DC2457A Demo Manual Datasheet by Analog Devices Inc.

l ’ LI” DEMO MANUAL DC2457A TECHNOLOGY L7HEWEAR 1
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DEMO MANUAL DC2457A
Description
LT8390EUFD
60V Low EMI Synchronous
4-Switch Buck-Boost Voltage Regulator
Demonstration circuit DC2457A is a 12V, 4A, 4-switch
synchronous buck-boost regulator featuring low EMI noise
and small footprint. It runs at 400kHz switching frequency.
Spread spectrum frequency modulation (SSFM) can be
turned on with a simple jumper, reducing EMI. DC2457A
also comes with other low EMI features including optimized
layout, input and output filters. It passes CISPR 25 class
5 conducted and radiated EMI.
The operating input voltage range of DC2457A is from 4V to
60V. The output voltage and EN/UVLO, are all programmed
by resistor dividers. EN/UVLO is set so the circuit will turn
off when the input voltage falls below 4V and will turn on
when the input voltage rises above 5V.
DC2457A features MOSFETs that complement the 5V
gate drive of the LT8390
®
to achieve high efficiency. 60V
MOSFETs are used on the input side of the 4-switch topol-
ogy while 25V MOSFETs are used on the output side. All
those MOSFETs are 3.3mm × 3.3mm footprint. Ceramic
capacitors are used at both the circuit input and output
because of their small size and high ripple current capability.
In addition to ceramic capacitors, there are two aluminum
polymer capacitors on the output. The input also has two
aluminum polymer capacitors.
The CTRL input is pulled up to the VREF pin through a
resistor to set the output current limit to its maximum,
and an external voltage on CTRL can be used to lower the
current limit if the resistor is removed. A capacitor at the
SS pin programs soft-start.
The PGOOD is status flag indicates when output voltage
is within ±10% of final regulation voltage.
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.
The LT8390’s proprietary peak current mode buck-boost
architecture ensures DC2457A runs either in discontinuous
conduction mode (DCM) or pulse-skipping mode (PSM)
without reversed inductor current. Both of them enhance
the light load efficiency.
To improve the EMI performance, the LT8390 has spread
spectrum frequency modulation. With the SYNC/SPRD
pin tied to INTVCC, LT8390 starts to spread its switch-
ing frequency ±15% around the programmed oscillator
frequency.
There is an EMI filter on the input of DC2457A. There is also
a small ferrite bead output filter. These filters, combined
with proper board layout and SSFM are effective to help
the circuit pass CISPR 25 class 5 conducted and radiated
EMI. Please follow the recommended layout and four-layer
thickness of DC2457A for low EMI applications.
The demo circuit is designed to be easily reconfigured to
many other applications, including the example schemat-
ics in the data sheet. Consult the factory for assistance.
The LT8390EUFD is available in a thermally enhanced 28-
lead (4mm × 5mm) plastic QFN package. The LT8390 data
sheet gives a complete description of the part, operation
and applications information. The LT8390 data sheet must
be read in conjunction with this demo manual to properly
use or modify demo circuit DC2457A.
Design files for this circuit board are available at
http://www.linear.com/demo/DC2457A
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DEMO MANUAL DC2457A
performance summary
Specifications are at TA = 25°C
PARAMETERS CONDITIONS MIN TYP MAX UNIT
Input Voltage Range (VIN) VOUT = 12V, IOUT = 1A 4 60 VDC
Output Voltage (VOUT) R7 = 110k, R8 = 10k 11.5 12.0 12.5 VDC
Maximum Output Current* 5V ≤ VIN ≤ 40V, VOUT = 12V 4 A
Switching Frequency R5 = 100k 400 kHz
Input EN Voltage R9 = 374k, R10 = 165k 5 VDC
Input UVLO Voltage R9 = 374k, R10 = 165k 4 VDC
Output Current Limit R2 = 15mΩ 6.67 A
*The maximum output current is based on 65°C temperature rise of components on demo circuit. The input range mentioned in table is also limited by
the same temperature rise. Wider input range and higher output current can be reached if larger copper area or force-air cooling is applied. The maximum
output current is also limited by inductor peak current.
VIN ; GND . L7LLUEGB LT8390 60V Low EMISYNCHRONOUS 4—SWHCH BUCK—BOOST VOLIAGE REGULATOR Dcz+57A swc/ssru no :vNc/ssru Lam/3350 m we m AM 27111 EN/uvLoLoAnEM CTRL END ‘5qu DUI} EXT smc 9"???- "SEE nEuu _ Izvnc o-AA )7 CONNECT 10 mm L + + 1 FOR swmuvm L7 LJUW
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DEMO MANUAL DC2457A
Quick start proceDure
Demonstration circuit DC2457A is easy to set up to evalu-
ate the performance of the LT8390EUFD. Refer to Figure
1 for proper measurement equipment setup and follow
the procedure below:
NOTE: Make sure that the voltage applied to VIN does
not exceed 60V.
