DC2067A - Demo Manual

DEMO MANUAL DC2067A
LT8710
Synchronous Inverting
DC/DC Converter
DESCRIPTION
Demonstration circuit 2067A is a synchronous inverting
converter (CUK topology) featuring the LT®8710 switching
controller. It regulates a –5V, 6A output from a 4.5V to 28V
input source, and operates at 300kHz switching frequency.
The LT8710 features simple negative or positive output
voltage programming. The DC2067 programs a –5V output
with a single resistor.
At light load, the LT8710 can operate at forced continuous
conduction mode (CCM) or discontinuous conduction
mode (DCM), set by its MODE pin. The DC2067A selects
DCM, which maintains high efficiency at light load.
The DC2067A can be modified from a CUK converter to
other topology. Synchronous SEPIC and synchronous
BOOST schematics are provided in the data sheet. Please
consult the factory or LT8710 data sheet for details regarding how to customize the DC2067A or how to design
different topologies for custom specifications.
There are some optional components on the DC2067A to
facilitate modifications; see Full Schematic Diagram for
component designation.
2. The optional RC snubber (R4, C1) across the flying
capacitor could help to damp the feedback control loop
for some applications using two separate inductors.
3. The optional input capacitors (CIN5, CIN6) or output
capacitors (CO5, CO6) could be installed to reduce
voltage ripple for some low voltage and/or high current
applications.
4. The optional RC (R24, C19) snubber could be installed to
damp the switch node spike and reduce the EMI noise.
5. The optional current sensing resistor filters (located near
CSP and CSN pins, ISP and ISN pins) might be required
in certain applications with excessive switching noise.
The LT8710 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 2067A.
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.
1. The optional N-FET (MN2) or P-FET (MP2) could be
added to increase power delivery and improve thermal
dissipation.
PERFORMANCE SUMMARY
PARAMETER
Specifications are at TA = 25°C
CONDITIONS
MIN
TYP
4.5
12
28
V
VIN = 4.5V to 28V, IOUT = 0A to 6A
–4.85
–5
–5.15
V
Input Voltage
Output Voltage
Maximum Output Current
Output Voltage Ripple
6
VIN = 4.5V to 28V, IOUT = 6A (20MHz BW)
Typical Switching Frequency
Efficiency
MAX
UNITS
A
25
mVP-P
300
kHz
VIN = 5V, IOUT = 6A
85
%
VIN = 12V, IOUT = 6A
88.5
%
VIN = 24V, IOUT = 6A
85.5
%
dc2067af
1
DEMO MANUAL DC2067A
QUICK START PROCEDURE
Demonstration circuit 2067A is easy to set up to evaluate the performance of the LT8710. Refer to Figure 1 for
proper measurement equipment setup and follow the
procedure below:
1.With the power off, connect the input power supply to
the board through VIN and PGND terminals. Connect
the load to the terminals VOUT and PGND on the board.
Make sure that the input power supply has sufficient
current rating at minimum input voltage for the required
output load.
2.Turn on the power at the input.
Note: Make sure that the input voltage does not exceed 28V.
3. Check for the proper output voltages. The output should
be regulated at –5.0V (±3%).
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
and PGND, or VOUT and PGND terminals. See Figure 2
for proper scope probe technique.
5.The DC2067A is equipped with an output capacitor
CO1 (270µF) that approximates typical system rail
capacitance. If the system board already has capacitance of similar value, CO1 can be removed. The input
capacitor CIN1 is used to help with filtering when the
board is connected to lab power supply with long leads.
The capacitor CIN1 can be removed if the input power
source is close and has low source impedance.
If there is no output, temporarily disconnect the load
to make sure that the load is not set too high.
4.Once the proper output voltage is established, adjust
the input voltage and load current within the operating
range and observe the output voltage regulation, ripple
voltage, efficiency and other parameters.
