DC2139A - Demo Manual

DEMO MANUAL DC2139A
LT8610A
42V, 3.5A Micropower
Synchronous Step-Down Regulator
Description
Demonstration circuit 2139A is a 42V, 3.5A micropower
synchronous step-down regulator featuring the LT®8610A.
The LT8610A 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 and is unloaded. The 2139A uses two
input ceramic capacitors in series to improve reliability in
case of an input capacitor short failure. Top and bottom
power switches, compensation components and other
necessary circuits are inside of the LT8610A to minimize
external components and simplify design.
output current and 2MHz switching frequency, the temperature rise will be significant. Either reducing the input
voltage, the output current or the switching frequency will
bring the temperature down to acceptable level without
external cooling.
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 2V or INTVCC can be applied
to the SYNC turret for pulse-skipping operation. Figure 1
shows the efficiency of the circuit at 12V input.
The LT8610A 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 2139A.
Figure 2 shows the thermal performance of the circuit.
When running at input voltage greater than 30V, 3.5A
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 in Figure 3 to Figure 5. The limits on those figures
are CISPR25, Class 5 peak limits. The circuit passes the
test with a wide margin.
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.
Performance Summary
Specifications are at TA = 25°C
SYMBOL
PARAMETER
CONDITIONS
VIN*
Input Supply Range
5.5
VOUT
Output Voltage
4.8
IOUT
Maximum Output Current
3.5
FSW
Switching Frequency
EFE
Efficiency at DC
MIN
1.85
IOUT = 1A
TYP
MAX
UNITS
42
V
5
5.2
V
A
2
92
2.15
MHz
%
*Refer to Figure 2 to determine the maximum input voltage. If IC temperature exceeds target, reduce input voltage, output current or switching frequency.
dc2139af
1
DEMO MANUAL DC2139A
Quick Start Procedure
Demonstration circuit 2139A is easy to set up to evaluate
the performance of the LT8610A. Refer to Figure 6 and
Figure 7 for proper measurement equipment setup and
follow the procedure below:
1.With power off, connect the input power supply to VIN
and GND. When evaluating EMI performance, input
power supply should be connected between VEMI and
GND.
2.With power off, connect the load VOUT and GND.
3.Check JP1 setting
4.Turn on the power at the input.
5.Carefully evaluate other design parameters as needed.
100
95
EFFICIENCY (%)
90
85
80
75
70
65
60
0
1
2
LOAD CURRENT (A)
3
DC2139a F01
Figure 1. LT8610A 12VIN to 5VOUT Efficiency at 2MHz
Switching Frequency
CASE TEMPERATURE RISE (°C)
140
TA = 25°C
fSW = 2MHz
ILOAD = 3.5A
120
100
80
60
40
20
0
fSW = 2MHz
ILOAD = 2.5A
8
12
fSW = 1MHz
ILOAD = 3.5A
20
28
16
24
INPUT VOLTAGE (V)
32
36
DC2139a F02
Figure 2. LT8610A Case Temperature Rise, VOUT = 5V, TA = 25°C
dc2139af
2
DEMO MANUAL DC2139A
Quick Start Procedure
Figure 3. 30MHz to 1GHz Radiated EMI Performance. VIN = 12V, VOUT = 5V, IOUT = 2.5A
Antenna Polarization: Horizontal; Switching Frequency: 2MHz.
Figure 4. 30MHz to 1GHz Radiated EMI Performance. VIN = 12V, VOUT = 5V, IOUT = 2.5A
Antenna Polarization: Vertical; Switching Frequency: 2MHz.
dc2139af
3
DEMO MANUAL DC2139A
Quick Start Procedure
Figure 5. 150kHz to 30MHz Radiated EMI Performance. VIN = 12V, VOUT = 5V, IOUT = 2.5A
Antenna Polarization: Vertical; Switching Frequency: 2MHz.
