LM614A/LM614 NATL SEMICOND (LINEAR) 225 D) Mm bS01L24 0068430 & National Semiconductor T-79-/o LM614A/LM614 Quad Operational Amplifiers and Adjustable Reference General Description The quad operational amplifiers are a versatile common- mode-to-the-negative-supply (single supply") type similar to the LM124 series, but with improved slew rate, improved power bandwidth, reduced cross-over distortion, and low supply current even while driven beyond swing limits. Later- al PNP input transistors enable tow input currents for large differential input voltages and swings above vt, The voltage reference is a three-terminal shunt-type band- gap similar to the adjustable LM185 series, but with anode committed to the V~ terminal and improved voltage accura- cy to 0.4%. Two resistors program the reference from 1.24V to 6.3V. The reference features operation over a shunt current range of 16 pA to 20 mA, low dynamic imped- ance, broad capacitive load range, and cathode terminal voltage ranging from a diode-drop below V~ to above vt, As a member of Nationals new Super-Block family, the LM614 Is a space-saving monolithic alternative to a muiti- chip solution, offering a high level of integration without sac- rificing performance, Features (Guaranteed over temperature & supply) Op Amps a Low operating current 250 pA (per op amp) 16 pA (reference) m Large supply voltage range 4V to S6V mw Large output swing (10k load) (V~ + 1V) to (vt 1.8) @ Input common-mode includes V7 to VF 1.4) Connection Diagram 1 V+ FEEDBACK TL/H/9926-1 Top View Order Number LM614lJ, LM614MJ, LM614CWM, LM6141WM, LM614AIN, LM614CN or LM6141N See NS Package Number J16A, M16B or N16GA Wide input differential voltage 36V m Standard quad op amp pin-out Reference = Adjustable output voltage 1.2V to 6.3V @ Tight initial tolerance available 0.4% @ Tolerant of load capacitance 0 to 2 Applications m Power supplies m Signal conditioning Order Number Prime Military LM614MJ Tested at 55C, + 256C, +125C Drift tested at 55C, +25C, +125C Prime Industrial LM614AIN Tested at +25C Drift tested at 40C, + 25C, +85C Industrial LM614IN Tested at +26C LM614IJ LM614IWM Commerical LM614CN Tested at +25C LM614CWM Packages J Hermetic Dual-In-Line Plastic Dual-In-Line WM Plastic Surface Mount Wide (0.3" ) 3-644NATL SEMICOND (LINEAR) ecE D MM 6501124 0064431 46 mw T-79-10 F Absolute Maximum Ratings ~ o If Military/Aerospace specified devices are required, Soldering Information > please contact the National Semiconductor Sales Dual-In-Line Package N Office/Distributors tor availability and specifications. (Soldering, 10 seconds) 260C 5 Voltage on Any Pin except Cathode Pin Small Outline Package a (referred to V~ pin) Vapor Phase (60 seconds) 218C z (Note 1) " 0.3V (Min) Infrared (15 seconds) 220C Military and Industrial 36V See AN-450 Surface Mounting Methods and Their Effect Commercial 32V on Product Reliability" for other methods of soldering sur- Current through Any input Pin face mount devices. and Cathode Pin 20mA Package Thermal Resistance (Note 3) Differential Input Voltage Hermetic DIP J16 100C/W Military and