DEMO MANUAL DC1901A
LTC3639EMSE
High Efficiency 150V, 100mA
Synchronous Buck Converter
DESCRIPTION
Demonstration circuit 1901A is a 150V input, 100mA
output DC/DC power supply featuring the LTC3639. The
IC operates in a high efficiency Burst Mode
®
operation
and includes internal high and low side power MOSFETs.
The board will accept an input voltage between 4V and
150V, and provide jumper selected output voltages of
1.8V, 3.3V, 5V and an option for additional voltages. The
IC includes internal soft-start and a provision for increas-
ing soft-start time.
Included on the board is an ON/OFF jumper that can also
be configured as a precision undervoltage lockout. Ad-
ditional PC pads are included for programming current
limit to optimize efficiency and for reducing output voltage
ripple and reducing component size. A terminal (FBO)
is included to allow multiple boards to be paralleled for
higher output current.
Output voltage between 800mV and V
IN
can be programmed
using optional resistors. (Higher voltage rating output
capacitors may be required.)
The LTC3639 data sheet gives a complete description of the
IC operation and application information. The data sheet
must be read in conjunction with this quick start guide.
Design files for this circuit board are available at
http://www.linear.com/demo
L,
LT, LTC, LTM, Linear Technology, the Linear logo and Burst Mode are registered trademarks
of Linear Technology Corporation. All other trademarks are the property of their respective
owners.
PERFORMANCE SUMMARY
PARAMETER
Input Voltage Range
1.8V Output Voltage
3.3V Output Voltage
5V Output Voltage
Maximum Output Current, I
OUT
Typical Efficiency
Typical Output Ripple
Specifications are at T
A
= 25°C
VALUE
4V to 150V
1.8V ±2%
3.3V ±2%
5V ±2%
100mA
87.3%
66mV
P-P
CONDITION
V
IN
= 12V, I
OUT
= 0A to 100mA
V
IN
= 12V, I
OUT
= 0A to 100mA
V
IN
= 12V, I
OUT
= 0A to 100mA
V
IN
= 4V to 150V, V
OUT
= 1.8V, 3.3V or 5V
V
IN
= 12V, V
OUT
= 5V, I
OUT
= 100mA
V
IN
= 150V, V
OUT
= 5V, I
OUT
= 100mA (20MHz BW)
dc1901af
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DEMO MANUAL DC1901A
QUICK START PROCEDURE
Demonstration circuit 1901A is easy to set up to evaluate
the performance of the LTC3639. Refer to Figure 1 for
the proper measurement equipment setup and follow the
procedure below:
1. With power off, connect the input power supply (set
for 0V) to V
IN
and GND (input return).
2. Select 5V output using jumper JP1 (B position) and
JP2 (A position). Select ON position for JP3.
3. Connect the 5V output load between V
OUT
and GND
(Initial load: no load).
4. Connect the DVMs to the input and outputs.
5. Turn on the input power supply and slowly increase to
12V. Check for the proper output voltages. (5V output
should be within 5V ±2%.)
6. Once the proper output voltages are established, ad-
just the loads within the operating range and observe
the output voltage regulation, ripple voltage and other
parameters.
7. With power off, move jumpers JP1 and JP2 to the other
fixed voltage settings (1.8V or 3.3V). Repeat steps 5
and 6. Check for the proper output voltage and other
parameters.
NOTE: When measuring the output or input voltage ripple,
do not use the long ground lead on the oscilloscope probe.
See Figure 2 for the proper scope probe technique. Short,
stiff leads need to be soldered to the (+) and (–) terminals
of an output capacitor. The probe’s ground ring needs to
touch the (–) lead and the probe tip needs to touch the
(+) lead.
ADDITIONAL NOTES:
CAUTION:
Be careful when testing with high voltage. High
voltage can result in an electric shock if care is
not taken.
For 5V output, V
IN
input voltage should be at least 5V or
higher.
