DC2346A - Demo Manual

DEMO MANUAL DC2346A
LT8601
42V Triple Monolithic
Synchronous Step-Down Regulator
Description
Demonstration circuit 2346A is a triple power supply
featuring the LT®8601. LT8601 is a 42V triple monolithic
synchronous step-down regulator. The demo circuit is
designed for 5V, 3.3V, and 1.8V outputs from a nominal
12V input, with switching frequency set at 2MHz to avoid
audio band. The 1.8V converter is powered from the 3.3V
output, and the 5V, 3.3V are powered from a wide range of
6V to 24V, transient to 42V. The current capability is 2.5A
for the 3.3V output, 1.5A for the 5V output, and 1.8A for
the 1.8V output when running individually. Up to 1A load
current can be applied to all the channels simultaneously
without special cooling.
efficiency and external component size. Each output can
be independently disabled using its own TRKSS or RUN
pin and be placed in a low quiescent current shutdown
mode. Table 1 summarizes the performance of the demo
board at room temperature. The circuit can be easily modified for different applications. Figure 4 shows the typical
thermal performance of the circuit.
Individual soft-start, current limit, input voltage, power
good for each output simplify the complex design of quadoutput power converters. All regulators are synchronized to
a common external clock input or a resistor programmable
250kHz to 2.2MHz internal oscillator. At all frequencies,
a 180° phase shift is maintained between 1 and 2 channels, reducing the input peak current and voltage ripple.
Programmable frequency allows optimization between
The LT8601 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 2346A.
Performance Summary
The demo board has an EMI filter installed on the bottom
layer. The radiated EMI performance of the board is shown
on Figure 3. The limit in Figure 3 is CISPR Class 5, Peak.
It shows the circuit passes the CISPR Class 5, Peak test
with a wide margin.
Design files for this circuit board are available at
http://www.linear.com/demo/DC2346A
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
Table 1.
PARAMETER
CONDITIONS
Input Voltage Range, VIN
Maximum Transient VIN
Transient
Standby Current When Switching
IOUT1,2,3 = 0mA, VIN = 12V
MIN
TYP
MAX
6
12
24
42
60
UNITS
V
V
µA
Output Voltage VOUT1
VIN = 12V, IOUT1 = 1A
4.80
5
5.20
V
Output Voltage VOUT2
VIN = 12V, IOUT2 = 1A
3.17
3.3
3.43
V
Output Voltage VOUT3
IOUT3 = 1A
1.73
1.8
1.87
Maximum Output Current IOUT1
VIN = 12V, IOUT2,3 = 0A
1.5
A
Maximum Output Current IOUT2
VIN = 12V, IOUT1,3 = 0A
2.5
A
Maximum Output Current IOUT3
IOUT1,2 = 0A
1.8
A
Switching Frequency
VIN = 12V, IOUT1,2,3 = 1A
1.85
Efficiency, Channel 1
VIN = 12V, IOUT1 = 1A
91
%
Efficiency, Channel 2
VIN = 12V, IOUT2 = 1A
89
%
Efficiency, Channel 3
VIN = 12V, IOUT3 = 1A
90
%
2
2.15
V
MHz
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DEMO MANUAL DC2346A
Quick Start Procedure
Demo circuit 2346A is easy to set up to evaluate the
performance of the LT8601. Refer to Figure 1 for proper
equipment setup and follow the procedure below.
1.With power off, connect the input power supply to the
board through VIN and GND terminals on the top layer.
Connect the loads to the terminals VOUT1 and GND,
VOUT2 and GND, VOUT3 and GND on the board. The
default positions of the headers are given in Table 2.
Table 2. Default Positions of the Headers
NAME
POSITION
EN/UVLO
JP1
ON
TRKSS1
JP4
ON
TRKSS2
JP5
ON
RUN3
JP2
RUN
SYNC
JP7
BURST
2.Turn on the power at the input. Increase VIN to 12V.
NOTE: Make sure that the input voltage is always within
spec. Refer to data sheet on the Burst Mode® operation
in light load and high VIN condition.
3. Check for the proper output voltages. The output should
be regulated at 5V (±4%), 3.3V (±4%), 1.8V (±4%).
