Version 4 SHEET 1 1624 748 WIRE 416 -64 96 -64 WIRE 96 0 96 -64 WIRE 112 0 96 0 WIRE 416 0 416 -64 WIRE 416 0 400 0 WIRE 672 0 416 0 WIRE 784 0 672 0 WIRE 672 16 672 0 WIRE 784 16 784 0 WIRE 112 96 96 96 WIRE 592 96 400 96 WIRE 672 112 672 80 WIRE 784 112 784 96 WIRE 32 192 0 192 WIRE 112 192 96 192 WIRE 464 192 400 192 WIRE 464 208 464 192 WIRE 592 224 592 96 WIRE 944 224 592 224 WIRE 16 288 0 288 WIRE 112 288 96 288 WIRE 464 288 464 272 WIRE 464 288 400 288 WIRE 592 288 464 288 WIRE 640 288 592 288 WIRE 752 288 720 288 WIRE 864 288 752 288 WIRE 944 288 944 224 WIRE 944 288 864 288 WIRE 1040 288 944 288 WIRE 464 304 464 288 WIRE 592 304 592 288 WIRE 752 304 752 288 WIRE 864 304 864 288 WIRE 944 304 944 288 WIRE 1040 304 1040 288 WIRE 112 384 96 384 WIRE 416 384 400 384 WIRE 592 400 592 384 WIRE 752 400 752 384 WIRE 752 400 704 400 WIRE 864 400 864 368 WIRE 864 400 752 400 WIRE 944 400 944 368 WIRE 1040 400 1040 384 WIRE 752 416 752 400 WIRE 592 480 592 464 WIRE 416 512 416 384 WIRE 704 512 704 400 WIRE 704 512 416 512 WIRE 752 512 752 496 FLAG 96 384 0 FLAG 0 288 0 FLAG 784 112 0 FLAG 944 400 0 FLAG 752 512 0 FLAG 1040 400 0 FLAG 1040 288 OUT FLAG 784 0 IN FLAG 464 368 0 FLAG 592 480 0 FLAG 672 112 0 FLAG 0 192 0 SYMBOL res 112 272 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R1 SYMATTR Value 130K SYMBOL voltage 784 0 R0 WINDOW 123 0 0 Left 2 WINDOW 39 0 0 Left 2 SYMATTR InstName V1 SYMATTR Value 12 SYMBOL ind 624 304 R270 WINDOW 0 32 56 VTop 2 WINDOW 3 5 56 VBottom 2 SYMATTR InstName L1 SYMATTR Value 3.3µ SYMATTR SpiceLine Rser=10m SYMBOL cap 448 208 R0 SYMATTR InstName C3 SYMATTR Value .47µ SYMBOL cap 928 304 R0 WINDOW 123 25 64 Left 2 WINDOW 3 37 37 Left 2 SYMATTR Value2 x2 SYMATTR Value 47µ SYMATTR InstName C4 SYMATTR SpiceLine V=10 Irms=0 Rser=0.002 Lser=0 SYMBOL res 736 288 R0 SYMATTR InstName R2 SYMATTR Value 1Meg SYMBOL res 736 400 R0 SYMATTR InstName R3 SYMATTR Value 576K SYMBOL cap 848 304 R0 SYMATTR InstName C5 SYMATTR Value 10p SYMBOL res 1024 288 R0 SYMATTR InstName Rload SYMATTR Value 0.66 SYMBOL schottky 448 368 M180 WINDOW 0 34 60 Left 2 WINDOW 3 32 11 Left 2 SYMATTR InstName D1 SYMATTR Value B540C SYMATTR Description Diode SYMATTR Type diode SYMBOL PowerProducts\\LT3976 256 192 R0 SYMATTR InstName U1 SYMBOL cap 576 400 R0 SYMATTR InstName C2 SYMATTR Value 470p SYMBOL res 576 288 R0 SYMATTR InstName R4 SYMATTR Value 2 SYMBOL cap 656 16 R0 SYMATTR InstName C6 SYMATTR Value 10µ SYMBOL cap 32 208 R270 WINDOW 0 32 32 VTop 2 WINDOW 3 0 32 VBottom 2 SYMATTR InstName C1 SYMATTR Value 0.005µ TEXT 912 480 Left 2 !.tran 3m startup TEXT 488 -80 Bottom 2 ;LT3976 - 40V, 5A, 2MHz Step-Down Switching Regulator with 3.3µA Quiescent Current\n3.3V Step-Down Converter\nInput: 4.3V to 42V Output: 3.3V @ 5A TEXT -72 520 Left 2 ;Note:\n A smaller value SS capacitor is used to reduce simulation time. Typical value should be 10nF.\n If the simulation model is not found please update with the "Sync Release" command from the "Tools" menu.\n It remains the customer's responsibility to verify proper and reliable operation in the actual application.\n Component substitution and printed circuit board layout may significantly affect circuit performance or reliability.\n Contact your local sales representative for assistance. This circuit is distributed to customers only for use with LTC parts.\n Copyright © 2012 Linear Technology Inc. All rights reserved.