Linear Technology DC2221A Quick setup guide

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dc2221af
DEMO MANUAL DC2221A
Description
LTC3807EFE
Low Quiescent Current,
High Voltage Step-Down Converter
Demonstration circuit 2221A is a low quiescent current,
synchronous buck converter featuring the LT C
®
3807EFE.
This demo board converts a 16V to 38V input voltage to
a 12V at 15A output.
The main features of this board include an internal LDO
for gate drive power from VIN or EXTVCC, RUN and
PGOOD pins, a mode selector that allows the converter
to run in constant current mode (CCM), pulse-skipping
or Burst Mode
®
operation, and selectable current limit.
The DC2221A supports an adjustable output voltage,
soft-start and tracking. The wide input voltage range of
16V to 38V is suitable for automotive and distributed DC
power systems where low quiescent current is important.
The LTC3807 data sheet gives a complete description of
this part, operation and application information. The data
sheet must be read in conjunction with this quick start
guide for demo circuit 2221A.
L, LT, LTC, LTM, Burst Mode, 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
The 40V rated MOSFETs, which are used on DC2221A, can
be operated at their rated voltage. MOSFETs with higher
voltage rating can be used for more safety margin.
The DC2221A supports the LFPAK, PowerPAK SO-8 and
Power 56 MOSFET packages. The following logic level
(SV gate) MOSFETs can be used with DC2221A.
RJK0451DPB Renesas
BSC093N04LS G Infineon
Si4124DY Vishay
FDS8447 Fairchild
For synchronization to an external clock, remove jumper
JP2 and apply sync signal on terminal SYNC.
Design files for this circuit board are available at
http://www.linear.com
Specifications are at TA= 25°C
PARAMETER CONDITIONS VALUE UNITS
Minimum Input Supply Voltage 16 V
Maximum Input Supply Voltage 38 V
Output Voltage Range VIN = 16V to 38V, IOUT = 0A to 15A 12 ± 2% V
Typical Switching Frequency 120 kHz
Typical Output Ripple (VOUT, 12V) VIN = 24V; ILOAD = 15A 80 mV
Efficiency Typical (VOUT, 12V) VIN = 24V; ILOAD = 15A 97 %
Supply Quiescent Current VIN = 24V; VOUT = 12V, IO= 0A, Burst Mode 110 μA
Supply Shutdown Current VIN = 24V 38 μA

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DEMO MANUAL DC2221A
Quick start proceDure
Demonstration circuit DC2221A is easy to set up to evalu-
ate the performance of the LTC3807EFE. 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 jumper JP1 in the ON position.
2. With power off, connect the input power supply to VIN
and GND.
3. Turn on the power at the input. Check for the proper
output voltage:
VOUT = 11.9V to 12.4V
NOTE. 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 voltages are established, adjust
the load within the operating range and observe the
output voltage regulation, ripple voltage, efficiency and
other parameters.
Figure 1. Proper Measurement Equipment Setup
Figure 2. Measuring Input or Output Ripple Across Terminals or Directly Across Bulk Capacitor
LOAD
+
–
IOUT
VIN SUPPLY
+
–
IIN
+ –
VOUT GND
COUT
GND VIN

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DEMO MANUAL DC2221A
