DC1860B - Demo Manual

DEMO MANUAL DC1860B
LT3748
No-Opto Isolated FlybacK
Converter for PSE Applications
Description
Demonstration circuit 1860B is an isolated flyback converter featuring the LT3748. This demo circuit is designed
for Power Sourcing Equipment (PSE) applications with a
52.5V output from a 10V to 15V DC input, with nominal
input voltage of 12V. The output current is from 0mA to
700mA, and is capable of a maximum short period overload
current of 900mA. Table 1 summarizes the performance
of the demo board. This demo circuit can also be easily
modified for different PSE applications with some predesigned transformers.
The LT3748 is a high input voltage isolated flyback controller operating with input supply voltages from 5V to 100V,
and 1.9A average gate drive source and sink current. The
LT3748 utilizes boundary mode operation to provide a high
PERFORMANCE SUMMARY
PARAMETER
efficiency, small size solution with improved regulation.
The part senses the isolated output voltage directly from
the primary side flyback waveform during the off time of
the power switch. No third winding, opto-coupler, or signal
transformer is required for regulation.
The LT3748 data sheet gives a complete description of
the part, operation and application information. The data
sheet must be read in conjunction with this quick start
guide for demo circuit 1860B.
Design files for this circuit board are available at
http://www.linear.com/demo
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear
Technology Corporation. All other trademarks are the property of their respective owners.
(TA = 25°C)
CONDITIONS
MIN
TYP
MAX
10
12
15
V
VIN = 10V – 15V
IOUT = 0V – 700 mA
50
52.5
55
V
700
Input Voltage Range
Output Voltage
UNITS
Maximum Output Current
VIN = 10V – 15V
Minimum Output Current
VIN = 10V – 15V
mA
Output Voltage Ripple (Peak to Peak)
VIN = 10V – 15V, IOUT = 0 – 700mA
150
mV
Efficiency
VIN = 13.2V, IOUT = 700mA
87.8
%
0
mA
dc1860bfa
1
DEMO MANUAL DC1860B
quick start procedure
Demo circuit 1860B is easy to set up to evaluate the
performance of the LT3748. Refer to Figure 1 for proper
equipment setup and follow the procedure below.
ex-board preload requirement. The efficiency is higher
than 90% without the preload resistors, but the output
may exceed 57V under no load or transient condition.
1.With power off, connect the input power supply to the
board through VIN (E1) and GND (E2) terminals.
5.Once the proper output voltage is established, adjust
the input voltage and load current within the operating
range and observe the output voltage regulation, ripple
voltage, efficiency and other parameters.
2. Connect the load to the terminals VOUT+ (E6) and VOUT–
(E7) on the board.
3.Turn on the power at the input. Increase VIN slowly to
10V.
NOTE: Make sure that the input voltage does not exceed
15V. If higher operating voltage is required, power components with higher voltage ratings should be used.
4. Check for the proper output voltages. The output should
be regulated at 52.5V (±5%).
NOTE: The LT3748 requires minimum load to maintain
good output voltage regulation. A zener diode D1 together
with preload resistors R2, R14, R15 and R16 are placed in
the output to clamp the output voltage to ~52.5V without
NOTE: When measuring the input or output voltage
ripples, 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
terminals of the input or output capacitor. See Figure 2 for
proper scope probe technique.
NOTE: A gate resistor of less than 10Ω can be added
to the demo circuit to slow down the turning off of the
switch, and reduce the switching node voltage spike. A
RC snubber can be added as well to the primary winding
of the transformer to damp the spike and reduce the EMI.
dc1860bfa
2
DEMO MANUAL DC1860B
quick start procedure
Figure 1. Proper Measurement Equipment Setup
+
VOUT
–
COUT
GND
dc1860b F02
Figure 2. Proper Scope Probe Placement for Measuring Input or Output Ripple
dc1860bfa
3
DEMO MANUAL DC1860B
quick start procedure
100
90
EFFICIENCY (%)
80
