5
4
3
2
1
REVISION HISTORY
ECO
REV
-
2
APPROVED
DESCRIPTION
PRODUCTION
DATE
06-15-10
CHARLIE Z.
D
D
VIN
INTVCC
E1
SYNC
E3
E4
INTVCC
MODE
2
BM
3
CCM
4
U1
LTC3865EUH-1
R2
0 Ohm
1
PS
27
C2
(OPT)
VID21
12
VID22
28
RUN1
30
162K
1%
R7
TRK/SS1
0 Ohm
C5
R9
(OPT)
C6
0.1uF
1000pF
R10
24.9K
29
MODE/PLLIN
SENSE1-
VID21
SENSE1+
VID22
TG1
RUN1
SW1
FREQ
3
BOOST1
TRK/SS1
BG1
VIN
1000pF
R13
15K
VOUT1
ITH2
PGND
7
C11
470pF
13
R14
(OPT)
20
R15
14
TRK/SS2
31
24
VID11
C14
0.1uF
VID12
RUN2
R19
100K
4
5
11
INTVCC
C3
0.1uF D1
R6
BG1
CMDSH-3TR
23
2.2
C7
22
EXTVCC
SW2
PGOOD1
BOOST2
VID11
BG2
C8
18
8
1
16
VID12
SENSE2+
C12
0.1uF D2
RUN2
SENSE2-
VSW2
220uF
4V
C4
1uF
6.3V
C
E6
GND
10
R20
VOUT2
L2
VL2-
2.2uH
IHLP-2525CZ-01 2R2
BG2
R18
9
+ COUT2
CIN3
7
CMDSH-3TR
C15
1000pF
COUT1
10uF
6.3V
10uF
16V
Q2A
Si4816BDY
56
15
19
VOUT1
3.3V / 5A
0.006
4.7uF
VIN
17
E5
RS1
23
21
R16
VL1-
Q1B
Si4816BDY
4
R8
VIN
VOUT1
L1
2.2uH
IHLP-2525CZ-01 2R2
7
TG2
TG2
VSW1
56
26
0 Ohm
R17
(OPT)
1
TRK/SS2
PGOOD2
10uF
16V
Q1A
Si4816BDY
TG1
25
0 Ohm
VOUT2
1.8V / 5A
0.006
COUT3
10uF
6.3V
Q2B
Si4816BDY
4
E8
RS2
+ COUT4
220uF
4V
C13
1uF
6.3V
E9
GND
23
100
100
E11
B
8
C1
100
R4
1000pF
0.1uF
6
CIN2
R3
32
ITH1
INTVCC
INTVCC
VIN
VINF
C9
220pF
C10
E10
GND
S1+
0 Ohm
2
E2
S11
100
R5
E7
0 Ohm
VOSENSE1
JP1
C
CIN1 +
39uF
16V
R11
R1
10K
VIN
4.5V - 14V
SGND
B
VOSENSE2
S2+
PGOOD2
33
8
S2-
E12
EXTVCC
C16
1uF
16V
INTVCC
R12
R22
100K
(Opt)
R21
0 Ohm
E13
PGOOD1
SHT. 2
SHT. 2
A
{
{
VID21
VID22
RUN1
VID11
VID12
RUN2
VID21
VID22
RUN1
VID11
VID12
A
RUN2
CUSTOMER NOTICE
NOTE: UNLESS OTHERWISE SPECIFIED.
1. ALL RESISTORS ARE IN OHMS, 0603.
ALL CAPACITORS ARE IN MICROFARADS, 0603.
APPROVALS
LINEAR TECHNOLOGY HAS MADE A BEST EFFORT TO DESIGN A
CIRCUIT THAT MEETS CUSTOMER-SUPPLIED SPECIFICATIONS;
TECHNOLOGY
HOWEVER, IT REMAINS THE CUSTOMER'S RESPONSIBILITY TO PCB DES.
RB
VERIFY PROPER AND RELIABLE OPERATION IN THE ACTUAL
APP ENG. CHARLIE Z. TITLE: SCHEMATIC
APPLICATION. COMPONENT SUBSTITUTION AND PRINTED
CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT
PERFORMANCE OR RELIABILITY. CONTACT LINEAR
TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE.
