Linear Technology DC2565A Quick setup guide

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dc2565af
DEMO MANUAL DC2565A
Description
LT8607
42V, 0.75A Micropower Synchronous
Step-Down Regulator
Demonstration Circuit 2565A is a 42V, 0.75A micropower
synchronous step-down regulator featuring the LT
®
8607.
The demo board is designed for 5V output from a 5.5V
to 42V input. The wide input range allows a variety of
input sources, such as automotive batteries and indus-
trial supplies. The LT8607 is a compact, high efficiency,
high speed synchronous monolithic step-down switch-
ing regulator that consumes less than 3μA of quiescent
current when output is regulated at 5V. Top and bottom
power switches, compensation components and other
necessary circuits are inside of the LT8607 to minimize
external components and simplify design.
The SYNC pin on the demo board is grounded by default
for low ripple Burst Mode
®
operation. Move JP1 to PULSE
SKIPPING position can change the operation mode to
pulse-skipping operation. Once JP1 is on SPREAD SPEC-
TRUM position, VCC is applied to the SYNC pin for low
EMI spread spectrum operation. To synchronous to an
external clock, move JP1 to SYNC and apply the external
clock to the SYNC turret. Figure 1 shows the efficiency
of the circuit.
L, LT, LTC, LTM, Linear Technology, the Linear logo and Burst Mode are registered trademarks
of Analog Devices, Inc. All other trademarks are the property of their respective owners.
performance summary
The demo board has an EMI filter installed. The radiated
EMI performances of the board (with EMI filter) are shown
in Figure 2 and Figure 3. The red lines in Figure 2 and
Figure 3 are CISPR25 Class 5 peak limit. To use the EMI
filter, the input should be tied to VEMI, not VIN. An induc-
tor L2, which is a 0Ω jumper on the board by default
now, can be added in the EMI filter to further reduce the
conducted emission.
The LT8607 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 DC2565A.
Design files for this circuit board are available at
http://www.linear.com/demo/DC2565A
Specifications are at TA= 25°C
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
VIN Input Voltage Range 5.5 42 V
VOUT Output Voltage 4.8 5 5.2 V
IOUT Maximum Output Current 0.75 A
fSW Switching Frequency 1.85 2 2.15 MHz
EFE Efficiency at DC VIN = 12V, IOUT = 0.75A 92.4 %

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DEMO MANUAL DC2565A
Quick start proceDure
DC2565A is easy to set up to evaluate the performance
of the LT8607. 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. See Figure 5 for the proper scope
technique.
1. Set an input power supply that is capable of 42V/0.75A.
Then turn off the supply.
2. With power off, connect the supply to the input termi-
nals VIN and GND.
3. Turn on the power at the input.
NOTE:Make sure that the input voltage never exceeds
42V.
4. Check for the proper output voltage of 5V. Turn off the
power at the input.
5. Once the proper output voltage is established, connect
a variable load capable of sinking 0.75A at 5V to the
output terminals V
OUT
and GND. Set the current for 0A.
a. If efficiency measurements are desired, an ammeter
can be put in series with the output load in order to
measure the DC2565A’s output current.
b. A voltmeter can be placed across the output ter-
minals in order to get an accurate output voltage
measurement.
6. Turn on the power at the input.
NOTE:If there is no output, temporarily disconnect the
load to make sure that the load is not set too high.
7. Once the proper output voltage is established again,
adjust the load and/or input within the operating range
and observe the output voltage regulation, ripple volt-
age, efficiency and other desired parameters.
8. An external clock can be added to the SYNC termi-
nal when SYNC function is used (JP1 on the SYNC
position). Please ensure that the chosen RT sets the
LT8607 switching frequency to equal or below the low-
est SYNC frequency. See the Synchronization section
in the data sheet.
Figure 1. Efficiency vs Load Current at 2MHz Switching Frequency
IOUT (A)
0
50
55
60
65
EFFICIENCY
70
75
100
95
90
85
80
0.15 0.3 0.45 0.6 0.75
DC2565A F01
VIN = 12V
VIN = 24V

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DEMO MANUAL DC2565A
Quick start proceDure
FREQUENCY (MHz)
0
–10
–5
10
15
0
5
AMPLITUDE (dBuV/m)
20
25
50 VERTICAL POLARIZATION
PEAK DETECTOR
45
40
35
30
100 200 300 400 500 600 700 800 900 1000
DC2565A F02
CLASS 5 PEAK LIMIT
FIXED FREQUENCY
SPREAD SPECTRUM MODE
FREQUENCY (MHz)
0
–10
–5
10
15
0
5
AMPLITUDE (dBuV/m)
20
25
50
45
40
35
30
100 200 300 400 500 600 700 800 900 1000
DC2565A F03
HORIZONTAL POLARIZATION
PEAK DETECTOR
CLASS 5 PEAK LIMIT
FIXED FREQUENCY
SPREAD SPECTRUM MODE
Figure 2. LT8607 Demo Circuit EMI Performance in CISPR25
Radiated Emission Test, Antenna Polarization: Vertical
(VIN = 14V, VOUT = 5V, IOUT = 0.75A, 2MHz Switching Frequency)
Figure 3. LT8607 Demo Circuit EMI Performance in CISPR25
Radiated Emission Test, Antenna Polarization: Horizontal
(VIN = 14V, VOUT = 5V, IOUT = 0.75A, 2MHz Switching Frequency)
Figure 4. Proper Measurement Equipment Setup
Figure 5. Measuring Output Ripple
V
OUT
GND