1. Set JP1 at NO SSFM/SYNC to disable SSFM, at SSFM
ON to enable SSFM, or at EXT SYNC and tie EXT SYNC
to external oscillator.
2. Connect the EN/UVLO terminal to ground with a clip-on
lead. Connect the power supply (with power off), load,
and meters as shown.
3. After all connections are made, turn on the input power
and verify that the input voltage is between 4V and 60V.
4. Remove the clip-on lead from EN/UVLO. Verify that the
output voltage is 12V.
NOTE: If the output voltage is low, temporarily discon-
nect the load to make sure that it is not set too high.
5. Once the proper output voltage is established, adjust
the input voltage and load within the operating ranges
and observe the output voltage regulation, ripple volt-
age, efficiency and other parameters.
Figure 1. Test Procedure Setup Drawing for DC2457A
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DEMO MANUAL DC2457A
test resuLts
Figure 4. Output Voltage Transient Response, VIN = 12V,
VOUT = 12V, IOUT = 2A to 4A to 2A
Figure 3. Efficiency vs IOUT at Different VIN
Figure 2. Efficiency vs VIN at Full Load
IOUT(1A/DIV)
VOUT_AC couple (0.2V/DIV)
200µs/DIV
INPUT VOLTAGE (V)
0
EFFICIENCY (%)
100
90
85
95
80 4020
DC2457a F02
3010
BUCK - BOOST
BUCK
BOOST
IOUT (A)
0
EFFICIENCY (%)
100
90
75
70
65
60
55
85
95
50
80
42
DC2457a F03
31
VIN = 9V
VIN = 12V
VIN = 24V
L7 HEW 5
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DEMO MANUAL DC2457A
test resuLts
Figure 5. DC2457A Conducted Peak and Average EMI—Passes CISPR 25 Class 5 Limits
Figure 6. DC2457A Radiated Peak and Average EMI—30MHz to 1GHz—Passes CISPR 25 Class 5 Limits
Figure 7. DC2457A Radiated Peak and Average EMI—150kHz to 30MHz—Passes CISPR 25 Class 5 Limits
80
70
60
40
50
30
20
10
0
–100.1 101
FREQUENCY (MHz)
PEAK CONDUCTED EMI (dBµV)
14VIN, 12VOUT
, 4A
CISPR25 CLASS 5 LIMITS
NOISE FLOOR
80
70
60
50
40
30
20
10
0
–100.1 101
FREQUENCY (MHz)
AVERAGE CONDUCTED EMI (dBµV)
14VIN, 12VOUT
, 4A
CISPR25 CLASS 5 LIMITS
NOISE FLOOR
50
40
30
20
10
0
–10 0 100 200 300 400 600500 700 800 900
FREQUENCY (MHz)
1000
PEAK RADIATED EMI (dBµV/m)
NOISE FLOOR
CISPR25 CLASS 5 LIMITS
14VIN, 12VOUT, 4A
50
40
30
20
10
0
–10 0 100 200 300 400 600500 700 800 900
FREQUENCY (MHz)
1000
AVERAGE RADIATED EMI (dBµV/m)
NOISE FLOOR
CISPR25 CLASS 5 LIMITS
14VIN, 12VOUT
, 4A
60
50
40
30
20
10
0
–10
0.1 1
FREQUENCY (MHz)
NOISE FLOOR
14VIN, 12VOUT, 4A
10
PEAK RADIATED EMI (dBµV/m)
CISPR25 CLASS 5 LIMITS
60
50
40
30
20
10
0
–100.1 1
FREQUENCY (MHz) 10
AVERAGE RADIATED EMI (dBµV/m)
14VIN, 12VOUT, 4A
NOISE FLOOR
CISPR25 CLASS 5 LIMITS
mu a zoo L7HCU§QB
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DEMO MANUAL DC2457A
tHermaL imaGe
Figure 8. Thermal Performance of DC2457A (VIN = 12V, VOUT = 12V, IOUT = 4A)
An example thermal image shows the temperature dis-
tribution on the DC2457A. The test is done in still air at
room temperature (25°C). The highest temp is below 52°C
around buck side MOSFET, at VIN = 12V, VOUT = 12V, and
4A load current.
