Vo = 5V 03 1 03 15 % Ty = 25°C, 20sec Pulse [e| aor oe | 0407 | ww Ripple Rejection Vo = 10V, f = 120Hz Cro = 0 dB Cay = 1048 [ [so fs | tags [Adjust Pin Current [000 5000 | HA Maps Adjust Pin Current Change 10MA < lout < Imax 2.5V_< (Vin — Vour) < 40V ry len {Minimum Load Current [Vw —Vor)=4ov | 35 | 85 Tm Current Limit (Vin ~ Vour) < 15V K and T Package 15 22 15 2.2 A H Package 0.5 08 05 08 A (Vin — Vour) = 40V, T; = 25°C K and T Package 015 04 0.15 04 A H Package 0.075 0.2 0.075 0.2 A Vout Temperature Stability O°C < T, < 125°C % Temp Vout Long Term Stability Ty = 125°C 03 1 03 1 % ‘Time (9% of Vour) Oe Thermal Resistance H Package 12 15 °C/W Junction to Case K Package 23 3 “c/w T Package 4 5 “c/w The @ denotes the specifications which apply over the full operating Note 2: Regulation is measured at constant junction temperature, using temperature range. pulse testing with a low duty cycle. Changes in output voltage due to Note 1: Uniess otherwise specified, these specifications apply for Viy heating effects are covered under the specification for thermal — Vour = 5V; and lour = 0.1A for the TO-39 and loyr = 0.5A for regulation. Load regulation is measured on the output pin at a point %" the TO-3 and T0-220 packages. Although power dissipation is below the base of the K and H package and at the junction of the wide internally limited, these specifications are applicable for power and narrow portion of the lead on the T package. dissipations of 2W for the TO-39, and 20W for the TO-3 and TO-220. Imax is 1.5A for the TO-3 and TO-220 packages and 0.5A for the TO- 39. Lae ana LT NEAR 4-139

TYPICAL PERFORMANCE CHARACTERISTICS Load Regulation fem Lin 220 Package) Adjustment Current O01 3 65 JSS wee) Se eo » US go Le $02 | nOnuA oe e°T TAT 8 al ime 8 | L| | —_| i 96 C4neeeeee re 75-50-25 0 25 50 75 100 125 150 tC) 10 20 20 40 75 25 25 75 125 TEMPERATURE INPUT-OUTPUT DIFFERENTIAL (V) TEMPERATURE (°C) Dropout Voltage Temperature Stability Minimum Operating Current TT) CT) {A = z a . 1.260 3‘ 4 CS LE pee o : Ty = -55° eos Stir “FR ‘0 oy 80-28 0 25 50 75 100 — 0 —25 0 2 50 75 100 125 150 °o LLL I 35 40 TEMPERATURE (°C) ‘TEMPERATURE INPUT-OUTPUT DIFFERENTIAL (V) Ripple Rejection Ripple Rejection (dB) Ripple Rejection 100 100 90 eer TEE ee 0 da eNOS ra TH Poop (Poe Oe F] rs Pett PeeeNe EO = cer} ofere NS abnee, I wee | we acta ° 0 5 0 #15 20 2 3 35 ° 10 100 1k 10k 100k 1M oot 0.1 1 10 QUTPUT VOLTAGE (Vv) FREQUENCY (Hz) OUTPUT CURRENT (A) Ly 4-140 7 @ AN es

TYPICAL PERFORMANCE CHARACTERISTICS Output Impedance Line Transient Response Load Transient Response g 1 is 38 os | G0, C= 0 T= 25°C Zé 08 ary omar | é | ee” LN [yi 8 oi ytd goo / ae 9 we indatwe vA -05 mY | oy ; ia] -05 = tae, = We 1 =-W 3 001 fo _fKo1s = 1008 | tt JY ; ts ad Vw = 1 8s a = {i | | Lt 10 100 tk 10k 100k 1M oO 10 20 30 40 Oo 10 20 30 40 FREQUENCY (Hz) TIME (us) TIME (us) —SS APPLICATIONS INFORMATION General: The LT117A develops a 1.25V reference volt- For example, using 2% resistors and +4% toler- age between the output and the adjustable terminal ance for Vper, calculations will show that the (see Figure 1). By placing a resistor, R1, betweenthese expected range of a 5V regulator design would be 4 | two terminals, a constant current is caused to flow 4.66V < Voyr < 5.36V or approximately + 7%. If the through Ri and down through R2 to set the overall © same example were used for a 15V regulator, the ex- output voltage. Normally this current is the specified pected tolerance would be + 8%. With these results minimum load current of 5mA or 10mA. most applications require some method of trimming, usually a trim pot. This solution is both expensive and vw Your not conducive to volume production. Lod 1 T ; =e / veut = er (1422) + oar One of the enhancements of Linear Technology's ad- = eS a, /"""" — |justable regulators over existing devices is tightened Re initial tolerance. This allows relatively inexpensive 1% = or 2% film resistors to be used for R1 and R2 while set- Figure 1 ting output voltage within an acceptable tolerance Because Ip, is very small and constant when com- Lge. pared with the current through Rj, it represents a . small error and can usually be ignored. With a guaranteed 1% reference, a 5V power supply design, using +2% resistors, would have a worst "tis easily seen from the above equation, that even if ©@8e manufacturing tolerance of + 4%. If 1% resistors the resistors were of exact value, the accuracy of the Were used, the tolerance would drop to + 2.5%. A plot output is limited by the accuracy of Vrer. Earlier ad- Of the worst case output voltage tolerance as a func- justable regulators had a reference tolerance of + 4%. __ tion of resistor tolerance is shown on the front page. This tolerance is dangerously close to the +5% sup- ply tolerance required in many logic and analog sys- tems. Further, many 1% resistors can drift 0.01%/°C adding another 1% to the output voltage tolerance. EEC LT WEAR A141

