DC392A - Demo Manual

QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 392
HIGH EFFICIENCY DUAL REGULATOR
LTC1628 or LTC3728
DESCRIPTION
Demonstration circuit 392 is a dual output, step-down,
synchronous buck converter featuring either the 150kHz
to 300kHz LTC1628EUH controller (DC392A-A), the
250kHz to 550kHz LTC3728EUH (DC392A-B) or 250kHz
to 550kHz LTC3728LUH (DC392A-C). All three ICs come
in a 5mm×5mm QFN package with an exposed pad for
low thermal impedance. The input voltage is from 7V up
to 24V. Output 1 is 5V with loads up to 4A and output 2
is 3.3V with loads up to 5A.
Design files for this circuit board are available. Call
the LTC factory.
Table 1. Performance Summary
PARAMETER
CONDITION
VALUE
Minimum Input Voltage
7V
Maximum Input Voltage
24V
VOUT1
VIN = 7V to 24V, IOUT1 = 0A to 4A
5V ±1%
VOUT2
VIN = 7V to 24V, IOUT1 = 0A to 5A
3.3V ±1%
Switching Frequency (LTC1628)
Switching Frequency (LTC3728)
Jumper selectable
Jumper selectable
150kHz–300kHz
250kHz–550kHz
QUICK START PROCEDURE
Demonstration circuit 392 is easy to set up to evaluate
the performance of the LTC1628 or LTC3728. Refer to
Figure 1 for proper measurement equipment setup and
follow the procedure below:
NOTE: The input voltage range should be 7V–24V in-
stead of 5V-24V as shown on the board.
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.
NOTE: The STBY and FLTCPL jumpers apply only to
demo circuit 392A-A (featuring the LTC1628). These
jumpers are not used for the DC392A-B or
DC392A-C which feature the LTC3728.
3. Set Vin to 12V (recommended). The rated input
voltage range is from 7V to 24V.
4. Remove the RUN1 jumper to switch on the Vout1
channel. The nominal output voltage of Vout1
should be 5V ±0.1V.
Increase load current on Vout1 to 4A. At 12V input
voltage, the input current should be less than 2A.
Slowly increase the input voltage to 24V. At 24V input, the input current should be less than 1.1A.
5. Decrease the load current of Vout1 to 0A. Reduce
the input voltage to 12V.
6. Remove the RUN2 jumper to switch on the Vout2
channel. The output voltage of Vout2 should be
3.3V ±0.05V.
7. Increase load current on Vout2 to 5A. At 12V input
voltage, the input current should be less than 1.8A.
Slowly increase the input voltage to 24V. At 24V input, the input current should be less than 1.0A.
2. Connect the loads at Vout1 and Vout2. The loads
can be up to 4A for Vout1 and 5A for Vout2. Pre-set
the loads to 0A.
1
QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 392
HIGH EFFICIENCY DUAL REGULATOR
+
+
+
+
–
+
–
–
LOAD
–
–
+
LOAD
–
–
–
+
+
+
–
Figure 1. Proper Measurement Equipment Setup
GND
VIN
Figure 2. Scope Probe Placement for
Measuring Input or Output Ripple
2
E7
1
1
1
1
1
1
LTC3728EUH
LTC3728LUH
392A-B
392A-C
3
LTC1628EUH
0
3
3
3
3
3
392A-A
1
0
0
0
0
0
U1
C24
0.01uF
JP6
RUN2
1
JP5
FCB
JP4
STBY
1
JP3
FSET
1
JP2
FLTCPL
1
JP1
RUN1
1
ASSEMBLY
3.3V LDO
E8
5V LDO
R16
1M
R12
1M
R9
1M
2
2
2
2
2
2
C15
0.01uF
L1
Table:
C18
0.01uF
C21
0.01uF
IHLP-2525CZ-01-2.2uH
IHLP-2525CZ-01-2.2uH
CDEP105-4R3MC-88
R7
1M
(Opt.)
R4
1M
2
C19
180pF
R14
20K
1%
R11
4.75K
1%
R10
8.06K
1%
L2
Dual
Output
1
R13
63.4K
1%
C14
1000pF
C16
100pF
C6
1500pF
C9
100pF
C1
0.1uF
C2
180pF
R5
105 K
1%
2
3
IHLP-2525CZ-01-2.2uH
TG1
0.006 ohm
C10
1uF
13
14
15
17
18
19
20
21
22
C17
0.1uF
1,2
2,3
1,2
1,2
1,2
1,2
JP1
JP2
JP3
JP4
JP5
JP6
JP8
2
Q2B
FDS6982S
4
C7
0.1uF
R8
10
4
Q1B
FDS6982S
Short Pin 1,2
Short Pin 1,2
Short Pin 2,3
Short Pin 2,3
Dual Output
D2
CMDSH-3
2
D3
CMDSH-3
Single Output
Jumpers Select
Short Pin
Ref.