MAXIMUM
TEMPERATURE
IS 51°C
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DEMO MANUAL DC2457A
parts List
ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER
Required Circuit Components
1 1 C1 CAP, 1µF, X7S, 100V, 10%, 0805 MURATA, GRJ21BC72A105KE11L
2 1 C2 CAP, 4.7µF, X5R, 10V, 10%, 0402 TDK, C1005X5R1A475K050BC
3 1 C3 CAP, 0.47µF, X5R, 16V, 10%, 0402 TDK, C1005X5R1C474K050BC
4 1 C4 CAP, 4.7nF, X7R, 16V, 10%, 0402 MURATA, GRM155R71C472KA01D
5 6 C5, C7, C8, C15, C16, C24 CAP, 0.1µF, X7R, 25V, 10%, 0402 AVX, 04023C104KAT2A
6 1 C6 CAP, 1µF, X7R, 25V, 10%, 0603 MURATA, GRM188R71E105KA12D
7 4 C9, C10, C21, C22 CAP, CER, 4.7µF, X7S, 100V, 20%, 1206 AVX, 12061Z475MAT2A
8 3 C11, C12, C23 CAP, 0.1µF, X5R, 100V, 10%, 0402 MURATA, GRM155R62A104KE14D
9 2 C13, C14 CAP, CER, 10µF, X7R, 25V, 10%, 1206 MURATA, GRM31CR71E106KA12L
10 2 C17, C18 CAP, ALUM, 22µF, 63V, 20%, 8mm × 10.5mm SUNCON ELEC, 63HVP22M
11 2 C19, C20 CAP, ALUM, 120µF, 25V, 20%, 6.3mm × 7.7mm SUNCON ELEC, 16HVHZ120M
12 1 C26 CAP, 100pF, X7R, 16V, 10%, 0402 AVX, 0402YC101KAT2A
13 1 D3 DIODE, SCHOTTKY, 40V, 1A, SOD-323F NXP, PMEG4010CEJ
14 2 FB1, FB2 BEAD, FERRITE, 1206 WURTH ELEKTRONIK, 742792118
15 1 L1 IND, 4.2µH WURTH, 744325420
16 1 L2 IND, 1.5µH WURTH, 744314150
17 2 M1, M2 XSTR, MOSFET, TSDSON-8 INFINEON, BSZ100N06LS3 G
18 2 M3, M4 XSTR, MOSFET, TSDSON-8 INFINEON, BSZ033NE2LS5
19 1 R1 RES, 0.004Ω, 1W, 0612 SUSUMU, KRL3216D-M-R004-F-T5
20 1 R3 RES, 0.015Ω, 1W, 0612 SUSUMU, KRL3216D-M-R015-F-T5
21 2 R5, R11 RES, 100k, 1/16W, 1%, 0402 VISHAY, CRCW0402100KFKED
22 1 R6 RES, 27k, 1/16W, 1%, 0402 VISHAY, CRCW040227K0FKED
23 1 R7 RES, 110k, 1/16W, 1%, 0402 VISHAY, CRCW0402110KFKED
24 1 R8 RES, 10k, 1/16W, 1%, 0402 VISHAY, CRCW040210K0FKED
25 1 R9 RES, 374k, 1/16W, 1%, 0402 VISHAY, CRCW0402374KFKED
26 1 R10 RES, 165k, 1/16W, 1%, 0402 VISHAY, CRCW0402165KFKED
27 4 R14, R15, R16, R17 RES, 10Ω, 1/16W, 1%, 0402 VISHAY, CRCW040210R0FKED
28 1 U1 IC, VOLTAGE REGULATOR, 28-QFN LINEAR TECHNOLOGY LT8390EUFD#PBF
Additional Demo Board Circuit Components
29 0 C25, C27, C28 (OPT) CAP, OPTION, 0402
30 0 C29 (OPT) CAP, OPTION, 0805
31 0 C30 (OPT) CAP, OPTION, 0805
32 0 C31, C32 (OPT) CAP, OPTION, 1206
33 0 D1, D2 (OPT) DIODE, OPTION, SOD-123
34 0 Q1 (OPT) XSTR, MOSFET, OPTION, PowerPAK 1212-8
35 3 R2, R4, R18 RES, 0Ω, 1/16W, 0402 VISHAY, CRCW04020000Z0ED
36 0 R12, R13, R21, R22, R23,
R24, R25, R26 (OPT)
RES, OPTION, 0402
37 0 R19, R20, R28 (OPT) RES, OPTION, 0805
38 0 R27 (OPT) RES, OPTION, 0612
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DEMO MANUAL DC2457A
parts List
ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER
Hardware: For Demo Board Only
39 4 E1, E2, E9, E10 TEST POINT, TURRET, 0.094" MTG HOLE MILL-MAX, 2501-2-00-80-00-00-07-0
40 7 E3, E4, E5, E6, E7, E8, E11 TEST POINT, TURRET, 0.061" MTG HOLE MILL-MAX, 2308-2-00-80-00-00-07-0
41 1 JP1 CONN, HEADER, 2X3, 2mm WURTH ELEKTRONIK, 62000621121
42 1 XJP1 SHUNT, 2mm WURTH ELEKTRONIK, 60800213421
43 4 J1, J2, J3, J4 CONN, JACK, BANANA, 0.218" KEYSTONE, 575-4
44 4 MH1 TO MH4 STAND-OFF, NYLON 0.375" WURTH ELEKTRONIK, 702933000
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DEMO MANUAL DC2457A
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 representa-
tion that the interconnection of its circuits as described herein will not infringe on existing patent rights.