Industrial 96V Molded DIPNi6 95C/W Commercial +92V Molded SO M16 Wide 140C/W Short Circuit Duration, Op Amp (Note 2) Continuous eS eee Noe 4) tev @5 pr, 1. Smee vem erate nae 65C to + ' ore 200 pF. < 10 +250 aximum unction Temperature Absolute maximum ratings indicate limits beyond which Operating Junction Temperature Range | jMin t0 Tax damage to the component may occur. Electrical specifica. CMe ct aoe tions do not apply when operating the device beyond its : 7 tated operating conditions. LM614C OC to +70C peraing conc Electrical Characteristics These specifications apply for V" = GND = OV, V* = BV, Vom = V*/2, Vour = V*/2, In = 100 pA, FEEDBACK pin shorted to GND, any package, unless otherwise specified. Limits in standard typeface are for Tj = 25C; limits in boldface type apply for Tyin to Tyax- Typ- LM614M LM614Al, LM614! LM614C Para- Conditions tcal Tested | Design | Tested | Design | Tested Design Unite meter (Note 5)| Limit Limit Limit Limit Limit Limit (Note 6) | (Note 7) | (Note 6) | (Note 7) | (Note 6) | (Note 7) Total | V* Current, RLoap = , 450 800 940 1000 pA max Supply | 4V < V* < 36V Over Ty Range 550 | 1000 1000 1070 | pAmax Current | (Commercial 32V) ; Supply ; Meets Total Supply Current, and 22 28 28 2.8 V min Voltage | See Vp Change with V* Change Test] 2.9 | 3 3 3 Vmin Range 46 36 36 92 V max 43 36 36 32 V max OPERATIONAL AMPLIFIERS Vos 4v < vt < 36V + +15 3.65 +3.65 +6.0 mV max Over | @V < V" < 32V Commercial) +20 | +8.0 +6.0 7.0 | mV max Supply Cos. Vom = OV through Voy = 10 | +35 3.5 +5.0 mV max Vom (VT - 1.4V),V" = 30V 1.85 | +50 +6.0 7.0 | mV max 3 | Average | LM614M & Al, Op Amp 3 Only | vre Vos _j (Note 8) 15 25 30 B ax Drift om put layin and Ip_in ~10 | +20 25 +95 nA max Current -tf 28 30 +40 | nAmax on los = Ia 4IN ~ IB_iN 02 ] +4 4 +4 nA max Current 0.38 | +4 8 8 | nAmax Average tos +6 pA Drift 8-545NATL SEMICOND (LINEAR) LM614A/LM614 CfE D MM 6501124 0068432 T Electrical Characteristics (continued These specifications apply for V~ = GND = OV, V T-79-10 = 5V, Vom = V"/2, Vout = V1/2, In = 100 pA, FEEDBACK pin shorted to GND, any package, unless otherwise specified. Limits in standard typeface are for Tj = 25C; limits in batdface type apply for Tain to Trax. Typ- LM614M LM614Al, LM6141 LM814C Para- leal Tested | Design| Tested | Design | Tested | Design meter Conditions (Notes) | Limit | Limit | Limit | Limit | Limit | Limit | Units (Note 6) |(Note 7)| (Note 6) | (Note 7) | (Note&) | (Note 7) Seat Differential: 1800 Mo Common-Mode: 3800 MQ ance Input C-to-GND, Non-Inverting input 57 F Cap. of Follower P Voltage [100 Hz, input Referred Nolse 74 aVv/{Az Current |100 Hz Bias Current Noise Noise 58 fANHz Common|Vt = 30V, -Mode |0V < Vow < (Vt 1.4V), 95 85 80 75 dB min Reject |CMRR = 20 log (AVoy/AVos} 90 80 78 70 =| dBmin Ratio Power |4V < Vt < 30V, Voy = V"/2, Supply |PSAR = 20 tog {AV*/AVog} 110 85 80 75 dB min Reject 100 80 75 70 dB min Ratio Voltage /AL = 10kM to GND, Vt = a0V, Gain, |5V < Vout < 25V, Open-Loop 500 100 100 94 V/mV Open |Ay = [AVourt/AVinbiFFl 50 40 40 40 min Loop Siew |Vt = 80V (Note 9) 0.70 +0.55 +0.55 +0.50 V/ps Rate +0.65 +0.45 +0.45 +0.45 min Gain- {Closed Loop Gain = 1000, 0.79 Band. |9dB Frequency < Gain, 0.52 MHz width |C. = 50 pF . Output [AL = 10 kf to GND Voltage |V* = a6V (82V.Commercia) =| vt 1.4) vt - 16 vt -47 vt -18 Vmin Swing vt 4.6lv~ 1.8 vi -4.9 vt 1.9] Vin High Output JRL = 10ka tovt Voltage Vt = 36V (32V Commercial) V~ +0.8/V~ + 0.90 V~ +.0.90 V~ + 0,95 V max Swing Vv +09/V" + 1.0 Vv + 1.0 Vv + 4.0} V max Low four |Your = Vt -2.5V, Vain = OV) -25 20 20 16 mA max Source |Viy = 0.3V 15 -13 -13 -13 j|mAmax 3-548NATL SEMICOND (LINEAR) eeE D MM bL501i1e4 0064433 1 PLOWT/VPLOWT Electrical Characteristics (continued . T-79-10 These specifications apply for V~ = GND = OV, V" = 5V, Voy = V*/2, Vout = V*/2, In = 100 pA, FEEDBACK pin shorted to GND, any packags, unless otherwise specified. Limits in standard typeface are for Tj = 25C; limits in boldface type apply for Tyin to Trax. Typ- LM614M LM614Al, L614! LM614C Para- Conditions ical Tested | Design | Tested | Design | Tested | Design Units meter (Note 6) | Limit Limit Limit Limit Limit Limit (Note 7) | (Note 8) | (Note 7) | (Note 8) | (Note 7) | (Note 8) lout Vout = 1.6V, Vin = OV, 17 15 14 13 mA min Sink VIN = 0.8V 9 8 1 441 mA min Short- Vout = OV, V+in = 3V, 30 37 -40 43 mA min Circuit | Vjn = 2V, Source: 40 -46 48 -50 | mAmin Current | Your = 5V, Vain = 2V, 30 40 60 70 mA max Vin = 8V, Sink: 32 60 80 90 | mAmax VOLTAGE REFERENCE (Note 10) Refer- 1.244 1.2390 1.2365 1.2191 Vimin ence 1.2490 1.2515 1.2689 V max Voltage (40.4%) (40.6%) (42%). Average | (Note 14) 10 20 so 150 PPM/C Temp. LM614AI 20 max Drift Average | Ty = 40C 400 PPM/ Time kHr Drift Ty = 150C 1000 PPM/ kHr Hyster- | Hyst = (Vro Vro)/ATy esis _| (Note 12) 9.2 BIG VR Vatioo pA] Vato pl 0.05 +1 +1 +1 mV max Change 0.1 +4 +4.4 1.14 | mV max un : Vaio ma] Vatioo pA} 1.5 5 5 5 mV max urTENt | (Note 13) 3.0 5 5.5 5.5 | mV max Resis- | AVario> 0.1 ma]/9.9 MA: 0.2 0.51 0.56 0.56 | Qmax tance AVAI100 > 16 pa]/84 WAS 0.6 12 13 13 2 max VR VAIVto = Vel VAiVro = 6.3V] Change | {5.06V between Anode and a 3 7 10 7 10 mv max with | FEEDBACK} ax High Vao VA Vav+ =svl Yat =sey) | Ot 12 #12 12 mV max Change (vt = 92V Cornmercial) oO.t 1.2 1.3 1.3 | mV max with vt Vatv+ =svi~Vrivt =a | 0.01 + #4 . #1 mV max Change 0.01 +14 +1.5 1.5 | mV max FEED- | fre: Vanope S Vep < .06V 22 35 35 50 nAmin BACK -29 -40 -40 -55 nA min Bias Current Va 10 Hz to 10,000 Hz, Vag = VR Noise 80 EVRMS 3-547NATL SEMICOND (LINEAR) LM614A/LM614 22 D MM 6501124 0068434 3 mm Electrical Characteristics Notes T-79-10 Note 4: More accurately, it is excessive current flow, with resulting excess heating, that limits the voltage on all pins. When any pin Is putled a diode drop below V-, a parasitic NPN transistor turns ON. No latch-up will occur as tong as the current through that pin ins below the Maxi Rating. Operation is undefined and unpredictable when any parasitic diode or transistor is conducting. Note 2; Simultaneous short-circuit of multiple op amps and reference while using high supply voltages may force junction temperature above maximum, and