70
60
50
40
30
20
VIN = 10V
VIN = 13.2V
VIN = 15V
10
0
0
100
200 300 400 500 600
700
LOAD CURRENT (mA)
dc1860b F03
Figure 3. Typical Efficiency Curve, (TA = 25°C)
53.0
Output Voltage (V)
52.5
52.0
51.5
51.0
50.5
50.0
VIN = 15V
VIN = 10V
0
100
200 300 400 500 600
700
LOAD CURRENT (mA)
dc1860b F04
Figure 4. Load Regulation
VOUT: 20V/DIV
VDS: 20V/DIV
Figure 5. Recovery from Short Circuit Fault
dc1860bfa
4
DEMO MANUAL DC1860B
parts list
ITEM
QTY
REFERENCE
PART DESCRIPTION
MANUFACTURER/PART NUMBER
Cap., X5R, 22µF, 16V, 20%, 1210
Taiyo Yuden EMK325BJ226MN
Required Circuit Components
1
2
C2, C3
2
1
C5
Cap., X7S, 0.22µF, 100V, 10%, 0805
TDK C2012X7S2A224KT
3
3
C6, C7, C8
Cap., X7S, 4.7µF, 100V, 20%, 1812
TDK C4532X7S2A475MT
4
1
C9
Cap., Elect. 470µF, 63V, 20%, J16-PANASONIC
PANASONIC EEVFK1J471M
5
1
C10
Cap., X5R, 4.7µF, 16V, 20%, 0805
Taiyo Yuden EMK212BJ475MG
6
1
C11
Cap., X5R, 0.33µF, 10V, 20%, 0603
AVX 0603ZD334MAT1A
7
1
C12
Cap., NPO, 470pF, 25V, 10%, 0603
AVX 06033A471KAT2A
8
1
C13
Cap., Ceramic 2.2nF, 250V, 10%, 1812
Murata GA343QR7GD222KW01L
9
2
C14, C15
Cap,, X7R, 6800pF, 25V, 20%, 0603
AVX 06033C682MAT2A
10
1
D1
Diode Zener 62V
ON Semi. 1SMB5943BT3
11
1
D2
Schottky Diode 1A/100V, PowerDItm123
Diodes Inc. DFLS1100
12
1
D3
Schottky Diode 3A, PowerDi5
Diodes Inc. PDS3200-13
13
1
L1
Inductor, 1.8µH
Würth Electronik 744318180
14
1
Q1
Mosfet N-Channel, 100V, LFPAK
Renesas HAT2173H-EL-E
15
2
R1, R13
Res., Chip, 16k, 0.25W, 5%, 1206
Vishay CRCW120616K0JNED
16
4
R2, R14, R15, R16
Res., Chip, 11.8k, 0.25W, 1%, 1206
Vishay CRCW120611K8FKEA
17
2
R3, R7
Res/Jumper, Chip, 0Ω, 1/16W, 1 AMP 0603
Vishay CRCW06030000Z0EA
18
1
R4
Res., Chip, 200k, 0.06W, 1%, 0603
Vishay CRCW0603200KFKEA
19
1
R5
Res., Chip, 36k, 0.06W, 5%, 0603
Vishay CRCW060336K0JNEA
20
1
R6
Res., Chip, 82.5k, 0.06W, 1%, 0603
Vishay CRCW060382K5FKEA
21
1
R8
Res., Chip, 22, 0.06W, 5%, 0603
Vishay CRCW060322R0JNEA
22
1
R9
Res., Chip, 270k, 0.06W, 5%, 0603
Vishay CRCW0603270KJNEA
23
1
R10
Res., Chip, 40.2k, 0.06W, 1%, 0603
Vishay CRCW060340K2FKEA
24
1
R11
Res., Chip, 6.04k, 0.06W, 1%, 0603
Vishay CRCW06036K04FKEA
25
1
R12
Res., 0.005, 0.25W, 1%, 1206
Vishay Dale WSL-1206-5L000-1%
26
1
T1
Transformer, XFMR
Würth Elektronik 750311591
27
1
U1
I.C., LT3748EMS
Linear Tech. Corp. LT3748EMS
Connector, Banana Jack
Keystone 575-4
Hardware For Demo Board Only
1
2
E1, E2
2
3
E5, E6, E7
Turret, Testpoint
Mill Max 2501-2-00-80-00-00-07-0
3
1
JP1
Headers, Sgl. Row, 3 Pins, 2mm Ctrs.
Samtec TMM-103-02-L-S
4
4
MH1, MH2, MH3, MH4 STAND-OFF, NYLON 0.25" tall
KEYSTONE, 8831(SNAP ON)
5
1
XJP1
Samtec 2SN-BK-G
Shunt, 2mm Ctrs.
6
1
FAB, 1860B, Rev 3.PCB
DEMO CIRCUIT 1860B
7
2
STENCILS - TOP & BOTTOM
STENCIL DC1860B
Additional Demo Board Circuit Components
1
0
C1 (Opt)
Cap., Alum 330µ,F 25V, 10%, 25cv330gX
2
0
C16 (Opt)
Cap., Alum. Elect. 100µF, 63V, ±20%, NipponChemi-Con/JA0 Nippon Chemi-Con EMZA630ADA101MJA0G
SANYO 25CV330gX
3
0
L2 (Opt)
Inductor, 47µH, IHLP4040
VISHAY IHLP-4040DZ-ER-470-M11
4
0
T2 (Opt)
Transformer, XFMR
Würth Elektronik 750311456
5
0
T3 (Opt)
Transformer, XFMR
Würth Elektronik 750311604
6
0
E3, E4 (Opt)
Turret, Testpoint
Mill Max 2501-2-00-80-00-00-07-0
dc1860bfa
5
6
1
2
3
4
JP1
C11
0.33uF
SHDN
RUN
E5
E2
E1
3
2
SHDN
1
EXT_EN
GND
VIN
10V-15V
+
A
VIN
C12
470pF
C15
6800pF
R10
40.2k
1%
R4
200k
1%
R5
36k
C1
330uF
25V
SANYO
(Opt)
R9
270k
A
R11
6.04k
1%
14
11
12
10
3
C2
22uF
16V
1210
VIN
1
REF
VC
TC
SS
8
9
GND GND
B
SENSE
GATE
RFB
INTVCC
U1
LT3748EMS
EN/UVLO
C3
22uF
16V
1210
B
7
6
16
5
R1
16k
1206
22
C14
6800pF
R8
0 Ohm
82.5k
1%
R7
D2
C10
DFLS1100
4.7uF
16V
0805
R6
R3
0 Ohm
C5
0.22uF
100V
0805
5
11
C13
CUSTOMER NOTICE
2.2nF
250V
1812
1
2
PDS3200-13
3
D3
C6
4.7uF
100V
1812
C
THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND
SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS.
C:\PADS PROJECTS\1860B\REV_B(09-17-12)\SCH\1860B_REV1.DSN
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.
R12
0.005
1206
1
750311591
12
3
DIODE
6
9
2
4
8
T1
10
7
Q1
HAT2173H-EL-E
Renesas
R13
16k
1206
SW
C
1

