DC2117A - Demo Manual

DEMO MANUAL DC2117A
LTC3895EFE
High Input Voltage
Synchronous Buck Converter
Description
Demonstration circuit 2117A is a single output high voltage nonisolated synchronous step-down converter that
drives all N-channel MOSFET power stage. It features the
LTC3895EFE, a high voltage step-down DC/DC controller
housed in a TSSOP-38 package with several pins removed
for high voltage spacing.
N-channel MOSFET gate drivers can be adjusted from
5V to 10V to enable the use of logic- or standard-level
MOSFETs to maximize efficiency. The EXTVCC pin permits
the LTC3895 to be powered from the output of the switching regulator or other available source, reducing power
dissipation and improving efficiency.
This DC2117A operates over an input voltage range from
14V to 130V, while the LTC®3895 can operate up to 150V.
This demo board produces a 12V output voltage with up to
a 5A output current, and is configured with a sense resistor
for over current protection and has optional DCR sensing.
A mode selector allows the DC2117A to operate in forced
continuous operation, pulse-skipping or low ripple Burst
Mode® operation during light loads. Additional features
include a power good output signal, a PLLIN, PHASEMD
and CLKOUT for multiphase operation.
To prevent high on-chip power dissipation in high input
voltage applications, the LTC3895 includes an NDRV pin
which drives the gate of an optional external N-channel
MOSFET acting as a low dropout linear regulator to supply
IC power and is an option on this board.
The LTC3895 data sheet gives a complete description of
the part, operation and application information and must
be read in conjunction with this demo board manual.
An internal charge pump allows for 100% duty cycle operation in dropout, a useful feature when powered from
a battery during discharge. The LTC3895’s powerful 1Ω
Performance Summary
Design files for this circuit board are available at
http://www.linear.com/demo/DC2117A
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
UNITS
Input Voltage Range
DC Up to 150VPK Transient
14V ~ 130V
Output Voltage VOUT
VIN = 14~130V, IOUT = 0~5A, JP4: FCM
12V ± 2% (11.76V ~ 12.24V)
Maximum Output Current IOUT(MAX)
VIN = 14~130V
5A
Default Operating Frequency (Typical)
150kHz
External Clock Sync Frequency Range
75kHz to 850kHz
Typical Full Load Efficiency (See Figure 4)
VIN = 48V, VOUT = 12V, IOUT = 5A, fSW = 150kHz
94.9%
*Important Note: 60V or higher voltage can result in an electric shock if care is not taken. Also, hot plugging the circuit to a power supply that has more
than 40V present at its output can produce a high voltage transient exceeding the absolute maximum input voltage which can damage the DC2117A
board.
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1
DEMO MANUAL DC2117A
Quick Start Procedure
Demonstration circuit DC2117A is easy to set up to evaluate the performance of the LTC3895EFE. Refer to Figure 1
for proper measurement 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. Measure the input or output voltage
ripple by touching the probe tip directly across the VIN
or VOUT and GND terminals or directly across relevant
capacitor. See Figure 2 for proper scope probe technique.
1.Place jumpers in the following positions:
JP1ON
JP4FCM
JP5ON
2.With power off, connect the input power supply to VIN
and GND.
3.Turn on the power at the input.
NOTE. Make sure that the input voltage is higher than
14V and does not exceed 130V.
4.Check the output voltage. The output voltage should
be between 11.76V and 12.24V.
Once the proper output voltage is established, adjust
the load within the operating range and observe the
output voltage regulation, output voltage ripple,
efficiency and other parameters.
NOTE. If there is no output, temporarily disconnect the
load to make sure that the load is not set too high.
JP8OFF
Figure 1. Proper Measurement Equipment Setup
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2
DEMO MANUAL DC2117A
Quick Start Procedure
+
–
COUT
VOUT
GND
Figure 2. Measuring Input or Output Ripple Across Terminals or Directly Across Ceramic Capacitor
Frequency Synchronization and Mode Selection
Demonstration circuit 2117A’s mode selector allows the
converter to run in forced continuous operation, pulseskipping operation, Burst Mode operation or Burst Mode
operation with adjustable clamp level by changing the
position of JP4. To synchronize the DC2117A to an external
clock, apply the sync signal to the PLLIN turret. Depending
upon the JP4 setting, the DC2117A will operate in different
modes. See Table 2 for the detailed description.
