Version 4 SHEET 1 2824 1208 WIRE -928 -1472 -992 -1472 WIRE -704 -1472 -768 -1472 WIRE -928 -1424 -928 -1472 WIRE -928 -1424 -1040 -1424 WIRE -768 -1424 -768 -1472 WIRE -656 -1424 -768 -1424 WIRE -1040 -1328 -1040 -1424 WIRE -656 -1328 -656 -1424 WIRE -928 -1280 -928 -1424 WIRE -768 -1280 -768 -1424 WIRE -1040 -1184 -1040 -1264 WIRE -1040 -1184 -1056 -1184 WIRE -928 -1184 -928 -1200 WIRE -848 -1184 -928 -1184 WIRE -768 -1184 -768 -1200 WIRE -768 -1184 -848 -1184 WIRE -656 -1184 -656 -1264 WIRE -640 -1184 -656 -1184 WIRE -928 -1168 -928 -1184 WIRE -768 -1168 -768 -1184 WIRE -1040 -1104 -1040 -1184 WIRE -656 -1104 -656 -1184 WIRE -336 -1056 -416 -1056 WIRE -64 -1056 -336 -1056 WIRE 32 -1056 -64 -1056 WIRE 160 -1056 112 -1056 WIRE -336 -1024 -336 -1056 WIRE -64 -1024 -64 -1056 WIRE 496 -1024 496 -1040 WIRE 624 -1024 496 -1024 WIRE 752 -1024 688 -1024 WIRE 880 -1024 752 -1024 WIRE 1040 -1024 960 -1024 WIRE -1040 -944 -1040 -1040 WIRE -928 -944 -928 -1088 WIRE -928 -944 -1040 -944 WIRE -768 -944 -768 -1088 WIRE -656 -944 -656 -1040 WIRE -656 -944 -768 -944 WIRE -336 -944 -336 -960 WIRE -240 -944 -336 -944 WIRE -64 -944 -64 -960 WIRE -64 -944 -160 -944 WIRE -928 -896 -928 -944 WIRE -928 -896 -992 -896 WIRE -768 -896 -768 -944 WIRE -704 -896 -768 -896 WIRE 576 -880 560 -880 WIRE 672 -880 640 -880 WIRE 688 -880 672 -880 WIRE 672 -848 672 -880 WIRE -144 -832 -176 -832 WIRE -128 -832 -144 -832 WIRE 752 -832 752 -1024 WIRE 752 -832 704 -832 WIRE -848 -816 -848 -1184 WIRE -848 -816 -992 -816 WIRE -592 -816 -848 -816 WIRE 160 -816 160 -1056 WIRE 208 -816 160 -816 WIRE 496 -816 496 -1024 WIRE 496 -816 288 -816 WIRE 640 -816 496 -816 WIRE -144 -800 -144 -832 WIRE 752 -800 704 -800 WIRE 880 -800 752 -800 WIRE 992 -800 944 -800 WIRE -592 -784 -592 -816 WIRE -64 -784 -64 -944 WIRE -64 -784 -112 -784 WIRE -336 -768 -336 -944 WIRE -176 -768 -336 -768 WIRE -64 -752 -112 -752 WIRE 160 -752 160 -816 WIRE 560 -752 560 -880 WIRE 560 -752 528 -752 WIRE 576 -752 560 -752 WIRE 672 -752 672 -784 WIRE 672 -752 640 -752 WIRE 688 -752 672 -752 WIRE -992 -720 -992 -816 WIRE -896 -720 -992 -720 WIRE -784 -720 -816 -720 WIRE -240 -704 -240 -832 WIRE -240 -704 -272 -704 WIRE -144 -704 -144 -736 WIRE -144 -704 -176 -704 WIRE -128 -704 -144 -704 WIRE -992 -656 -992 -720 WIRE -976 -656 -992 -656 WIRE -800 -656 -896 -656 WIRE 992 -656 992 -800 WIRE 992 -656 960 -656 WIRE -992 -592 -992 -656 WIRE -896 -592 -992 -592 WIRE -784 -592 -816 -592 WIRE -64 -592 -64 -752 WIRE -64 -592 -96 -592 WIRE 160 -592 160 -688 WIRE 160 -592 144 -592 WIRE 752 -544 752 -800 WIRE 864 -544 752 -544 WIRE 1104 -544 944 -544 WIRE -992 -528 -992 -592 WIRE -976 -528 -992 -528 WIRE -800 -528 -896 -528 