a For convenience, a table of standard 1% resistor val- _ eliminates the need for this diode when the adjustment ues is shown below. pin is bypassed with a capacitor to improve ripple Table of 2% and 1% Standard Resistance Values rejection. 1.00 147 | 215 | 3.46 | 4.64 | 6.81 If a very large output capacitor is used, such as a 402 | 150 | Zar a | 43 898 100,F shown in Figure 2, the regulator could be dam- 107 158 232 3.40 499 732 aged or destroyed if the input is accidentally shorted tp 182 Ep 8 Fey 780 to ground or crowbarred. This is due to the output ca- 115 | 169 | 249 | 365 | 536 | 787 pacitor discharging into the output terminal of the reg- tae |} tae | BOF | $83] 882) 828 to safely discharge the capacitor. tao | ry | Bb | $0 | Seo) Bee Load Regulation: Because the LT117A is a three-termi- 33 386 387 422 | 6.19 | 9.09 nal device, it is not possible to provide true remote ta | o0¢ | gor | ane | O33 | 33 load sensing. Load regulation will be limited by the re- 143 | 210 | 309 | 453 | 665 | 9.76 sistance of the wire connecting the regulator to the Standard Resistance Values are obtained from the Decade Table load. For the data sheet specification, regulation is by multiplying by multiples of 10. As an example, 1.21 can repre- measured at the bottom of the package. Negative side sont 1.219, 12.19, 1249, 121KM ete. sensing is a true Kelvin connection, with the bottom of Bypass Capacitors: Input bypassing using a 1yF tanta- _the output divider returned to the negative side of the ium or 254 electrolytic is recommended when te ine !98¢-Although itmay nat be immediately obvious, best put filter capacitors are more than 5 inches from the _'0ad regulation is obtained when the top of the divider device. Improved ripple rejection (80 dB) can be ac- _' Connected directly to the case not to the load. This complished by adding a 10uF capacitor from the ad- iS illustrated in Figure 3. If R1 were connected to the just pin to ground. increasing the size of the capacitor 'ad, the effective resistance between the regulator to 20,.F will help ripple rejection at low output voltage 471d the load would be since the reactance of this capacitor should be small R2 + R1 “at , compared to the voltage setting resistor, R2. For im- Re X (A) » Ry = Parasitic Line Resistance. proved AC transient response and to prevent the pos- . ne . sibility of oscillation due to unknown reactive load, a Connected as shown, R, is not multiplied by the divid- (uF capacitor is also recommended at the output. Be- _&! Fatio. Rp is about 0.0040 per foot using 16 guage cause of their low impedance at high frequencies, the Wire. This translates to 4mV/ft at 1A load current, so it best type of capacitor to use is solid tantalum. important to keep the positive lead between regulator and load as short as possible. Protection Diodes: The LT117A/317A do not require a » protection diode from the adjustment terminal to the PARASITIC output (see Figure 2). Improved internal circuitry vw LUNE RESISTANCE [a | i RI TOCASE ADL + 100uF \\e - 104F Sos Re NOT NEEDED T ae CONNECT R2 = + = TO LOAD Connections for Best Load Regulation Figure 2 Figure 3 SSS 4-142 LY lite

1.2V-25V Adjustable Regulator Improving Ripple Rejection vw Yn Your Vout vw Yu our sv *Ler th cot T tF Tae = + hid Re ci* & 5K 3839, 10 uf = (C1 IMPROVES RIPPLE REJECTION R2 Xc SHOULD BE SMALL + Optional — improves transient Vout = 1.28v (1 +=) COMPARED TO R2 response ° feces ‘sf rom 5V Regulator with Shut Down <usita w Remote Sensing vn eae ed Vout Usiza ax + ea oaieaed rie i ae Rp (MAX DROP 300m) urea tak | : i] PP R 1219 + 8 21V Programming Supply for UV PROM/EEROM 3832 100pF aw RET 2 UISATA = = i SJ + + ial z 1 J es Tt” av

2816 EEPROM Supply Programmer for Read/Write Control \\ re SEIEST GFOnDESRED Fick TE

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i SCHEMATIC DIAGRAM LTA17A/LT317A {J ve 3102 (3 ow 200, r) ot ase Wie: g "18k 16k ceo 025° oe ct TE i lf nm pF | : " {) Your [] Ab ee PACKAGE DESCRIPTION K Package TO-3 STEEL Metal Can T Package TO-220 Plastic H Package 3-Lead Metal Can 0225 039 ia Rm) aaa ‘Gs 20080 205020000 ™ 0420-0480 a gS eBz020 ‘ose5— 1082) swt oor TAPERED 1°, 2 SES 080 ois esto ere vecaoy ee I [see seat Teter 101) oro The. wl om sp a A a Ben . ‘e080 | = Tore = Tron Basta jaar oS auwosc0% [esasonn a rr ors 10010 x am=000 ae ‘Boaz02sq ost Oeer ws (TT imax Toe Te) [Tima Tn Tae] Peco ee 317A ° ; 317A . o 3171 FE ee oe ee 4-144 LT nee