Table 2. Mode Selection and Synchronized Operation Options
CONFIGURATION
JP4
MODE WITH SYNC SIGNAL SUPPLIED TO PLLIN
Forced Continuous Operation
FCM
FCM
PS
PS
BURST ADJ
FCM
BURST DEFAULT
FCM
Pulse-Skipping Operation
Burst Mode Operation with Adjustable Clamp Level
Burst Mode Operation with Default Clamp
100% Duty
Demonstration circuit 2117A features 100% duty cycle
operation in dropout. Set the JP5 to ON position to activate
this feature. Set JP5 to OFF position disables the internal
charge pump and enables boost refresh, allowing for 99%
duty cycle operation in dropout.
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3
DEMO MANUAL DC2117A
Optional Inductor DCR Current Sensing
Demonstration circuit 2117A provides an optional circuit
for inductor DCR current sensing. Inductor DCR current
sensing uses the DCR of the inductor to sense the inductor
current instead of discrete sense resistors. The advantages
of DCR sensing are lower cost, reduced board space and
higher efficiency, but the disadvantage is a less accurate
current limit. If DCR sensing is used, be sure to select an
inductor current with a sufficiently high saturation current
or use an iron powder type material.
Refer to Table 3 for optional inductor DCR current sensing
setup and to the data sheet for more details.
Table 3. Optional Inductor DCR Current Sensing
CONFIGURATION
RS1
R24
R28
C16
R37
R38
R39
R40
Current Sense
Resistor (Default)
Ref Sch
Ref Sch
Ref Sch
OPEN
OPEN
OPEN
OPEN
OPEN
0Ω Copper
OPEN
OPEN
0Ω
0Ω
Inductor DCR Current
Sensing
Calculated Value from Data Sheet
Low Quiescent Current Applications and Measurement
The typical quiescent current (IQ) of the LTC3895 controller
is 40µA in sleep mode as specified in the LTC3895 data
sheet. However, the input current of the DC2117A board
can be higher than this value because of additional circuit
outside of the IC. To reduce the total input current, large
value FB divider resistors should be used. In addition, some
jumpers and resistors should be configured accordingly.
Refer to Table 4 for the low input quiescent current setup.
Table 4. Low Input Quiescent Current Configuration
Reference Designator
R1
Function
Stuffing Option
R2
OVLO
OPEN
0Ω
R23
JP3
JP4
JP5
JP8
PGOOD
INTVCC Jumper
MODE Selector
100% DUTY
BIAS Supply
OPEN
OPEN
BURST ADJ or
BURST DEFAULT
OFF
OFF
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4
DEMO MANUAL DC2117A
EXTVCC Bias Supply
By default, the DC2117A EXTVCC turret is tied to the 12V
VOUT to save IC power loss.
Alternatively, EXTVCC can also be powered by an external
power supply:
To power the EXTVCC from onboard bias supply:
1. Leave the JP7 OPEN.
1. Leave the JP7 OPEN. This step disconnects the EXTVCC
from VOUT.
2. Keep the JP8 at the OFF position.
3. Apply a DC voltage (<14V) between the EXTVCC and
GND turret, after the input voltage is established. Ensure
that EXTVCC ≤ VIN.
2. Keep the JP8 at the ON position. The onboard BIAS
supply output voltage is 12V.