thus should not be continuous. Note 3; Junction temperature may be catculated using Ty = Ta + Ppja- The given thermal resistances are worst-case for packages in sockets in still air. Nominal Oj, are Q5C/W tor LM614 in J package, 80C/W for the N package, and 110C/W for the WM package, for packages soldered to copper-clad board with dissipation from one op amp or reference output transistor. Note 4: Human body model, 100 pF discharged through a 1.5 kf. resistor. Note 5: Typical values in standard typeface are for Ty = 25C; values in boldface type apply to the military temperature range. These values represent the most likely parametric norm. Note 6: Tested limits are guaranteed and 100% tested. Note 7: Design limits are guaranteed via correlation, but are not 100% tested. Note 8; Offset voltage drift is calculated from the measurement of the offset voltage at 25C and at the temperature extremes. The drift is AVog/AT, where AVog Is the lowest value subtracted from the highest, and AT is the temperature range. Note 6: Slow rate Is measured with the op amp in a voltage follower configuration. For rising slew rate, tha input voltage is driven from 5V to 25V, and the output voltage transition is sampled at 10V and 20V. For falling slew rate, the Input voltage is driven from 25V to 5V, and the output voltage transition is sampled at 20V and 10V. Hote 10: V,o is the Cathode-te-Anade voltage ((e. the reference output voltage, 1.2V to 6.3V). V; Is the Cathode-to-FEEDBACK voltage (nominally 1.2V). Note 11: Average rof e drift is lated from the mea: it of the raf voltage at 25C and at the temperatura extremes. The drift, In ppm/*C, Is 108*AVa/Varesto]ATy, Where AVR Is the lowest value subtracted from the highest, Vatzs-c] Is the value at 25C, and AT, is the temperature range. Note 12: Hysteresis Is AVao/ATy, where AVRo is the change in Vao caused by a change in Ty, after the has been deh ized". To d nize the reference, Its Junction temperature should be cycled In the following pattern, spiraling In toward 25C: 25C, 125C, 55C, 85C, ~40G, 70C, OG, 25C, Note 13: Low contact resistance is required for accurate measurement. Simplified Schematic Diagrams Op Amp Su Su HQ Qe 15 vt 5p] 42z 6K 8K a oH - > ~ a ; A 1 | our 12K 12K ye : a - O TL/H/9526~2 Reference Blas 2pA oy op aup REF. 9 64K TL/H/8326-3 3-548NATL SEMICOND (LINEAR) eee D Ty = REFERENCE VOLTAGE (V) REFERENCE VOLTAGE CHANGE (mV) REFERENCE VOLTAGE (V) FEEDBACK CURRENT (nA} Typical Performance Characteristics (Reference) 26C, FEEDBACK pin shorted to V- = OV, unless otherwise noted Reference Voltage vs Temperature * on 5 Representative Units 1.24 60-40-20 0 20 40 60 80 100120140 JUNCTION TEMPERATURE (C) Reference Voltage vs Current and Temperature Vio = Vp 5 Be =55 5, Q > 125% =55C 25C 125% 5 l 2x10% 2x1078 2xto 2xio3 2x1072 REFERENCE CURRENT (A) Reference Voltage vs Reference Current 488M 19? -1074 210% j0v4 1072 REFERENCE CURRENT (A) FEEDBACK Current vs FEEDBACK-to-Anode Voitage ~ oO = Pw eh A MD 10 8 =10 =20 = 40 101234565 0 7 0 ANODE TO = FEEDBACK VOLTAGE (V) Vper Change (2) seSeSsgegs REFERENCE VOLTAGE