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DEMO MANUAL DC2565A
parts List
ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER
Required Circuit Components
1 1 C2 CAP., X7R, 4.7µF, 50V, 10% 1206 MURATA, GRM31CR71H475K
2 1 C4 CAP., X7R, 0.22µF, 16V, 10%, 0603 MURATA, GRM188R71C224KA01D
3 1 C5 CAP., C0G, 10pF, 25V, 5%, 0603 AVX, 06033A100JAT2A
4 1 C6 CAP., X7R, 22µF, 10V, 10%, 1206 MURATA, GRM31CR71A226KE15L
5 1 C7 CAP., X7R, 1.0µF, 25V, 10%, 0603 MURATA, GRM188R71E105KA12D
6 1 C8 CAP., X7R, 0.01µF, 16V, 10%, 0603 MURATA, GRM188R71C103KA01D
7 1 L1 IND., 3.3µH WURTH ELECTRONICS, 74438336033
8 1 R2 RES., CHIP, 18.2k, 1/10W, 1%, 0603 VISHAY, CRCW060318K2FKEA
9 1 R3 RES., CHIP, 49.9k, 1/10W, 1%, 0603 VISHAY, CRCW060349K9FKEA
10 2 R1, R4 RES., CHIP, 1M, 1/10W, 1%, 0603 VISHAY, CRCW06031M00FKEA
11 1 R5 RES., CHIP, 187k, 1/10W, 1%, 0603 VISHAY, CRCW0603187KFKEA
12 1 U1 IC, REGULATOR, MSE10 LINEAR TECH., LT8607EMSE#PBF
Additional Demo Board Circuit Components
1 1 C1 CAP., ALUM 22µF 63V SUN ELECT, 63CE22BS
2 2 C3, C10 CAP., X7R, 4.7µF, 50V, 10% 1206 MURATA, GRM31CR71H475K
3 1 C9 CAP., X7R, 4.7µF, 16V, 10%, 0805 MURATA, GRM21BR71C475K73L
4 1 C11 CAP., X7R, 1µF, 50V, 10%, 0805 MURATA, GRM21BR71H105KA12L
5 2 C12, C13 CAP., X7R, 0.1µF, 50V, 10%, 0603 MURATA, GRM188R71H104KA93D
6 1 FB1 FERRITE BEAD 0805 TDK, MPZ2012S331AT000
7 1 L2 RES., CHIP, 0Ω, 3/4W, 2010 VISHAY, CRCW20100000Z0EF
8 0 R6 (OPT.) RES., 0603
Hardware: For Demo Board Only
1 9 E1-E9 TESTPOINT, TURRET, 0.094" MILL-MAX, 2501-2-00-80-00-00-07-0
2 1 E10 (OPT.) TESTPOINT, TURRET, 0.094"
3 1 JP1 DOUBLE ROW HEADER 2 × 4 0.079" WURTH ELECTRONICS, 62000821121
4 1 XJP1 SHUNT, 0.079" CENTER WURTH ELECTRONICS, 60800213421
5 4 MH1-MH4 STAND-OFF, NYLON 0.50" TALL WURTH ELECTRONICS, 702935000

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DEMO MANUAL DC2565A
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
5
5
4
4
3
3
2
2
1
1
DD C C
B B
A A
ALL CAPACITORS ARE 0603.
NOTES: UNLESS OTHERWISE SPECIFIED
1. ALL RESISTORS ARE 0603.
SUNCON 63CE22BS
(2MHz)
SYNC SPREAD SPECTRUM PULSE SKIPPING BURST
VOUT
VCC
VCC
R2
18.2k
E6
EN/UV
E5
SYNC
E9
GND
L1
3.3µH
74438336033
+
C1 22µF 63V
R4
1.00M
C6
22µF 10V 1206
E7
TR/SS
C11 1µF
50V
0805
C8
0.01µF
C4
0.22µF
C10 4.7µF 50V 1206
R3 49.9k
E8 PG
C7
1µF
R6 (Opt)
E3
VOUT
5V /0.75A
JP1
1 2
3 5 7
4 6
8
E4
GND
L2
0 2010
R1 1.00M
R5 187k C5
10pF
E1
VEMI
5.5V - 42V
C3 4.7µF 50V 1206
C13 0.1µF 50V
C2 4.7µF 50V 1206
FB1
MPZ2012S331AT000
U1 LT8607EMSE
VIN
9
EN/UV
10
SYNC
5
VCC
3
TR/SS
7
RT
4
FB 6
PG 8
SW 2
BST 1
GND
11
C12 0.1µF 50V
C9 4.7µF 16V 0805
E2
GND
E10
VIN
5.5V - 42V

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DEMO MANUAL DC2565A
 LINEAR TECHNOLOGY CORPORATION 2017
LT 0517 • 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
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