DC2243A - Demo Manual

DEMO MANUAL DC2243A
LT3668
40V Step-Down Regulator
with Dual Tracking LDOs
Description
Demonstration circuit 2243A is a triple power supply that
includes one 400mA step-down regulator and two 200mA
low dropout (LDO) linear tracking regulators featuring the
LT®3668. The demo circuit is designed for one 6V and dual
5V outputs from a 7V to 40V input. Two LDO outputs are
configured as post-regulators of the switching regulator
output. The total current capability of three output channels is up to 400mA, while the two LDO regulators are
capable of 200mA each.
The switching frequency of the step-down regulator can be
programmed via an oscillator resistor (R8) over a 250kHz
to 2.2 MHz range. The default setting is 600kHz.
The LT3668 internal boost diode and loop compensation
reduce the components count and solution size. The current mode control scheme creates fast transient response
and good loop stability. The switching regulator has cycleby-cycle current limit and diode current sense, providing
protection against shorted outputs.
JP1 can be used to set the whole LT3668 in shutdown
mode. JP3 and JP4 enable and disable the outputs of the
dual 5V tracking LDOs respectively.
The LT3668 data sheet gives a complete description of
the part, operation and application information. The data
sheet must be read in conjunction with this quick start
guide for demo circuit 2243A. Proper board layout is essential for both proper operation and maximum thermal
performance. See the data sheet section “PCB Layout”.
Design files for this circuit board are available at
http://www.linear.com/demo/DC2243A
L, LT, LTC, LTM, 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
Specifications are at TA = 25°C
SYMBOL
PARAMETER
CONDITIONS
VIN1
Input Supply Range of VIN1
fSW
Switching Frequency
VOUT1
MIN
TYP
MAX
UNITS
7
40
V
VIN1 = 12V, VOUT1 = 6V/IOUT1 = 400mA
VOUT2 = 5V/IOUT2 = 0
VOUT3 = 5V/IOUT3 = 0
510
690
kHz
Output Voltage 1
VIN1 = 12V, VOUT1 = 6V/IOUT1 = 0 ~ 400mA
VOUT2 = 5V/IOUT2 = 0
VOUT3 = 5V/IOUT3 = 0
5.88
6.12
V
VOUT2
Output Voltage 2
VIN1 = 12V, VOUT1 = 6V/IOUT1 = 0
VOUT2 = 5V/IOUT2 = 0 ~ 190mA
VOUT3 = 5V/IOUT3 = 0
4.9
5.1
V
VOUT3
Output Voltage 3
VIN1 = 12V, VOUT1 = 6V/IOUT1 = 0
VOUT2 = 5V/IOUT2 = 0
VOUT3 = 5V/IOUT3 = 0 ~ 190mA
4.9
5.1
V
IOUT1 + IOUT2 + IOUT3
Maximum Total Output Current
400
IOUT2, IOUT3
Maximum LDO Output Current
190
mA
200
mA
dc2243af
1
DEMO MANUAL DC2243A
description
100
90
EFFICIENCY (%)
80
70
60
50
40
VOUT1 = 6V
fSW = 600kHz
IOUT2 = 0A
IOUT3 = 0A
30
20
10
0
VIN1 = 12V
VIN1 = 24V
0.1
0.2
0.3
VOUT1 LOAD CURRENT (A)
0.4
DC2234 F01
Figure 1. VOUT1 Typical Efficiency vs. Load Current
Quick Start Procedure
Demonstration circuit 2243A is easy to set up to evaluate the performance of the LT3668. Refer to Figure 2 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. See Figure 3 for the proper
scope technique.
1.Place JP1, JP3 and JP4 on the EN position.
2.With power off, connect the input power supply to VIN1
and GND.
4.Turn on the power at the input.
NOTE: Make sure that the input voltage does not exceed
40V.
5.Check for the proper output voltages:
VOUT1 = 6V, VOUT2 = 5V, VOUT3 = 5V
NOTE: If there is no output, temporarily disconnect the
load to make sure that the loads are not set too high or
are shorted.