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2
DEMO MANUAL DC2067A
QUICK START PROCEDURE
Figure 1. Proper Measurement Equipment Setup
INPUT OR OUTPUT CAPACITOR
Figure 2. Proper Scope Probe Placement for Measuring Input or Output Ripple
–5VOUT Efficiency vs Load Current
95
90
EFFICIENCY (%)
85
80
75
70
65
60
55
50
5VIN
12VIN
24VIN
0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6
LOAD CURRENT (A)
Figure 3. Typical Efficiency Curve
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3
DEMO MANUAL DC2067A
QUICK START PROCEDURE
N-FET Temperature Rise vs Input Voltage
80
TEMPERATURE RISE (°C)
70
60
50
40
30
20
6AOUT
5AOUT
4AOUT
10
0
4.5
6
20
16
12
INPUT VOLTAGE (V)
9
24
28
Figure 4. N-FET (MN1) Temperature Rise vs Input Voltage
VOUT
20mV/DIV
2µs/DIV
Figure 5. Output Voltage Ripple at 12VIN and 6AOUT, 20MHz Bandwidth
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4
DEMO MANUAL DC2067A
PARTS LIST
ITEM
QTY REFERENCE
Required Circuit Components
1
6
C2, C3, C4, CIN2, CIN3, CIN4
2
1
C5
3
2
C11, C14
4
1
C13
5
1
C15
6
1
C16
7
1
C17
8
1
C18
9
1
CIN1
10
1
CO1
11
3
CO2, CO3, CO4
12
1
D1
13
1
D2
14
1
L1
15
1
MN1
16
1
MP1
17
1
R1
1
R3
18
19
8
R5, R6, R7, R9 ,R12, R15, R16, R18
20
1
R5, R6, R7, R9, R12, R15, R16, R19
21
1
R13
22
1
R17
23
2
R19, R23
24
1
R20
25
1
R21
26
1
R22
27
1
U1
28
1
Additional Demo Board Circuit Components
1
0
C1 (OPT)
2
0
C20, CIN5, CIN6, CO5, CO6 (OPT)
3
0
C6, C7, C8, C9, C10 (OPT)
4
0
C12 (OPT)
5
0
C19 (OPT)
6
0
MN2 (OPT)
7
0
MP2 (OPT)
8
0
R2 (OPT)
9
0
R4, R24 (OPT)
10
0
R10, R11, R14 (OPT)
Hardware-For Demo Board Only
1
14
E1-E14
2
1
JP1
3
1
XJP1
4
4
MH1-MH4
PART DESCRIPTION
MANUFACTURER/PART NUMBER
CAP., X7R, 10µF, 50V, 10% 1210
CAP., X7R, 0.47µF, 16V, 10% 0805
CAP., X7R, 2.2µF, 16V, 10%, 0805
CAP., X7R, 4.7µF, 50V, 10%, 1206
CAP., X7R, 4.7nF, 16V, 10%, 0603
CAP., C0G, 100pF, 50V, 5%, 0603
CAP., X7R, 470nF, 16V, 10%, 0603
CAP., X7R, 47nF, 16V, 10%, 0603
ALUMINUM CAP., 330µF, 35V,
OS-CON, 270µF, 10V, E7 SIZE
CAP., X5R, 100µF, 6.3V, 20% 1210
DIODE, PMEG4030EP, SOD128
DIODE, SCHOTTKY 30V 500MA SOD323F
IND, 2.2µH
N-CH FET, POWERPAK SO-8
P-CH FET, DPAK
RES., SENSE, 0.002Ω, 1W, 1% RL3720W
RES., SENSE, 0.006Ω, 1W, 1% RL3720W
Res., Chip, 0Ω, 0.1W, 0603
Res., Chip, 499Ω, 0.1W, 1%, 0603
Res., Chip, 60.4k, 0.1W, 1%, 0603
Res., Chip, 12.7k, 0.1W, 1%, 0603
Res., Chip, 100k, 0.1W, 1%, 0603
Res., Chip, 10k, 0.1W, 1%, 0603
Res., Chip, 118k, 0.1W, 1%, 0603
Res., Chip, 12.1k, 0.1W, 1%, 0603
IC, DC/DC CONVERTER, TSSOP-20
