DC1992A - Demo Manual

DEMO MANUAL DC1992A
LT8620
65V, 2A Micropower Synchronous
Monolithic Step-Down Regulator
Description
Demonstration circuit 1992A is a 65V, 2A micropower
synchronous monolithic step-down regulator featuring
the LT®8620. The LT8620 is a compact, high efficiency,
high speed synchronous monolithic step-down switching
regulator that consumes only 2.5µA of quiescent current
when output is regulated at 5V. Top and bottom power
switches, compensation components and other necessary
circuits are inside of the LT8620 to minimize external
components and simplify design.
The SYNC pin on the demo board is grounded by default
for low ripple Burst Mode® operation. To synchronous
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 2V or INTVCC can
be applied to the SYNC turret pulse skipping operation.
Figure 1 shows the efficiency of the circuit at 12V input.
Performance Summary
The demo board has an EMI filter installed. The board and
the IC are designed to minimize conducted and radiated
EMI. The radiated EMI performances of the board are shown
on Figure 2 to Figure 4. The limits on those figures are
CISPR25, Class 5 peak limits. It shows the circuit passes
the test with a wide margin.
The LT8620 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 1992A.
Design files for this circuit board are available at
http://www.linear.com/demo/DC1992A
L, LT, LTC, LTM, Linear Technology, Burst Mode and the Linear logo are registered trademarks
of Linear Technology Corporation. All other trademarks are the property of their respective
owners.
Specifications are at TA = 25°C
SYMBOL
PARAMETER
VIN
Input Supply Range
CONDITIONS
MIN
5.5
VOUT
Output Voltage
4.8
IOUT
Maximum Output Current
fSW
Switching Frequency
EFE
Efficiency at DC
TYP
5
MAX
V
5.2
V
2
1.85
IOUT = 1A
UNITS
65
A
2
92
2.15
MHz
%
100
95
EFFICIECNY (%)
90
85
80
75
70
65
60
0
0.5
1.0
1.5
LOAD CURRENT (A)
2.0
dc1992a F01
Figure 1. LT8620 12VIN to 5VOUT Efficiency at 2MHz Switching Frequency
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DEMO MANUAL DC1992A
Description
Figure 2. 30MHz to 1GHz Radiated EMI Performance. VIN = 12V, VOUT = 5V, IOUT = 2A
Antenna Polarization: Horizontal; Switching Frequency: 2MHz
Figure 3. 30MHz to 1GHz Radiated EMI Performance. VIN = 12V, VOUT = 5V, IOUT = 2A
Antenna Polarization: Vertical; Switching Frequency: 2MHz
Figure 4. 150kHz to 30MHz Radiated EMI Performance. VIN = 12V, VOUT = 5V, IOUT = 2A
Antenna Polarization: Vertical; Switching Frequency: 2MHz
(In the Frequency Range Between 150kHz and 30MHz, Only Vertical Polarization Is Required)
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DEMO MANUAL DC1992A
Quick Start Procedure
Demonstration circuit 1992A is easy to set up to evaluate the performance of the LT8620. Refer to Figure 5 and
Figure 6 for proper measurement equipment setup and
follow the procedure below:
2.With power off, connect the load VOUT and GND.
1.With power off, connect the input power supply to VIN
and GND.
5.Carefully evaluate other design parameters as needed.
3.Check JP1 setting
4.Turn on the power at the input.
