Linear Technology LT8610A Quick setup guide

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dc2139af
DEMO MANUAL DC2139A
Description
LT8610A
42V, 3.5A Micropower
Synchronous Step-Down Regulator
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
thatconsumesonly2.5µAofquiescentcurrentwhenoutput
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.
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.
Figure 2 shows the thermal performance of the circuit.
When running at input voltage greater than 30V, 3.5A
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
output current and 2MHz switching frequency, the tem-
perature 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 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.
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.
Design files for this circuit board are available at
http://www.linear.com/demo
Specifications are at TA= 25°C
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
VIN* Input Supply Range 5.5 42 V
VOUT Output Voltage 4.8 5 5.2 V
IOUT Maximum Output Current 3.5 A
FSW Switching Frequency 1.85 2 2.15 MHz
EFE Efficiency at DC IOUT = 1A 92 %
*Refer to Figure 2 to determine the maximum input voltage. If IC temperature exceeds target, reduce input voltage, output current or switching frequency.
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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.
Figure 1. LT8610A 12VIN to 5VOUT Efficiency at 2MHz
Switching Frequency
Figure 2. LT8610A Case Temperature Rise, VOUT = 5V, TA= 25°C
LOAD CURRENT (A)
0
EFFICIENCY (%)
100
95
85
75
90
80
70
65
60 21 3
DC2139a F01
INPUT VOLTAGE (V)
8
CASE TEMPERATURE RISE (°C)
140
120
80
40
100
60
20
02416 32
DC2139a F02
362012 28
TA= 25°C
fSW = 2MHz
ILOAD = 3.5A
fSW = 2MHz
ILOAD = 2.5A
fSW = 1MHz
ILOAD = 3.5A
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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.
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DEMO MANUAL DC2139A
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)
Quick start proceDure
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DEMO MANUAL DC2139A
Figure 6. Proper Measurement Equipment Setup
Figure 7. Measure Output Ripple
Quick start proceDure
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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)
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DEMO MANUAL DC2139A
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
D D C C B B A A
ALL CAPACITORS ARE 0402.
NOTES: UNLESS OTHERWISE SPECIFIED 1. ALL RESISTORS ARE 0402.
SUNCON 63CE22BS
(2MHz)
*
*
REFER TO THE DEMO MANUAL FOR VIN RANGE.
*
VOUT
R6 OPT R6 OPT
C15 0.1uF
50V
C15 0.1uF
50V
R5 243k R5 243k
E2
GND E2 GND
E9
GND
E9
GND
E6
EN/UV
E6
EN/UV
R1 1M R1 1M
C2 4.7uF
50V
1206 C2 4.7uF
50V
1206
U1
LT8610AEMSE
U1
LT8610AEMSE
VIN
5
VIN
6
EN/UV
4
SYNC
1
INTVCC
13
TR/SS
2
RT
3
NC
7
GND
8
FB 16
PG 15
BIAS 14
SW 11 SW 10 SW 9
BST 12
GND
17
C12 0.1uF
50V
C12 0.1uF
50V
E10
VIN
5.5V - 42V E10
VIN
5.5V - 42V
C17 0.1uF
50V
C17 0.1uF
50V
JP1
GND SYNC
JP1
GND SYNC
1 3 2
C18 4.7uF
50V
1206 C18 4.7uF
50V
1206
C7
1uF 10V
C7
1uF 10V
E5
SYNC
E5
SYNC
C11 0.1uF
50V
C11 0.1uF
50V
L1
2.2uH
XAL5030-222MEC
L1
2.2uH
XAL5030-222MEC
R2
18.2k 0603
R2
18.2k 0603
C19 4.7uF
50V
1206 C19 4.7uF
50V
1206
FB1FB1
E7
TR/SS
E7
TR/SS
C9 1uF 0805 16V C9 1uF 0805 16V
R4 1Meg R4 1Meg
C8 0.1uF C8 0.1uF
L2
4.7uH
L2
4.7uH
C5
4.7pF
C5
4.7pF
C20 4.7uF
50V
1206 C20 4.7uF
50V
1206
C16 0.1uF
50V
C16 0.1uF
50V
C6 47uF 10V 1210 C6 47uF 10V 1210
C3 4.7uF
50V
1206 C3 4.7uF
50V
1206
E8 PG E8 PG
+
C1 22uF 63V
+
C1 22uF 63V
R3 49.9k R3 49.9k
E4 GND E4 GND
C10 4.7uF
50V
1206 C10 4.7uF
50V
1206
C13 0.1uF
50V
C13 0.1uF
50V
C4 0.1uF 10V C4 0.1uF 10V
E3
VOUT
5V / 3.5A
E3
VOUT
5V / 3.5A
E1
VEMI
5.5V - 42V E1
VEMI
5.5V - 42V
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DEMO MANUAL DC2139A
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
[phone] ●FAX: [phone] ●www.linear.com
 LINEAR TECHNOLOGY CORPORATION 2014
LT 0614 • PRINTED IN USA
DEMONSTRATION BOARD IMPORTANT NOTICE
Linear Technology Corporation (LT C ) 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 LT C 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 LT C 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. LT C assumes no liability for applications assistance,
customer product design, software performance, or infringement of patents or any other intellectual property rights of any kind.
LT C 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 LT C applica-
tion engineer.
Mailing Address:
Linear Technology
1630 McCarthy Blvd.
Milpitas, CA 95035
Copyright © 2004, Linear Technology Corporation
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