Quick start proceDure
Figure 3. 12V Output, Efficiency vs Load, Burst Mode Operation, VIN 16V, 24V, 36V
89
90
91
92
93
94
95
96
97
98
99
0.1 1 10 100
Efficiency (%)
Load Current (A)
VIN = 36V
VIN = 24V
VIN = 18V

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DEMO MANUAL DC2221A
parts List
ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER
Required Circuit Components
1 1 Q4 N Channel, MOSFET INFINEON., BSC093N04LS
2 1 Q2 N Channel, MOSFET INFINEON., BSC035N04LS
3 1 RS1 RES, 0.003Ω, 1W, 1%, 2512 PANASONIC ERJM1WSF3M0U
4 1 R1 RES., 2.2Ω, 1%, 0603 VISHAY, CRCW06032R20FNEA
5 3 R2, R8, R10 RES., 0Ω, 1%, 0603 VISHAY, CRCW06030000Z0EA
6 2 R4, R20 RES., 100k, 1%, 0603 VISHAY, CRCW0603100KFKEA
7 1 R5 RES., 511k, 1%, 0805 VISHAY, CRCW0805511KFKEA
8 1 R6 RES., 27.4k, 1%, 0603 VISHAY, CRCW060327K4FKEA
9 1 R7 RES., 35.7k, 1%, 0603 VISHAY, CRCW060335K7FKEA
10 1 R13 RES., 10Ω, 1%, 0603 VISHAY, CRCW060310R0FKEA
11 1 R15 RES., 2Ω, 1%, 0603 VISHAY, CRCW06032R00FNEA
12 1 R17 RES., 15.4k, 1%, 10603 VISHAY, CRCW060315K4FKEA
13 1 R18 RES., 1k, 1%, 0603 VISHAY, CRCW06031K00FKEA
14 1 C12 CAP., X7R, 4.7nF, 50V, 10%, 0603 YAGEO CC0603KRX7R9BB472
15 1 C14 CAP., NPO, 47pF, 50V, 5%, 0603 NIC, NMC0603NPO470J50TRPF
16 2 C25, C30 CAP., X7R, 2.2µF, 50V, 10%, 0805 TDK, C2012X7R1H225K125AC
17 1 D1 DIODE, SCHOTTKY, SOD-323 CENTRAL SEMI., CMDSH-4ETR
22 1 L1 IND., 8.6µH, Pulse., PG1083.103NL
23 1 C16 CAP., Sanyo, 150µF, 16V, 20% SANYO, 16SVPC150M
24 2 C2, C23 CAP., X7R, 10µF, 50V, 10%, 1210 AVX, 12105C106KAT2A
25 1 C15 CAP., X7R, 10µF, 16V, 10%, 1206 MURATA, GCM31CR71C106KA64L
26 1 C3 CAP., Sanyo, 82µF, 50V, 20% SANYO, 50HVH82M
27 3 C4, C9, C13 CAP., X7R, 0.1µF, 100V, 10%, 0603 MURATA, GRM188R72A104KA35D
28 1 C5 CAP., COG, 10pF, 50V, 5%, 0603 AVX., 06035A100JAT2A
29 1 C6 CAP., X5R, 4.7µF, 16V, 10%, 0805 MURATA, GRM219R61C475KE15D
30 2 C7, C17 CAP., X7R, 1µF, 16V, 10%, 0603 TDK, C1608X7R1C105K
31 1 C8 CAP., X7R, 1000pF, 10V, 5%, 0603 AVX, 0603ZC102JAT2A
32 1 U1 I.C., LTC3807EFE#PBF, LINEAR TECH., LTC3807EFE#PBF
Additional Demo Board Circuit Components
33 0 R3, R9, R11, R12, R19, R21 RES., OPTIONAL
34 R22, R23, R24, R25 (OPT) OPTIONAL
35 0 C11, C18, C19, C20, C21, C22, OPTIONAL
36 C24, C26, C27, C28, C29, C31-C34 (OPT) OPTIONAL
37 1 R14 RES., 1M, 1% 0805 VISHAY, CRCW08051M00FKEA
38 1 R16 RES., 57.6k, 1% , 0603 VISHAY, CRCW060357K6FKEA
39 0 Q3, D3, Q1 (OPT) OPTIONAL
Hardware: For Demo Board Only
40 1 FAB, PRINTED CIRCUIT BOARD DEMO CIRCUIT 2221A
41 10 E1-E10 TESTPOINT, TURRET, .094" MILL-MAX, 2501-2-00-80-00-00-07-0
42 2 JP1, JP2 JMP, 3-PIN, 1 ROW, 0.079" SULLINS, NRPN031PAEN-RC
43 2 XJP1, XJP2 SHUNT, .079" CENTER SAMTEC, 2SN-BK-G
44 4 J1, J2, J3, J4 CONN, BANANA JACK, KEYSTONE-575-4 KEYSTONE, 575-4
45 4 MTGS at 4 Corners STANDOFF, NYLON .5 1/2" KEYSTONE, 8833 (SNAP-ON)

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DEMO MANUAL DC2221A
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
D D CC B B A A
NOTES:
12V / 15A
16V - 38V
RUN
ON OFF
BURST
FCM
MODE
3. FOR SYNCHRONIZATION REMOVE JUMPER JP2 'MODE' AND CONNECT SOURCE OF THE SYNC SIGNAL TO TERMINALS E8 'SYNC' AND E9 'GND'