SIZE
2. INSTALL SHUNTS AS SHOWN.
C:\PADS PROJECTS\1480A\SCH\1480A_REV2.DSN
THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND
SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS.
5
4
3
2
N/A
SCALE = NONE
DATE:
1630 McCarthy Blvd.
Milpitas, CA 95035 www.linear.com
Phone: (408)432-1900
Fax: (408)434-0507
LTC CONFIDENTIAL - FOR CUSTOMER USE ONLY
DUAL 5A BUCK CONVERTER WITH
PIN SELECTABLE OUTPUTS
IC NO.
LTC3865EUH-1
DEMO CIRCUIT1480A
Friday, September 24, 2010
1
SHEET
REV.
2
1
OF
2
5
4
3
VIN
D
RUN1
ON
R23
(OPT)
1
RUN2
RUN1
3
ON
D
R24
(OPT)
1
S1+
VSW1
RUN2
2
3
OFF
R28
(OPT)
JP2
JP3
INTVCC
R25
R26
R27
(OPT)
(OPT)
R29
(OPT)
S2+
R34
(OPT)
VID11
VID11
VID21
E15
C
R36
(OPT)
INTVCC
VL2-
R31
R32
(OPT)
(OPT)
(OPT)
NOTE: WHEN DCR SENSING IS IMPLEMENTED SHORT RS1
AND RS2.
DO NOT POPULATE R3, R4, R18 AND R20.
R38
10K
VID12
E16
VID12
E17
VID22
VID22
CIN4
R39
(OPT)
R40
(OPT)
(OPT)
VIN
CIN5
(OPT)
56
VSW1
TG1
4
{
RUN1
{
RUN2
VID11
VID12
VID21
VID22
RUN1
2
VID11
1
VID12
Q1
7
8
Q2
BG2
2
Q3
FDS6982AS
(OPT)
1
B
Q4
FDS6982AS
(OPT)
OPTIONAL MOSFETS
VID21
VID22
VID12/VID22
VOUT1/VOUT2 (V)
INTVCC
INTVCC
INTVCC
FLOAT
5.0
3.3
GND
2.5
CUSTOMER NOTICE
1.8
FLOAT
INTVCC
FLOAT
FLOAT
0.6 or External Divider
FLOAT
GND
1.5
GND
INTVCC
1.2
GND
FLOAT
1.0
GND
GND
1.1
LINEAR TECHNOLOGY HAS MADE A BEST EFFORT TO DESIGN A
CIRCUIT THAT MEETS CUSTOMER-SUPPLIED SPECIFICATIONS;
HOWEVER, IT REMAINS THE CUSTOMER'S RESPONSIBILITY TO
VERIFY PROPER AND RELIABLE OPERATION IN THE ACTUAL
APPLICATION. COMPONENT SUBSTITUTION AND PRINTED
CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT
PERFORMANCE OR RELIABILITY. CONTACT LINEAR
TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE.
APPROVALS
PCB DES.
APP ENG.
TECHNOLOGY
RB
4
3
1630 McCarthy Blvd.
Milpitas, CA 95035 www.linear.com
Phone: (408)432-1900
Fax: (408)434-0507
A
LTC CONFIDENTIAL - FOR CUSTOMER USE ONLY
CHARLIE Z. TITLE: SCHEMATIC
SIZE
THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND
SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS.
5
VSW2
3
RUN2
VID11/VID21
INTVCC
56
4
7
8
Q2
BG1
VIN
TG2
3
Q1
B
C
OPTIONAL DCR SENSING
INTVCC
R37
(OPT)
A
S2-
R30
VID21
R35
(OPT)
SHT. 1
VL1-
(OPT)
VSW2
E14
S1-
INTVCC
R33
10K
SHT. 1
1
VIN
2
OFF
2
N/A
SCALE = NONE
2
DATE:
DUAL 5A BUCK CONVERTER WITH
PIN SELECTABLE OUTPUTS
IC NO.
LTC3865EUH-1
DEMO CIRCUIT1480A
Friday, September 24, 2010
SHEET
1
REV.
2
2
OF
2