Linear Technology LTC3624 Quick setup guide

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dc2359afb
DEMO MANUAL DC2359A
Description
LTC3624
High Efficiency Synchronous
Step-Down Regulator with
Ultralow Quiescent Current
Demonstration circuit 2359A is a synchronous step-down
regulatorusingLT C
®
3624HMSEmonolithic buckregulator.
The DC2359A operates from an input voltage range of 2.7V
to 17V and provides and adjustable output voltage range
from 1.2V to 5V(VOUT < VIN) at 2A of continuous output
current. A user-selectable mode input is provided with
the following options: Burst Mode
®
operation provides
the highest efficiency at light loads, while Pulse-Skipping
mode (PS) provides the lowest output voltage ripples.
Forced Continuous mode (FC) is also available for low
EMI and noise interference.
The MODE/SYNC pin can also be used to synchronize
the switching frequency to an external clock signal. The
switching frequency is fixed at 1MHz with a ±40% sync
capture range.
The regulator features ultralow quiescent current and high
efficiencies over a wide VIN and VOUT range. DC2359A
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
uses very low profile surface mount components and all
ceramic output capacitor solutions. The compact 12-lead
MSE (5mm × 4mm × 1mm) thermally enhanced package
makes LTC3624HMSE an excellent choice for battery
powered equipment, emergency radio and general pur-
pose step-down power supplies. The H-Grade version is
specified over an operating junction temperature range
of –40°C to 150°C, typically required for automotive, in-
dustrial and military applications that are subject to high
ambient temperatures.
It is recommended to read the data sheet and demo manual
ofLTC3624 prior usingor makingany changes toDC2359A.
Design files for this circuit board are available at
http://www.linear.com/demo/DC2359A
Specifications are at TA= 25°C
PARAMETER CONDITIONS VALUE
Input Voltage Range 2.7V to 17V
On Board User Selectable Output Voltages VIN = 2.7V to 17V, IOUT = 2A
(VOUT < VIN)
1.2V, 1.8V, 2.5V, 3.3V and 5V
Default Mode Setting JP2 Burst Mode (“BM” on Circuit Board)
Fixed Switching Frequency Internally Programmed Frequency 1MHz ±20%
Default Output Voltage VOUT VIN = 12V, VOUT = 5V, IOUT = 0A to 2A 5V ±2%
Maximum Continuous Output Current IOUT 2A
Output Voltage Ripples (Peak to Peak) VIN = 12V, VOUT = 5V, IOUT = 2A 8.8mV (Figure 7)
Load Transient Response VIN = 12V, VOUT = 5V, IOUT_STEP = 1A to 2A,
COUT = 1 × 47µF
219mV (Figure 8)
Thermal Performance VIN = 12V, VOUT = 5V, IOUT = 2A,
fSW = 1MHz, TA= 25°C
Figure 9
Efficiency VIN = 12V, VOUT = 5V, IOUT = 2A, BM,
fSW = 1MHz, TA= 25°C
89.7% (Figure 3)

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dc2359afb
DEMO MANUAL DC2359A
Quick start proceDure
Demonstration circuit 2359A is easy to set up to evaluate
the performance of the LTC3624HMSE. Please refer to
Figure 1 for proper measurement equipment setup and
follow the procedure below:
1. Place jumpers in the following positions for a typical
5V output application:
Table 1. Typical 5V Output Voltage Jumper Selection
JP1 JP2 JP7
RUN MODE/SYNC VOUT
ON BM 5.0V
2. With power off, connect the input power supply at
VIN(E1) and GND (E2)
3. Connect the Load between VOUT (E8) and GND (E9).
Preset the load to 0A.
4. Connect the DMMs to the input and output to monitor
the input voltage and output voltage.
5. Turn on the power supply at the input. The RUN pin
jumper should be at “ON” position. Measure and make
sure the input supply voltage is 12V. The output voltage
should be 5V ±2%.
6. Once the input and output voltages are properly es-
tablished, adjust the loads within the operating range
(0Ato 2A Max) and observe the output voltage regula-
tion, output voltage ripple, switch node waveform and
other parameters. Refer to Figure 2 for proper output
voltage ripple measurement.
7. To select other output voltages, use the on board user
selectable output voltage jumpers. Shutting down
LTC3624HMSE by placing RUN pin jumper (JP1) to the
OFF position or turn off the input power supply. Refer
to the following table (Table 2) for the output voltage
selection and repeat step 2 to 6.
Table 2. Output Voltage Jumper Selection
JP3 JP4 JP5 JP6 JP7 JP8*
1.2V 1.8V 2.5V 3.3V 5V User Select
*If JP8 is selected, R6 needs to be calculated and inserted to obtain the
desired output voltage.
NOTE 1: To measure the input/output voltage ripple prop-
erly, do not use the long ground lead on the oscilloscope
probe. See Figure 2 for the proper scope probe technique.
Short, stiff leads need to be soldered to the (+) and (–)
terminals of an output capacitor. The probe’s ground ring
needs to touch the (–) lead and the probe tip needs to
touch the (+) lead.
NOTE 2: The DC2359A can also be used to evaluate the
LTC3624HMSE-2 (2.25MHz) by simply replacing U1 with
the LTC3624HMSE-2 and changing inductor L1 to 1.5µH
(Coilcraft XAL4020-152ME).