FAB, PRINTED CIRCUIT BOARD
MURATA, GRM32ER71H106KA12L
MURATA, GRM21BR71C474KA01L
MURATA, GRM21BR71C225KA12L
TDK, C3216X7R1H475K
MURATA, GRM188R71C472A01D
TDK, C1608C0G1H101J
MURATA, GRM188R71C474KA88D
TDK, C1608X7R1C473K
NIPPON, EMZA350ADA331MJA0G
SANYO/PANASONIC, 10SVPC270M
MURATA, GRM32ER60J107ME20L
NXP, PMEG4030EP
NXP, PMEG3005EJ+115
WÜRTH, 74485540220
FAIRCHILD, FDMS86500L
FAIRCHILD, FDD4141
SUSUMU, RL3720WT-R002-F
SUSUMU, RL3720WT-R006-F
VISHAY, CRCW06030000Z0EA
VISHAY, CRCW0603499RFKEA
VISHAY, CRCW060360K4FKEA
VISHAY, CRCW060312K7FKEA
VISHAY, CRCW0603100KFKEA
VISHAY, CRCW060310K0FKEA
VISHAY, CRCW0603118KFKEA
VISHAY, CRCW060312K1FKEA
LINEAR TECH., LT8710EFE#PBF
DEMO CIRCUIT 2067A REV 4
CAP., 2220
CAP., 1210
CAP., 0603
CAP., 1206
CAP., 0805
N-CH FET, POWERPAK SO-8
P-CH FET, DPAK
RES., SENSE, RL3720W
RES., 1210
RES., 0603
TESTPOINT, TURRET, 0.094" PBF
3-PIN 0.079 SINGLE ROW HEADER
SHUNT, 0.079" CENTER
STAND-OFF, NYLON 0.50"
MILL-MAX, 2501-2-00-80-00-00-07-0
SULLINS, NRPN031PAEN-RC
SAMTEC, 2SN-BK-G
KEYSTONE, 8833(SNAP ON)
dc2067af
5
SYNC
AGND
EN/FBIN
PGND
VIN
4.5V - 28V
E11
E10
E9
E4
E3
E2
E1
5
SYNC
CIN2
10uF
50V
1210
CIN3
10uF
50V
1210
CIN4
10uF
50V
1210
MN1
FDMS86500L
R1
0.002
RL3720W
CCM
DCM
4
JP1
MODE
3
INTVCC
1. ALL RESISTORS ARE 0603.
ALL SMD CAPACITORS ARE 0603.
4
C14
2.2uF
0805
R17
12.7K
2
BG
MP1
FDD4141
4
12
16
13
14
15
INTVCC
EN/FBIN
VIN
CSN
CSP
C5
0.47uF
0805
R8
499
3
D1
PMEG4030EP
U1
LT8710EFE
VIN
1
R20
10K
10uF
50V
C4
1210
C13
4.7uF
50V
1206
50V
C3
1210
1210
NOTE: UNLESS OTHERWISE SPECIFIED
EN/FBIN
330uF
35V
+ CIN1
VIN
L1B
2.2uH
74485540220
2
3
10uF
50V
10uF
3
4
VC
FLAG
INTVEE
BIAS
FBX
ISN
RL3720W
R3 0.006
R21
C17 118k
470nF
R23
100K
3
L1A
2.2uH
74485540220
1
BIAS
INTVEE
FLAG
VC
8
9
4
2
R22
12.1K
C15
4.7nF
FBX
1
C18
47nF
IMON
A
B
C
D
8
7
6
5
1
2
3
C2
1
BG
11
MODE
17
4
3
SS
SYNC
19
1
2
10
TG
7
ISP
RT
18
RT
SS
ISP
6
PMEG3005EJ
ISN
6
D2
20
GND
21
GND
5
IMON
C16
100pF
C11
2.2uF
0805
R13
60.4k
2
2
R19
100K
VOUT
CO4
100uF
6.3V
1210
CO3
100uF
6.3V
1210
1
IMON
INTVCC
CO2
100uF
6.3V
1210
1
+
5
E14
E13
E12
E8
E7
E6
CO1
270uF
10V
E5
FLAG
IMON
INTVCC
PGND
VOUT
-5V , 6A
A
B
C
D
DEMO MANUAL DC2067A
SIMPLE SCHEMATIC DIAGRAM
dc2067af
SYNC
AGND
EN/FBIN
PGND
VIN
4.5V - 28V
E11
E10
E9
E4
E3
E2
E1
5
SYNC
CIN2
10uF
50V
1210
CIN3
10uF
50V
1210
CIN4
10uF
50V
1210
MN2
OPT
CIN6
OPT
1210
R1
0.002
RL3720W
4 NG
MN1
FDMS86500L
CIN5
OPT
1210
0
R15
0
R7
CCM
JP1
MODE
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.
