1
dc1999af
DEMO MANUAL DC1999A
DESCRIPTION
LTC3111EDHD
15V, 1.5A Synchronous
Buck-Boost DC/DC Converter
Demonstration circuit 1999A is a fixed frequency syn-
chronous buck-boost converter with an extended input
and output range. The unique 4-switch, single inductor
architecture provides low noise and seamless operation
from input voltages above, below, or equal to the output
voltage.
The LT C
®
3111 features selectable PWM or Burst Mode
®
operation, and an easily synchronizable oscillator. Jumper
JP1 is provided to enable the converter. The demo board
is configured for 800kHz. A jumper, JP2, is provided to
select PWM, or Burst Mode operation. A clock signal can
also be applied to JP2 if synchronization is desired.
The LTC3111 operates with a 2.5V to 15V input voltage
range and a VOUT range from 2.5V to 15V. The demon-
stration board has been designed to operate with VIN
from 2.5V to 15V and an output current up to 1.5A. For
VIN < 5V, IOUT capability is reduced. VOUT is set to 5.0V.
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
Typical demo board efficiency is shown in Figure 2 for
several loads. The demo board has the provision to set an
accurate run threshold. Consult the LTC3111data sheet for
more information. The transient response of the converter
to a 100mA to 600mA transient at input voltages of 3.5V
and 12V are presented in Figures 3 and 4.
The LTC3111 data sheet has detailed information about
the operation, specifications, and applications of the part.
The data sheet should be read in conjunction with this
Quick Start Guide.
Design files for this circuit board are available at
http://www.linear.com/demo
INPUT VOLTAGE RANGE 2.5V to 15V
VOUT 5V
IOUT 1.5A for VIN > 5V
Specifications are at TA = 25°C
2
dc1999af
DEMO MANUAL DC1999A
QUICK START PROCEDURE
Using short twisted-pair leads for any power connections
and with all loads and power supplies off, refer to Figure1
for the proper measurement and equipment setup. The
power supply should not be connected to the circuit until
told to do so in the procedure below.
When measuring the input or output voltage ripple, care
must be taken to avoid a long ground lead on the oscil-
loscope probe.
1. JP1, JP2 and Load Settings to start:
JP1 (RUN) = OFF
JP2 (PWM) = 800kHz (Fixed Frequency)
LOAD = 0.1A/50Ω 10W Resistor
2. With power OFF connect the power supply as shown in
Figure 1. If accurate current measurements are desired
(for efficiency calculations for example) then connect
an ammeter in series with the supply as shown. The
ammeter is not required however.
3. Connect the load to VOUT as shown in Figure 1. Again,
connect an ammeter if accurate current measurement
or monitoring is desired.
4. Turn on the power supply and slowly increase voltage
until the voltage at VIN is 2.5V. Move Jumper JP1 to
ON.
5. Verify VOUT is ~5.0V.
6. VIN can now be varied between 2.5V and 15.0V. VOUT
should remain in regulation.
7. IOUT can also be varied from 0A to 1.5A. For VIN < 5.0V,
maximum IOUT is reduced. This reduction is due to IIN
increasing as VIN decreases. Once the input current
limit is reached, VOUT will fall out of regulation.
Note: If VOUT drops out of regulation, check to be sure
the maximum load has not been exceeded, or that VIN is
not below the minimum value (2.5V).
Figure 1. Measurement Setup
3
dc1999af
DEMO MANUAL DC1999A
QUICK START PROCEDURE
Figure 2. Typical Efficiency as a Function of Input Voltage and Load Current
Figure 3. Typical Transient Load Response for a
100mA to 600mA Transient Load VIN = 3.5V
Figure 4. Typical Transient Load Response for a
100mA to 600mA Transient Load VIN = 12V
4
dc1999af
