DC1129A - Demo Manual

QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 1129A
SYNCHRONOUS STEP-DOWN DC/DC CONVERTER
LTC3610EWP
DESCRIPTION
Demonstration circuit DC1129A is a synchronous step
down converter featuring the LTC®3610, the high efficiency, high density DC/DC regulator. The input voltage range is from 4.5V to 24V. The output voltage is
jumper selectable from 1.2V to 2.5V. The rated load
current is 12A. The regulator includes the controller
and power MOSFETs in the 9mm by 9 mm QFN package.
The constant on time valley mode current control structure delivers very low duty cycle with excellent load
transient response. The MSFET RDS(on) sensing
eliminates external sensing resistor and improves supply efficiency.
Discontinuous mode operation and continuous mode at
light load is also jumper selectable. A forced continuous
control reduces noise and RF interference while discontinuous control provides high efficiency at light loads.
Design files for this circuit board are available.
Call the LTC Factory.
, LTC and LT are registered trademarks of Linear Technology Corporation.
Table 1. Performance Summary (TA = 25°C)
PARAMETER
CONDITION
VALUE
Minimum Input Voltage
4.5V
Maximum Input Voltage
24V
Output Voltage VOUT
Jumper selectable (open for 0.6V)
1.2V, 1.5V, 1.8V, 2.5V ± 2%
Maximum Continuous Output Current
De-rating is necessary for certain VIN, VOUT, and thermal
conditions, see datasheet
12ADC
Operating Frequency
Programmable
750kHz
Efficiency
VIN=12V, VOUT =1.5V, IOUT =12A
83%, See Figure 3
Load Transient
VIN=12V, VOUT =1.5V
See Figure 5
QUICK START PROCEDURE
Demonstration circuit DC1129A is easy to set up to
evaluate the performance of the LTC3610. Please refer to Figure 1 for proper measurement equipment
setup and follow the procedure below:
1. Place jumpers in the following positions for a
typical 1.5VOUT application:
Vout Select
RUN FCB
1.5V
ON
CCM
Preliminary
2. With power off, connect the input power supply, load and meters as shown in Figure 1.
Preset the load to 0A and Vin supply to be
less than 24V.
3. Turn on the power at the input. The output
voltage should be 1.5V ± 2%.
4. Once the proper output voltage is established,
adjust the load within the operating range and
observe the output voltage regulation, ripple
voltage, efficiency and other parameters.
Output ripple should be measured across the
output bulk capacitor as shown in Figure 2.
5. For optional load transient test, apply adjustable pulse signal between IOSTEP CLK and
GND pins. Pulse amplitude sets the current
1
QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 1129A
SYNCHRONOUS STEP-DOWN DC/DC CONVERTER
–
Iout
A
–
Load
0 -12A
+
V
Vout
+
Vin
–
–
–
+
V
A
+
–
+
Iin
nector J6 (5mV/A). Output voltage transient
response should be measured at J5 with a
BNC cable.
+
step. The pulse signal should have very small
duty cycle (<5%) to limit the thermal stress
on the transient load circuit. The output transient current can be monitored at BNC con-
Optional
5V Bias
Figure 1. Test Setup of DC1129A (EXTVCC Bias Supply is Optional)
+
Input or Output Capacitor
Figure 2. Scope Probe Placements for Measuring Input or Output Ripple.