scHematic DiaGram
VIN
4V - 60V
EN/UVLO
GND
GND
ALL CAPACITORS ARE 0402.
NOTE: UNLESS OTHERWISE SPECIFIED
400kHz
ALL RESISTORS ARE 0402.
12V 4A
OUT
PGOOD
ISMON
EXT SYNC
GND
CTRL
LOADEN
*
SEE DEMO MANUAL
*
C5
0.1uF
C1
1uF
100V
0805
C12
0.1uF
0402
100V
E4
C24
0.1uF
0402
25V
R6
27K
R4
0
E2
E2
R12
OPT
C21
1206
4.7uF
100V
R21
OPT
L2
1.5uH
744314150
Wurth Elektronik
R25
OPT
R20
OPT
0805
U1
LT8390EUFD
EN/UVLO6
PGOOD
14
TEST
7
CTRL
10
LOADEN
8
ISP 11
SYNC/SPRD
19
SS
15
LOADTG
20
VC
17
RT
18
VREF
9
ISMON
13
LSN 3
LSP 2
ISN 12
FB 16
TG2 22
SW2 23
BG2 25
BG1 26
SW1 28
TG1 1
BST1 27
BST2 24
VIN 4
INTVCC
5
GND
29
VOUT 21
JP1
SSFM
EXT SYNC
NO SYNC/SSFM
SYNC/SSFM
1
5
3
2
4
6
R5
100K
1%
C9
4.7uF
1206
100V
Q1
OPT
4
5
6
7
1
2
38
R13
OPT
C8
0.1uF
0402
M4
BSZ033NE2LS5
C32
1206
OPT
R23
OPT
FB2
742792118
R26
OPT
R7
110K
1%
R11
100K
J3
+
C17
22uF
63HVP22M
63V
C13
10uF
1206
25V
J4
C2
4.7uF
10V
E7
R15
10
R27
OPT
0612
13
24
M1
BSZ100N06LS3 G
C30
OPT
0805
C6
1uF
25V
0603
R14
10
C29
OPT
0805
C11
0.1uF
0402
100V
E6
E1 C10
4.7uF
1206
100V
E11
D1
OPT
SOD-123
J1
C16
0.1uF
0402
25V
R22
OPT
R28
OPT
0805
R24
OPT
+
C19
120uF
16V
16HVHZ120M
C25
OPT
R16
10
C3
0.47uF
M3
BSZ033NE2LS5
C27
OPT
E3
C31
OPT
1206
C22
1206
100V
4.7uF
R3
0.015
KRL3216D-M-R015-F-T5
13
24
+
C20
120uF
16V
16HVHZ120M
E9
R18
0
R10
165K
M2
BSZ100N06LS3 G
E5
R17
10
C26
100pF
J2
R1
0.004
KRL3216D-M-R004-F-T5
13
24
E10
R2
0
FB1
742792118
Wurth Elektronik
+
C18
22uF
63V
63HVP22M
L1
4.2uH
744325420
Wurth Elektronik
D3
PMEG4010CEJ
C15
0.1uF
0402
25V
R8
10K
1%
C28
OPT
C7
0.1uF
0402
D2
OPT
SOD-123
C14
10uF
1206
25V
R19
OPT
0805
E8
E8
R9
374K
C23
0.1uF
0402
100V
C4
4.7nF
ISP
ISN
VIN
INTVCC
INTVCC
VREF
VREF
LOADTG
LOADTG
ISN
ISP
VIN
‘IO
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DEMO MANUAL DC2457A
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900 FAX: (408) 434-0507 www.linear.com
© LINEAR TECHNOLOGY CORPORATION 2017
LT 0117 • PRINTED IN USA
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:
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Copyright © 2004, Linear Technology Corporation