WIRE -416 -496 -416 -1056 WIRE -384 -496 -416 -496 WIRE -992 -464 -992 -528 WIRE -896 -464 -992 -464 WIRE -784 -464 -816 -464 WIRE -416 -464 -416 -496 WIRE 160 -464 -416 -464 WIRE 160 -416 160 -464 WIRE -992 -400 -992 -464 WIRE -976 -400 -992 -400 WIRE -784 -400 -896 -400 WIRE -992 -336 -992 -400 WIRE -896 -336 -992 -336 WIRE -784 -336 -816 -336 WIRE 160 -320 160 -336 WIRE 176 -320 160 -320 WIRE -992 -272 -992 -336 WIRE -976 -272 -992 -272 WIRE -784 -272 -896 -272 WIRE 176 -240 176 -320 WIRE 400 -240 176 -240 WIRE 496 -240 400 -240 WIRE 688 -240 576 -240 WIRE -992 -208 -992 -272 WIRE -896 -208 -992 -208 WIRE -784 -208 -816 -208 WIRE 176 -208 176 -240 WIRE -992 -144 -992 -208 WIRE -976 -144 -992 -144 WIRE -784 -144 -896 -144 WIRE 400 -128 400 -240 WIRE 512 -128 400 -128 WIRE 688 -128 688 -240 WIRE 688 -128 576 -128 WIRE 176 -96 176 -128 WIRE 176 -96 160 -96 WIRE -992 -80 -992 -144 WIRE -896 -80 -992 -80 WIRE -784 -80 -816 -80 WIRE 496 -32 480 -32 WIRE 528 -32 496 -32 WIRE 608 -32 592 -32 WIRE 32 0 -176 0 WIRE 496 0 496 -32 WIRE -176 16 -176 0 WIRE 400 16 400 -128 WIRE 464 16 400 16 WIRE 688 32 688 -128 WIRE 688 32 528 32 WIRE 1104 32 1104 -544 WIRE 1104 32 688 32 WIRE 1152 32 1104 32 WIRE 32 48 32 0 WIRE 32 48 0 48 WIRE 80 48 32 48 WIRE 464 48 160 48 WIRE 1104 64 1104 32 WIRE 496 96 496 64 WIRE 496 96 480 96 WIRE 528 96 496 96 WIRE 608 96 608 -32 WIRE 608 96 592 96 WIRE 640 96 608 96 WIRE -176 112 -176 96 WIRE -176 112 -208 112 WIRE 1040 176 1040 -1024 WIRE 1104 176 1104 144 WIRE 1104 176 1040 176 WIRE 1104 224 1104 176 WIRE 1104 224 1088 224 FLAG 1152 32 OUT IOPIN 1152 32 Out FLAG 0 48 IN IOPIN 0 48 In FLAG 688 -880 +15V FLAG -128 -832 +15V FLAG -128 -704 -15V FLAG 688 -752 -15V FLAG -704 -1472 +15V FLAG -704 -896 -15V FLAG 1088 224 GND_LD FLAG 960 -656 GND_INT FLAG 144 -592 GND_FLT1 FLAG -96 -592 GND_REF FLAG 160 -96 GND_AMP FLAG 480 -32 +30V FLAG -784 -720 GND_REF FLAG -800 -656 GND_FLT1 FLAG -784 -592 GND_INT FLAG -800 -528 GND_AMP FLAG -784 -464 GND_LD FLAG 480 96 -30V FLAG -992 -1472 +30V FLAG -992 -896 -30V FLAG -208 112 GND_IN FLAG -784 -400 GND_IN FLAG -592 -784 0 FLAG -272 -704 GND_U2A FLAG 528 -752 GND_U2B FLAG 640 96 GND_U1 FLAG -784 -272 GND_U2B FLAG -784 -336 GND_U2A FLAG -784 -208 GND_U1 FLAG -640 -1184 GND_15 FLAG -1056 -1184 GND_30 FLAG -784 -144 GND_15 FLAG -784 -80 GND_30 FLAG -384 -496 FILT_OUT IOPIN -384 -496 Out FLAG 496 -1040 INT_OUT IOPIN 496 -1040 Out SYMBOL res 592 -256 R90 WINDOW 0 -1 53 VBottom 0 WINDOW 3 35 55 VTop 0 SYMATTR InstName R4 SYMATTR Value 10k SYMBOL res 1088 48 R0 WINDOW 0 51 34 Left 0 WINDOW 3 48 65 Left 0 SYMATTR InstName R7 SYMATTR Value 8 SYMBOL cap 576 -144 R90 WINDOW 0 12 72 VBottom 0 WINDOW 