4.Once the proper output voltage is established, adjust
the input voltage and load currents within the operating range, and observe the output voltage regulation,
transient, ripple voltage, efficiency and other parameters.
NOTE: Refer to the thermal derating curves in LT8601
data sheet for high input voltage and/or high ambient
temperature operations.
NOTE: By default, SYNC is grounded, and the circuit
is set in low ripple Burst Mode operation. The circuit
can be set in pulse-skipping Mode, and it runs in full
frequency with lower load current. Refer to the data
sheet for details on the input voltage and load current
ranges that the circuit runs in full frequency. To synchronize to an external clock, apply the external clock
to the SYNC turret.
NOTE: When measuring the input or output voltage
ripples, care must be taken to avoid a long ground lead
on the oscilloscope probe. Measure the input or output
voltage ripple by touching the probe tip directly across
the VIN or VOUT capacitor terminals. See Figure 2 for
proper scope probe technique.
NOTE: Do not overload unless proper thermal cooling
method such as air flow or heat sink is applied.
NOTE: If there is no output, temporarily disconnect the
load to make sure that the load is not set too high, and
the headers of EN/UVLO, TRKSS1, TRKSS2, and RUN3
are set in right positions.
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DEMO MANUAL DC2346A
Quick Start Procedure
Figure 1. Proper Measurement Equipment Setup
VIN OR VOUT
GND
Figure 2. Proper Scope Probe Placement for Measuring Input or Output Ripple
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DEMO MANUAL DC2346A
Quick Start Procedure
Amplitude (dBuV/m)
Detector: Peak
Polarity: Horizontal
60
55
50
45
40
35
30
25
20
15
10
5
0
-5
-10
-15
Data
Class 5 Peak
0
100
200
300
400
500
600
700
800
900
1000
Frequency (MHz)
Amplitude (dBuV/m)
Detector: Peak
Polarity: Vertical
60
55
50
45
40
35
30
25
20
15
10
5
0
-5
-10
-15
Data
Class 5 Peak
0
100
200
300
400
500
600
700
800
900
1000
Frequency (MHz)
Figure 3. Radiated EMI Performance (Vertical/Horizontal), VIN = 14V, IOUT1,2,3 = 1A
(CISPR25 Radiated Emission Test with Class 5 Peak Limits)
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DEMO MANUAL DC2346A
Quick Start Procedure
A. VIN = 24V
B. VIN = 14V
Figure 4. Thermal Image Top View, IOUT1,2,3 = 1A, TA = 25°C, FSW = 2MHz
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DEMO MANUAL DC2346A
Parts List
ITEM
QTY
REFERENCE
PART DESCRIPTION
MANUFACTURER/PART NUMBER
Cap, 4.7µF X7R 50V 10% 1206
TDK C3216X7R1H475K
Required Circuit Components
1
1
CPVIN1
2
1
CPVIN2
Cap, 10µF X7R 50V 10% 1210
Murata GRM32ER71H106KA12L
3
1
CPVIN3
Cap, 4.7µF X7R 10V 10% 0805
Murata GRM21BR71A475KA73L
4
1
CVIN
Cap, 1µF X7R 50V 10% 0805
TDK C2012X7R1H105K
5
1
C1
Cap, 4.7µF X5R 10V 10% 0603
TDK C1608X5R1A475K
6
2
C2, C11
Cap, 0.1µF X5R 10V 10% 0402
AVX 0402ZD104KAT2A
7
1
C3
Cap, 4.7pF NPO 25V 10% 0603
AVX 06033A4R7KAT2A
8
4
C4, C15, C18, C35
Cap, 47µF X5R 10V 20% 1206
Murata GRM31CR61A476ME15L
9
3