100
95
90
EFFICIENCY (%)
85
80
75
70
65
60
VIN = 48V
55
VIN = 130V
50
VIN = 72V
0
0.5
1
1.5
2
3
2.5
IOUT (A)
3.5
4
4.5
5
DC2117a F03
Figure 3. DC2117A VOUT Typical Efficiency vs Load Current
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5
DEMO MANUAL DC2117A
EXTVCC Bias Supply
20MHz BW
VOUT
100mV/DIV
200µs/DIV
DC2117a F04
Figure 4. DC2117A VOUT 1.25A ~ 2.5A Load Transient at VIN = 48V
20MHz BW
VOUT
100mV/DIV
200µs/DIV
DC2117a F05
Figure 5. DC2117A VOUT 1.25A ~ 2.5A Load Transient at VIN = 130V
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6
DEMO MANUAL DC2117A
Parts List
ITEM
QTY
REFERENCE
PART DESCRIPTION
MANUFACTURER/PART NUMBER
Required Circuit Components
1
1
CIN1
CAP, 100µF 20% 200V ELEC
NIC NRB-XS101M200V16x20TBF
2
5
CIN2, CIN3, CIN4, CIN5, C14
CAP, 1812 0.47µF 10% 200V X7R
MURATA GRM43DR72E474KW01L
3
2
CIN6, CIN7
CAP, 1210 0.1µF 10% 200V X7R
MURATA GRM32DR72D104KW01L
4
1
COUT1
CAP, 1210 22µF 10% 16V X7R
TDK C3225X7R1C226K
5
2
COUT2, COUT3
CAP, 7343 150µF 20% 16V
AVX TPSD157M016R0125
6
3
C2, C4, C13
CAP, 0603 0.1µF 10% 25V X7R
TDK C1608X7R1E104K
7
1
C3
CAP, 0603 1nF 10% 50V X7R
AVX 06035C102KAT2A
8
1
C6
CAP, 0603 4700pF 10% 50V X7R
AVX 06035C472KAT2A
9
1
C7
CAP, 0603 1µF 20% 16V X7R
TDK C1608X7R1C105M
10
1
C9
CAP, 0603 10pF 10% 50V X7R
AVX 06035C100KAT2A
11
1
C10
CAP, 0603 100pF 5% 50V NPO
AVX 06035A101JAT2A
12
1
C11
CAP, 1206 0.033µF 20% 200V
VISHAY VJ1206Y333MXCAC
13
1
C12
CAP, 0603 4.7µF 20% 16V X5R
TDK C1608X5R1C475M080AC
14
1
C15
CAP, 1210 4.7µF 20% 16V X7R
AVX 1210YC475KAT2A
15
1
L1
IND, 33µH 15%
WURTH ELEKTRONIK 7443633300
16
1
L2
IND, 470µH
COILCRAFT MSS1048T-474KLB
17
1
L3
IND, 1µH
VISHAY IHLP-1616BZER1R0M11
18
3
Q2, Q3, Q4
XSTR, N-CHANNEL DMOS FET
INFINEON BSC520N15NS3G
19
1
RS1
RES, 2512 0.006Ω 5% 1/4W
VISHAY WSL25126L000FEA18
20
1
R1
RES, 0603 191kΩ 1% 1/10W
VISHAY CRCW0603191KFKEA
21
1
R2
RES, 0603 1.74kΩ 1% 1/10W
VISHAY CRCW06031K74FKEA
22
1
R6
RES, 0603 301kΩ 1% 0.1W
VISHAY CRCW0603301KFKEA
23
8
R8, R10, R22, R24, R27, R28,
R29, R35
RES, 0603 0Ω JUMPER
VISHAY CRCW06030000Z0EA
24
1
R9
RES, 0603 10MΩ 5% 1/10W
VISHAY CRCW060310M0JNEA
25
1
R12
RES, 0603 2.2Ω 5% 1/10W
VISHAY CRCW06032R20JNEA
26
1
R13
RES, 0603 10kΩ 1% 1/10W