CHANGE (mV) _SATHODE CAPACITANCE (F) NOISE VOLTAGE (nVrms// Fiz) Reference Voltage Drift = Ss 2 O 250 S00 750 1000 1250 1500 1750 2000 TE (Hours) Reference Voijtage vs Current and Temperature omicoy| 1KoTM If 57 125% 25C 4.86 125C o 55C 25C 85C Veo =6.5 eit mie axiom ato 2xtom? REFERENCE CURRENT (A) Reference AC 4 Stability Range TTI 955 57) 25 125C __| 1255,,S6.3 to? + B we aaa, 3a 36V 107 R 4 tort 4 Wo tout 4 4 | o!2 fo tor8 tot 1073 19? REFERENCE SHUNT CURRENT (A) Stay io 197% ton! Reference Noise Voltage vs Frequency. rH lk Co ai FREQUENCY er REFERENCE VOLTAGE (V) REFERENCE VOLTAGE () FEEDBACK CURRENT {nA} SMALL SIGNAL RESISTANCE (0) T-79-10 Accelerated Reference Voltage Drift vs Time 6 ACERESENTATIVE UNIT UNITS HYSTERESS HISTORY R 0 100 200 300 #500 TIME EHASED AT 150C (hrs) Reference Voltage vs 5 Reference Current =, 25C 23C =55%C 1 ato? =194 gt07 to 10? REFERENCE CURRENT (A) FEEDBACK Current vs FEEDBACK-to-Anode Voltage 2 2 = 10123486 10 0 % 4 ANODE = TO FEEDBACK VOLTAGE (V) Reference Small-Signal _ Resistance vs Frequency 10000 8 ] Ci 1% 193 io ie 1k FREQUENCY (Hz) TL/H/9926-4 M@ 6501124 0066435 5 3-549 PLOWT/VPloWLM614A/LM614 SEMICOND (LINEAR) 22 D M@ b501124 CObS43b 7 = Typical Performance Characteristics (Reference) (continued) T-79-10 T) = 25C, FEEDBACK pin shorted to V~ = OV, unless otherwise noted Reference Voltage with Reference Voltage with Reference Power-Up Time FEEDBACK Voltage Step , 100 ~ 12 .A Current Step s e = |, STEP, = 4 i t Tizpal 3 2 | s E 5 3 125C | 4 nak : 3 3 0 5 \ =55C 250 f 2 125C = LL 160 200 300 400 500 600 700 0 100 200 300 400 $00 600 700 THE (us) THE (us) TME (3) Reference Step Response for 100 pA ~ 10mA Reference Voltage Change Current Step 20 with Supply Voltage Step Veo AC COUPLED (rr) REFERENCE VOLTAGE (mV) <5 9 100 200 300 400 500 600 700 TE (us) TE (ms) TUH/9926-8 Typical Performance Characteristics (Op Amps) VF = 5V, V = GND = OV, Voy = V+/2, Vour = V*/2: Ty = 26C, unless otherwise noted input Common-Mode Vos vs Junction Voltage Range vs Temperature on 9 Input Bias Current vs Temperature Representative Units Common-Mode Voltage 4 S 3 3 = 3 3 got 5 3 3 0 g 2 i bol 3 3 g -2 = 8 -3 <4 20 =0-40-20 0 20 40 60 80 100120140 60-40-20 0 20 40 60 80 100120140 101234510 0 40 & & JUNCTION TEMPERATURE (6) JUNCTION TEMPERATURE (C) THPUT VOLTAGE (V) Slew Rate vs Temperature Large-Signal Output Voltage Swing and Output Sink Current Step Response vs Temp. and Current 6 5 4 vot z ei = = 2 4 B v-2 g g 0 3 5 -1 42 a ES 5 4 ve 5 6 6 yr 60-40-20 0 20 40 60 80 100120140 0 40 2 o 50 60-40~20 0 20 40 60 80 100120140 JUNCTION TEMPERATURE (C} TIME (ys) JUNCTION TEMPERATURE (C) TL/H/9328-5 3-550NATL SEMICOND (LINEAR) 22E D Typical Performance Characteristics (Op Amps) (Continued) V = 5V, V7 = GND = OV, Voy = V4/2, Vour = V4/2, Ty = Output Sink Current vs and Temp. 2.83" << 36y 2 Os Eo - 3 10 1 3 20 5 W 40 -50 10 f <3 -2 +100 f Yeurpuy REFERENCED Your () Output Impedance vs tot Frequency and Gain =I5 s A a to! 192 tof 108 108 FREQUENCY (Hz) Op Amp Voitage Noise vs Frequency 1000 g i g 5 FREQUENCY (Hz) Small-Signal Voltage