C5, C16, C19
Cap, 0.1µF X7R 50V 10% 0603
Murata GRM188R71H104KA93D
10
1
C6
Cap, Alum 22µF 50V 10%
Sun Elect. 50CE22BSS
11
1
C14
Cap, 12pF NPO 25V 10% 0603
AVX 06033A120KAT2A
12
1
C17
Cap, 22pF NPO 25V 5% 0603
AVX 06033A220JAT2A
13
1
C27
Cap, 220pF X7R 25V 10% 0603
AVX 06033C221MAT2A
14
2
C29, C30
Cap, 10µF X5R 50V 10% 1206
TDK CGA5L3X5R1H106K160AB
15
2
C32, C33
Cap, 47nF X7R 25V 20% 0603
AVX 06033C473MAT2A
16
3
C36, C37, C39
Cap, 0.1µF X7R 50V 10% 0402
TDK CGA2B3X7R1H104K050BB
17
1
FB1
Ferrite Bead, 330Ω
TDK Corp. MPZ2012S331AT000
18
1
L1
Inductor, 3.3µH XAL5030
Coilcraft XAL5030-332MEC
19
1
L2
Inductor, 1.5µH XAL5030
Coilcraft XFL5015-152MEC
20
1
L3
Inductor, 1µH ±30% NPIS42LS
NIC Comp. Corp. NPIS42LS1R0YTRF
21
1
L5
Inductor, 0.22µH
Vishay IHLP-1212BZ-ER-R22M11
22
1
R1
Res, Chip 806k 0.06W 1% 0603
Vishay CRCW0603806KFKEA
23
2
R2, R5
Res, Chip 200k 0.06W 1% 0603
Vishay CRCW0603200KFKEA
24
1
R3
Res, Chip 464k 0.06W 1% 0603
Vishay CRCW0603464KFKEA
25
1
R4
Res, Chip 340k 0.06W 1% 0603
Vishay CRCW0603340KFKEA
26
3
R6, R7, R8
Res, Chip 19.1k 0.06W 1% 0603
Vishay CRCW060319K1FKEA
27
4
R10, R15, R19, R21
Res, Chip 100k 0.06W 1% 0603
Vishay CRCW0603100KFKEA
28
1
R11
Res, Chip 187k 0.06W 1% 0603
Vishay CRCW0603187KFKEA
29
1
R12
Res, Chip 150k 0.06W 1% 0603
Vishay CRCW0603150KFKEA
30
1
R18
Res, Chip 28.7k 0.06W 1% 0603
Vishay CRCW060328K7FKEA
31
1
U1
IC, Buck Regulator QFN(40) (UJ) 6MM × 6MM
Linear Technology Corporation LT8601EUJ#PBF
Additional Demo Board Circuit Components
1
0
R31 (Opt)
Res, 0603
Hardware: For Demo Board Only
1
0
TP1,TP2 (Opt)
Testpoint
2
5
XJP1, XJP2, XJP4, XJP5,
XJP7
Shunt, 2mm Ctrs
3
17
E1, E2, E3, E4, E5, E6, E7, TEST POINT, TURRET, 0.094" MTH HOLE
E8, E9, E11, E12, E15, E16,
E17, E18, E20, E21
Samtec 2SN-BK-G
Mill Max 2501-2-00-80-00-00-07-0
4
5
JP1, JP2, JP4, JP5, JP7
Headers, 3 Pins 2mm Ctrs
Samtec TMM-103-02-L-S
5
1
JP6
Jumper, 2 Pins 2mm Ctrs
Samtec TMM-102-02-L-S
dc2346af
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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.
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1. All Resistors 0603.
2. All Capacitors 0603.
See Demo Manual for details
on VOUT current capability.
THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND
SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS.
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SCALE = NONE
LINEAR TECHNOLOGY HAS MADE A BEST EFFORT TO DESIGN A
CIRCUIT THAT MEETS CUSTOMER-SUPPLIED SPECIFICATIONS;
HOWEVER, IT REMAINS THE CUSTOMER'S RESPONSIBILITY TO
PCB DES.
VERIFY PROPER AND RELIABLE OPERATION IN THE ACTUAL
APPLICATION. COMPONENT SUBSTITUTION AND PRINTED
APP ENG.
CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT
PERFORMANCE OR RELIABILITY. CONTACT LINEAR
TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE.
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DEMO MANUAL DC2346A
Schematic Diagram
dc2346af
7
DEMO MANUAL DC2346A
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
dc2346af
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