DC447A - Demo Manual

QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 447
2-PHASE DUAL OUTPUT POWER SUPPLY
LTC3728EUH
DESCRIPTION
Demonstration circuit 447 is a step-down converter featuring the LTC3728EUH regulator. The PolyPhaseTM dual
output controller LTC3728EUH drives two high current
synchronous buck converters. Input is 5V–14V, output 1
is 2.5V with loads up to 13A and output 2 is 1.8V with
loads up to 13A.
For applications with input voltage less than 5V, DC447
includes a circuit footprint on the bottom side to provide
a 5V bias power supply.
Design files for this circuit board are available. Call
the LTC factory.
Table 1. Performance Summary
PARAMETER
CONDITION
VALUE
Minimum Input Voltage
5V
Maximum Input Voltage
14V
VOUT1
VIN = 5V to 14V, IOUT1 = 0A to 13A
2.5V
VOUT2
VIN = 5V to 14V, IOUT1 = 0A to 13A
1.8V
Nominal Switching Frequency
450kHz
QUICK START PROCEDURE
Demonstration circuit 447 is easy to set up to evaluate
the performance of the LTC3728EUH. Refer to Figure 1
for proper measurement equipment setup and follow the
procedure below:
3. With the power off, connect the input 5V–14V (rec-
NOTE: When measuring the input or output voltage rip-
4. Increase the load at VOUT1 to 13A. With a 12V input,
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 input or output and ground terminals. See Figure 2
for proper scope probe technique.
the input current should be less than 3.5A. Slowly decrease the input voltage to 5V. At 5V input voltage, the
input current should be less than 8A.
1. Before powering up, place the jumpers as shown in
Figure 1.
2. Connect the loads at VOUT1 and VOUT2. Set the load
current to 0A.
ommended 12V) power supply to VIN and GND.
VOUT1 should be within 2.5V ±0.1V and VOUT2
should be 1.8V ±0.1V.
5. Decrease the load at VOUT1 to 0A. Increase the input
voltage to 12V.
6. Increase the load on VOUT2 to 13A. With a 12V input,
the input current should be less than 2.5A. Slowly decrease the input voltage to 5V. At 5V input, the input
current should be less than 6A.
1
QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 447
2-PHASE DUAL OUTPUT POWER SUPPLY
–
+ +
+
–
–
–
–
+
LOAD
–
+
+
+
+
–
–
+
LOAD
GND
Figure 1. Proper Measurement Equipment Setup
VIN
–
Figure 2. Scope Probe Placement for
Measuring Input or Output Ripple
2
5
VO1SEN
E5
VO1SEN
PG
E1
PG
4
2
1
E4
5VBIAS
5VBIAS
C9
33PF
5
1
6
R11 15K C14 1000PF
C16
33PF
100K
7
R23
OPT
8
9
2
BM.
P.S.
C.C.M
1
3
R20
JP2
FCB
C21
0.01UF
C15
0.01UF
2
R25
OPT
OFF
1
R24
OPT
C66
OPT
R14
20.5K
1%
11
C20