Gain vs and Load 140 = 120 yeu #00 8 180 3 @ 8 4 90 EB 2 g 0 0 =20 40 =90 =80 =80 fov2 19? tot 198 FREQUENCY (Hz) PHASE SHIFT (DEG) NOISE CURRENT (farms //Hz) OUTPUT VOLTAGE (mv) OUTPUT CURRENT (mA) MAGNITUDE (dB) Slew Rate vs. Temp with Common-Mode Valtage below V 10123 28 2% 30 3132 OUTPUT YOLTAGE () Small-Signal Pulse 0 Response vs Temp. Qo 2 4 6 8 10 TWE (us) Op Amp Current Nolse 0 vs Frequency 10 FREQUENCY (Hz) z Follower Small-Signal 4 Frequency Response 2 0 0 2 45 -4 20 E Goad 1OpF a eat - 61 218 153 Fi 3 ~190 2% 80 100 200 $00 1000 2000 FREQUENCY (kHz) OUTPUT VOLTAGE (mv) OUTPUT VOLTAGE SWING (V) MAGNITUDE, (dB) CMRR (dB) 25C, unless otherwise noted T-79-10 Output Swing, 0 Large Signal 25% FREQUENCY (Hz) Smail-Signal Pulse Response vs Load 2268 o BEBB Common-Mode Input Voltage Re! a6) 1 TO TME (us) Small-Signal Voltage Gain ve Frequency and Temperature tot FREQUENCY (Hz) Jection Ratio Ve = 15Y Ye=rt8V M@ 6501124 0068437 9 PHASE SHIFT (DEG) Ly Hf LY vi ritoo 'OWa or? 19? ie io* FREQUENCY (Hz) 108 TL/H/9326-6 3-551 PLOWT/VPLOWTLM614A/LM614 SEMICOND (LINEAR) 22 D m@ b5011c4 0068436 0 ) 7 T-79-10 | Typical Performance Characteristics (Op Amps) (Continued) vit = 5V,V~ = GND = OV, Vom = V"/2, Vout = */2, Ty = 25C, unless otherwise noted Power Supply Current vs Power Supply Voltage 1000 $00 80 x 70 600 B 500 3 400 300 a. S 200 400 0 =100 =1 0 1 2 3 4 5 10 20 30 40 50 60 TOTAL SUPPLY VOLTAGE () TL/H/9326-7 Positive Power Supply Negative Power Supply Voltage Rejection Ratio Voltage Rejection Ratio 140 120 100 Sw s id e 60 . e co) vo 20 =15V 0 40 2 10 = to?sto# tf iz 10 ~= 02s to# =~ t08 FREQUENCY (Hz) FREQUENCY (Hz) TL/H/9326-21 TL/H/9326-22 Input Offset Current vs Input Blas Current vs Junction Temperature Junction Temperature 1000 8 ~ 6 p~ _ 4 0 baad z 2 = 5 0 4 6 & A eS =2 Lo 8 7 | 3 Hs 1000 aa 2 -sg / = a 7 ~i0 - 6 Representative Units 12 ~60 4020 0 20 40 60 80 100120140 JUNCTION TEMPERATURE (C) TL/H/9926-24 =60 -40-20 0 20 40 60 80 100120140 JUNCTION TEMPERATURE (C) TL/H/9328-98 3-552LM614A/LM614 nu g g g r/o. si _ 3: 8 ; y a 2 +2 Te fe ol OS : : 8 : a} * 2 2g A #S | s o = 5 BS 2 ~ = = = = ee mt aE DEORE : ry se Ae: BE 3 83 = SE | KM ,V\WW CG, a = g5 ww? 3 es ACE es gE SO O zs XQ. 25 3 28 | " SUNN co ul TU mu & 2 m2 3 gs F 2 3 z 5 2 g 2 2 2 << s 5 g 2 g 3 ut =O 2o 2 2 S 4 Q 2 32 2 3 3 s = zs 2 =e & 3S = a > 8 $3 g | OBE g 2 E 3 > a 25 = 3s & os 5 = ge ee 53 4 5 <5 Z8 LAMA? ze = @ 8s 8g 2 o g SUNN a & EF = 3-553NATL SEMICOND (LINEAR) LM614A/LM614 22 D M@ bLSO1124 GObs440 4 a Typical Performance Distributions (continued) T-79-10 Voltage Reference Broad-Band Op Amp Voitage Op Amp Current Nolse Distribution Noise Distribution Noise Distribution 30 30 30 100 Hi 100 Hz 10 Sf 10,000 Hz eh wi Amps 1, 2s 3, 4 10 20 20 10 g 8 a 5 5 5 10 {0 10 10 4B 1216 20-24 28 32 36 40 44 48 OOH 16 2437 40 48 56 6472 60 85.96 ONT 1824 32 40 48 $6 6472 80 68 96 VOLTAGE NOISE (Vays) VOLTAGE NOISE (npys /Hz ) CURRENT NOISE (fAgus /VHz) TL/H/9326-35 TL/H/9326-38 TL/H/9926-37 Application Information VOLTAGE REFERENCE Reference Blasing The voltage reference !s of a shunt