DEMO MANUAL DC2479A-B
LTM4650EY-1
Dual Phase Single 50A
DC/DC μModule Regulator
DESCRIPTION
Demonstration circuit 2479A-B features the
LTM
®
4650EY-1,
the high efficiency, high density, dual 25A, single 50A
switch mode step-down power module regulator. The
input voltage is from 4.5V to 15V. The output voltage is
programmable from 0.6V to 1.8V. DC2479A-B is configured
as dual-phase, single-output, which can deliver up to 50A
maximum. The board designs with minimum components
to demonstrate this high efficiency, high density µModule.
As explained in the data sheet, output current de-rating is
necessary for certain V
IN
, V
OUT
, and thermal conditions.
These features and the availability of the LTM4650EY-1
in a compact 16mm
×
16mm
×
5.01mm BGA package
make it ideal for use in many high-density point-of-load
applications. The LTM4650-1 data sheet must be read
in conjunction with this demo manual for working on or
modifying the demo circuit DC2479A-B.
Design files for this circuit board are available at
http://www.linear.com/demo/DC2479A-B
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.
BOARD PHOTO
Figure 1. LTM4650-1/DC2479A-B Demo Board
dc2479abf
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DEMO MANUAL DC2479A-B
PERFORMANCE SUMMARY
PARAMETER
Input Voltage Range
Output Voltage V
OUT
Maximum Continuous Output Current
Default Operating Frequency
Efficiency
Load Transient
V
IN
= 12V, V
OUT
= 1.0V, I
OUT
= 50A, f
SW
= 500 kHz
V
IN
= 12V, V
OUT
= 1.0V, I
STEP
= 25A to 37.5A
V
IN
= 4.5~15V, I
OUT
= 0~50A
De-Rating is Necessary for Certain V
IN
, V
OUT
and Thermal Conditions,
See Data Sheet for Detail.
CONDITIONS/NOTES
Specifications are at T
A
= 25°C
VALUE
4.5V ~ 15V
1.0V ± 1.5% (0.985V ~ 1.015V)
50A
500kHz
86.6%, See Figure 4
< 60mV
P-P
, See Figure 5
QUICK START PROCEDURE
Demonstration circuit DC2479A-B is easy to set up to
evaluate the performance of the LTM4650EY-1. Please
refer to Figure 1 for proper measurement setup and follow
the procedure below:
1. With power off, connect the input power supply, load
and meters as shown in Figure 2. Preset the load to 0A
and V
IN
supply to 12V.
2. Turn on the power supply at the input. The output volt-
age should be 1.0V ± 1.5% (0.985V~1.015V).
3. Once the proper output voltage is established, adjust the
load within the operating range and observe the output
voltage regulation, output voltage ripple, efficiency and
other parameters. Output ripple can be measured at J6
with BNC cables.
4. (Optional) For optional load transient test, apply an
adjustable pulse signal between “IOSTEP CLK” and
“GND” test point. Pulse amplitude (3V~3.5V) sets the
load step current amplitude. The output transient current
can be monitored at the BNC connector J5 (10mV/A).
The pulse signal should have very small duty cycle
(< 10%) to limit the thermal stress on the transient
load circuit.
2
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DEMO MANUAL DC2479A-B
QUICK START PROCEDURE
+
1m
–
LOAD (0A ~ 50A)
+
V
OUT
–
dc2479ab F02
–
+
+ +
–
–
V
IN
4.5V-15V
Figure 2. Test Setup of DC2479A-B
+
V
OUT
C
OUT
GND
–
Figure 3. Measuring Output Voltage Ripple
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DEMO MANUAL DC2479A-B
QUICK START PROCEDURE
Efficiency at V
IN
= 12V, V
O
= 1.0V
90%
85%
EFFICIENCY
80%
75%
70%
1
5
10
15
20
25
30
35
40
45
50
dc2479 F04
LOAD CURRENT
Figure 4. Efficiency vs Load Current at V
IN
= 12V, V
O
= 1V, f
SW
= 500kHz
V
O
(20MHz BW) [20mV/DIV, AC COUPLED]
25A – 37.5A LOAD STEP
Figure 5. Measured 25A – 37.5A Load Transient Response (V
IN
= 12V, V
OUT
= 1.0V, f
SW
= 500kHz)
4
dc2479abf
DEMO MANUAL DC2479A-B
QUICK START PROCEDURE
V
OUT
(20MHz BW) [5mV/DIV]
Figure 6. Output Voltage Ripple at V
IN
= 12V, V
OUT
= 1V, I
OUT
= 50A, f
SW
= 500kHz
Figure 7. Thermal Performance at V
IN
= 12V, V
OUT
= 1V, I
OUT
= 50A, T
A
= 23.8°C, No Air Flow
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