6.Once the proper output voltages are established, adjust
the loads within the operating ranges and observe the
output voltage regulation, ripple voltage, efficiency and
other parameters.
3.With power off, connect loads from VOUT1 to GND, from
VOUT2 to GND, and from VOUT3 to GND.
2
dc2243af
DEMO MANUAL DC2243A
Quick Start Procedure
–
VIN1
+
+
–
VOUT1
–
+
–
LOAD
–
VOUT3
+
–
LOAD
VOUT2
+
+
+
–
–
–
+
–
–
+
+
–
+
LOAD
+
Figure 2. Proper Measurement Equipment Setup
VOUT
GND
Figure 3. Measuring Input or Output Ripple
dc2243af
3
DEMO MANUAL DC2243A
Parts List
ITEM
QTY
REFERENCE
PART DESCRIPTION
MANUFACTURER/PART NUMBER
Required Circuit Components
1
1
C2
CAP., X7R 2.2µF 100V 10% 1206
AVX, 12061C225KAT2A
2
1
C3
CAP., X7R 0.22µF 25V 10% 0603
AVX, 06033C224KAT2A
3
1
C4
CAP., NPO 22pF 25V 5% 0603
AVX, 06033A220JAT2A
4
1
C5
CAP., X5R 22µF 25V 20% 1210
MURATA, GRM32ER61E226ME15L
5
2
C7, C11
CAP., X5R 10µF 10V 10% 1206
AVX, 1206ZD106KAT2A
6
2
C9, C10
CAP., X5R 1µF 25V 20% 0603
AVX, 06033D105MAT2A
7
1
D1
DIODE, SCHOTTKY 60V 1A POWERDI123
DIODES INC., DFLS160-7
8
1
L1
INDUCTOR, 27µH
SUMIDA, CDRH5D28RHPNP-270MC
9
1
R1
RES., CHIP 243k 0.10W 1% 0603
VISHAY, CRCW0603243KFKEA
10
1
R5
RES., CHIP 150k 0.10W 5% 0603
VISHAY, CRCW0603150KJNEA
11
1
R7
RES., CHIP 931k 0.10W 1% 0603
VISHAY, CRCW0603931KFKEA
12
1
R8
RES., CHIP 174k 0.10W 1% 0603
VISHAY, CRCW0603174KFKEA
13
1
R9
RES., CHIP 294k 0.10W 1% 0603
VISHAY, CRCW0603294KFKEA
14
1
U1
I.C., VOLTAGE REG. MSOP(16)-MSE16
LINEAR TECH., LT3668EMSE#PBF
Additional Demo Board Circuit Components
1
1
C1
CAP., Alum 10µF 63V 20% OSCON-CE-6.3
SUN ELECTRONIC INDUSTRIES, 63CE10GA
2
1
C6
CAP., X7R 0.1µF 25V 10% 0603
MURATA, GRM188R71E104KA01D
3
0
C8, C12, C17, C18 (Opt)
CAP., 0603
4
2
C13, C14
CAP., X7R 0.047µF 25V 20% 0603
5
0
C15, C16 (OPT)
CAP., OSCON-CE-6.3
AVX, 06033C473MAT2A
6
0
C19, C20 (OPT)
CAP., 1206
7
0
FB1 (OPT)
FERRITE BEAD, 600Ω/500mA 0603
8
0
L2 (OPT)
INDUCTOR, 4.7µH
SUMIDA, CDRH2D18/LDNP-4R7NC
9
4
R6, R13, R17, R18
RES/JUMPER, CHIP 0Ω 0.25W 5A 0603
VISHAY, CRCW06030000Z0EA
10
2
R10, R12
RES., CHIP 1.50k 0.10W 1% 0603
VISHAY, CRCW06031K50FKEA
11
2
R19, R20
RES., CHIP 200k 0.10W 5% 0603
VISHAY, CRCW0603200KJNEA
TDK, MMZ1608S601AT
Hardware: For Demo Board Only
1
18
E1–E18
TURRET, TESTPOINT
MILL-MAX, 2501-2-00-80-00-00-07-0
2
3
JP1, JP3, JP4
HEADERS, 3 PINS 2mm CTRS.