SCALE = NONE
APP ENG. ZHONGMING Y.
PCB DES.
DATE:

SIZE
D
+
VOUT-
VOUT+
[email protected]
E4
VOPT(Opt)
C9
470uF
63V
E7
E6
IC NO.



E
SHEET
1
OF
2
1
REV.

TITLE: SCHEMATIC
R16
11.8k
1%
1206
E3
VOPT+
[email protected]
(Opt)

 www.linear.com


R15
11.8k
1%
1206
VOUT+
DATE
Oct 01, 2012

R14
11.8k
1%
1206
TECHNOLOGY
R2
11.8k
1%
1206
L1
1.8uH
744318180
Wurth Electronik
E
ZHONGMING Y.
REVISION HISTORY
APPROVED
DESCRIPTION
PRODUCTION
VOPT
D
D1
1SMB5943BT3
C8
4.7uF
100V
1812
APPROVALS
C7
4.7uF
100V
1812

ECO REV
1
2
3
4
DEMO MANUAL DC1860B
Schematic Diagram
dc1860bfa
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no representation that the interconnection of its circuits as described herein will not infringe on existing patent rights.
1
2
3
4
A
A
SW
1
2
5
3
12
1
750311604
(Opt)
9
11
8
3
5
6
2
4
T3
750311456
(Opt)
9
10
6
7
T2
VOPT
DIODE
APPROVALS
C
B
THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND
SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS.
C:\PADS PROJECTS\1860B\REV_B(09-17-12)\SCH\1860B_REV1.DSN
C
SCALE = NONE
L2
D
DATE:

SIZE
IC NO.
D



E
SHEET
2
OF
1
2
REV.