regulator topology that models as a simple zener diode, With current |, flowing In the forward direction there Is the familiar diode transfer function. |, flowing in the reverse direction forces the refer- ence voltage to be developed from cathode to anode. The cathode may swing from a diode drop below V~ to the ref- erence voltage or to the avalanche voltage of the parallel protection diode, nominally 7V. A 6.3V reference with Vis 8V is allowed. Anode committed to V~ TL/H/9926-9 FIGURE 1. Voltages Associated with Reference (Current Source I, (s External) The reference equivalent circuit reveals how V; is held at the constant 1.2V by feedback, and how the FEEDBACK pin passes little current. To generate the required reverse current, typically a resistor Is connected from a supply voltage higher than the refer- ence voltage. Varying that voltage, and so varying |;, has small effect with the equivalent series resistance of less than an ohm at the higher currents. Alternatively, an active current source, such as the LM134 series, may generate |,. Capacitors in parallel with the reference are allowed. See the Reference AC Stability Range typical curve for capact- tance valuesfrom 20 pA to 3 mA any capacitor value Is stable. With the references wide stability range with resis- tive and capacitive loads, a wide range of RC filter values will perform noise filtering. Aneel =V- FIGURE 2. Reference Equivalent Circuit TL/H/8926-10 5V 100 uA | 38K Vro = Vr = 1,2V. TL/H/9926~11 FIGURE 3. 1.2V Reference Adjustable Reference The FEEDBACK pin allows the reference output voltage, Vro. to vary from 1.24V to 6.3V. The reference attempts to hold V, at 1.24V. If V; is above 1.24V, the reference will conduct current from Cathode to Anode; FEEDBACK cur- rent always remains low. If FEEDBACK is connected to An- ode, than Vio = Vy = 1.24V. For higher voltages FEED- BACK is held at a constant voltage above Anodesay 3.76V for Vig = 5V. Connecting a resistor across the cans- taint V; generates a current I=R1/V, flowing from Cathode into FEEDBACK node. A Thevenin equivalent 3.76V is gen- erated from FEEDBACK to Anode with R2=3.76/1. Keep |NATL SEMICOND {LINEAR} 2ecE D MM 6501124 O0b4441, 0 mm Application Information (continued) greater than one thousand times larger than FEEDBACK bias current for <0.1% errorl232 pA for the military grade over the military temperature range (12.5.5 pA for a 1% untrimmed error for a commercial part.) isv TL/H/9926-12 FIGURE 4. Thevenin Equivalent of Reference with 5V Output Vp3 1.24 3 Veo s5V p | i= 32uA TL/H/9326~13 Ri = Vr/l = 1.24/32 = 39k R2 = Ri ((Vro/Vr) 1} = 99k (5/1.24) 1)} = 118k FIGURE 5. Resistors R1 and R2 Program Reference Output Voltage to be 5V Understanding that V, is fixed and that voltage sources, re- sistors, and capacitors may be tied to the FEEDBACK pin, a range of V, temperature coefficlents may be synthesized. 