QUICK START GUIDE FOR DEMONSTRATION CIRCUIT DC455
HIGH EFFICIENCY DUAL PHASE 2-OUTPUT POWER SUPPLY
LTC3707EGN
DESCRIPTION
Demonstration circuit DC455 is a dual output, step-
down, synchronous buck converter featuring the 150kHz
to 300kHz LTC3707EGN controller. This controller can
operate with input voltages from 7V to 21V. Output 1 is
5V with loads up to 5A and output 2 is 3.3V with loads
up to 5A.
Design files for this circuit board are avail-
able. Call the LTC factory.
Table 1.
Performance Summary
PARAMETER CONDITION VALUE
Minimum Input Voltage 7V
Maximum Input Voltage 21V
V
OUT1
V
IN
= 7V to 21V, I
OUT1
= 0A to 5A 5V%
V
OUT2
V
IN
= 7V to 24V, I
OUT1
= 0A to 5A 3.3V%
Switching Frequency Jumper selectable 150kHz–300kHz
QUICK START PROCEDURE
Demonstration circuit DC455 is easy to set up to
evaluate the performance of the LTC3707EGN. Refer to
Figure 1 for proper measurement equipment setup and
follow the procedure below:
NOTE:
When measuring the input or output voltage rip-
ple, care must be taken to avoid a long ground lead on
the oscilloscope probe. Measure the input or output
voltage ripple by touching the probe tip directly across
the Vin or Vout and GND terminals. See Figure 2 for
proper scope probe technique.
1.
With the power off, place the jumpers as shown in
Figure 1.
2.
Connect the desired loads to Vout1 and Vout2. The
loads can be as high as 5A for Vout1 and 5A for
Vout2. Pre-set the load current to 0A.
3.
Set Vin to 7V (recommended). The rated input volt-
age range is 7V to 21V.
4.
Switch on the Vout1 channel by removing the RUN1
jumper. Vout1 should be 5V ±0.1V.
5.
Increase the load current of Vout1 to 5A. At 7V in-
put voltage, the input current should be less than
4A. Slowly increase the input voltage up to 21V. At
21V input voltage, the input current should be less
than 1.5A.
6.
Decrease Vout1 load current to 0A. Reduce the in-
put voltage to 7V. Switch on the Vout2 channel by
removing the RUN2 jumper. The output voltage of
Vout2 should be 3.3V ±0.05V.
7.
Increase the load current of Vout2 to 5A. At 7V in-
put, the input current should be less than 3A.
Slowly increase the input voltage to 21V. At 21V in-
put, the input current should be less than 1.0A.
1
QUICK START GUIDE FOR DEMONSTRATION CIRCUIT DC455
HIGH EFFICIENCY DUAL PHASE 2-OUTPUT POWER SUPPLY
+
–
+
–
+
–
+
–
+
–
+–
+–
+–
LOAD
+–
LOAD
VIN
GND
Figure 1.
Proper Measurement Equipment Setup Figure 2.
Scope Probe Placement for
Measuring Input or Output Ripple
2
5
5
4
4
3
3
2
2
1
1
D D
C C
B B
A A
NOTES: UNLESS OTHERWISE SPECIFIED,
[1] OPTIONAL.
5V@5A
Vo1+
VIN+
3.3V@5A
Vo2+
FCB
PG
VIN-
Vo1-
Vo2-
OPT
OPT
STBY FREQ
RUN1
RUN2
EXTVCC
SHT 2
SHT 2
SHT 2
SHT 2
SHT 2
SHT 2
5V LDO
7V-21V
PS
CCM
ON
OFF
HI
LO
ON
OFF
OFFON
<
PRODUCTION RELEASE
03 01-16-02
REVISION HISTORY
DESCRIPTION DATE APPROVEDECO REV
3
DC455A
Tuesday, March 19, 2002
12
B
SCH,LTC3707 HIGH EFFICIENCY DUAL-PHASE, 2 OUTPUT
POWER SUPPLY
455A-3.DSNNONE
MEI 08-30-01
SIZE
SCALE:
CAGE CODE DWG NO REV
SHEET OF
FILENAME:
TITLE
CONTRACT NO.