3 -16 -16 VTop 0 SYMATTR InstName C11 SYMATTR Value 4.7p SYMATTR SpiceLine Rser=.05 SYMBOL res 192 -112 R180 WINDOW 0 52 86 Left 0 WINDOW 3 51 36 Left 0 SYMATTR InstName R3 SYMATTR Value 499 SYMBOL cap 624 -1040 M90 WINDOW 0 -4 33 VBottom 0 WINDOW 3 40 33 VTop 0 SYMATTR InstName C2 SYMATTR Value .22µ SYMATTR SpiceLine Rser=.023 SYMBOL res 848 -560 M90 WINDOW 0 0 56 VBottom 0 WINDOW 3 32 56 VTop 0 SYMATTR InstName R8 SYMATTR Value 680k SYMBOL res 864 -1040 M90 WINDOW 0 0 56 VBottom 0 WINDOW 3 32 56 VTop 0 SYMATTR InstName R23 SYMATTR Value 680k SYMBOL cap 880 -816 M90 WINDOW 0 0 32 VBottom 0 WINDOW 3 32 32 VTop 0 SYMATTR InstName C4 SYMATTR Value .22µ SYMATTR SpiceLine Rser=.023 SYMBOL res 176 -320 R180 WINDOW 0 53 80 Left 0 WINDOW 3 48 38 Left 0 SYMATTR InstName R1 SYMATTR Value 10K SYMBOL res -256 -960 M90 WINDOW 0 2 60 VBottom 0 WINDOW 3 30 61 VTop 0 SYMATTR InstName R9 SYMATTR Value 100k SYMBOL cap -48 -1024 M0 WINDOW 0 -48 13 Left 0 WINDOW 3 -34 54 Left 0 SYMATTR InstName C10 SYMATTR Value 1µ SYMATTR SpiceLine Rser=.03 SYMBOL cap -320 -1024 M0 WINDOW 0 41 11 Left 0 WINDOW 3 47 49 Left 0 SYMATTR InstName C12 SYMATTR Value 1µ SYMATTR SpiceLine Rser=.03 SYMBOL res 16 -1072 M90 WINDOW 0 0 56 VBottom 0 WINDOW 3 35 70 VTop 0 SYMATTR InstName R12 SYMATTR Value 29.4k SYMBOL cap 176 -752 M0 WINDOW 0 44 5 Left 0 WINDOW 3 44 38 Left 0 SYMATTR InstName C13 SYMATTR Value 4.7µ SYMATTR SpiceLine Rser=.03 SYMBOL res 192 -832 M90 WINDOW 0 0 56 VBottom 0 WINDOW 3 32 56 VTop 0 SYMATTR InstName R13 SYMATTR Value 12.4k SYMBOL voltage -768 -1296 R0 WINDOW 0 46 37 Left 0 WINDOW 3 46 77 Left 0 WINDOW 123 0 0 Left 0 WINDOW 39 40 58 Left 0 SYMATTR InstName V1 SYMATTR Value 15 SYMBOL voltage -768 -1072 R180 WINDOW 0 -69 24 Left 0 WINDOW 3 -73 79 Left 0 WINDOW 123 0 0 Left 0 WINDOW 39 38 53 Left 0 SYMATTR InstName V2 SYMATTR Value -15 SYMBOL Opamps\\OP275 -144 -832 M0 WINDOW 0 -143 44 Left 0 WINDOW 3 -167 82 Left 0 SYMATTR InstName U2A SYMBOL Opamps\\OP275 672 -880 M0 WINDOW 0 -133 26 Left 0 WINDOW 3 -157 57 Left 0 SYMATTR InstName U2B SYMBOL voltage -176 0 R0 WINDOW 123 -229 89 Left 0 WINDOW 39 0 0 Left 0 WINDOW 0 -148 20 Left 0 WINDOW 3 -229 59 Left 0 SYMATTR Value2 AC 1 SYMATTR InstName VIN SYMATTR Value SINE(0 .5 {freq}) SYMBOL voltage 176 48 R90 WINDOW 123 0 0 Left 0 WINDOW 39 0 0 Left 0 WINDOW 3 86 -216 VRight 0 WINDOW 0 52 26 VRight 0 SYMATTR Value PULSE(-.022727 .022727 0.2 .001 .001 8 8.002) SYMATTR InstName VOFF SYMBOL Opamps\\opamp2 496 -32 R0 WINDOW 3 -223 -31 Left 0 WINDOW 0 -197 -66 Left 0 SYMATTR Value OPA541e SYMATTR InstName U1 SYMBOL voltage -928 -1296 R0 WINDOW 0 -68 37 Left 0 WINDOW 3 -67 82 Left 0 WINDOW 123 0 0 Left 0 WINDOW 39 39 55 