15V 10k > > E NEGATIVE Tc A TL/H/9926-14 FIGURE 6. Output Voltage has Negative Temperature Coefficient (TC) lf R2 has Negative TC T-79-10 TL/H/9326-~15 FIGURE 7. Output Voltage has Pasitive TC if 1 has Negative TC TL/H/9926-16 FIGURE 8. Diode in Serles with R1 Causes Voltage across R1 and R2 to be Proportional to Absolute Temperature (PTAT) Connecting a resistor across Cathode-to-FEEDBACK cre- ates a 0 TC current source, but a range of TCs may be synthesized. z+ 164A! = 16 ual TL/H/9926-17 |= Vr/R1 = 1.24/R1 FIGURE 9. Current Source is Programmed by R1 3-555 PLOINT/VPlSINTLM614A/LM614 SEMICOND {LINEAR} 226 ) MM 6501124 coba4y4e 2 mm Application Information (Continued) TL/H/9326-18 FIGURE 10. Proportional-to-Absolute-Temperature Current Source THERMISTOR TL/H/9926-19 FIGURE 11. Negative-TC Current Source Hysteresis The reference voltage depends, slightly, on the thermal his- tory of the die. Competitive micro-power products varyal- ways check the data sheet for any given device. Do not assume that no specification means no hysteresis. OPERATIONAL AMPLIFIERS Any amp or the reference may be biased In any way with no affect on the other amps or reference, except when a sub- strate diode conducts (see Guaranteed Electrical Charac- teristics Note 1). One amp input may be outside the com- T-79-10 mon-mode range, another amp may be operated as a com- parator, another with all terminals floating with no effect on the others (tying inverting input to output and non-inverting input to V~ on unused amps is preferred). Choosing operat- ing points that cause oscillation, such as driving too large a capacitive load, is best avoided. OP Amp Output Stage These op amps, like their LM124 series, have flexible and relatively wide-swing output stages. There are simple rules to optimize output swing, reduce cross-over distortion, and optimize capacitive drive capability: 1) Output Swing: Unloaded, the 42 pA pull-down will bring the output within 300 mV of V~ over the military tempera- ture range. If more than 42 pA Is required, a resistor from output to V~ will help. Swing across any load may be improved slightly if the load can be tied to Vt, at the cost of poorer sinking open-loop voltage gain 2) Cross-over Distortion: The LM614 has lower cross-over distortion (a 1 Vee deadband versus 3 Vee for the LM124), and increased slew rate as shown in the charac- teristic curves. A resistor pull-up or pull-down will force class-A operation with only the PNP or NPN output tran- sistor conducting, eliminating cross-over distortion 8) Capacitive Drive: Limited by the output pole caused by the output resistance driving capacitive loads, a pull- down resistor conducting 1 mA or more reduces the out- put stage NPN re until the output resistance is that of the current limit 252. 200 pF may then be driven without os- cillation. OP Amp Input Stage The lateral PNP input transistors, unlike most op amps, have BVggo equal to the absolute maximum supply voltage. Also, they have no diode clamps to the positive supply nor across the inputs. These features make the Inputs look like high impedances to input sources producing large differen- tial and common-mode voltages. Typical Applications. For typical applications, refer to the LMi24 Op Amp and LM185 Adjustable Reference datasheets. 3-556