(In the frequency range between 150kHz and 30MHz, only vertical polarization is required)
dc2139af
4
DEMO MANUAL DC2139A
Quick Start Procedure
Figure 6. Proper Measurement Equipment Setup
Figure 7. Measure Output Ripple
dc2139af
5
DEMO MANUAL DC2139A
Parts List
ITEM
QTY
REFERENCE
PART DESCRIPTION
MANUFACTURER/PART NUMBER
Required Circuit Components
1
2
C2, C19
CAP, X7R, 4.7µF, 50V, 10%, 1206
MURATA, GRM31CR71H475KA12L
2
2
C4, C8
CAP, X7R, 0.1µF, 16V, 10%, 0402
MURATA, GRM155R71C104KA88D
3
1
C5
CAP, C0G, 4.7pF, 25V, ±0.1pF, 0402
MURATA, GRM1555C1E4R7BZ01D
4
1
C6
CAP, X7R, 47µF, 10V, 10%, 1210
MURATA, GRM32ER71A476KE15L
5
1
C7
CAP, X5R, 1µF, 10V, 10%, 0402
MURATA, GRM155R61A105K
6
1
L1
IND, 2.2UH
COILCRAFT, XAL5030-222MEC
7
2
R1, R4
RES, CHIP, 1M, 1/16W, 1% 0402
NIC, NRC04F1004TRF
8
1
R2
RES, CHIP, 18.2k, 1/10W, 1% 0603
VISHAY, CRCW060318K2FKED
9
1
R3
RES, CHIP, 49.9k, 1/16W, 1% 0402
VISHAY, CRCW040249K9FKED
10
1
R5
RES, CHIP, 243k, 1/16W, 1% 0402
VISHAY, CRCW0402243KFKED
11
1
U1
IC, LT8610AEMSE MSE16
LINEAR TECHNOLOGY CORPORATION, LT8610AEMSE#PBF
Additional Demo Board Circuit Components
1
1
C1
CAP, ALUM, 22µF, 63V
SUN ELECT, 63CE22BS
2
4
C3, C10, C18, C20
CAP, X7R, 4.7µF, 50V, 10%, 1206
MURATA, GRM31CR71H475KA12L
3
1
C9
CAP, X7R, 1µF, 16V, 10%, 0805
AVX, 0805YC105KAT2A
4
6
C11, C12, C13,
C15, C16, C17
CAP, X7R, 0.1µF, 50V, 10%, 0402
TDK, C1005X7R1H104K
5
1
FB1
FERRITE BEAD 0805
TDK, MPZ2012S101AT
6
1
L2
IND 4.7UH
VISHAY, IHLP2020BZ-ER4R7M01
7
0
R6
RES, OPT, 0402
OPT
Hardware: For Demo Board Only
1
10
E1 TO E10
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
SAMTEC, TMM103-02-L-S
3
1
XJP1
SHUNT, 0.079" CENTER
SAMTEC, 2SN-BK-G
4
4
MH1 TO MH4
STAND-OFF, NYLON 0.50" TALL
KEYSTONE, 8833(SNAP ON)
dc2139af
6
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
D
*
GND
*
VEMI
5.5V - 42V
E2
E1
E10
5
E7
E9
E5
GND
JP1
C18
4.7uF
50V
1206
C20
4.7uF
50V
1206
SYNC
C10
4.7uF
50V
1206
C3
4.7uF
50V
1206
L2
4.7uH
3
2
1
22uF
63V
SUNCON
63CE22BS
+ C1
4
* REFER TO THE DEMO MANUAL FOR VIN RANGE.
1. ALL RESISTORS ARE 0402.
ALL CAPACITORS ARE 0402.
NOTES: UNLESS OTHERWISE SPECIFIED
TR/SS
GND
SYNC
E6
C16
0.1uF
50V
C15
0.1uF
50V
EN/UV
C12
0.1uF
50V
C11
0.1uF
50V
FB1
4
C7
1uF
10V
C19
4.7uF
50V
1206
C2
4.7uF
50V
1206
C8
0.1uF
C17
0.1uF
50V
C13
0.1uF
50V
R2
18.2k
(2MHz)
0603
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
FB
PG
BIAS
SW
SW
SW
BST
U1
LT8610AEMSE
GND
17
VIN
5.5V - 42V
5
16
15
14
11
10
9
12
2
R5
243k
C4
0.1uF
10V
2
C5
49.9k
R3
4.7pF
1Meg
R4
XAL5030-222MEC
L1
2.2uH
C6
47uF
10V
1210
VOUT
1
1
C9
1uF
16V
0805
E8
E4
E3
PG
GND
VOUT
5V / 3.5A
A
B
C
D
DEMO MANUAL DC2139A
Schematic Diagram
dc2139af
7
DEMO MANUAL DC2139A
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
dc2139af
8
Linear Technology Corporation
LT 0614 • PRINTED IN USA
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900
●
FAX: (408) 434-0507 ● www.linear.com
 LINEAR TECHNOLOGY CORPORATION 2014
Similar pages