R13
26.1K
1%
12
1000PF
R18
10
C19
180PF
PLLIN
VIN
BG1
FCB
EXTVCC
ITH1
INTVCC
SGND
PGND
3.3VOUT
BG2
BOOST2
ITH2
VOSENSE2
SW2
SENSE2-
TG2
SENSE2+
RUN/SS2
LTC3728EUH
4
1
D1
B320A
4
D
VOUT1
VOUT1
C4
C69
180UF 4V
7343
J1
VOUT1
[email protected]
C27
1UF
0603
+
J6
GND
2
1
2
3
24
D2
CMDSH-3
1
2
23
22
VIN
21
C10
1UF
0603
20
19
C8
4.7UF
10V
0805
VIN
C7
1UF 16V
0805
C24
C25
4.7UF 4.7UF
25V
25V
1210 1210
18
17
1
C17
0.1UF
15
14
2
D3
CMDSH-3
4
4
4
D4
B320A
4
13
R17
10
J3
VIN
C12
C13 +C11
4.7UF 4.7UF
56UF,25V
25V
25V OSCON
1210
1210
Q3
Si7860DP
Q7
OPT
Q8
OPT
Q4
Si7856DP
R15
0.003
2512
L2
1.3UH
5V-14V
J4
GND
VOUT2
C
VOUT2
C28
+
C22 1UF
0603
C70
220UF 2.5V
J5
VOUT2
[email protected]
J2
GND
R28
10
C23
0.1UF
JP3
RUN/SS2
INTVCC
E3
FREQSET
R3
0.003
2512
2
4
JP1
RUN/SS1
ON
3
3
BOOST1
C5
0.1UF
25
4
1
SYNC
C6 1000PF
VOSENSE1
4
1
2
3
R10 15K
SW1
26
5
6
7
8
OFF
2
SENSE1-
L1
1.3UH
27
1
2
3
1
TG1
1
2
3
31
PG
SENSE1+
1
2
3
1000PF
RUN/SS1
Q2
Si7856DP
5
6
7
8
20K
30
Q6
OPT
1
2
3
2
R6
C3
1%
R7
11.8K
ON
3
OPT
Q5
OPT
5
6
7
8
C1
0.1UF
C65
Q1
Si7860DP
5
6
7
8
R8
10
5
6
7
8
R4
30K
R16
1M
>5VIN
1
2
3
28
C31
OPT
C
JP4
U1
R27
1
R9
1M
<5VIN
5
6
7
8
R2
10
C26
1UF
0603
OPT
L1 & L2= SUMIDA
CDEP105-1R3MC-50
1
2
3
R1
10
INPUT SEL.
3
5
6
7
8
C2
180PF
1
5
6
7
8
R26
10
R5
43.2K
1%
2
R19
100K
D
SYNC
E2
3
INTVCC
VO2SEN
E6
+C32
7343
OPTIONAL BIAS CIRCUIT
OPTIONAL DISTRIBUTED CA PS
C33
1210
C34
1210
C35
1210
C36
1210
C37
1210
C38
1210
C39
1210
C40
1210
C41
1210
L3
4.7UH
VIN
C42
1210
>5VIN
3
+C43
7343
C44
1210
C45
1210
C46
1210
C47
1210
C48
1210
C49
1210
C50
1210
C51
1210
C52
1210
B
TOKO, FSLM2520-4R7
D5
CMDSH-3
U2
<5VIN
1
5
JP5
BIAS INPUT
VOUT1
NOTES: UNLESS OTHERWISE SPECIFIED
2
VIN
B
4
3
C30
10UF
10V
1206
C53 + C67
1210
7343
VIN
SW
1
2
SD
FB
GND
2
LT1613
SOT23-5
5VBIAS
1
C29
10UF
10V
1206
5VBIAS
R21
37.4K
R22
12.1K
1. ALL RESISTORS ARE IN OHMS, 0603.
A
2. R23=R24=R25=0 OHM WILL B E ASSEMBLED ONLY
IF TWO OUTPUTS ARE TIED TOGETHER FOR HIGH
CURRENT OUTPUT.
VOUT2
CONTRACT NO.
+C54
7343
3. INSTALL SHUN TS ON JP1-JP5 PIN 2 AND 3.
IF VIN<5V, INST ALL SHUNTS ON JP4 AND JP5
PIN 1 AND 2.
C55
1210
C56
1210
C57
1210
C58
1210
C59
1210
C60
1210
C61
1210
C62
1210
C63
1210
C64 + C68
1210
7343
1630 McCarthy Blvd.
Milpitas, CA 95035
Phone: (408)432-1900
TECHNOLOGY Fax: (408)434-0507
LTC Confi dential-For Customer Use Only
APPROVALS
DRAWN:
KIM T.
CHECKED:
TITLE:
APPROVED:
ENGINEER:
WEI C.
DESIGNER:
2-PHASE DUAL OUTPUT PO WER SUPPLY
SIZE
A
DATE:
5
4
3
2
DWG NO.
REV
DC447A-1 * LTC37 28EUH
Friday, August 02, 2002
SHEET
1
1
A
OF
1
A
Similar pages