Linear Technology DC1596A Quick setup guide

1
dc1596afa
DEMO MANUAL DC1596A
DESCRIPTION
LTC3607EUD
Dual 600mA 15V Monolithic
Synchronous Step-Down Regulator
Demonstration circuit DC1596 is a dual output regulator
consisting of two constant-frequency step-down convert-
ers, based on the LT C
®
3607 monolithic dual channel
synchronous buck regulator. The DC1596 has an input
voltagerangeof4.5Vto15V,witheachregulatorcapableof
delivering up to 600mA of output current. The DC1596 can
operate in either Burst Mode
®
operation or pulse-skipping
mode. In shutdown, the DC1596 quiescent current is less
than 1µA. The DC1596 is a very efficient circuit attaining
up to 90%. The DC1596 uses the LTC3607’s16-lead QFN
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
package, which has an exposed pad on the bottom side
of the IC for better thermal performance. These features,
plus a set operating frequency range of 2.25MHz, make
the DC1596 demo board an ideal circuit for industrial or
distributed power applications.
Design files for this circuit board are available at
http://www.linear.com/demo
Specifications are at TA= 25°C
PARAMETER CONDITIONS VALUE
Minimum Input Voltage 4.5V
Maximum Input Voltage 15V
Run RUN Pin = GND
RUN Pin = VIN
Shutdown
Operating
Output Voltage VOUT1 Regulation VIN1 = 4.5V to 15V, IOUT1 = 0A to 600mA 1.2V ±4% (1.152V-1.148V)
1.5V ±4% (1.44V-1.56V)
1.8V ±4% (1.728V-1.872V)
Typical Output Ripple VOUT1 VIN1 = 12V, IOUT1 = 600mA (20MHz BW) <20mVP-P
Output Voltage VOUT2 Regulation VIN2 = 4.5V to 15V, IOUT2 = 0A to 600mA 2.5V ±4% (2.425V-2.6V)
3.3V ±4% (3.168V-3.432V)
5V ±4% (4.8V-5.2V)
Typical Output Ripple VOUT2 VIN2 = 12V, IOUT2 = 600mA (20MHz BW) <20mVP-P
Mode Setting Mode Pin Floating
Mode Pin Grounded
Burst Mode Operation
Pulse-Skipping
Burst Mode Operation Output Current Thresholds Channel 1: PVIN1 = 12V, VOUT1 = 1.8V
Channel 2: PVIN2 = 12V, VOUT2 = 3.3V
IOUT1 < 480mA
IOUT2 < 360mA
Pulse-Skipping Operation Output Current
Thresholds
Channel 1: PVIN1 = 12V, VOUT1 = 1.8V
Channel 2: PVIN2 = 12V, VOUT2 = 3.3V
IOUT1 < 330mA
IOUT2 < 240mA
Switching Frequency 2.25MHz ±20%