Left 0 SYMATTR InstName V3 SYMATTR Value 30 SYMBOL voltage -928 -1072 R180 WINDOW 0 43 40 Left 0 WINDOW 3 41 83 Left 0 WINDOW 123 0 0 Left 0 WINDOW 39 37 55 Left 0 SYMATTR InstName V4 SYMATTR Value -30 SYMBOL ind -912 -704 R270 WINDOW 0 32 56 VTop 0 WINDOW 3 5 56 VBottom 0 SYMATTR InstName L9 SYMATTR Value 100n SYMATTR SpiceLine Rser=.004 SYMBOL ind -992 -640 R270 WINDOW 0 32 56 VTop 0 WINDOW 3 5 56 VBottom 0 SYMATTR InstName L10 SYMATTR Value 100n SYMATTR SpiceLine Rser=.004 SYMBOL ind -912 -576 R270 WINDOW 0 32 56 VTop 0 WINDOW 3 5 56 VBottom 0 SYMATTR InstName L11 SYMATTR Value 100n SYMATTR SpiceLine Rser=.004 SYMBOL ind -992 -512 R270 WINDOW 0 32 56 VTop 0 WINDOW 3 5 56 VBottom 0 SYMATTR InstName L12 SYMATTR Value 100n SYMATTR SpiceLine Rser=.004 SYMBOL ind -912 -448 R270 WINDOW 0 32 56 VTop 0 WINDOW 3 5 56 VBottom 0 SYMATTR InstName L13 SYMATTR Value 100n SYMATTR SpiceLine Rser=.004 SYMBOL ind -992 -384 R270 WINDOW 0 32 56 VTop 0 WINDOW 3 5 56 VBottom 0 SYMATTR InstName L14 SYMATTR Value 100n SYMATTR SpiceLine Rser=.004 SYMBOL cap -176 -848 R90 WINDOW 0 0 32 VBottom 0 WINDOW 3 32 32 VTop 0 SYMATTR InstName C3 SYMATTR Value 0.1µ SYMATTR SpiceLine Rser=.05 SYMBOL cap -176 -720 R90 WINDOW 0 0 32 VBottom 0 WINDOW 3 32 32 VTop 0 SYMATTR InstName C1 SYMATTR Value 0.1µ SYMATTR SpiceLine Rser=.05 SYMBOL cap 640 -896 R90 WINDOW 0 0 32 VBottom 0 WINDOW 3 32 32 VTop 0 SYMATTR InstName C5 SYMATTR Value 0.1µ SYMATTR SpiceLine Rser=.05 SYMBOL cap 640 -768 R90 WINDOW 0 0 32 VBottom 0 WINDOW 3 32 32 VTop 0 SYMATTR InstName C6 SYMATTR Value 0.1µ SYMATTR SpiceLine Rser=.05 SYMBOL cap 592 -48 R90 WINDOW 0 0 32 VBottom 0 WINDOW 3 32 32 VTop 0 SYMATTR InstName C7 SYMATTR Value 0.1µ SYMATTR SpiceLine Rser=.05 SYMBOL cap 592 80 R90 WINDOW 0 0 32 VBottom 0 WINDOW 3 32 32 VTop 0 SYMATTR InstName C8 SYMATTR Value 0.1µ SYMATTR SpiceLine Rser=.05 SYMBOL ind -992 -256 R270 WINDOW 0 32 56 VTop 0 WINDOW 3 5 56 VBottom 0 SYMATTR InstName L3 SYMATTR Value 100n SYMATTR SpiceLine Rser=.004 SYMBOL ind -912 -320 R270 WINDOW 0 32 56 VTop 0 WINDOW 3 5 56 VBottom 0 SYMATTR InstName L4 SYMATTR Value 100n SYMATTR SpiceLine Rser=.004 SYMBOL ind -912 -192 R270 WINDOW 0 32 56 VTop 0 WINDOW 3 5 56 VBottom 0 SYMATTR InstName L5 SYMATTR Value 100n SYMATTR SpiceLine Rser=.004 SYMBOL cap -672 -1328 R0 SYMATTR InstName C14 SYMATTR Value 10µ SYMATTR SpiceLine Rser=0.7 SYMBOL cap -672 -1104 R0 SYMATTR InstName C9 SYMATTR Value 10µ SYMATTR SpiceLine Rser=0.7 SYMBOL cap -1056 -1104 R0 WINDOW 0 -44 8 Left 0 WINDOW 3 -57 60 Left 0 SYMATTR InstName C15 SYMATTR Value 4700µ SYMATTR SpiceLine Rser=0.053 Rpar=10.64k SYMBOL ind -992 -128 R270 WINDOW 0 32 56 VTop 0 WINDOW 3 5 56 VBottom 0 SYMATTR