VISHAY CRCW060310K0FKEA
27
1
R14
RES, 0603 10kΩ 5% 1/10W
VISHAY CRCW060310K0JNEA
28
1
R15
RES, 0603 140kΩ 1% 1/10W
VISHAY CRCW0603140KFKEA
29
3
R16, R17, R23
RES, 0603 100kΩ 5% 1/10W
VISHAY CRCW0603100KJNEA
30
1
R18
RES, 0603 49.9kΩ 1% 0.1W
VISHAY CRCW060349K9FKEA
31
1
R25
RES, 0603 30.1kΩ 1% 1/10W
VISHAY CRCW060330K1FKEA
32
1
R26
RES, 0603 80.6kΩ 1% 1/10W
VISHAY CRCW060380K6FKEA
33
2
R30, R36
RES, 0603 10Ω 1% 1/10W
VISHAY CRCW060310R0FKEA
34
1
R31
RES, 0603 2MΩ 1% 1/10W
VISHAY CRCW06032M00FKEA
35
1
R32
RES, 0603 267kΩ 1% 1/10W
VISHAY CRCW0603267KFKEA
36
1
R34
RES, 0603 196kΩ 1% 1/10W
VISHAY CRCW0603196KFKEA
37
1
U1
IC, SYNCHRONOUS BUCK CONVERTER
LINEAR TECH. LTC3895EFE
38
1
U2
IC, SYNCHRONOUS STEP DOWN REGULATOR
LINEAR TECH LTC3639EMSE
dc2117af
7
DEMO MANUAL DC2117A
Parts List
ITEM
QTY
REFERENCE
PART DESCRIPTION
MANUFACTURER/PART NUMBER
Additional Demo Board Circuit Components
1
0
CIN8
CAP, 1812 OPTION
OPTION
2
0
COUT4
CAP, 7343 OPTION
OPTION
3
0
C1, C5, C8, C16
CAP, 0603 OPTION
OPTION
4
0
D1, D2
DIODE, OPTION
OPTION
5
0
L1 - ALTERNATE
IND, 33µH 15%
WURTH ELEKTRONIK 7443643300
6
0
L4
IND, 22µH OPTION
COILCRAFT SER2915H-223KL OPTION
7
0
Q1
XSTR, POWER
OPTION
8
0
Q5
XSTR, NMOS OPTION
OPTION
9
0
Q6, Q7
XSTR, OPTIMOS POWER - TRANSISTOR OPTION
INFINEON IPD320N20N3 G OPTION
10
0
Q12, Q13
XSTR, OPTION
OPTION
11
0
R3, R4, R5, R7, R11, R19, R20,
R21, R37, R38, R39, R40
RES, 0603 OPTION
OPTION
12
0
R33
RES, 1206 OPTION
OPTION
Hardware: For Demo Board Only
1
11
E2, E3, E4, E5, E6, E7, E8, E9,
E10, E11, E12
TURRET
MILL-MAX 2501-2-00-80-00-00-07-0
2
3
JP1, JP5, JP8
HEADER, 3PIN, 2mm
SULLINS NRPN031PAEN-RC
3
1
JP2
HEADER, 4PIN 2mm
SULLINS NRPN041PAEN-RC
4
3
JP3, JP6, JP7
HEADER, 2PIN, 2mm
SULLINS NRPN021PAEN-RC
5
1
JP4
HEADER, DOUBLE ROW 2X4 2mm
SULLINS NRPN042PAEN-RC
6
4
J1, J2, J3, J4
JACK, BANANA
KEYSTONE 575-4
7
8
XJP1, XJP2, XJP3, XJP4, XJP5,
XJP6, XJP7, XJP8
SHUNT, 2mm
SAMTEC 2SN-BK-G
8
4
STANDOFF, SNAP ON
KEYSTONE_8833
dc2117af
8
D
C
B
A
E3
E5
PGOOD
PLLIN
CLKOUT
E11
E9
E8
INTVCC
MODE
SS
1
R16
100k
R17
100k
100K
R23
INTVCC
R18
49.9k
1%
JP3
R8
0
R6
301k
1%
0.1uF
C4
7
JP4
8
6
4
3
5
2
1
MODE
INTVCC
OFF
ON
JP5
100% DUTY
3
2
1
2
10k
R14
C8 OPT
SENSE1-
INTVCC
BURST DEFAULT
BURST ADJ.
P.S.
