DC2019B - Demo Manual

DEMO MANUAL DC2019B
LT8614
42V, 4A Micropower
Synchronous Step-Down
Silent Switcher
DESCRIPTION
Demonstration circuit 2019B is a 42V, 4A micropower
synchronous step-down Silent Switcher™ featuring the
LT®8614. The demo board is designed for 5V output
from a 5.8V to 42V input. The wide input range allows a
variety of input sources, such as automotive batteries and
industrial supplies. The LT8614 is a compact, ultralow
emission, high efficiency and high speed synchronous
monolithic step-down switching regulator. The integrated
power switches and inclusion of all necessary circuitry
reduce the components count and solution size. Special
Silent Switcher architecture minimizes EMI/EMC emissions. Ultralow 2.5µA quiescent current in Burst Mode®
operation achieves high efficiency at very light loads. Fast
minimum on-time of 30ns enables high VIN to low VOUT
conversion at high frequency.
The LT8614 switching frequency can be programmed either
via oscillator resistor or external clock over a 200kHz to
3MHz range. The SYNC pin on the demo board is grounded
by default for low ripple Burst Mode operation. To synchronize to an external clock, move JP1 to SYNC and
apply the external clock to the SYNC turret. Once JP1 is
on SYNC position, a DC voltage of higher than 3V can be
applied to the SYNC turret for pulse-skipping operation.
Figure 1 shows the efficiency of the circuit at 12V input in
Burst Mode operation (input from VIN turret pin). Figure 2
shows the LT8614 temperature rising on DC2019B demo
board under different load conditions. The rated maximum
load current is 4A, while derating is necessary for certain
VIN and thermal conditions.
The demo board has an EMI filter installed. The EMI performance of the board (with EMI filter) is shown in Figure 3.
The red line in Figure 3 is CISPR25 Class 5 peak limit.
The figure shows that the circuit passes the test with a
wide margin. To achieve EMI/EMC performance as shown
in Figure 3, the input EMI filter is required and the input
voltage should be applied at VEMI turret pin.
The LT8614 data sheet gives a complete description of the
part, operation and application information. The data sheet
must be read in conjunction with this demo manual for
demo circuit 2019B. The LT8614 is assembled in a 3mm
× 4mm plastic QFN package with exposed pads for low
thermal resistance. Proper board layout is essential for both
low EMI operation and maximum thermal performance.
See the data sheet sections, “Low EMI PCB Layout” and
“High Temperature Considerations.”
Design files for this circuit board are available at
http://www.linear.com/demo/DC2019B
L, LT, LTC, LTM, Linear Technology, Burst Mode and the Linear logo are registered trademarks
and Silent Switcher is a trademark of Linear Technology Corporation. All other trademarks are
the property of their respective owners.
PERFORMANCE SUMMARY
Specifications are at TA = 25°C
SYMBOL
PARAMETER
CONDITIONS
VIN
Input Supply Range
VOUT
Output Voltage
IOUT
Maximum Output Current
fSW
Switching Frequency
EFE
Efficiency at DC
MIN
TYP
5.8
4.85
Derating is Necessary for Certain VIN and
Thermal Conditions
42
5
5.15
4
1.85
VIN = 12V, IOUT = 3A
MAX
UNITS
V
V
A
2
91.3
2.15
MHz
%
dc2019bfb
1
DEMO MANUAL DC2019B
PERFORMANCE
100
95
VOUT = 5V
90 fSW = 2MHz
90
80
TEMPERATURE RISING (°C)
EFFICIENCY (%)
100
85
80
75
70
VIN = 12V
VOUT = 5V
fSW = 2MHz
65
60
0
0.5
1
1.5 2 2.5 3
LOAD CURRENT (A)
3.5
60
50
40
30
20
10
4
12
6
18
24
30
36
42
INPUT VOLTAGE (V)
IOUT = 4A
IOUT = 2.5A
IOUT = 3.5A
IOUT = 2A
dc2019a F02
IOUT = 3A
dc2019a F01
Figure 2. Temperature Rising vs Input Voltage
Figure 1. Efficiency vs Load Current
(Input from VIN Turret Pin)
50
70
DETECTOR: +PEAK
AMPLITUDE (dBµV/m)
40
30
20
10
CLASS 5 PEAK
DATA
0
0
100
200
300
400
600
500
FREQUENCY (MHz)
700
800
900
1000
dc2019a F03
Figure 3. LT8614 Demo Circuit EMI Performance in CISPR25 Radiated Emission Test (14V Input from VEMI Turret Pin, IOUT = 4A)