Figure 1. Proper Measurement Equipment Setup
dc1901af
2
DEMO MANUAL DC1901A
QUICK START PROCEDURE
+
V
OUT
C
OUT
GND
–
Figure 2. Measuring Output Voltage Ripple
LTC3639 5V
OUT
90
85
80
EFFICIENCY (%)
EFFICIENCY (%)
75
70
65
60
55
50
45
40
0
12V
IN
, 5V
OUT
36V
IN
, 5V
OUT
120V
IN
, 5V
OUT
10 20 30 40 50 60 70 80 90 100
LOAD CURRENT (A)
dc1901 F03a
LTC3639 3.3V
OUT
90
85
80
EFFICIENCY (%)
75
70
65
60
55
50
45
40
0
12V
IN
, 3.3V
OUT
36V
IN
, 3.3V
OUT
120V
IN
, 3.3V
OUT
10 20 30 40 50 60 70 80 90 100
LOAD CURRENT (A)
dc1901 F03b
LTC3639 1.8V
OUT
90
85
80
75
70
65
60
55
50
45
40
0
12V
IN
, 1.8V
OUT
36V
IN
, 1.8V
OUT
120V
IN
, 1.8V
OUT
10 20 30 40 50 60 70 80 90 100
LOAD CURRENT (A)
dc1901 F03c
Figure 3. Efficiency vs Load Current
dc1901af
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DEMO MANUAL DC1901A
PARTS LIST
ITEM
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
QTY
1
1
1
1
1
1
1
2
1
0
0
0
5
3
3
REFERENCE
C1
C2
C4
C6
C9
L1
R1
R3, R6
U1
C3
C8
R2, R4, R7, R8
E1, E2, E3, E4, E5
JP1, JP2, JP3
XJP1, XJP2, XJP3
PART DESCRIPTION
ALUM. ELECT 22μF 200V MVE Series 12.5x16mm
CAP., X7R, 1μF, 200V, 10% 2220
CAP., X7R, 47nF, 25V, 10% 0603 0.047μF
CAP., X7R, 100μF, 10V, 20% 1210
CAP., X7R, 0.1μF, 25V, 10% 0603
INDUCTOR, 220μH
RES., CHIP, 2M, 1/10W, 5% 0603
RES., CHIP, 0Ω, 1/10W, 0603
IC., LTC3639EMSE MSE16(12), 4X3MM
CAP., 0603
CAP., 1210
RES., 0603
TESTPOINT, TURRET, 0.094"
HEADER, 3 PIN 0.079" SINGLE ROW
SHUNT, 0.079" CENTER
MANUFACTURER/PART NUMBER
NIPPON CHEMI-CON, EMVE201ARA220MKG5S
KEMET, C2220X105K2RAC7533
AVX, 06033C473KAT2A
TAIYO YUDEN, LMK325ABJ107MM-T
AVX, 06033C104KAT2A
SUMIDA, CDRH105RNP-221NC
VISHAY, CRCW06032M00JNEA
VISHAY, CRCW06030000Z0EA
LINEAR TECH., LTC3639EMSE#PBF
OPT
OPT
OPT
MILL-MAX, 2501-2-00-80-00-00-07-0
SULLINS, NRPN031PAEN-RC
SAMTEC, 2SN-BK-G
Required Circuit Components
Additional Demo Board Circuit Components
Hardware: For Demo Board Only
dc1901af
4
5
4
3
2
1
REVISION HISTORY
ECO
1
PRODUCTION
CHARLIE Z. 11-16-12
REV
DESCRIPTION
APPROVED
DATE
D
D
VIN
U1
LTC3639EMSE
L1
R1
2M
JP3
1
ON
2
14
R2
OPT
OFF
B A
3
JP1
12
1
2
B A
3
JP2
R3
0
5
R8
VIN
11
1
2
6
10
C4
47nF
1.8V
3.3V
5.0V
EXT. R
R7
OPT
3
7
220uH
CDRH105R
R6
0
C6
100uF
10V
1210
9
C8
OPT
1210
3
VIN
4V - 150V
E1
VIN
SW
1
E2
C9
0.1uF
VOUT
1.8V/3.3V/5V
100mA
GND
E3
SCHEMATIC DIAGRAM
+
RUN
VFB
C1
22uF
200V
C2
1uF
200V
2220
GND
E4
C
OVLO
VPRG2
VPRG1
*
C
FBO
*
*
VOUT
JP1
B
A
B
A
JP2
B
B
A
A
ISET
NC
NC
NC
NC
GND
GND
8
16
17
SS
GND
FBO
OPT
R4
OPT
C3
OPT
2
4
13
15
E5
B
B
NOTE: UNLESS OTHERWISE SPECIFIED
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.
1. ALL RESISTORS ARE 0603.
ALL CAPACITORS ARE 0603.
2. FOR 5V OUTPUT, VIN RANGE IS 6V-150V.
CUSTOMER NOTICE
APPROVALS
LE T.
CHARLIE Z.
TITLE: SCHEMATIC
TECHNOLOGY
1630 McCarthy Blvd.
Milpitas, CA 95035
Phone: (408)432-1900
www.linear.com
Fax: (408)434-0507
LTC Confidential-For Customer Use Only
A
A
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
APP ENG.
APPLICATION. COMPONENT SUBSTITUTION AND PRINTED
CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT
PERFORMANCE OR RELIABILITY. CONTACT LINEAR
TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE.
HIGH EFFICIENCY, 150V, 100mA SYNCHRONOUS STEP-DOWN CONVERTER
SIZE
IC NO.
REV.
N/A
SCALE = NONE
3
THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND
SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS.
4
LTC3639EMSE
DEMO CIRCUIT 1901A
DATE:
1
Friday, November 16, 2012
2
SHEET 1
1
OF 1
5
DEMO MANUAL DC1901A
dc1901af
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