1
+ C8
4.7uF
10V
1
24
23
C5
0.1uF
25
Jumpers Select
RUN/SS2
TG2
SW2
BOOST2
BG2
PGND
INTVCC
EXTVCC
BG1
VIN
BOOST1
SW1
26
JP7
R17
10
R18
10
SENSE2+
SENSE2-
VOSENSE2
ITH2
3.3VOUT
SGND
ITH1
FCB
STBYMD
FREQSET
VOSENSE1
SENSE1-
SENSE1+
FLTCPL
27
0.006 ohm
12
11
9
8
7
6
5
4
3
2
1
31
RUN/SS1
U1
See Table
Ref.
R3
C20
1000pF
C3
1000pF
30
28
0.008 ohm
Single
Output
JP8
ITH
IHLP-2525CZ-01-2.2uH
CDEP105-4R3MC-88
C23
0.1uF
R6
20K
1%
JP7
VOSENSE
R1
10
R2
10
32
NC
NC
10
29
NC
NC
16
Single
Output
3
3
2
2
Q1A
FDS6982S
5
6
3
5
6
Q2A
FDS6982S
L1
See Table
L2
See Table
D4
MBRM140T3
(Opt.)
D1
MBRM140T3
(Opt.)
7
8
1
1
7
8
Dual
Output
1
R15
0.008
C12
10uF
35V
R3
See Table
C13
10uF
35V
+ C22
180uF,4V
SP
+ C11
33uF,35V
Sanyo
+ C4
150uF,6V
SP
C32
1uF
C25
1uF
E6
Gnd
3.3V @ 5A
E5
Vout2+
E4
Gnd
5V to 2 4V
E3
Vin
E2
Gnd
5V @ 4A
E1
Vout1+
QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 392
HIGH EFFICIENCY DUAL REGULATOR
3
A
B
C
D
E
4
4
2
1
2
C21
0.01uF
1
Dual
Output
2
0
FREQSET
VIN
23
3
STBYMD
BG1
22
4
FCB
EXTVCC
21
5
ITH1
INTVCC
20
6
SGND
PGND
19
7
3.3VOUT
BG2
18
8
ITH2
BOOST2
17
9
VOSENSE2
SW2
15
SENSE2-
TG2
14
RUN/SS2
13
11
SENSE2+
C10
1uF
C17
0.1uF
7
8
+ C4
150uF,6V
SP
2
R8
10
C25
1uF
E3
Vin
D4
MBRM140T3
(Opt.)
C12
10uF
35V
C13
10uF
35V
+ C11
33uF,35V
Sanyo
2
L2
See Table
4
Q2B
FDS6982S
3
5V to 24V
E4
Gnd
2
D3
CMDSH-3
5V @ 4A
E2
Gnd
D1
MBRM140T3
(Opt.)
C7
0.1uF
+ C8
4.7uF
10V
1
E1
Vout1+
1
VOSENSE1
R3
See Table
1
1
3
BOOST1
24
4
D2
CMDSH-3
2
5
6
C5
0.1uF
NC
25
NC
26
SW1
3
Single
Output
R15
0.008
Q2A
FDS6982S
E5
Vout2+
+ C22
180uF,4V
SP
R17
10
R18
10
C23
0.1uF
3
TG1
SENSE1-
2
12
JP8
ITH
29
32
C20
1000pF
R13
63.4K
1%
C19
180pF
0
3
1
JP6
RUN2
1
C14
1000pF
C16
100pF
R14
20K
1%
C18
0.01uF
3
1
2
C15
0.01uF
0
1
R16
1M
R11
4.75K
1%
SENSE1+
L1
See Table
Q1A
FDS6982S
7
8
1
JP5
FCB
C6
1500pF
C9
100pF
1
27
5
6
2
0
3
JP4
STBY
1
R10
8.06K
1%
3
1
JP3
FSET
1
0
31
Q1B
FDS6982S
FLTCPL
10
1
30
U1
See Table
3
2
3
JP2
FLTCPL
1
R12
1M
R7
1M
(Opt.)
2
3
JP1
RUN1
1
2
R9
1M
C3
1000pF
RUN/SS1
NC
R6
20K
1%
28
NC
R4
1M
C1
0.1uF
C2
180pF
R5
105K
1%
2
JP7
VOSENSE
Single
Output
3
16
Dual
Output
1
R1
10
R2
10
C32
1uF
3.3V @ 5A
E6
Gnd
0
E7
2
5V LDO
E8
3.3V LDO
Jumpers Select
Ref.