SULLINS, NRPN031PAEN-RC
3
3
XJP1, XJP3, XJP4
SHUNT, 2mm CTRS.
SAMTEC, 2SN-BK-G
4
4
MH1–MH4
STANDOFF, NYLON 0.25''
KEYSTONE, 8831(SNAP ON)
4
dc2243af
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.
A
B
C
D
EN
DIS
EN
DIS
DIS
EN
3
2
1
3
2
1
3
2
1
R10
PG
C19
1206
(OPT)
E18
47nF
C14
1.50k
1%
R12
47nF
C13
1.50k
1%
VIN1
FB1
200k
200k
VOUT1
E12
EN3 / ILIM3
E9
EN2 / ILIM2
VIN1
4.7uH
C20 CDRH2D18/LDNP‐4R7NC
Sumida
1206
(OPT)
(OPT)
L2
EMI Filter
R20
R5
150k
VOUT1
C1
10uF
63V
R19
E7
+
VIN1
MMZ1608S601AT
0603
(OPT)
E5
EN
E8
E3
E1
4
5
1. ALL RESISTORS ARE 0603
ALL CAPACITORS ARE 0603
4
3
13
12
4
14
C2
2.2µF
100V
1206
VOUT1_5V
fs=600KHz
174k
1%
R8
NOTE: UNLESS OTHERWISE SPECIFIED
VIN1_EMI
JP4
EN3
JP3
EN2
JP1
ENABLE
GND
GND
VIN1
7V TO 40V
TRANSIENT TO 60V
5
IN1
E2
ADJ3
7
C18
(Opt)
0603
ADJ3
3
6
C11
10µF
10V
1206
OUT3
U1
LT3668EMSE
C10
1µF
IN2
FB1
DA
SW
5
IN3/BD
ADJ2
0 Ohm
R18
9
10
11
8
16
1
0.22µF
OUT2
BOOST
2
C3
C9
1µF
C17
(Opt)
0603
E17
ADJ2
R9
294k
1%
0 Ohm
R13
D1
DFLS160‐7
VOUT3
0 Ohm
R6
931k
1%
R7
C4
22pF
L1
27µH
CDRH5D28RHPNP‐270M
Figure 4. DC2243A Demo Circuit Schematic
0 Ohm
R17
17
GND
EN3/ILIM3
EN2/ILIM2
RT
PG
EN
15
3
2
2
C7
10µF
10V
1206
R1
243k
1%
VOUT1_5V
C5
22µF
25V
1210
VOUT3
VOUT2
VOUT1
C12
OPT
(Opt)
+ C16
C8
OPT
(Opt)
+ C15
C6
0.1uF
1
1
E14
E13
E15
E11
E10
E16
E6
E4
GND
VOUT3
5V / 200mA
IN3/BD
GND
VOUT2
5V / 200mA
IN2
GND
*
VOUT1
6V / * SEE DEMO MANUAL FOR CURRENT CAPABILITY
A
B
C
D
DEMO MANUAL DC2243A
Schematic Diagram
dc2243af
5
DEMO MANUAL DC2243A
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,
customer product design, software performance, or infringement of patents or any other intellectual property rights of any kind.
LTC 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 LTC application engineer.
Mailing Address:
Linear Technology
1630 McCarthy Blvd.
Milpitas, CA 95035
Copyright © 2004, Linear Technology Corporation
6
dc2243af
Linear Technology Corporation
LT 0315 • PRINTED IN USA
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900
●
FAX: (408) 434-0507 ● www.linear.com
 LINEAR TECHNOLOGY CORPORATION 2015
Similar pages