Linear Technology DC1737A Quick setup guide

1
dc1737af
DEMO MANUAL DC1737A
DESCRIPTION
LTC3863
Low IQInverting
DC/DC Converter
Demonstration circuit 1737A is a current-mode inverting
DC/DC converter featuring the LT C
®
3863.
The board operates from an input range of 4.5V to 16V,
and provides a –5.2V, 1.7A output or a –12V, 1A output
(jumper selectable). It operates at 400kHz and may be
synchronized to an external clock. A soft-start feature
controls output voltage slew rate at start-up, reducing
current surge and voltage overshoot. Burst Mode
®
opera-
tion that improves efficiency at light loads can be enabled
with a jumper. A power good output signal is provided.
The demonstration board has options for larger MOSFET
and diode packages on the back of the board for higher
output current requirements.
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
This board is suitable for a wide range of automotive,
telecom, industrial, and other applications. The LTC3863
is available in small 12-pin thermally enhanced MSOP and
DFN Packages. For other output requirements, see the
LTC3863 data sheet or contact the LT C factory.
Design files for this circuit board are available at
http://www.linear.com/demo
Specifications are at TA= 25°C
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
VIN Input Supply Range 4.5 16 V
VOUT Output Voltage –5.2V/–12V V
IOUT Output Current Range, Continuous Free Air 0 –1.7/1.0 A
fSW Switching (Clock) Frequency 400 kHz
VOUT P-P Output Ripple VIN = 12V, VOUT = –12V, IOUT = 1A (20MHz BW) 30 mVP-P
VREG Output Regulation Line and Load (4.5VIN to 16VIN, –12VOUT, 0A to 1A Out) ±0.1 %
POUT/PIN Efficiency (See Figure 3) VIN = 12V, VOUT = –12V, IOUT = 1A 89.3 %
Approximate Size Component Area ×Top Component Height 0.9 ×0.8 ×0.18 Inches

2
dc1737af
DEMO MANUAL DC1737A
QUICK START PROCEDURE
Demonstration circuit 1737 is easy to set up to evaluate
the performance of the LTC3863. Refer to Figure 1 for
proper measurement equipment setup and follow the
procedure below:
Note:Whenmeasuringtheoutputvoltageripple, care must
be taken to avoid a long ground lead on the oscilloscope
probe. Measure the output voltage ripple by touching the
probe tip and ground ring directly across the last output
capacitor as shown in Figure 1.
1. Set an input power supply that is capable of 4.5V to
16V to 5V. Then turn off the supply.
2. Withpower off, connect the supplyto the input terminals
+VIN and –VIN.
a. Inputvoltages lower than 4.5V can keepthe converter
from turning on due to the undervoltage lockout
feature of the LTC3863.
b. If efficiency measurements are desired, an ammeter
capable of measuring 2A DC or a resistor shunt can
be put in series with the input supply in order to
measure the DC1737A’s input current.
c. A voltmeter with a capability of measuring at least
16V can be placed across the input terminals in order
to get an accurate input voltage measurement.
3. Turn on the power at the input.
Note: Make sure that the input voltage never exceeds 16V.
4. Check for the proper output voltage of –5.2V. Turn off
the power at the input.
V
–
+
V
–
+
VOUT VIN
VIN
IOUT
LOAD
+
–
A
– +
IIN
A
– +
+
Figure 1. Proper Measurement Equipment Setup

3
dc1737af
DEMO MANUAL DC1737A
QUICK START PROCEDURE
IOUT (A)
EFFICIENCY (%)
90
85
80
65
75
70
1
0.01 0.1
VIN = 5V
VIN = 12V
IOUT (A)
EFFICIENCY (%)
90
85
80
65
75
70
1
0.01 0.1
VIN = 5V
VIN = 12V
5. Once the proper output voltage is established, connect
a variable load capable of sinking 1.7A at 5.2V to the
output terminals +VOUT and –VOUT. Set the current
for 0A.
a. If efficiency measurements are desired, an ammeter
or a resistor shunt that is capable of handling 1.7A
DC can be put in series with the output load in order
to measure the DC1737A’s output current.
b. Avoltmeterwithacapabilityofmeasuring at least 12V
can be placed across the output terminals in order
to get an accurate output voltage measurement.
6. Turn on the power at the input.
Note: If there is no output, temporarily disconnect the load
to make sure that the load is not set too high.
7. Once the proper output voltage is again established,
adjust the load and/or input within the operating range
and observe the output voltage regulation, ripple volt-
age, efficiency and other desired parameters.
8. Remove the VOUT jumper to observe operation at
–12VOUT up to 1A.
Figure 2. –12VOUT Efficiency with Burst Mode Operation
at Light Loads
Figure 4. Output Ripple at 12VIN, –12VOUT and 1A Out
(50mV, 2µs/Div, 20MHz)
Figure 5. Transient Response Waveform at 12VIN, –12VOUT
and 0.5A to 1A to 0.5A Out (0.5A, 100mV, 10µs/Div)
Figure 3. –5.2VOUT Efficiency with Burst Mode Operation
at Light Loads

