Version 4 SHEET 1 4288 2324 WIRE 2272 752 1552 752 WIRE 1840 800 1664 800 WIRE 2080 800 1920 800 WIRE 1232 832 1088 832 WIRE 1328 832 1232 832 WIRE 1824 832 1328 832 WIRE 1088 848 1088 832 WIRE 1232 864 1232 832 WIRE 1920 864 1504 864 WIRE 2064 864 1920 864 WIRE 2128 864 2064 864 WIRE 2160 864 2128 864 WIRE 1824 896 1824 832 WIRE 1920 896 1920 864 WIRE 1088 944 1088 928 WIRE 1232 944 1232 928 WIRE 1552 960 1552 752 WIRE 1568 960 1552 960 WIRE 1696 960 1648 960 WIRE 2064 960 2064 864 WIRE 2064 960 2048 960 WIRE 1328 1056 1328 832 WIRE 1696 1056 1328 1056 WIRE 2272 1056 2272 752 WIRE 2272 1056 2048 1056 WIRE 2368 1056 2272 1056 WIRE 2576 1056 2368 1056 WIRE 2688 1056 2576 1056 WIRE 2800 1056 2688 1056 WIRE 2896 1056 2800 1056 WIRE 1328 1072 1328 1056 WIRE 2272 1072 2272 1056 WIRE 2576 1072 2576 1056 WIRE 2688 1072 2688 1056 WIRE 2896 1072 2896 1056 WIRE 2368 1088 2368 1056 WIRE 1696 1152 1376 1152 WIRE 2224 1152 2048 1152 WIRE 1504 1168 1504 864 WIRE 2128 1168 2128 864 WIRE 2688 1168 2688 1136 WIRE 2896 1168 2896 1152 WIRE 2272 1184 2272 1168 WIRE 2368 1184 2368 1152 WIRE 2368 1184 2272 1184 WIRE 1504 1248 1504 1232 WIRE 1696 1248 1504 1248 WIRE 2128 1248 2128 1232 WIRE 2128 1248 2048 1248 WIRE 1504 1264 1504 1248 WIRE 2128 1264 2128 1248 WIRE 1328 1344 1328 1168 WIRE 1504 1344 1504 1328 WIRE 1504 1344 1328 1344 WIRE 1664 1344 1664 800 WIRE 1664 1344 1504 1344 WIRE 1696 1344 1664 1344 WIRE 2080 1344 2080 800 WIRE 2080 1344 2048 1344 WIRE 2128 1344 2128 1328 WIRE 2128 1344 2080 1344 WIRE 2272 1344 2272 1184 WIRE 2272 1344 2128 1344 WIRE 1328 1440 1328 1344 WIRE 1328 1440 1280 1440 WIRE 1696 1440 1328 1440 WIRE 2272 1440 2272 1344 WIRE 2272 1440 2048 1440 WIRE 1328 1456 1328 1440 WIRE 2272 1456 2272 1440 WIRE 1280 1472 1280 1440 WIRE 2800 1472 2800 1056 WIRE 2800 1472 2688 1472 WIRE 2912 1472 2800 1472 WIRE 2688 1488 2688 1472 WIRE 2912 1520 2912 1472 WIRE 1696 1536 1376 1536 WIRE 2224 1536 2048 1536 WIRE 1280 1552 1280 1536 WIRE 1328 1552 1280 1552 WIRE 2800 1552 2800 1472 WIRE 1328 1568 1328 1552 WIRE 2272 1568 2272 1552 WIRE 2688 1584 2688 1568 WIRE 2688 1584 2576 1584 WIRE 2688 1600 2688 1584 WIRE 2912 1600 2912 1584 WIRE 1616 1632 1600 1632 WIRE 1696 1632 1680 1632 WIRE 2576 1632 2576 1584 WIRE 2576 1632 2048 1632 WIRE 2688 1696 2688 1680 WIRE 1696 1728 1664 1728 WIRE 2096 1728 2048 1728 WIRE 2288 1728 2096 1728 WIRE 2800 1728 2800 1632 WIRE 2800 1728 2288 1728 WIRE 2912 1728 2912 1680 WIRE 2912 1728 2800 1728 WIRE 2096 1744 2096 1728 WIRE 2800 1744 2800 1728 WIRE 1696 1824 1664 1824 WIRE 2096 1824 2048 1824 WIRE 2208 1824 2160 1824 WIRE 2288 1824 2288 1728 WIRE 2336 1824 2288 1824 WIRE 2448 1824 2416 1824 WIRE 2448 1840 2448 1824 WIRE 2800 1840 2800 1824 WIRE 1792 1904 1792 1888 WIRE 1872 1904 1872 1888 WIRE 1952 1904 1952 1888 WIRE 1792 2000 1792 1984 WIRE 1952 2000 1952 1984 FLAG 1088 944 0 FLAG 1328 1568 0 FLAG 2272 1568 0 FLAG 2688 1168 0 FLAG 2896 1168 0 FLAG 2800 1840 0 FLAG 2688 1696 0 FLAG 1952 2000 0 FLAG 1872 1904 0 FLAG 1792 2000 0 FLAG 1600 1632 0 FLAG 1664 1728 0 FLAG 1664 1824 0 FLAG 2896 1056 OUT FLAG 1088 832 IN FLAG 2160 928 0 FLAG 1232 944 0 FLAG 2448 1840 0 SYMBOL VOLTAGE 1088 832 R0 WINDOW 123 0 0 Left 2 WINDOW 39 0 0 Left 2 SYMATTR InstName V1 SYMATTR Value 3 SYMBOL nmos 1376 1072 M0 WINDOW 0 1 8 Right 2 WINDOW 3 40 105 Right 