1. ALL RESISTORS ARE 0603.
ALL SMD CAPACITORS ARE 0603.
4
C14
2.2uF
0805
R17
12.7K
INTVCC
3
BG
MP1
FDD4141
4
4
12
16
13
14
15
PG
INTVCC
EN/FBIN
VIN
CSN
CSP
R23
100K
3
1
4
C17
470nF
R21
118k
R2
OPT
VC
FLAG
INTVEE
BIAS
INTVEE
FLAG
VC
9
4
2
C18
47nF
BIAS
R22
12.1K
C16
100pF
0
C11
2.2uF
0805
C8
OPT
60.4k
R18
C15
4.7nF
FBX
1
0
R12
R13
0.006
R11
OPT
8
ISN
C6
OPT
R10
OPT
R3
RL3720W
RL3720W
FBX
C7
OPT
R9
0
74485540220
L1A
2.2uH
D2
PMEG3005EJ
C5
0.47uF
0805
R5
0
3
MP2
OPT
R8
499
3
3
D1
PMEG4030EP
U1
LT8710EFE
VIN
2
C13
4.7uF
50V
1206
0
1
R20
10K
C10
OPT
NG
R6
OPT
C20
1210
R24
OPT
1210
DCM
C9
OPT
4
10uF
50V
C4
1210
C19
OPT
0805
50V
NOTE: UNLESS OTHERWISE SPECIFIED
EN/FBIN
330uF
35V
+ CIN1
VIN
L1B
2.2uH
74485540220
2
3
10uF
50V
10uF
OPT
2220
C1
C3
1210
1210
C2
OPT
1210
R4
IMON
A
B
C
D
8
7
6
5
1
2
3
8
7
6
5
1
2
3
PG 1
1
BG
11
MODE
17
4
3
SS
SYNC
19
1
2
Q2-G
10
TG
SS
7
ISP
RT
18
RT
6
ISN
ISP
20
GND
21
GND
5
IMON
2
C12
OPT
1206
R14
OPT
2
0
R16
R19
100K
CO6
OPT
1210
CO5
OPT
1210
VOUT
CO4
100uF
6.3V
1210
CO3
100uF
6.3V
1210
1
IMON
INTVCC
CO2
100uF
6.3V
1210
1
+
5
E14
E13
E12
E8
E7
E6
CO1
270uF
10V
E5
FLAG
IMON
INTVCC
PGND
VOUT
-5V , 6A
A
B
C
D
DEMO MANUAL DC2067A
FULL SCHEMATIC DIAGRAM (OPTIONAL COMPONENTS SHOWN)
dc2067af
7
DEMO MANUAL DC2067A
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
dc2067af
8
Linear Technology Corporation
LT 0114 • PRINTED IN USA
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900
●
FAX: (408) 434-0507 ● www.linear.com
 LINEAR TECHNOLOGY CORPORATION 2014
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