4
dc1737af
DEMO MANUAL DC1737A
PARTS LIST
ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER
Required Circuit Components
1 1 CIN1 Cap., SMT, 100µF, 20V, SVP OSCON SANYO, 20SVP100M
2 2 CIN2, CIN3 CAP.,X7R, 10µF, 25V, 20%, 1210 TDK, C3225X7R1E106M
3 2 COUT1, COUT2 CAP.,X7R, 33µF, 16V, 20%, 1812 TDK, C4532X7R1C336M
4 2 COUT3, COUT5 CAP.,POSCAP, 150µF, 16V 7343 PANASONIC, 16TQC150MYF
5 1 COUT4 CAP.,X7R, 1µF, 16V, 10%, 0603 AVX, 0603YC105KAT2A
6 1 C1 Cap., NPO, 100pF, 50V, 10%, 0603 AVX, 06035A101kAT1A
7 1 C2 Cap., X7R, 27nF 25V, 10%, 0603 AVX, 06033C273KAT
8 1 C3 Cap., NPO, 390pF, 25V, 1%, 0603 AVX, 06033A391FAT2A
9 1 C5 Cap., X7R, 0.47µF, 16V, 20%, 0603 AVX, 0603YC474MAT2A
10 1 C6 Cap., X7R, 0.1µF, 16V, 20%, 0603 AVX, 0603YC104MAT2A
11 1 C7 Cap., X7R, 0.1µF, 100V, 20%, 0805 TDK, C2012X7R2A104M
12 1 C8 CAP., NPO, 68pF, 50V, 5%, 0603 AVX, 06035A680JAT2A
13 1 D1 DIODE, PDS540, POWERDI5-2PIN DIODES INC, PDS540-13
14 1 L1 IND, 10uH, 20%, D104C TOKO, 919AS-100M=P3
15 1 Q1 TRANSISTOR, SI7129DN, PWRPAK1212-8 VISHAY, Si7129DN-T1-GE3
16 1 R1 RES., CHIP, 61.9k, 1/16W, 1% , 0603 VISHAY, CRCW060361K9FKED
17 1 R2 RES., CHIP, 14.7k, 1/16W, 1% , 0603 VISHAY, CRCW060314K7FKED
18 1 R3 RES., CHIP, 80.6k, 1/16W, 1% , 0603 VISHAY, CRCW060380K6FKED
19 1 R5 RES., CHIP, 523k, 1/16W, 1% , 0603 VISHAY, CRCW0603523KFKED
20 1 R7 RES., 0.016 1/2W 1% 2010 VISHAY, WSL2010R0160FEA
21 1 R8 RES., CHIP, 100k, 1/16W, 1% , 0603 VISHAY, CRCW0603100KFKED
22 1 R9 RES., CHIP, 698k, 1/10W, 1% , 0603 VISHAY, CRCW0603698KFKED
23 1 R11 RES., CHIP, 45.3k, 1/16W, 1% , 0603 VISHAY, CRCW060345K3FKED
24 1 U1 IC, LTC3863EMSE, MSE12 LINEAR TECH.CORP. LTC3863EMSE
Additional Demo Board Circuit Components
25 0 COUT6 CAP., OPT KE0 OPT
26 0 C4 CAP., OPT 0603 OPT
27 1 R4 RES., OPT 0603 OPT
28 2 R6, R10 RES., CHIP, 0Ω, 1/16W, 0603 VISHAY, CRCW06030000Z0ED
Hardware For Demo Board Only
29 7 E1, E2, E3, E4, E5, E6, E7 TESTPOINT, TURRET, .090” pbf MILL-MAX, 2501-2-00-80-00-00-07-0
30 2 JP1, JP3 JMP, 0.079 SINGLE ROW HEADER, 3-PIN SULLINS, NRPN031PAEN-RC
31 1 JP2 JMP, 0.079 DOUBLE ROW HEADER, 6-PIN SULLINS, NRPN062PAEN-RC
32 4 J1, J2, J3, J4 CONN, BANANA JACK KEYSTONE 575-4
33 3 XJP1, XJP2, XJP3 SHUNT, 0.079" CENTER SAMTEC, 2SN-BK-G
34 4 MTGS AT 4 CORNERS STAND-OFF, SNAP ON NYLON 0.50" tall KEYSTONE, 8833(SNAP ON)

5
dc1737af
DEMO MANUAL DC1737A
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

6
dc1737af
DEMO MANUAL DC1737A
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
[phone] ●FAX: [phone] ●www.linear.com
 LINEAR TECHNOLOGY CORPORATION 2013
LT 0513 • 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

Mouser Electronics
Authorized Distributor
Click to View Pricing, Inventory, Delivery & Lifecycle Information:
Analog Devices Inc.:
DC1737A