dc2019bfb
2
DEMO MANUAL DC2019B
QUICK START PROCEDURE
Demonstration circuit 2019B is easy to set up to evaluate the performance of the LT8614. Refer to Figure 4 for
proper measurement equipment setup and follow the
procedure below.
NOTE: When measuring the input or output voltage ripple,
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 VEMI
or VOUT and GND terminals. See Figure 5 for the proper
scope technique.
1. Place JP1 on GND position.
2. With power off, connect the input power supply to VEMI
and GND. If the EMI/EMC performance is not important,
the input EMI filter can be bypassed by connecting the
input power supply to VIN and GND.
5. Check for the proper output voltage (VOUT = 5V).
NOTE: If there is no output, temporarily disconnect the
load to make sure that the load is not set too high or
is shorted.
6. Once the proper output voltage is established, adjust
the load within the operating ranges and observe the
output voltage regulation, ripple voltage, efficiency and
other parameters.
7. An external clock can be added to the SYNC terminal when SYNC function is used (JP1 on the SYNC
position). Please ensure that the chosen RT sets the
LT8614 switching frequency to equal or below the
lowest SYNC frequency. See the data sheet section,
“Synchronization.”
3. With power off, connect the load from VOUT to GND.
4. Turn on the power at the input.
NOTE: Make sure that the input voltage does not
exceed 42V.
Figure 5. Measuring Output Ripple
Figure 4. Proper Measurement Equipment Setup
dc2019bfb
3
DEMO MANUAL DC2019B
PARTS LIST
ITEM
QTY
REFERENCE
PART DESCRIPTION
MANUFACTURER/PART NUMBER
Required Circuit Components
1
2
C2, C12
CAP., X5R, 1µF, 50V, 10%, 0603
TDK, C1608X5R1H105K
2
2
C4,C8
CAP., X7R, 0.1µF, 16V, 10%, 0603
MURATA, GRM188R71C104KA01D
3
1
C5
CAP., C0G, 4.7pF, 25V, ±0.25p, 0603
AVX, 06033A4R7CAT2A
4
1
C6
CAP., X7R, 47µF, 10V, 10%, 1210
MURATA, GRM32ER71A476KE15L
5
2
C7, C13
CAP., X7R, 1µF, 25V, 10%, 0603
MURATA, GRM188R71E105KA12D
6
1
C9
CAP., X5R, 4.7μF, 25V, 10%, 0603
MURATA, GRM188R61E475KE11D
7
1
C11
CAP., X5R, 10µF, 50V, 10%, 1206
MURATA, GRM31CR61H106KA12L
8
1
L1
IND, 1.5µH, IHLP2020CZ-01
VISHAY, IHLP2020CZER1R5M01
9
2
R1, R3
RES., CHIP, 100k, 1/10W, 1%, 0603
VISHAY, CRCW0603100KFKEA
10
1
R2
RES., CHIP, 18.2k, 1/10W, 1%, 0603
VISHAY, CRCW060318K2FKEA
11
1
R4
RES., CHIP, 1M, 1/10W, 1%, 0603
VISHAY, CRCW06031M00FKEA
12
1
R5
RES., CHIP, 243k, 1/10W, 1%, 0603
VISHAY, CRCW0603243KFKEA
13
1
U1
IC, REGULATOR, 20-QFN, UDC
LINEAR TECHNOLOGY, LT8614EUDC#PBF
Additional Demo Board Circuit Components
1
1
C1
CAP., ALUM, 22µF, 63V
SUN ELECT., 63CE22BS
2
1
C3
CAP., X7R, 4.7µF, 50V, 10%, 1206
MURATA, GRM31CR71H475KA12L
3
1
C10
CAP., X7R, 10µF, 50V, 10%, 1210
MURATA, GRM32ER71H106KA12L
4
1
C14
CAP., X7R, 0.1µF, 50V, 10%, 0402
TDK, C1005X7R1H104K
5
1
FB1
CHIP BEAD, MPZ2012
TDK, MPZ2012S300AT
6
1
L2
IND., 0.22µH,IHLP1616AB-01
VISHAY, IHLP1616ABERR22M01
7
0
R6 (OPT)
RES., 0603
8
1
R7
RES., CHIP, 0, 1/10W, 0603
VISHAY, CRCW06030000Z0EA
Hardware: For Demo Board Only
1
10
E1-E10
TESTPOINT, TURRET, 0.094" pbf
MILL-MAX, 2501-2-00-80-00-00-07-0
2
1
JP1
HEADER, 3 PIN, 0.079", SINGLE ROW
SULLINS, NRPN031PAEN-RC
3
1
XJP1
SHUNT, 0.079", CENTER
SAMTEC, 2SN-BK-G
4
4
MH1-MH4
STAND-OFF, NYLON, 0.50" TALL
KEYSTONE, 8833 (SNAP-ON)
dc2019bfb
4
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.













































 










































 















 
 
 









 
 
 





















 






















SCHEMATIC DIAGRAM


DEMO MANUAL DC2019B
dc2019bfb
5
DEMO MANUAL DC2019B
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
dc2019bfb
6
Linear Technology Corporation
LT 0515 REV B • PRINTED IN USA
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900
●
FAX: (408) 434-0507 ● www.linear.com
 LINEAR TECHNOLOGY CORPORATION 2013
Similar pages