2
dc1596afa
DEMO MANUAL DC1596A
QUICK START PROCEDURE
The DC1596 is easy to set up to evaluate the performance
of the LTC3607. For a proper measurement equipment
configuration, set up the circuit according to the diagram
in Figure 1.
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 the proper scope probe
technique in Figure 2.
Please follow the procedure outlined below for proper
operation.
1. Connect the input power supply tothe PVIN1/PVIN2 and
GND terminals (VIN1 and VIN2 are separate nodes but
are connected). Connect the loads between the VOUT
and GND terminals. Refer to Figure 1 for the proper
measurement equipment setup.
Before proceeding to operation, insert jumper shunts
XJP1 and XJP2 into the OFF positions of headers JP1
and JP2, shunt XJP3 into the pulse-skip position of
MODE header JP3, and shunt XJP4 into the VOUT1
voltage options of choice of header JP4: 1.2V, 1.5V, or
1.8V, and shunt XJP5 into the VOUT2 voltage options
of choice of header JP5: 2.5V, 3.3V, or 5V.
2. Apply 5.5V at PVINs 1, 2. Measure both VOUTs; they
should read 0V. If desired, one can measure the shut-
down supply current at this point. The supply current
will be less than 1µA in shutdown.
3. Turn on VOUT1 and VOUT2 by shifting shunts XJP1
and XJP2 from the OFF positions to the ON positions.
Both output voltages should be within a tolerance of
±2%.
4. Vary the input voltages from 5.8V(the minimum VIN is
dependent on VOUT) to 15V, and the load currents from
0A to 600mA. Both output voltages should be within
±4% tolerance.
5. Set the load current of both outputs to 600mA and the
input voltages to 12V, and then measure each output
ripple voltage (refer to Figure 2 for proper measure-
ment technique); they should each measure less than
20mVAC. Also, observe the voltage waveform at either
switch node (Pin 5 for reg.1 and Pin 8 for reg.2) of each
regulator. The switching frequencies should be about
2.25MHz ±20% (T= 555ns and 370ns). Both switch
node waveforms should be rectangular in shape, and
180° out-of-phase with each other.
6. To operate the ckt.s in Burst Mode operation, change
the shunt position of header JP3 to BURST MODE.
7. Regulators 1 (PVIN1) and 2 (PVIN2) are completely
separated from each other; thus, they can be powered
from different individual input supplies (if R11 is re-
moved), as can the signal input supply, SVIN. However,
SVIN must powered for either regulator to function
(SVIN is connected to PVIN1 through a filter on the
demo board.).
8. When finished, insert shunts XJP1 and XJP2 to the OFF
position(s) and disconnect the power.
Warning: If the power for the demo board is carried in
long leads, the input voltage at the part could “ring”, which
could affect the operation of the circuit or even exceed the
maximum voltage rating of the IC. To eliminate the ring-
ing, a small tantalum capacitor (for instance, AVXpart #
TPSY226M035R0200) is inserted on the pads between
the input power and return terminals on the bottom of the
demo board. The (greater) ESR of the tantalum capacitor
will dampen the (possible) ringing voltage caused by the
long input leads. On a normal, typical PCB, with short
traces, this capacitor is not needed.

3
dc1596afa
DEMO MANUAL DC1596A
QUICK START PROCEDURE
VIN GND
Figure 1. Proper Measurement Equipment Setup
Figure 2. Measuring Input or Output Ripple

4
dc1596afa
DEMO MANUAL DC1596A
QUICK START PROCEDURE
VSW1
10V/DIV
VSW2
10V/DIV
200ns/DIV
PVIN1,2 = 12V
VOUT1 = 1.8V AT IOUT1 = 600mA
VOUT2 = 3.3V AT IOUT2 = 600mA
PULSE-SKIPPING MODE
DC1596A F03
VOUT1
20mV/DIV
AC VOLTAGE
VOUT2
20mV/DIV
AC VOLTAGE
Figure 3. Switch Operation Figure 4. Load Step Response
Figure 6. Load Step ResponseFigure 5. Load Step Response
20µs/DIV
VIN = 12V
VOUT1 = 1.2V
400mA LOAD STEP (200mA TO 600mA)
PULSE-SKIPPING MODE, fSW = 2.25MHz
DC1596A F04
VOUT
100mV/DIV
AC-COUPLED
IOUT
200mA/DIV
20µs/DIV
VIN = 12V
VOUT1 = 1.5V
400mA LOAD STEP (200mA TO 600mA)
PULSE-SKIPPING MODE, fSW = 2.25MHz
DC1596A F05
VOUT
100mV/DIV
AC-COUPLED
IOUT
200mA/DIV
20µs/DIV
VIN = 12V
VOUT1 = 1.8V
400mA LOAD STEP (200mA TO 600mA)
PULSE-SKIPPING MODE, fSW = 2.25MHz
DC1596A F06
VOUT
100mV/DIV
AC-COUPLED
IOUT
200mA/DIV