PULSE SKIP
1. ALL RESISTORS AND CAPACITORS ARE 0603 2. INSTALL SHUNTS AS SHOWN.
5/6/142
S+ S-
TG
RS+
S+ S-
RS+
BG
INTVCC
VIN
INTVCC
VOUT
VIN
VOUT
VIN
INTVCC
VOUT
INTVCC
INTVCC
INTVCC
VIN
VIN
REVISION HISTORY
DESCRIPTION DATEAPPROVEDECO REV
DING L.PRODUCTION
__
REVISION HISTORY
DESCRIPTION DATEAPPROVEDECO REV
DING L.PRODUCTION
__
REVISION HISTORY
DESCRIPTION DATEAPPROVEDECO REV
DING L.PRODUCTION
__
SIZE
DATE:
.VER.ONCI
SHEET OF
TITLE:
APPROVALS
PCB DES.
APP ENG.
TECHNOLOGY Fax: [phone]
Milpitas, CA 95035 Phone: [phone] McCarthy Blvd. LTC Confidential-For Customer Use Only
CUSTOMER NOTICE
LINEAR TECHNOLOGY HAS MADE A BEST EFFORT TO DESIGN A CIRCUIT THAT MEETS CUSTOMER-SUPPLIED SPECIFICATIONS; HOWEVER, IT REMAINS THE CUSTOMER'S RESPONSIBILITY TO VERIFY PROPER AND RELIABLE OPERATION IN THE ACTUAL APPLICATION. COMPONENT SUBSTITUTION AND PRINTED CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT PERFORMANCE OR RELIABILITY. CONTACT LINEAR TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE.
THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND
SCHEMATIC
SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS.
SCALE = NONE
www.linear.com
2
Thursday, July 24, 2014
1 1
LOW QUIESCENT CURRENT HIGH VOLTAGE STEP-DOWN CONVERTER
HZ
Ding L.
N/A
LTC3807EFE
DEMO CIRCUIT 2221A
SIZE
DATE:
.VER.ONCI
SHEET OF
TITLE:
APPROVALS
PCB DES.
APP ENG.
TECHNOLOGY Fax: [phone]
Milpitas, CA 95035 Phone: [phone] McCarthy Blvd. LTC Confidential-For Customer Use Only
CUSTOMER NOTICE
LINEAR TECHNOLOGY HAS MADE A BEST EFFORT TO DESIGN A CIRCUIT THAT MEETS CUSTOMER-SUPPLIED SPECIFICATIONS; HOWEVER, IT REMAINS THE CUSTOMER'S RESPONSIBILITY TO VERIFY PROPER AND RELIABLE OPERATION IN THE ACTUAL APPLICATION. COMPONENT SUBSTITUTION AND PRINTED CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT PERFORMANCE OR RELIABILITY. CONTACT LINEAR TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE.
THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND
SCHEMATIC
SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS.
SCALE = NONE
www.linear.com
2
Thursday, July 24, 2014
1 1
LOW QUIESCENT CURRENT HIGH VOLTAGE STEP-DOWN CONVERTER
HZ
Ding L.
N/A
LTC3807EFE
DEMO CIRCUIT 2221A
SIZE
DATE:
.VER.ONCI
SHEET OF
TITLE:
APPROVALS
PCB DES.
APP ENG.
TECHNOLOGY Fax: [phone]
Milpitas, CA 95035 Phone: [phone] McCarthy Blvd. LTC Confidential-For Customer Use Only
CUSTOMER NOTICE
LINEAR TECHNOLOGY HAS MADE A BEST EFFORT TO DESIGN A CIRCUIT THAT MEETS CUSTOMER-SUPPLIED SPECIFICATIONS; HOWEVER, IT REMAINS THE CUSTOMER'S RESPONSIBILITY TO VERIFY PROPER AND RELIABLE OPERATION IN THE ACTUAL APPLICATION. COMPONENT SUBSTITUTION AND PRINTED CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT PERFORMANCE OR RELIABILITY. CONTACT LINEAR TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE.
THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND
SCHEMATIC
SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS.
SCALE = NONE
www.linear.com
2
Thursday, July 24, 2014
1 1
LOW QUIESCENT CURRENT HIGH VOLTAGE STEP-DOWN CONVERTER
HZ
Ding L.