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DEMO MANUAL DC2359A
Figure 2. Scope Probe Placement for Measuring Output Voltage Ripple
Figure 1. Proper Measurement Equipment Setup
+ –
VOUT GND
COUT
Quick start proceDure

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DEMO MANUAL DC2359A
Figure 5. Burst Mode –Efficiency vs Load Current at 5VIN Figure 6. Forced Continuous Mode –
Efficiency vs Load Current at 5VIN
Figure 3. Burst Mode –Efficiency vs Load Current at 12VIN Figure 4. Forced Continuous Mode –
Efficiency vs Load Current at 12VIN
Quick start proceDure
LOAD CURRENT (A)
0.01
70
EFFICIENCY (%)
75
80
85
90
0.10 1.00
1.10
DC2359a F03
65
60
55
50
95
100
1.2VOUT
1.8VOUT
2.5VOUT
3.3VOUT
5.0VOUT
LOAD CURRENT (A)
0.0
EFFICIENCY (%)
100
95
85
75
65
55
90
80
70
60
50 1.0 1.5
DC2359a F04
2.00.5
1.2VOUT
1.8VOUT
2.5VOUT
3.3VOUT
5.0VOUT
LOAD CURRENT (A)
0.0
EFFICIENCY (%)
100
95
85
75
65
55
90
80
70
60
50 1.0 1.5
DC2359a F06
2.00.5
1.2VOUT
1.8VOUT
2.5VOUT
3.3VOUT
0.01 0.10 1.00
1.10
LOAD CURRENT (A)
70
EFFICIENCY (%)
75
80
85
90
DC2359a F05
65
60
55
50
95
100
1.2VOUT
1.8VOUT
2.5VOUT
3.3VOUT

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DEMO MANUAL DC2359A
Quick start proceDure
Figure 7. Measured Output Voltage Ripple
t(1µs/DIV)
DC2359a F07
VOUT
20mV/DIV
VSW
10V/DIV
fSW = 1MHz
VIN = 12V
VOUT = 5V
ILOAD = 2A
L = 3.3µH
C
OUT
= 1x 47µF/6.3V/X5R/1206
20MHz BW LIMIT
VP-P = 8.8mV

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DEMO MANUAL DC2359A
Figure 8. Load Transient Response
Quick start proceDure
t(50µs/DIV)
VOUT
200mV/DIV
IOUT
1A/DIV
fSW = 1MHz
VIN = 12V
VOUT = 5V
ILOAD = 1A TO 2A
L = 3.3µH
C
OUT
= 1x 47µF/6.3V/X5R/1206
CFF = 15pF
20MHz BW LIMIT
VP-P = 219mV
1A TO 2A
DC2359a F08

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DEMO MANUAL DC2359A
Quick start proceDure
Figure 9. Thermal Performance
VIN = 12V
VOUT = 5V
ILOAD = 2A
L = 3.3µH
fSW = 1MHz
NO FORCED AIRFLOW
T
A
= 25°C
DC2359a F09