5
dc1596afa
DEMO MANUAL DC1596A
QUICK START PROCEDURE
Figure 7. Load Step Response Figure 8. Load Step Response
Figure 9. Load Step Response
LOAD CURRENT (A)
0000.1
EFFICIENCY (%)
60
70
80
1
DC1596A F10
50
40
20 000.1 00.1 0.1
30
100
90
VIN = 5V, VO1 = 1.8V
VIN = 12V, VO1 = 1.8V
VIN = 5V, VO2 = 3.3V
VIN = 12V, VO2 = 3.3V
L1: 2.2µH 1616BZ VISHAY
L2: 4.7µH 1616BZ VISHAY
Burst Mode OPERATION
fSW = 2.25MHz
Figure 10. Efficiency
20µs/DIV
VIN = 12V
VOUT2 = 2.5V
400mA LOAD STEP (200mA TO 600mA)
PULSE-SKIPPING MODE, fSW = 2.25MHz
DC1596A F07
VOUT
100mV/DIV
AC-COUPLED
IOUT
200mA/DIV
20µs/DIV
VIN = 12V
VOUT2 = 3.3V
400mA LOAD STEP (200mA TO 600mA)
PULSE-SKIPPING MODE, fSW = 2.25MHz
DC1596A F08
VOUT
100mV/DIV
AC-COUPLED
IOUT
200mA/DIV
20µs/DIV
VIN = 12V
VOUT2 = 5V
400mA LOAD STEP (200mA TO 600mA)
PULSE-SKIPPING MODE, fSW = 2.25MHz
DC1596A F09
VOUT
100mV/DIV
AC-COUPLED
IOUT
200mA/DIV

6
dc1596afa
DEMO MANUAL DC1596A
PARTS LIST
ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER
Required Circuit Components
1 2 CFFW1, CFFW2 CAP., NPO, 22pF, 25V, 5%, 0402 AVX, 04025A220JAT2A
2 2 CIN1BYP, CIN2BYP CAP., X7R, 0.1µF, 16V, 10%, 0603 AVX, 0603YC104KAT2A
3 2 COUT1, COUT2 CAP., X5R, 10µF, 6.3V, 10%, 0805 AVX, 08056D106KAT2A
4 2 CIN1, CIN2 CAP., X5R, 10µF, 16V, 10%, 1206 AVX, 1206YD106KAT2A
5 1 L1 Inductor, 2.2µH VISHAY, IHLP1616BZER2R2M11
6 1 L2 Inductor, 4.7µH VISHAY, IHLP1616BZER4R7M11
7 1 R1 RES., CHIP, 210k, 1%, 0402 VISHAY, CRCW0402210KFKED
8 1 R2 RES., CHIP, 887k, 1%, 0402 VISHAY, CRCW0402887KFKED
9 1 R6 RES., CHIP, 196k, 1%, 0402 VISHAY, CRCW0402196KFKED
10 1 R7 RES., CHIP, 105k, 1%, 0402 VISHAY, CRCW0402105KFKED
11 1 U1 IC., LTC3607EUD, 16-PIN QFN 3X3 LINEAR TECH., LTC3607EUD
Additional Demo Board Circuit Components
1 3 COUT3, COUT4, CF CAP., X7R, 0.1µF, 16V, 10%, 0603 AVX, 0603YC104KAT2A
2 2 CIN3, CIN4 CAP., TANT, 22µF, 35V, 20%, CASE Y AVX, TPSY226M035R0200
3 0 COUT5, COUT6 (OPT.) CAP., X5R, 47µF, 6.3V, 10%, 1210 AVX, 12106D476KAQ2A
4 0 CIN5, CIN6 (OPT.) CAP., X5R, 47µF, 20V, 10%, 1812
5 1 RF RES., CHIP, 100Ω, 1/16W, 5%, 0402 VISHAY, CRCW0402100RJNED
6 1 R3 RES., CHIP, 210k, 1%, 0402 VISHAY, CRCW0402210KFKED
7 1 R4 RES., CHIP, 280k, 1%, 0402 VISHAY, CRCW0402280KFKED
8 1 R5 RES., CHIP, 140k, 1%, 0402 VISHAY, CRCW0402140KFKED
9 1 R8 RES., CHIP, 121k, 1%, 0402 VISHAY, CRCW0402105KFKED
10 0 R9, R10 (OPT.) RES., 0402
11 1 R11 RES., CHIP, 0Ω, 1%, 0805 VISHAY, CRCW08050000Z0ED
12 2 RSD1, RSD2 RES., CHIP, 5.1M, 5%, 0402 VISHAY, CRCW04025M10JNED
13 2 RPG1, RPG2 RES., CHIP, 100k, 1%, 0402 VISHAY, CRCW0402100KFKED
Hardware
1 12 E1-E12 Testpoint, TURRET, 0.094" MILL-MAX-2501-2-00-80-00-00-07-0
2 2 JP1,JP2 0.079 SINGLE ROW HEADER, 3-PIN SAMTEC, TMM103-02-L-S
3 2 JP4,JP5 0.079, 2X4 HEADER SAMTEC, TMM104-02-L-D
4 1 JP3 0.079, 2X3 HEADER SAMTEC, TMM103-02-L-D
5 5 JP1-JP5 SHUNT, FOR JP1-JP5 SAMTEC, 2SN-BK-G