N/A
LTC3807EFE
DEMO CIRCUIT 2221A
C26 OPT C26 OPT
C9
0.1uF
C9
0.1uF
C34 OPT C34 OPT
R17
15.4K
R17
15.4K
R8 0 R8 0
Q1
OPT
Q1
OPT
3
1
2
4
5
E10
GND
E10
GND
C11
OPT
C11
OPT
R3 OPT R3 OPT
+
C20 OPT 7343
+
C20 OPT 7343
C19 OPT C19 OPT
D1D1
21
R21 OPT R21 OPT
E2
GND
E2
GND
J3
VOUT
J3
VOUT
R16
57.6K
R16
57.6K C13
0.1uF
C13
0.1uF
R2
0
R2
0
C18
OPT
C18
OPT
R18 1K R18 1K
Q4
BSC093N04LS
Q4
BSC093N04LS
3
1
2
4
5
RS1
0.003
2512 RS1
0.003
2512
R15
2
R15
2
R22 OPT R22 OPT C17
1uF
C17
1uF
R25 OPT R25 OPT
D3
OPT
D3
OPT
2 1
C33 OPT C33 OPT
J2
GND J2 GND
E7 GND E7 GND
C24 OPT C24 OPT
C2 10uF 50V 1210 C2 10uF 50V 1210
R11
OPT
R11
OPT
C6
4.7uF
0805
C6
4.7uF
0805
R13
10
R13
10
C32 OPT C32 OPT
R6
27.4K
R6
27.4K
TP2
GND
TP2
GND
R24 OPT R24 OPT
TP1
Vin_EMI
TP1
Vin_EMI
JP2JP2
1
3
2
4
56
C28 OPT C28 OPT
E4
EXTVCC
E4
EXTVCC
R7 35.7K R7 35.7K
C25 2.2uF 50V 0805 C25 2.2uF 50V 0805
C7 1uF C7 1uF
E1
VIN E1 VIN
J4 GND J4 GND
L2
OPT
L2
OPT
C29 OPT C29 OPT
+
C16
150uF 16V
16SVPC150M
+
C16
150uF 16V
16SVPC150M
R23 OPT R23 OPT
R12 OPT R12 OPT
C12
4.7nF
C12
4.7nF
U1 LTC3807EFE U1 LTC3807EFE
VIN
19
PGOOD
11
EXTVCC
17
TRACK/SS
1
RUN
6
ITH
10
SGND
4
SGND
5
PGND
18
PLLIN/MODE
3
ILIM
20 BG 15
SW 13
TG 12
BOOST 14
SENSE+ 8
SENSE- 7 INTVCC 16
VFB 9
FREQ 2
SGND
21
C15
10uF
1206
C15
10uF
1206
C5 10pF C5 10pF
E6 VOUT E6 VOUT
C27 OPT C27 OPT
C8
1000pF
C8
1000pF
L1
10uH
L1
10uH
+
C3 82uF/50V
+
C3 82uF/50V
Q3 OPT Q3 OPT
3
1
2
4
5
C31 OPT C31 OPT
R5 511K 0805 R5 511K 0805
Q2
BSC035N04LS
Q2
BSC035N04LS
3
1
2
4
5
R4
100k
R4
100k
J1
VIN J1 VIN
E3
PGOOD
E3
PGOOD
R14
1 Meg
0805 R14
1 Meg
0805
+
C22 OPT 7343
+
C22 OPT 7343
E8
SYNC
E8
SYNC
+
C21 OPT 7343
+
C21 OPT 7343
R9
OPT
R9
OPT
E5
TRACK
E5
TRACK
JP1
ON 10th?? OFF
RUN
JP1
ON 10th?? OFF
RUN
1
3
2
R1 2.2 R1 2.2
R20
100K
R20
100K
R19 OPT R19 OPT
C14
47pF
C14
47pF
E9
GND
E9
GND
C4 0.1uF 50V C4 0.1uF 50V
R10
0
R10
0
C30
2.2uF
C30
2.2uF
C23 10uF 50V 1210 C23 10uF 50V 1210

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DEMO MANUAL DC2221A
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
[phone] ●FAX: [phone] ●www.linear.com
 LINEAR TECHNOLOGY CORPORATION 2014
LT 0814 • 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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