Figure 5. Proper Measurement Equipment Setup
Figure 6. Measure Output Ripple
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DEMO MANUAL DC1992A
Parts List
ITEM
QTY
REFERENCE
PART DESCRIPTION
MANUFACTURER/PART NUMBER
Required Circuit Components
1
1
C2
CAP., X7R, 2.2µF, 100V, 10%, 1206
MURATA, GRM31CR72A225K
2
1
C4
CAP., X7R, 0.1µF, 16V, 10%, 0402
MURATA, GRM155R71C104KA88D
3
1
C5
CAP., C0G, 10pF, 25V, 10%, 0603
AVX, 06033A100KAT2A
4
1
C6
CAP., X7R, 47µF, 10V, 10%, 1210
MURATA, GRM32ER71A476KE2015L
5
1
C7
CAP., X5R, 1.0µF, 10V, 10%, 0402
MURATA, GRM155R61A105K
6
1
C8
CAP., X7R, 0.1µF, 16V, 10%, 0603
MURATA, GRM188R71C104K
7
1
L1
IND, 2.2µH XFL4020
COILCRAFT, XFL4020-222MEC
8
1
R2
RES., CHIP, 18.2k, 1/10W, 1%, 0603
VISHAY, CRCW060318K2FKED
9
1
R3
RES., CHIP, 49.9k, 1/16W, 1%, 0603
VISHAY, CRCW060349K9FKED
10
2
R1, R4
RES., CHIP, 1M, 1/16W, 1%, 0603
VISHAY, CRCW06031M00FKED
11
1
R5
RES., CHIP, 243k, 1/16W, 1%, 0603
VISHAY, CRCW0603243KFKED
12
1
U1
IC, LT8620EMSE, MSE16
LINEAR TECH. CORP., LT8620EMSE#PBF
Additional Demo Board Circuit Components
1
1
C1
CAP., ALUM, 10µF, 100V
SUN ELECT, 100CE10BS
2
2
C3, C10
CAP., X7S, 4.7µF, 100V, 10%, 1210
TDK, C3225X7S2A475K
3
1
C9
CAP., X7R, 1.0µF, 16V, 10%, 0805
AVX, 0805YC105KAT2A
4
2
C11, C12
CAP., X7R, 0.1µF, 100V, 10%, 0603
MURATA, GRM188R72A104K
5
1
C13
CAP., X5R, 0.1µF, 100V, 10%, 0402
MURATA, GRM155R62A104K
6
1
FB1
FERRITE BEAD 0805
TDK, MPZ2012S221A
7
1
L2
IND, 4.7µH IHLP2020BZ-01
VISHAY, IHLP2020BZ-ER4R7M01
8
0
R6 (OPT)
RES., 0603
Hardware: For Demo Board Only
1
9
E1-E9
TESTPOINT, TURRET, 0.094" PBF
MILL-MAX, 2501-2-00-80-00-00-07-0
2
1
JP1
3 PIN 0.079" SINGLE ROW HEADER
SULLIN, 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)
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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.
A
B
C
GND
VIN
5.5V - 65V
E2
E1
5
TR/SS
GND
SYNC
EN/UV
C11
0.1uF
100V
C3
4.7uF
100V
1210
GND
SYNC
C10
4.7uF
100V
1210
JP1
L2
4.7uH
3
2
1
10uF
100V
SUNCON
100CE10BS
+ C1
1. ALL RESISTORS ARE 0603.
ALL CAPACITORS ARE 0603.
4
C7
1uF
0402
6.3V
C2
2.2uF
100V
1206
NOTES: UNLESS OTHERWISE SPECIFIED
E7
E9
E5
E6
C12
0.1uF
100V
FB1
4
C8
0.1uF
C13
0.1uF
100V
0402
R2
18.2k
(2MHz)
R6
OPT
R1
1M
3
8
7
3
2
13
1
4
6
5
3
GND
NC
RT
TR/SS
INTVCC
SYNC
EN/UV
VIN
VIN
U1
LT8620EMSE
GND
17
D
5
FB
PG
BIAS
SW
SW
SW
BST
16
15
14
11
10
9
12
2
2
R5
243k
C4
0.1uF
16V
0402
C5
49.9k
10pF
1Meg
R4
R3
XFL4020-222MEC
L1
2.2uH
C6
47uF
10V
1210
VOUT
1
C9
1uF
16V
0805
1
E8
E4
E3
PG
GND
VOUT
5V / 2A
A
B
C
D
DEMO MANUAL DC1992A
Schematic Diagram
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DEMO MANUAL DC1992A
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
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Linear Technology Corporation
LT 0614 • PRINTED IN USA
1630 McCarthy Blvd., Milpitas, CA 95035-7417
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●
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