APPROVALS DATE
DRAWN
CHECKED
APPROVED
ENGINEER
DESIGNER
UNLESS OTHERWISE SPECIFIED
DIMENSIONS ARE IN INCHES
TOLERANCE ON ANGLE - - -
2 PLACES - - - 3 PLACES - - -
INTERPRET DIM AND TOL
PER ASME Y14.5M -1994
THIRD ANGLE PROJECTION
DO NOT SCALE DRAWING
TECHNOLOGY
1630 McCarthy Blvd.
Milpitas, CA 95035
Phone: (408)432-1900
Fax: (408)434-0507
LTC CONFIDENTIAL - For Customer Use Only
INTVCC
TG1
SW1
BG1
TG2
SW2
BG2
QVIN
INTVCC
QVIN
QVIN
VIN
VIN
VIN
INTVCC
QVIN
TP3
C3
0.1uF
TP4
+
C2
180uF
4V
L1
4.3uH
R12
1M
R2
0.008
D1
[1]
C4
0.1uF
C8
1000pF
C13
68pF
R9
1M
C19
0.01uF
C6
0.1uF
TP6
+
C1
150uF
6.3V
C15
1uF
R10
1M
R7
6.34K
C18
0.1uF
TP7
R14
10
R18
100K
C24
[1]
TP5
R15
10
R1
0.007
+
C27
33uF
25V
R25 0
C21
0.01uF
Q2B
FDS6982S
4
3
5 6
L2
4.3uH
D2
[1]
TP8
C20
0.01uF
Q1B
FDS6982S
4
3
5 6
C7
1000pF
Q2A
FDS6982S
2
1
7 8
C26
10uF
35V
C17
[1]
C11
1000pF
TP1
C12
1000pF
D3
BAT54A
SOT-23
1
2
3
C14
68pF
R11
10
R8
5.1K
C9
68pF
R5
20.0K
1%
C10
33pF
R6
20.0K
1%
R16
10
R3
105K
1%
JP6
1 3
2
TP9
C23
4.7uF
JP2
1 3
2
TP10
C25
10uF
35V
+
C16
4.7uF
10V
C22
4.7uF
JP5
1 3
2
JP4
1 3
2
Q1A
FDS6982S
2
1
7 8
JP1
13
2
U1
LTC3707EGN
1
2
3
4
5
6
7
8
9
10
11
12
13
14 15
16
17
18
19
20
21
22
23
24
25
26
27
28
RUN/SS1
SENSE1+
SENSE1-
VoSENSE1
FREQSET
STBYMD
FCB
ITH1
SGND
3.3Vout
ITH2
VoSENSE2
SENSE2-
SENSE2+ RUN/SS2
TG2
SW2
BOOST2
BG2
PGND
INTVcc
EXTVcc
BG1
VIN
BOOST1
SW1
TG1
PG
R17
100K
C5
0.1uF
TP2
R13
10
R4
63.4K
1%
5
5
4
4
3
3
2
2
1
1
D D
C C
B B
A A
NOTES: UNLESS OTHERWISE SPECIFIED,
[1] OPTIONAL.
5V@5A
Vo1+
VIN+
3.3V@5A
Vo2+
FCB
PG
VIN-
Vo1-
Vo2-
OPT
OPT
STBY FREQ
RUN1
RUN2
EXTVCC
SHT 2
SHT 2
SHT 2
SHT 2
SHT 2
SHT 2
5V LDO
7V-21V
PS
CCM ON
OFF HI
LO
ON
OFF
OFFON
<
PRODUCTION RELEASE
0 3 01-16-02
REVISION HISTORY
DESCRIPTION DATE APPROVEDECO REV
3
DC455A
Tuesday, March 19, 2002
12
B
SCH,LTC3707 HIGH EFFICIENCY DUAL-PHASE, 2 OUTPUT
POWER SUPPLY
455A-3.DSNNONE
MEI 08-30-01
SIZE
SCALE:
CAGE CODE DWG NO REV
SHEET OF
FILENAME:
TITLE
CONTRACT NO.