Preliminary
2
QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 1129A
SYNCHRONOUS STEP-DOWN DC/DC CONVERTER
Efficiency vs. Load Current W/ 12Vin
90%
Efficiency (%)
80%
70%
Vo=1.2V
Vo=1.5V
60%
Vo=1.8V
Vo=2.5V
50%
0
2
4
6
8
10
12
14
16
Load Current (A)
Figure 3. Measured Supply Efficiency with Different VIN and VOUT
Figure 4. Thermal image of DC1129
Vin = 12V
Vout =1.5V
Iout = 12A
Tambient = 25°C, No airflow
Cross 1: MOSFETs
Cross 2: Inductor
Preliminary
3
QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 1129A
SYNCHRONOUS STEP-DOWN DC/DC CONVERTER
Istep
4A/DIV
Cout (AC)
100mV/DIV
Vin = 12V
Vout =1.5V
3A to 9A LOAD STEP
Cout = 2 X 22uF ceramic, X5R, 0805, 2X100uF ceramic, X5R, 1812
Figure 5. Measured Load Transient Response (3-9A Step, 25% to 75%)
Preliminary
4
R1
OPT
CSS
0.1UF
INTVCC
JP2
1.2V
JP3
1.5V
JP4
1.8V
JP5
2.5V
R9
60.4K
R10
40.2K
R11
30.1K
R12
19.1K
32
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
C6 R8
OPT 137K
SGND
SGND
VON
PGOOD
VRNG
ITH
FCB
SGND
ION
SGND
VFB
EXTVCC
SGND
SGND
SGND
SGND
PVIN
SW
PGND
PVIN
PVIN
PVIN
PVIN
PVIN
SW
SW
SW
SW
SW
SW
SW
SW
PGND
PGND
PGND
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
EXTVCC
E2
EXTVCC
INTVCC
C7
OPT
C8
4.7UF
16V
0805
+ CIN3
CIN1
CIN2
10UF
35V
1206
CIN4
CIN5
1210
OPT
150UF
35V
SANYO
CIN6
CIN7
1206
OPT
J2
E3 PGND
35ME150WXV
L1
0.47UH
TOKO
FDV0630
VOUT
CO1
CO2 +
100UF
6.3V
1812
CO3
CO4
330UF
6.3V
7343
OPT
E5
J3
CO6
CO5
22UF
6.3V
0805
E6
R13
1
Q1
SUD50N03
1
C9
1UF
35V
R16
10K
VOUT
C10
4.7UF
6.3V
J5
VOUT
J6
IOSTEP
R5
0.005
2512
E8
DYNAMIC TRANSIENT CIRCUIT
NOTES: UNLESS OTHERWISE SPECIFIED
1. ALL RESISTORS ARE IN OHMS, 0603.
ALL CAPACITORS ARE 0603.
2. INSTALL SHUNT ON JP1 PINS 1 AND 2, JP3.
CUSTOMER NOTICE
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
CIRUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT
PERFORMANCE OR RELIABILITY. CONTACT LINEAR
TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE.
THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND
SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS.
CONTRACT NO.
APPROVALS
DRAWN:
TECHNOLOGY
KIM T.
CHECKED:
APPROVED:
ENGINEER:
MANJING X.
DESIGNER:
VOUT
12A MAX.
J4 PGND
3
E7
C5
47PF
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
U1
LTC3610CUP
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
SGND
R3
11K
VIN
E1 4.5V-24V
VIN
2
VOUT
SELECT
R7
60.4K
2
RUN/SS
VOUT
PGOOD
J1
R14
SGND
SGND
RUN/SS
BOOST
NC
NC
SW
PVIN
PVIN
PVIN
PVIN
PVIN
PVIN
PVIN
PVIN
PVIN
C2
0.01UF
C3 100PF
C4
R6
1000PF 7.5K
SW
SGND
Preliminary
E4
D1
C1
CMDSH-3
0.22UF 16V
1 BOOST
R2
OPT
R4
100K
PGOOD
3
2
1
2
SGND
SGND
SVIN
SVIN
SVIN
INTVCC
INTVCC INTVCC
SW
PGND
PGND
PGND
PGND
PGND
PGND
PGND
PGND
PGND
INTVCC
INTVCC
IOSTEP
CLK
1630 McCarthy Blvd.
Milpitas, CA 95035
Phone: (408)432-1900
Fax: (408)434-0507
LTC Confidential-For Customer Use Only
TITLE: SCHEMATIC
HIGH INPUT VOLTAGE AND HIGH CURRENT DENSITY STEP-DOWN CONVERTER
SIZE
A
DATE:
DWG NO.