InstName L6 SYMATTR Value 100n SYMATTR SpiceLine Rser=.004 SYMBOL ind -912 -64 R270 WINDOW 0 32 56 VTop 0 WINDOW 3 5 56 VBottom 0 SYMATTR InstName L15 SYMATTR Value 100n SYMATTR SpiceLine Rser=.004 SYMBOL cap -1056 -1328 R0 WINDOW 0 -44 8 Left 0 WINDOW 3 -57 60 Left 0 SYMATTR InstName C16 SYMATTR Value 4700µ SYMATTR SpiceLine Rser=0.053 Rpar=10.64k TEXT 264 -32 Left 0 ;SIMULATED\nAUDIO\nAMPLIFIER TEXT 1136 152 Left 0 ;(SIMULATED\nLOAD) TEXT -472 -1240 Left 0 ;DC-OFFSET-ZEROING SERVO TEXT 640 -952 Left 0 ;MPP TEXT 888 -736 Left 0 ;MPP TEXT 608 -1176 Left 0 ;DIFFERENTIAL\nINTEGRATOR TEXT 88 -688 Left 0 ;MPE TEXT -40 -936 Left 0 ;MPE TEXT -400 -944 Left 0 ;MPE TEXT 336 -1464 Center 0 ;"DC SERVO" FOR AUDIO AMPLIFIER\n \n(C) Copyright 2007, T.P. Gootee\nPermission granted for non-commercial use only.\n AUTHOR: TOMG@FULLNET.COM\nTO DOWNLOAD THE LT-SPICE SIMULATION FILES FOR THIS SCHEMATIC, GO TO HTTP://WWW.FULLNET.COM/~TOMG/GOOTEESP.HTM . TEXT -432 -1176 Left 0 ;"DC-ACCURATE"\nLOW-PASS FILTER,\n1.9 Hz, -60dB/DECADE TEXT 568 -408 Left 0 ;MPP = w/ Polypropylene dielectric\nMPE = w/Polyester dielectric\nAll resistors are 1% or better metal film. TEXT 240 -408 Left 0 ;R1's VALUE SHOULD\nPROBABLY BE AT\nLEAST 20X R3's VALUE. TEXT -488 -184 Left 0 !.include op275.sub TEXT -490 -86 Left 0 !.tran 0 8 0 {1/(1000*freq)} TEXT -488 -224 Left 0 !.param freq = 60 TEXT -488 -120 Left 0 !.options plotwinsize=0 TEXT -488 -152 Left 0 !.include OPA541E.sub TEXT -1104 8 Left 0 ;PCB TRACE OR WIRE\nINDUCTANCE AND RESISTANCE:\nJUST ESTIMATE 25 nH/inch and\n0.001 Ohm/inch @ 4 inches, for now. \nSee which GNDS should not be combined, etc,\nand analyze effects of traces' or wires'\nlengths, widths, and thicknesses. TEXT -488 -256 Left 0 !;.options gmin=1e-013 TEXT -296 -384 Left 0 ;Add buffer/follower here\nto measure "true" FILT_OUT,\nduring Transient Analysis runs. TEXT -496 184 Left 0 ;To plot power dissipation of a component, hold down ALT and Left-Click on component.\nTo calculate average value of a plot for the currently-zoomed plot area, hold down CTRL and Left-Click on plot label.\nTo plot an equation, Right-Click on a plot label and enter the equation. [e.g. V(INT_OUT)/I(R13)] TEXT -488 -48 Left 0 !;ac dec 200 .1 100000 TEXT 120 -32 Center 0 ;OFFSET\nSTEP TEXT -744 -832 Left 0 ;STAR\nGROUND LINE Normal -48 -464 -48 -416 LINE Normal -48 -448 -48 -464 LINE Normal -48 -448 -48 -464 LINE Normal -48 -416 -48 -400 LINE Normal -64 -448 -48 -464 LINE Normal -32 -448 -48 -464 RECTANGLE Normal 1184 -288 -488 -1264 2 RECTANGLE Normal 1192 -1280 -488 -1496 RECTANGLE Normal 304 -528 -448 -1200 2 RECTANGLE Normal 1136 -480 416 -1200 2 RECTANGLE Normal 928 272 -512 160