Linear Technology LT8609 User manual

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dc2195bf
DEMO MANUAL DC2195B
DESCRIPTION
LT8609/LT8609A
42V, 2A Micropower Synchronous
Step-Down Regulator
Demonstration circuit 2195B is a 42V, 2A micropower
synchronous step-down regulator featuring the LT8609/
LT8609A. There are two assembly versions. DC2195B-A
is for the LT8609A and DC2195B-B is for the LT8609.
The difference is the LT8609A has slower edge speeds
for improved EMI at the expense of a small efficiency loss.
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 industrial sup-
plies. The LT8609/LT8609A 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,compensationcomponentsandother necessary
circuits are inside of the LT8609 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
SKIPPINGpositioncanchangethe operationmodeto pulse-
skipping operation. Once JP1 is on SPREAD SPECTRUM
position, VCC is applied to the SYNC pin for low EMI spread 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
spectrum operation. To synchronize 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.
The demo board has an EMI filter installed. Under spread
spectrum operation, the radiated EMI performances of
the board (with EMI filter) are shown in Figures 2 and
3. The red lines in Figures 2 and 3 are CISPR25 Class 5
peak limit. To use the EMI filter, the input should be tied
to VEMI, not VIN. An inductor 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.
This board is suitable for a wide range of automotive,
telecom,industrial, andothergeneral purposeapplications.
The LT8609/LT8609Adata sheet gives a complete descrip-
tion of the part, operation and application information. The
data sheet must be read in conjunction with this demo
manual for DC2195B.
Design files for this circuit board are available at
http://www.linear.com/demo/DC2195B
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 2 A
fSW Switching Frequency 1.85 2 2.15 MHz
EFE (LT8609A) Efficiency for DC2195B-A VIN = 12V, IOUT = 1A 92.1 %
EFE (LT8609) Efficiency for DC2195B-B VIN = 12V, IOUT = 1A 92.9 %
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DEMO MANUAL DC2195B
QUICK START PROCEDURE
DC2195B is easy to set up to evaluate the performance of
theLT8609/LT8609A.Refer toFigure4 for propermeasure-
ment 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/2A.
Then turn off the supply.
2. Withpower off, connect thesupply to the input terminals
VEMI 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 2A at 5V to the output
terminals VOUT 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 DC2195B’s output current.
b. A voltmeter can be placed across the output terminals
in orderto get an accurateoutput 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 again established,
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 terminal
when SYNC function is used (JP1 on the SYNC posi-
tion). Please ensure that the chosen RTsets the LT8609/
LT8609A switching frequency to equal or below the
lowest SYNC frequency. See the data sheet section,
“Synchronization.”
Figure 1. Efficiency vs Load Current at 12V Input 2MHz Switching Frequency
IOUT (A)
0
EFFICIENCY (%)
100
90
70
80
60
95
75
55
85
65
50 1.5
DC2195 F01
210.5
LT8609A
LT8609
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DEMO MANUAL DC2195B
QUICK START PROCEDURE
Figure 2. LT8609A Demo Circuit EMI Performance in CISPR25 Radiated Emission Test (VIN = 14V, VOUT =
5V, IOUT = 2A, 2MHz Switching Frequency)
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DEMO MANUAL DC2195B
QUICK START PROCEDURE
Figure 3. LT8609 Demo Circuit EMI Performance in CISPR25 Radiated Emission Test (VIN = 14V, VOUT = 5V,
IOUT = 2A, 2MHz Switching Frequency)
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DEMO MANUAL DC2195B
QUICK START PROCEDURE
Figure 4. Proper Measurement Equipment Setup
Figure 5. Measuring Output Ripple
V
OUT
GND
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DEMO MANUAL DC2195B
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 AVX, 0603YC224KAT2A
3 1 C5 CAP., C0G, 10pF, 25V, 5%, 0603 AVX, 06033A100JAT2A
4 1 C6 CAP., X7R, 47µF, 10V, 10%, 1210 MURATA, GRM32ER71A476KE20L
5 1 C7 CAP., X7R, 1.0µF, 25V, 10%, 0603 MURATA, GRM188R71E105KA12D
6 1 C8 CAP., X7R, 0.01µF, 16V, 10%, 0603 AVX, 0603YC103KAT2A
7 1 L1 IND., 2.2µH COILCRAFT, XFL4020-222MEC
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
DC2195B-A Version Specific Components
1 1 U1 IC, REGULATOR, MSE10 LINEAR TECH., LT8609AEMSE#PBF
DC2195B-B Version Specific Components
1 1 U1 IC, REGULATOR, MSE10 LINEAR TECH., LT8609EMSE#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 TDK, C2012X7R1H105K
5 2 C12, C13 CAP., X7R, 0.1µF, 50V, 10%, 0603 MURATA, GRM188R71H104KA93D
6 1 FB1 FERRITE BEAD 0805 TDK, MPZ2012S221A
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" SULLINS NRPN042PAEN-RC
4 1 XJP1 SHUNT, 0.079" CENTER SAMTEC 2SN-BK-G
5 4 MH1-MH4 STAND-OFF, NYLON 0.50" TALL KEYSTONE, 8833 (SNAP ON)
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DEMO MANUAL DC2195B
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
FOR ASSEMBLY
VERSIONS
*
U1
DC2195B-A LT8609AEMSE DC2195B-B LT8609EMSE
VOUT
VCC
VCC
R2
18.2k
E6
EN/UV
E5
SYNC
E9
GND
L1
2.2µH
XFL4020-222MEC
+
C1 22µF 63V
R4
1.00M
C6
47µF 10V 1210
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 / 2A
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
U1 *
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 DC2195B
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
[phone] ●FAX: [phone] ●www.linear.com
 LINEAR TECHNOLOGY CORPORATION 2016
LT 0216 REV B • 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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