DEMO MANUAL DC1999A
PARTS LIST
ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER
Required Circuit Components
1 1 C2 CAP CER 47µF 16V 20% X5R 1210 MURATA, GRM32ER61C476ME15L
2 3 C3, C10, C12 CAP CER 1µF 16V 10% X5R 0603 MURATA, GRM188R61C105KA93D
3 2 C4, C5 CAP CER 0.1µF 16V 10% X7R 0402 MURATA, GRM155R71C104KA88D
4 1 C6 CAP CER 22pF 50V 1% NP0 0402 MURATA, GJM1555C1H220FB01D
5 1 C7 CAP CER 1500pF 16V 10% 0402 AVX, 0402YC152KAT2A
6 1 C8 CAP CER 47pF 50V 5% NP0 0402 MURATA, GRM1555C1H470JZ01D
7 1 C9 CAP CER 100µF 16V 20% X5R 1210 TAIYO YUDEN, EMK325ABJ107MM-T
8 1 C11 CAP CER 100pF 50V 5% NP0 0402 MURATA, GRM1555C1H101JA01D
9 1 L1 INDUCTOR, 10µH COILCRAFT, XAL5050-103M
10 1 R1 RES 845k 1/16W 1% 0402 SMD PANASONIC, ERJ-2RKF8453X
11 1 R2 RES 158k 1/16W 1% 0402 SMD PANASONIC, ERJ-2RKF1583X
12 1 R3 RES 11.5k 1/16W 1% 0402 SMD PANASONIC, ERJ-2RKF1152X
13 1 R4 RES 41.2k 1/16W 1% 0402 SMD PANASONIC, ERJ-2RKF4122X
14 1 R5 RES 1.00M 1/16W 1% 0402 SMD PANASONIC, ERJ-2RKF1004X
15 1 R6 RES 0402 SMD (DNP)
16 1 R7 RES 49.9Ω 1/16W 1% 0402 SMD PANASONIC, ERJ-2RKF49R9X
17 1 U1 15V, 1.5A SYNCHRONOUS BUCK-BOOST DC/DC CONVERTER LINEAR TECH., LTC3111EDE #PBF
Additional Demo Board Circuit Components
1 0 C1 (OPT)CAP, TANT LOW ESR 47µF 35V 20% SMD AVX, TPSE476M035R0200
Hardware-For Demo Board Only
1 5 E1-E5 TURRET, 0.09 DIA MILL-MAX, 2501-2-00-80-00-00-07-0
3 2 JP1, JP2 JMP, 3-PIN 1 ROW 0.079CC SAMTEC, TMM-103-02-L-S
4 2 XJP1, XJP2 SHUNT, 0.079" CENTER SAMTEC, 2SN-BK-G
5 4 STAND OFF STAND-OFF, NYLON 0.375" TALL KEYSTONE, 8832 (SNAP ON)
5
dc1999af
DEMO MANUAL DC1999A
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
A
A
B
B
C
C
D
D
E
E
4 4
3 3
2 2
1 1
PWM
800kHz
BURST
OSC SYNC
1. ALL RESISTORS ARE IN
OHMS, 0402.
2. INSTALL SHUNTS
AS SHOWN.
NOTE: UNLESS
OTHERWISE
SPECIFIED
RUN
RUN
ON
OFF
TANT
1210 0603 1210
0603
0603
Vin > 5.0 V
VIN
VOUT
VCC
PWM/SYNC
VCC
PWM/SYNC
RUN
VIN
RUN
SIZE
DATE:
IC NO. REV.
SHEET OF
TITLE:
APPROVALS
PCB DES.
APP ENG.
TECHNOLOGY Fax: (408)434-0507
Milpitas, CA 95035
Phone: (408)432-1900
1630 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
3
DEMO CIRCUIT 1999A
11
15V, 1.5A SYNCHRONOUS BUCK-BOOST DC / DC CONVERTER
N/A LTC3111EDE
NC
JB
2 - 6 - 14
SIZE
DATE:
IC NO. REV.
SHEET OF
TITLE:
APPROVALS
PCB DES.
APP ENG.
TECHNOLOGY Fax: (408)434-0507
Milpitas, CA 95035
Phone: (408)432-1900
1630 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
3
DEMO CIRCUIT 1999A
11
15V, 1.5A SYNCHRONOUS BUCK-BOOST DC / DC CONVERTER
N/A LTC3111EDE
NC
JB
2 - 6 - 14
SIZE
DATE:
IC NO. REV.
SHEET OF
TITLE:
APPROVALS
PCB DES.
APP ENG.
TECHNOLOGY Fax: (408)434-0507
Milpitas, CA 95035
Phone: (408)432-1900
1630 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
3
DEMO CIRCUIT 1999A
11
15V, 1.5A SYNCHRONOUS BUCK-BOOST DC / DC CONVERTER
N/A LTC3111EDE
NC
JB
2 - 6 - 14
E5
GND
E5
GND
C10
1uF
C10
1uF
C7
1500pF
C7
1500pF
E2
VOUT
5.0V / 1.5A
E2
VOUT
5.0V / 1.5A
C11
100pF
C11
100pF
R3
11.5K
R3
11.5K
E3
GND
E3
GND
E4
GND
E4
GND
+
C1
OPT
+
C1
OPT
C5
0.1uF
C5
0.1uF
R5
1M
1%
R5
1M
1%
JP2JP2
1
2
3
C12
1uF
C12
1uF
C9
100uF
16V
C9
100uF
16V
R1
845k
1%
R1
845k
1%
JP1JP1
1
2
3
C6 22pFC6 22pF
C8
47pF
C8
47pF
C2
47uF
16V
C2
47uF
16V
R4
41.2K
R4
41.2K
R6
DNP
R6
DNP
C4
0.1uF
C4
0.1uF
R2
158K
1%
R2
158K
1%
E1
VIN
2.5V - 15.0V
E1
VIN
2.5V - 15.0V
L1
10uH
L1
10uH
U1
LTC3111EDE
U1
LTC3111EDE
SW1
6
NC 11
BST1
7
SGND 14
VIN
5
VCC
12
PWM/SYNC
13
RUN
4
SW2 9
SNSGND
3
BST2 8
VOUT 10
COMP 1
FB 2
GND
15
C3
1uF
C3
1uF
R7
49.9
1%
R7
49.9
1%
6
dc1999af
DEMO MANUAL DC1999A
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com
LINEAR TECHNOLOGY CORPORATION 2014
LT 0214 • 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