7
dc1596afa
DEMO MANUAL DC1596A
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
RUN2
ON OFF
RUN1
ON
OFF
600mA 600mA
4.5V - 15V
1.2V
VFB1
1.5V 1.8V
2.5V 5V 3.3V
VFB2
USER SELECT
USER SELECT
4.5V - 15V
PULSE-SKIP EXT SYNC MODE/SYNC BURST MODE
DUAL 600mA MONOLITHIC, SYNCHRONOUS STEP-DOWN REGULATOR
[*] CIN3 AND CIN4 ARE INSERTED ON DC1596A TO DAMPEN THE (POSSIBLE) RINGING VOLTAGE DUETO THE USE OF LONG INPUT LEADS. ON A NORMAL, TYPICAL PCB, WITH SHORT TRACES, CIN3 AND CIN4 ARE NOT NEEDED.
**
TOM G.PRODUCTION2 3-15-13
__
REVISION HISTORY DESCRIPTION DATEAPPROVEDECO REV
2
Thursday, May 16, 2013
11
HZ
TG
N/A
LTC3607EUD DEMO CIRCUIT 1596A
SIZE DATE:
IC NO. REV.
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
E11
GND
R6
196k 1%
E7
VOUT1
RPG1
100k
RF
100
E3
GND
CIN1BYP 0.1uF 16V
E6
SYNC
E12
GND
CFFW1 22pF
COUT2 10uF 6.3V
CFFW2 22pF
+CIN3
22uF
35V
RPG2 100k
RSD1
5.1M
JP1
1 2 3
E2
PVIN2
JP5
1 2 3 4 5 6
87
E4
PGOOD1
R5
140k 1%
COUT1 10uF 6.3V
R2 887k 1%
JP4
1 2 3 4 5 6
87
R4
280k 1%
E10
GND
JP2
1 2 3
R10
OPT
L2
4.7uH
IHLP-1616BZER4R7M11
Vishay
JP3
1 2 3 4 5 6
R3 210k 1%
E8
VOUT2
CIN1 10uF 16V
COUT3 0.1uF 16V
+CIN5
47uF
20V OPT
CIN2 10uF 16V
R7
105k 1%
E9
GND
+CIN4
22uF
35V
CIN2BYP 0.1uF 16V
RSD2
5.1M
COUT5 47uF 6.3V OPT
E5
PGOOD2
COUT6 47uF 6.3V OPT
L1
2.2uH
IHLP-1616BZER2R2M11
Vishay
R11 0 Ohm 0805
E1
PVIN1
COUT4
0.1uF
16V
CF 0.1uF
R1 210k 1%
U1
LTC3607EUD
9
1
13
10
2
14
85
3
11
6
7
12
4
15 16
17
PGND2
MODE/SYNC
RUN2
SGND
PGOOD1
VFB2
SW2SW1
SVIN
PGOOD2
PVIN1
PVIN2
SGND
PGND1
VFB1 RUN1
GND
R8
121k 1%
+CIN6
47uF
20V OPT
R9
OPT

8
dc1596afa
DEMO MANUAL DC1596A
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
[phone] ●FAX: [phone] ●www.linear.com
 LINEAR TECHNOLOGY CORPORATION 2013
LT 0114 REV A • 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