APPROVALS DATE
DRAWN
CHECKED
APPROVED
ENGINEER
DESIGNER
UNLESS OTHERWISE SPECIFIED
DIMENSIONS ARE IN INCHES
TOLERANCE ON ANGLE - - -
2 PLACES - - - 3 PLACES - - -
INTERPRET DIM AND TOL
PER ASME Y14.5M -1994
THIRD ANGLE PROJECTION
DO NOT SCALE DRAWING
TECHNOLOGY
1630 McCarthy Blvd.
Milpitas, CA 95035
Phone: (408)432-1900
Fax: (408)434-0507
LTC CONFIDENTIAL - For Customer Use Only
INTVCC
TG1
SW1
BG1
TG2
SW2
BG2
QVIN
INTVCC
QVIN
QVIN
VIN
VIN
VIN
INTVCC
QVIN
TP3
C3
0.1uF
TP4
+
C2
180uF
4V
L1
4.3uH
R12
1M
R2
0.008
D1
[1]
C4
0.1uF
C8
1000pF
C13
68pF
R9
1M
C19
0.01uF
C6
0.1uF
TP6
+
C1
150uF
6.3V
C15
1uF
R10
1M
R7
6.34K
C18
0.1uF
TP7
R14
10
R18
100K
C24
[1]
TP5
R15
10
R1
0.007
+
C27
33uF
25V
R25 0
C21
0.01uF
Q2B
FDS6982S
4
3
5 6
L2
4.3uH
D2
[1]
TP8
C20
0.01uF
Q1B
FDS6982S
4
3
5 6
C7
1000pF
Q2A
FDS6982S
2
1
7 8
C26
10uF
35V
C17
[1]
C11
1000pF
TP1
C12
1000pF
D3
BAT54A
SOT-23
1
2
3
C14
68pF
R11
10
R8
5.1K C9
68pF
R5
20.0K
1%
C10
33pF
R6
20.0K
1%
R16
10
R3
105K
1%
JP6
1 3
2
TP9
C23
4.7uF
JP2
1 3
2
TP10
C25
10uF
35V
+
C16
4.7uF
10V
C22
4.7uF
JP5
1 3
2
JP4
1 3
2
Q1A
FDS6982S
2
1
7 8
JP1
13
2
U1
LTC3707EGN
1
2
3
4
5
6
7
8
9
10
11
12
13
14 15
16
17
18
19
20
21
22
23
24
25
26
27
28
RUN/SS1
SENSE1+
SENSE1-
VoSENSE1
FREQSET
STBYMD
FCB
ITH1
SGND
3.3Vout
ITH2
VoSENSE2
SENSE2-
SENSE2+ RUN/SS2
TG2
SW2
BOOST2
BG2
PGND
INTVcc
EXTVcc
BG1
VIN
BOOST1
SW1
TG1
PG
R17
100K
C5
0.1uF
TP2
R13
10
R4
63.4K
1%
5
5
4
4
3
3
2
2
1
1
D D
C C
B B
A A
SHT 1
SHT 1
SHT 1
SHT 1
SHT 1
SHT 1
[1][1]
[1]
[1][1]
[1]
LTC CONFIDENTIAL - For Customer Use Only
3
DC455A
Monday, January 28, 2002
22
A
SCH,LTC3707 HIGH EFFICIENCY DUAL PHASE, 2 OUTPUT
POWER SUPPLY
455A-3.DSNNONE
MEI 01-16-02
SIZE
SCALE:
CAGE CODE DWG NO REV
SHEET OF
FILENAME:
TITLE
CONTRACT NO.