FCM
R7
OPT
SENSE1+
140k 1%
R15
C9 10pF
VOSP
OPT
R5
C1
R25
30.1k
1%
OPT
R19
3
R26
80.6k
1%
OPT
R20
C10 100pF
INTVCC
OPT
R2 1.74k 1%
R27
0
OPT
R21
C6 4700pF
C3
1nF
R13
10K 1%
R3
OPT
INTVCC
VIN
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
R1
191k
1%
DRVUV
DRVSET
FREQ
NC
GND
PGOOD
PLLIN
GND
CLKOUT
CPUMP_EN
GND
MODE
ITH
VFB
SS
SENSE1-
SENSE1+
VPRG
OVLO
LTC3895EFE
U1
GND
39
4
TG
SW
BOOST
BG
DRVCC
NDRV
VIN
EXTVCC
RUN
PHASMD
ILIM
INTVCC
20
21
22
24
26
28
30
32
BG
TG
R22
0
1
1
C11
0.033uF
200V
JP6
1uF
C7
EXTVCC
34
36
37
C2 0.1uF
INTVCC
38
R4
R10
VIN
C13
0.1uF
D1
Q7
OPT
Q6
OPT
OPT
1
R12
2.2
0
INTVCC
OPT
2
3
4
2
3
2
3
5
5
SW
TG
SW
BG
BG
SW
TG
4.7uF
C12
Q1
OPT
4
3
2
1
JP2
Q2
4
3
2
1
4
R35
0
R33
OPT
R31
2M
1%
VIN
OFF
ON
4
Q5
OPT
SENSE1+
JP8
R37 OPT
6
THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND
SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS.
200V
R24
0
11
5
12
14
3
R28
ISET
FBO
OVLO
RUN
VIN
SCALE = NONE
W _A
`\
APPROVALS
1
4
3
200V
0.47uF
CIN3
2SW
2512
LTC3639EMSE
U2
0
R40 OPT
7
REV
VFB
SW
10
6
7
9
1
R29
0
VOUT
VOUT
J4
E10
C15
4.7uF
16V
R30
10
1%
GND
VIN-
EXTVCC
E12
GND
GND
12V, 5A
J3
E7
E6
J2
14V - 130V
VIN
VIN
LTC3895EFE
DEMO CIRCUIT 2117A
REV.
1630 McCarthy Blvd.
Milpitas, CA 95035
Phone: (408)432-1900 www.linear.com
Fax: (408)434-0507
LTC Confidential-For Customer Use Only
R34
196k
R32
267k
1%
EXTVCC
D2
OPT
COUT3 COUT4
+ OPT
+ OPT
7343
7343
+ CIN1
100uF
200V
J1
RUN
W_
W_
W_
APPROVED
Tuesday, May 03, 2016
IC NO.
8
SHEET 1
OF 1
4
HIGH INPUT VOLTAGE SYNCHRONOUS
BUCK CONVERTER
7
DATE:
N/A
SIZE
MSS104BT
L2 470uH
COUT2
+ 150uF
16V
7343
R36
10
1%
VOSP
L3
1.0uH
TECHNOLOGY
JP7
COUT1
22uF
16V
1210
VOUT
200V
CIN8
OPT
200V
VIN
CIN5
0.47uF
VIN
E2
E4
03/30/16
PROD - Parts addition
DATE
05/28/13
06/26/15
PROD
8
PROTO
200V
TITLE: SCHEMATIC
SS
VPRG2
REVISION HISTORY
DESCRIPTION
0.47uF
CIN2
VPRG1
RS1 0.006
ECO
0.47uF
CIN4
C16 OPT
OPT
R39
OPT
R38
7443633300
L1 33uH
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.
3
2
VBIAS
1
C14
0.47uF
200V
1812
SENSE1-
R11
OPT
CIN6
0.1uF
200V
1210
R9
10M
Q3
BSC520N15NS3G
VIN
OPT
C5
CIN7
0.1uF
200V
1210
OFF
ON
Q4
BSC520N15NS3G
JP1
RUN
6
CUSTOMER NOTICE
SW
4
BSC520N15NS3G
90
180
120
PHASE MD
INTVCC
5
1
2
3
5
1
2
3
5
1
2
3
5
1
2
3
3
GND
2
NC
NC
NC
NC
2
4
13
15
GND
GND
8
16
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.
17
1
D
C
B
A
DEMO MANUAL DC2117A
Schematic Diagram
dc2117af
9
DEMO MANUAL DC2117A
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,
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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
dc2117af
10 Linear Technology Corporation
LT 0616 • PRINTED IN USA
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900
●
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