C24
0.01uF
Short Pin
JP1
1,2
JP2
2,3
JP3
1,2
JP4
1,2
JP5
1,2
JP6
1,2
Table:
1
ASSEMBLY
U1
392A-A
LTC1628EUH
392A-B
LTC3728EUH
IHLP-2525CZ-01-2.2uH
392A-C
LTC3728LUH
IHLP-2525CZ-01-2.2uH
L1
CDEP105-4R3MC-88
L2
Jumpers Select
R3
0.008 ohm
Ref.
IHLP-2525CZ-01-2.2uH
0.006 ohm
IHLP-2525CZ-01-2.2uH
0.006 ohm
CDEP105-4R3MC-88
LINEAR TECHNOLOGY CORPORATION
Single Output
Dual Output
JP7
Short Pin 2,3
Short Pin 1,2
JP8
Short Pin 2,3
Short Pin 1,2
Title
Size
High Efficiency Dual Regulator
Document Number
DEMO 392A-A,B,C
Date: Wednesday, July 10, 2002
A
B
C
D
1
1630 McCARTHY BLVD.
MILPITAS, CA 95035
(408) 432-1900
(408) 434-0507 FAX
Rev
LTC1628EUH or LTC3728EUH
Sheet
E
1
of
1
Itm Qty.
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
29
30
31
32
2
2
3
1
4
5
3
1
2
1
1
1
0
2
2
8
8
8
2
1
1
5
1
1
2
1
4
0
1
1
4
4
Reference
C9,C16
C2,C19
C3,C20,C14
C6
C15,C18,C21,C24
C1,C5,C7,C17,C23
C10,C25,C32
C8
C12,C13
C11
C4
C22
D1,D4 (OPTIONAL)
D2,D3
L1,L2
E1-E8
JP1-JP8
FOR ( JP1-JP8 )
Q1,Q2
R3
R15
R1,R2,R8,R17,R18
R11
R10
R6,R14
R13
R4,R9,R12,R16
R7 (OPTIONAL)
R5
U1
Part
CAP., NPO
100pF 50V
CAP., NPO
180pF 50V
CAP., NPO 1000pF 25V
CAP., X7R 1500pF 50V
CAP., X7R 0.01uF 10V
CAP., X7R
0.1uF 10V
CAP., X5R
1uF 6.3V
CAP., TANT 4.7uF 10V
CAP., Y5V
10uF 35V
CAP., SP
33uF 35V
CAP., SP
150uF 6.3V
CAP., SP
180uF
4V
DIODE, SCHOTTKY 40V 1A
DIODE, SUPER MINI SCHOTTKY
INDUCTOR, SMT 2.2uH
TESTPOINT, TURRET, .094"
HEADER, 3PIN 1 ROW .079CC
SHUNT, .079" CENTER
MOSFET FDS6982S
RES., CHIP 0.006
1/4W 5%
RES., CHIP 0.008
1/4W 5%
RES., CHIP
10 1/16W 5%
RES., CHIP 4.75K 1/16W 1%
RES., CHIP 8.06K 1/16W 1%
RES., CHIP 20.0K 1/16W 1%
RES., CHIP 63.4K 1/16W 1%
RES., CHIP
1M 1/16W 5%
RES., CHIP
1M 1/16W 5%
RES., CHIP 105K 1/16W 1%
I.C., LTC3728EUH
SCREW, #4-40, 1/4"
STANDOFF, #4-40 1/4"
Manufacture
AVX, 06035A101JAT1A
0603
AVX, 06035A181JAT1A
0603
AVX, 06033A102JAT1A
0603
AVX, 06035C152KAT1A
0603
AVX, 0603ZC103KAT1A
0603
AVX, 0603ZC104MAT1A
0603
TAIYO YUDEN, JMK107BJ105MA
0603
AVX, TACR475M010R
0805
TAIYO YUDEN, GMK325F106ZH
1210
SANYO, 35CV33BS
PANASONIC, EEFUE0J151R
CASE-D
PANASONIC, EEFUE0G181R
CASE-D
ON SEMI., MBRM140T3
POWERMITE
CENTRAL SEMI., CMDSH-3
SOD323
VISHAY, IHLP-2525CZ-01-2.2uH
MILL-MAX 2501-2
COMM-CON 2802S-03-G1
COMM-CON CCIJ2MM-138G
FAIRCHILD FDS6982S
SO8
IRC, LRF1206-01-R006-J
1206
IRC, LRF1206-01-R008-J
1206
AAC, CR16-100JM
0603
AAC, CR16-4751FM
0603
AAC, CR16-8061FM
0603
AAC, CR16-2002FM
0603
AAC, CR16-6342FM
0603
AAC, CR16-105JM
0603
AAC, CR16-105JM
0603
AAC, CR16-1053FM
0603
LINEAR, LTC3728EUH
32 PIN MLP
ANY
MICRO PLASTICS 14HTSP101
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