2 SYMATTR InstName Q1 SYMATTR Value FDS6890A SYMBOL nmos 1376 1456 M0 WINDOW 0 0 11 Right 2 WINDOW 3 35 100 Right 2 SYMATTR InstName Q2 SYMATTR Value FDS6890A SYMBOL schottky 1488 1168 R0 WINDOW 0 26 2 Left 2 WINDOW 3 27 60 Left 2 SYMATTR InstName D1 SYMATTR Value CMDSH2-3 SYMATTR Description Diode SYMATTR Type diode SYMBOL cap 1488 1264 R0 WINDOW 0 24 13 Left 2 WINDOW 3 26 55 Left 2 SYMATTR InstName C8 SYMATTR Value .22µ SYMBOL ind 1824 816 R270 WINDOW 0 32 56 VTop 2 WINDOW 3 5 56 VBottom 2 SYMATTR InstName L1 SYMATTR Value 3.3µ SYMATTR SpiceLine Rser=14m Rpar=1K SYMBOL nmos 2224 1072 R0 WINDOW 0 52 16 Left 2 WINDOW 3 57 138 Left 2 SYMATTR InstName Q3 SYMATTR Value FDS6890A SYMBOL schottky 2112 1168 R0 SYMATTR InstName D2 SYMATTR Value CMDSH2-3 SYMATTR Description Diode SYMATTR Type diode SYMBOL cap 2112 1264 R0 SYMATTR InstName C9 SYMATTR Value .22µ SYMBOL nmos 2224 1456 R0 WINDOW 0 57 0 Left 2 WINDOW 3 57 96 Left 2 SYMATTR InstName Q4 SYMATTR Value FDS6890A SYMBOL schottky 1296 1536 R180 WINDOW 0 24 64 Left 2 WINDOW 3 24 0 Left 2 SYMATTR InstName D3 SYMATTR Value PMEG2020AEA SYMATTR Description Diode SYMATTR Type diode SYMBOL schottky 2352 1152 M180 WINDOW 0 24 72 Left 2 WINDOW 3 21 2 Left 2 SYMATTR InstName D4 SYMATTR Value PMEG2020AEA SYMATTR Description Diode SYMATTR Type diode SYMBOL cap 2672 1072 R0 SYMATTR InstName C16 SYMATTR Value 100µ SYMATTR SpiceLine Rser=18m SYMBOL res 2784 1536 R0 SYMATTR InstName R1 SYMATTR Value 205K SYMBOL res 2784 1728 R0 SYMATTR InstName R3 SYMATTR Value 127K SYMBOL cap 2896 1520 R0 WINDOW 39 24 77 Left 2 SYMATTR Value 270p SYMATTR InstName C2 SYMBOL res 2672 1472 R0 SYMATTR InstName R5 SYMATTR Value 205K SYMBOL res 2672 1584 R0 SYMATTR InstName R6 SYMATTR Value 66.5K SYMBOL res 1936 1888 R0 SYMATTR InstName R7 SYMATTR Value 100 SYMBOL res 1776 1888 R0 SYMATTR InstName R8 SYMATTR Value 59K SYMBOL cap 1680 1616 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName C1 SYMATTR Value 1n SYMBOL res 2880 1056 R0 SYMATTR InstName Rload SYMATTR Value 1.2 SYMBOL res 2896 1584 R0 SYMATTR InstName R2 SYMATTR Value 1.3K SYMBOL cap 2144 864 R0 WINDOW 3 26 48 Left 2 SYMATTR Value 4.7µ SYMATTR InstName C7 SYMBOL LTC3785-1 1872 1392 R0 SYMATTR InstName U2 SYMBOL res 1552 976 R270 WINDOW 0 32 56 VTop 2 WINDOW 3 0 56 VBottom 2 SYMATTR InstName R9 SYMATTR Value 100K SYMBOL cap 1216 864 R0 SYMATTR InstName C5 SYMATTR Value 22µ SYMATTR SpiceLine Rser=5m SYMBOL cap 2096 1808 M90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName C3 SYMATTR Value 1n SYMBOL res 2304 1808 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R4 SYMATTR Value 12K SYMBOL res 2432 1808 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R10 SYMATTR Value 66.5K TEXT 2464 1856 Left 2 !.tran 2m startup TEXT 1888 744 Bottom 2 ;LTC3785-1 - 10V, High Efficiency, Buck-Boost Controller with Power Good\n10W Li-Ion/9V Wall Adapter Buck-Boost Controller with Power Good\nInput: 2.7V to 10V Output: 3.3V @ 3A, Fsw = 500kHz TEXT 1312 2024 Left 2 ;Note:\n Component substitutions have been made based on available component models and parasitics are not modeled\n A smaller value SS capacitor (C1) is used to reduce simulation time. Typical value should be 2.2nF.\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 © 2014 Linear Technology Inc. All rights reserved.