DC1129A-1 * LTC3610CUP
Tuesday, March 27, 2007
SHEET
REV
A-1
1 OF 1
5
QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 1129A
SYNCHRONOUS STEP-DOWN DC/DC CONVERTER
DCM
JP6
CCM
FCB
DC1129A Schematic
RUN/SS
1
ON
2
JP1
3
OFF
QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 1129A
SYNCHRONOUS STEP-DOWN DC/DC CONVERTER
DC1129A BOM
Item Qty
Reference
Part Description
Manufacturer / Part #
REQUIRED CIRCUIT COMPONENTS
1
2
3
2
1
2
CIN1,CIN2
CIN3
CO1,CO2
CAP., X5R, 10UF 35V, 1206
CAP., ELECTROLYTIC, 150UF 35V
CAP., X5R, 100UF 6.3V 20%, 1812
TAIYO YUDEN, GDK316BJ106ML
SANYO, 35ME150WXV+TS
TDK, C4532X5R0J107MT
4
5
6
2
1
1
CO5,CO6
CSS
C1
CAP., X5R, 22UF 6.3V 20%, 0805
CAP., X7R, 0.1UF 25V 20%, 0603
CAP., X7R, 0.22UF 16V 20%, 0603
TDK, C2012X5R0J226M
TDK, C1608X7R1E104M
TDK, C1608X7R1C224M
7
8
9
1
1
1
C2
C3
C4
CAP., X7R, 0.01UF 25V 20%, 0603
CAP., NPO, 100PF 50V, 0603
CAP., NPO, 1000PF 50V, 0603
TDK, C1608X7R1E103M
AVX, 06035A101KAT2A
AVX, 06035A102KAT2A
10
11
12
1
1
1
C5
C8
C9
CAP., NPO, 47PF 50V 10%, 0603
CAP., X5R, 4.7UF 16V, 0805
CAP., X5R, 1UF 35V 20%, 0603
AVX, 06035A470KAT2A
TDK, C2012X5R1C475M
TAIYO YUDEN, GMK107BJ105MA-T
13
14
15
1
1
0
D1
L1
L1
DIODE,SCHOTTKY, SOD323
IND, 0.47UH, L-TOKO-FDV0630
IND, 0.36UH, L-TOKO-FDH1040
CENTRAL SEMI., CMDSH-3
TOKO, FDV0630-R47M=P3
TOKO, FDH1040B-R36M=P3
16
17
18
19
20
21
1
1
1
1
1
1
R3
R6
R7
R8
R10
R13
RES., Chip 11K 1/16W 5%,0603
RES., Chip 7.5K 1/16W 1%,0603
RES., Chip 60.4K 1/16W 1%,0603
RES., Chip 137K 1/16W 1%,0603
RES., Chip 40.2K 1/16W 1%,0603
RES., Chip 1 1/16W 5%,0603
AAC, CR16-113JM
AAC, CR16-7501FM
AAC, CR16-6042FM
AAC, CR16-1373FM
AAC, CR16-4022FM
AAC, CR16-1R0JM
22
23
1
1
R14
U1
RES., Chip 2 1/16W 5%,0603
I.C., LTC3610EWP, QFN64UP
AAC, CR16-2R0JM
LINEAR TECH., LTC3610EWP
OPT
ADDITIONAL DEMO BOARD CIRCUIT COMPONENTS
1
2
3
0
0
0
CIN4,CIN5
CIN6,CIN7
CO3,CO4
CAP., 1210
CAP., 1206
CAP., 7343
OPT
OPT
OPT
4
5
6
0
1
1
C6,C7
C10
Q1
CAP., 0603
CAP., X5R, 4.7UF 6.3V 10%, 0603
XTER, N-CH, 30V, DPAK-TO252AA
OPT
AVX, 06036D475KAT
VISHAY, SUD50N03-10CP
7
8
9
10
11
12
0
0
1
1
1
1
R1
R2
R4
R5
R9
R11
RES., 0603
RES., Chip 39.2K 1/16W 1%,0603
RES., Chip 100K 1/16W 5%,0603
RES., Chip 0.005 1W 1%,2512
RES., Chip 60.4K 1/16W 1%,0603
RES., Chip 30.1K 1/16W 1%,0603
OPT
AAC, CR16-3922FM
AAC, CR16-104JM
PANASONIC, ERJM1WSF5M0U
AAC, CR16-6042FM
AAC, CR16-3012FM
13
14
1
1
R12
R16
RES., Chip 19.1K 1/16W 1%,0603
RES., Chip 10K 1/16W 5%,0603
AAC, CR16-1912FM
AAC, CR16-103JM
HARDWARE FOR DEMO BOARD ONLY
1
8
E1,E2,E3,E4,E5,E6,E7,E8
TESTPOINT, TURRET, 0.064"
MILL-MAX, 2308-2
2
3
2
4
JMP, 3PIN 1 ROW .079CC
JMP, 2PIN 1 ROW .079CC
SAMTEC, TMM-103-02-L-S
SAMTEC, TMM-102-02-L-S
4
5
6
7
3
4
2
4
JP1,JP6
JP2,JP3,JP4,JP5
SHUNTS ON JP1&JP6 PINS 1&2,
AND JP3
J1,J2,J3,J4
J5,J6
MTG 4 CORNERS
SHUNT, .079" CENTER
JACK, BANANA,KEY-575
CONN, BNC, 50 OHMS
STAND-OFF, NYLON (SNAP ON), 0.50" TALL
SAMTEC, 2SN-BK-G
KEYSTONE, 575-4
CONNEX, 112404
KEYSTONE, 8833
Preliminary
6
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