SCHEMATIC
TECHNOLOGY
E

 www.linear.com


C16
100uF
63V
(Opt)
VOUT+
47uH
IHLP-4040DZ-ER-470-M11
VISHAY
(Opt)
VOPT
LINEAR TECHNOLOGY HAS MADE A BEST EFFORT TO DESIGN A
CIRCUIT THAT MEETS CUSTOMER-SUPPLIED SPECIFICATIONS;
HOWEVER, IT REMAINS THE CUSTOMER'S RESPONSIBILITY TO PCB DES.

VERIFY PROPER AND RELIABLE OPERATION IN THE ACTUAL
APP ENG. ZHONGMING Y. TITLE:
APPLICATION. COMPONENT SUBSTITUTION AND PRINTED
CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT
PERFORMANCE OR RELIABILITY. CONTACT LINEAR
TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE.
CUSTOMER NOTICE
Optional Circuit
VIN
B
1
2
3
4
DEMO MANUAL DC1860B
Schematic Diagram
dc1860bfa
7
DEMO MANUAL DC1860B
DEMONSTRATION BOARD IMPORTANT NOTICE
Linear Technology Corporation (LTC) provides the enclosed product(s) under the following AS IS conditions:
This demonstration board (DEMO BOARD) kit being sold or provided by Linear Technology is intended for use for ENGINEERING DEVELOPMENT
OR EVALUATION PURPOSES ONLY and is not provided by LTC for commercial use. As such, the DEMO BOARD herein may not be complete
in terms of required design-, marketing-, and/or manufacturing-related protective considerations, including but not limited to product safety
measures typically found in finished commercial goods. As a prototype, this product does not fall within the scope of the European Union
directive on electromagnetic compatibility and therefore may or may not meet the technical requirements of the directive, or other regulations.
If this evaluation kit does not meet the specifications recited in the DEMO BOARD manual the kit may be returned within 30 days from the date
of delivery for a full refund. THE FOREGOING WARRANTY IS THE EXCLUSIVE WARRANTY MADE BY THE SELLER TO BUYER AND IS IN LIEU
OF ALL OTHER WARRANTIES, EXPRESSED, IMPLIED, OR STATUTORY, INCLUDING ANY WARRANTY OF MERCHANTABILITY OR FITNESS
FOR ANY PARTICULAR PURPOSE. EXCEPT TO THE EXTENT OF THIS INDEMNITY, NEITHER PARTY SHALL BE LIABLE TO THE OTHER FOR
ANY INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES.
The user assumes all responsibility and liability for proper and safe handling of the goods. Further, the user releases LTC from all claims
arising from the handling or use of the goods. Due to the open construction of the product, it is the user’s responsibility to take any and all
appropriate precautions with regard to electrostatic discharge. Also be aware that the products herein may not be regulatory compliant or
agency certified (FCC, UL, CE, etc.).
No License is granted under any patent right or other intellectual property whatsoever. LTC assumes no liability for applications assistance,
customer product design, software performance, or infringement of patents or any other intellectual property rights of any kind.
LTC currently services a variety of customers for products around the world, and therefore this transaction is not exclusive.
Please read the DEMO BOARD manual prior to handling the product. Persons handling this product must have electronics training and
observe good laboratory practice standards. Common sense is encouraged.
This notice contains important safety information about temperatures and voltages. For further safety concerns, please contact a LTC application engineer.
Mailing Address:
Linear Technology
1630 McCarthy Blvd.
Milpitas, CA 95035
Copyright © 2004, Linear Technology Corporation
dc1860bfa
8
Linear Technology Corporation
LT 0213 REV A • PRINTED IN USA
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900
●
FAX: (408) 434-0507 ● www.linear.com
 LINEAR TECHNOLOGY CORPORATION 2011
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