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DC1820A-A

P1-P3P4-P6
1
dc1820aabf
DEMO MANUAL
DC1820A-A/DC1820A-B
DESCRIPTION
LTC3646/LTC3646-1
High Efficiency Low Quiescent Current
Step-Down Converter
Demonstration circuit 1820A-A/1820A-B is a step-down
DC/DC converter using LTC3646/LTC3646-1 monolithic
synchronous buck regulator. The input voltage range is
from 4V to 40V. The output voltage range of LTC3646 is
2V to 30V, for LTC3646-1 is 0.6V to 15V. It can deliver up
to 1A of output current. At light load conditions, DC1820A
can operate in Burst Mode
®
operation to improve the ef-
ficiency. The user can choose to use internal or external
compensation. The switching frequency of LTC3646/
LTC3646-1 is programmable from 200kHz to 3MHz. It can
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
be synchronized to an external clock through the MODE/
SYNC pin. The LTC3646/3646-1 data sheet must be read
in conjunction with this demo manual prior to working on
or modifying demonstration circuit 1820A.
Design files for this circuit board are available at
http://www.linear.com/demo
Specifications are at T
A
= 25°C
PARAMETER CONDITIONS/NOTES VALUE
Input Voltage Range 4V to 40V
Output Voltage V
OUT
Jumper Selectable 3.3V, 5V
Maximum Continuous Output Current 1A
Default Operating Frequency 1.5MHz
Efficiency V
IN
= 12V, V
OUT
= 5V, I
OUT
= 1A 91.0% See Figure 3
Load Transient V
IN
= 12V, V
OUT
= 5V See Figure 4
2
dc1820aabf
DEMO MANUAL
DC1820A-A/DC1820A-B
V
IN
+
+
–
+
–
+
+–
+–
LOAD
QUICK START PROCEDURE
Demonstration circuit 1820A is an easy way to evaluate
the performance of the LTC3646/LTC3646-1. 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
application:
MODE EXTVCC RUN V
OUT
SELECT
FCC GND ON 3.3V
2. With power off, connect the input power supply, load
and meters as shown in Figure 1. Preset the load to 0A
and V
IN
supply to be 0V.
3. Turn on the power at the input. Increase V
IN
to 12V (Do
not hot-plug the input supply or apply more than the
rated maximum voltage of 40V to the board or the
part may be damaged). The output voltage should be
regulated and deliver the selected output voltage ±2%.
4. Vary the input voltage from 4V to 40V and adjust the
load current from 0A to 1A. Observe the output voltage
regulation, ripple voltage, efficiency, and other param-
eters.
5. To measure input or output ripple, please refer to Figure 2
for proper measurement setup.
Figure 1. Proper Measurement Equipment Setup
3
dc1820aabf
DEMO MANUAL
DC1820A-A/DC1820A-B
QUICK START PROCEDURE
Figures 3a and 3b. Measured DC1820A Efficiency at Different V
IN
and V
OUT
(Burst Mode Operation Enabled)
LTC3646 Efficiency, V
OUT
= 3.3V LTC3646 Efficiency, V
OUT
= 5V
Figure 4. Measured Load Transient Responses
LOAD (A)
0
EFFICIENCY (%)
100
10
90
70
50
30
80
60
40
20
0
dc1820aab F03a
1.00.4 0.80.2 0.6
V
IN
= 5V
V
IN
= 12V
V
IN
= 18V
V
IN
= 24V
V
IN
= 36V
(a)
LOAD (A)
0
EFFICIENCY (%)
100
10
90
70
50
30
80
60
40
20
0
dc1820aab F03b
1.00.4 0.80.2 0.6
V
IN
= 12V
V
IN
= 18V
V
IN
= 24V
V
IN
= 36V
(b)
V
OUT
: 50mV/DIV
I
OUT_STEP
: 500mA/DIV
dc1820aab F04
V
IN
= 12V
V
O
= 5V
0A TO 500mA LOAD STEP
Figure 2. Measuring V
IN
or V
OUT
Ripple
INPUT OR OUTPUT CAPACITOR
P1-P3P4-P6

DC1820A-A

Mfr. #:
Buy DC1820A-A
Manufacturer:
Analog Devices Inc.
Description:
Power Management IC Development Tools LTC3646 (MSOP) Demo Board - 4V to 40V In
Lifecycle:
New from this manufacturer.
Delivery:
DHL FedEx Ups TNT EMS
Payment:
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