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DEMO MANUAL DC2359A
parts List
ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER
Required Circuit Components
1 1 CFF CAP, 0402 15pF 1% 50V NPO AVX 04025U150FAT2A
2 1 CIN CAP, 47μF 20% 20V 33mΩ PANASONIC OSCON 20SVPA47M
3 2 C2, C3 CAP, 1206 22μF 10% 25V X5R MURATA GRM31CR61E226KE15L
4 1 C4 CAP, 1206 47μF 20% 6.3V X5R TAIYO YUDEN JMK316BJ476ML-T
5 1 C8 CAP, 0603 2.2μF 10% 10V X5R AVX 0603ZD225KAT2A
6 1 L1 IND, 3.3μH XAL4030-332ME
7 2 R1, RSET RES, 0402 619kΩ 1% 1/16W VISHAY CRCW0402619KFKED
8 1 R2 RES, 0402 309kΩ 1% 1/16W VISHAY CRCW0402309KFKED
9 1 R3 RES, 0402 196kΩ 1% 1/16W VISHAY CRCW0402196KFKEA
10 1 R4 RES, 0402 137kΩ 1% 1/16W VISHAY CRCW0402137KFKED
11 1 R5 RES, 0402 84.5kΩ 1% 1/16W VISHAY CRCW040284K5FKED
12 2 R7, R12 RES, 0402 0Ω JUMPER VISHAY CRCW04020000Z0ED
13 1 R11 RES, 0402 1MΩ 5% 1/16W VISHAY CRCW04021M00JNED
14 1 U1 IC, MONOLITHIC SYNCHRONOUS BUCK
REGULATOR
LINEAR TECH LTC3624HMSE#PBF
Additional Demo Board Circuit Components
1 0 C5 CAP, 1206 22μF 20% 6.3V X5R OPTION TAIYO YUDEN EMK316BJ226ML-T OPTION
2 0 C6 CAP, 1210 OPTION OPTION
3 0 C7 CAP, 0402 OPTION OPTION
4 0 R6, R8, R9, R10 RES, 0402 OPTION OPTION
Hardware
1 10 E1, E2, E3, E4, E5, E6, E7, E8,
E9, E10
TURRET MILL-MAX 2501-2-00-80-00-00-07-0
2 1 JP1 HEADER, 3-PIN, 2mm SAMTEC TMM-103-02-L-S
3 1 JP2 HEADER, 4-PIN, 2mm SAMTEC TMM-104-02-L-S
46 JP3, JP4, JP5, JP6, JP7, JP8 HEADER, 2-PIN, 2mm SAMTEC TMM 102-02-L-S
5 4 MH1, MH2, MH3, MH4 STANDOFF, SNAP ON KEYSTONE 8833
6 3 XJP1, XJP2, XJP7 SHUNT, 2mm SAMTEC 2SN-BK-G

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DEMO MANUAL DC2359A
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 C C B B A A
[1]
CIN IS AN OPTIONAL CAPACITOR. IT IS INSERTED ON THE DC2359A TO DAMPEN THE (POSSIBLE) RINGING VOLTAGE DUE TO THE LONG INPUT LEADS. ON A NORMAL, TYPICAL PCB, WITH SHORT TRACES, THE CAPACITOR IS NOT NEEDED.
NOTES: [2]
FOR FCM OPERATION, STUFF R9 AND R10 WITH 1MEG OHM RESISTOR.
[2]
[2]
[2]
VOUT
Coilcraft XAL4030-332ME
ADJ
INTVCC
INTVCC
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
1
Wednesday, August 12, 2015
11
MONOLITHIC SYNCHRONOUS BUCK REGULATOR
` \
Z _
N/A
LTC3624HMSE DEMO CIRCUIT 2359A
WITH ULTRA-LOW QUIESCENT CURRENT
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
1
Wednesday, August 12, 2015
11
MONOLITHIC SYNCHRONOUS BUCK REGULATOR
` \
Z _
N/A
LTC3624HMSE DEMO CIRCUIT 2359A
WITH ULTRA-LOW QUIESCENT CURRENT
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
1
Wednesday, August 12, 2015
11
MONOLITHIC SYNCHRONOUS BUCK REGULATOR
` \
Z _
N/A
LTC3624HMSE DEMO CIRCUIT 2359A
WITH ULTRA-LOW QUIESCENT CURRENT
E10
GND
22uF C3 25V
1206
RSET 619k 1%
R10 OPT
JP1
ON OFF
RUN
1 3 2
U1
LTC3624HMSE (1MHz)
VIN
3
RUN
5
INTVCC
9
MODE/SYNC
10
PGOOD 6
FB 8
12 GND
11
GND
VIN
4
NC 7
SW 1 SW 2
C8 2.2uF 10V 0603
R1 619k 1%
E7
RUN
JP8 USER SELECT
15pF CFF
JP7 5.0V
E2
GND
E3
INTVCC
OPT C5 1206
R4 137k 1%
JP2
BM
FCM / SYNC
MODE
PS
1 3 2 4
R6 OPT
C7 OPT
47uF C4 6.3V
1206
R3
196k
1%
R11
1Meg
E4
SYNC
R8 OPT
E8
VOUT
2A
E5
GND
22uF C2 25V
1206
E1
VIN
2.7V - 17V
E6
PGOOD
R5 84.5K 1%
R2 309k 1%
R9 OPT
C6 OPT 1210
JP6 3.3V
JP3 1.2V
+
CIN
47uF
20V
[1] R12
0
JP5 2.5V
R7 0
JP4 1.8V
L1
3.3uH
E9
GND

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DEMO MANUAL DC2359A
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
[phone] ●FAX: [phone] ●www.linear.com
© LINEAR TECHNOLOGY CORPORATION 2015
LT 1015 REV B • PRINTED IN USA
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
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FOR ANY PARTICULAR PURPOSE. EXCEPT TO THE EXTENT OF THIS INDEMNITY, NEITHER PARTY SHALL BE LIABLE TO THE OTHER FOR
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observe good laboratory practice standards. Common sense is encouraged.
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engineer.
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