APPROVALSDATE
DRAWN
CHECKED
APPROVED
ENGINEER
DESIGNER
UNLESS OTHERWISE SPECIFIED
DIMENSIONS ARE IN INCHES
TOLERANCE ON ANGLE - - -
2 PLACES - - - 3 PLACES - - -
INTERPRET DIM AND TOL
PER ASME Y14.5M -1994
THIRD ANGLE PROJECTION
DO NOT SCALE DRAWING
TECHNOLOGY
1630 McCarthy Blvd.
Milpitas, CA 95035
Phone: (408)432-1900
Fax: (408)434-0507
PRODUCTION RELEASE
301-16-02
REVISION HISTORY
DESCRIPTION DATE APPROVEDECO REV
TG1
BG1
SW1
BG2
SW2
TG2
VIN
VIN
C29
10uF
35V
Q3
FDS6680A
4
5
6
7
8
3
1
2
Q4
FDS6680B
4
5
6
7
8
3
1
2
Q5
FDS6680A
4
5
6
7
8
3
1
2
Q6
FDS6680B
4
5
6
7
8
3
1
2
C28
10uF
35V
Linear Technology Corporation
LTC3707EGN Parts List DC455A Rev 3
3/19/2002
Item
Qty
Ref
Desc
Part Number
1 1 C1 CAP, SPCL PLYMR 150uF 6.3V 20% 7343 PANASONIC EEFUE0J151R
2 1 C2 CAP, SPCL PLYMR 180uF 4V 20% 7343 PANASONIC EEFUE0G181R
3 5 C3,C4,C5,C6,C18 CAP, X7R 0.1uF 10V 20% 0603 AVX 0603ZC104MAT1A
5 3 C9,C13,C14 CAP, NPO 68pF 50V 5% 0603 AVX 06035A680JAT2A
6 1 C10 CAP, NPO 33pF 50V 5% 0603 AVX 06035A330JATA1A
7 4 C7,C8,C11,C12 CAP, NPO 1000pF 25V 5% 0603 AVX 06033A102JAT1A
8 1 C15 CAP, X5R 1uF 6.3V 10% 0603 AVX 06036D105KAT
9 1 C16 CAP, TANT 4.7uF 10V 20% 0805 AVX TACR475M010R
10 0 C24,C17,C28,C29 DO NOT STUFF OPTION
11 3 C19,C20,C21 CAP, X7R 0.01uF 10V 10% 0603 AVX 0603ZC103KAT1A
12 2 C23,C22 CAP, X5R 4.7uF 6.3V 20% 0805 TAIYO YUDEN JMK212BJ475MG-T
13 2 C25,C26 CAP, Y5V 10uF 35V 1210 MURATA GRM235Y5V106Z035
14 1 C27 CAP, ELECTROLYTIC 33uF 25V 20% SANYO 25CV33AX
15 0 D1,D2
DIODE, MBRM140T3 SCHOTTKY DO-216AA
(OPTIONAL)
MOTOROLA MBRM140T3
16 1 D3 DIODE, BARRIER DOUBLE DIODES BAT54A SOT-23 DIODES INC. BAT54A
17 5 JP1,JP2,JP4,JP5,JP6 HEADER, 3PIN, 2mm COMM CON 2802S-03G2
18 2 L1,L2 IND, 4.3uH SUMIDA CDEP105-4R3MC-88
20 2 Q2,Q1 XSTR, FDS6982S DUAL N-FET 6.3A SO8 FAIRCHILD FDS6982S
21 0 Q3,Q5 XSTR, FDS6680A N-CHANNEL POWER MOSFET SO8 (OPTIONAL) FAIRCHILD FDS6680A
22 0 Q4,Q6 XSTR, FDS6680B N-CHANNEL POWER MOSFET SO8 (OPTIONAL) FAIRCHILD FDS6680B
23 1 R1 RES, 0.007 OHM 5% 1/4W 1206 IRC LRF1206-01-R007
24 1 R2 RES, 0.008 OHM 5% 1/4W 1206 IRC LRF1206-01-R008
25 1 R3 RES, 105K OHM 1% 1/16W 0603 AAC CR16-1053FM
26 1 R4 RES, 63.4K OHM 1% 1/16W 0603 AAC CR16-6342FM
27 2 R5,R6 RES, 20.0K OHM 1% 1/16W 0603 AAC CR16-2002FM
28 1 R7 RES, 6.34K OHM 1% 1/16W 0603 AAC CR16-6341FM
29 1 R8 RES, 5.1K OHM 5% 1/16W 0603 AAC CR16-512JM
30 3 R9,R10,R12 RES, 1M OHM 5% 1/16W 0603 AAC CR16-105JM
31 5 R11,R13,R14,R15,R16 RES, 10 OHM 5% 1/16W 0603 AAC CR16-100JM
32 2 R18,R17 RES, 100K OHM 5% 1/16W 0603 AAC CR16-104JM
33 1 R25 RES, 0 OHM 1/16W JUMPER 0603 AAC CJ06-000M
34 4 TP1,TP8,TP9,TP10 TURRET, .061 MILL-MAX 2308-2-00-44
35 6 TP2,TP3,TP4,TP5,TP6,TP7 TURRET, .090 MILL-MAX 2501-2
36 1 U1 IC, LTC3707EGN DUAL PHASE DUAL OUTPUT SYNC BUCK CONTROLLER LINEAR TECH LTC3707EGN
4SCREW, 4-40 1/4" ANY
4STANDOFF, NYLON 4-40 1/4" ?
