DEMO MANUAL DC2268A-E
LTM4630EY-1
Dual 18A or Single 36A
μModule Regulator
DESCRIPTION
Demonstration circuit 2268A-E is a high efficiency, high
density, dual 18A, switch mode step-down power supply
on a compact 1.5' × 1.2' PCB. It features the
LTM4630-1
μModule regulator. The input voltage is from 4.5V to 15V.
The output voltage is programmable from 0.6V to 1.8V.
DC2268A-E can deliver up to 18A maximum in each chan-
nel. With the help of external compensation, ±3% transient
accuracy can be achieved with 25% load step. As explained
in the data sheet, output current derating is necessary
for certain V
IN
, V
OUT
, and thermal conditions. The board
operates in continuous conduction mode in heavy load
conditions. For high efficiency at low load currents, the
resistor jumper (R1/R2) selects pulse-skipping mode for
noise sensitive applications or Burst Mode
®
in less noise
sensitive applications. Two outputs can be connected in
parallel for a single 36A output solution with optional jumper
resistors. The board allows the user to program how its
output ramps up and down through the TRACK/SS pin.
Remote output voltage sensing is available for improved
output voltage regulation at the load point. An optional
input inductor L1 reduces the EMI noise for noise sensitive
applications. DC2268A can be easily inserted to an edge
connector for testing and debugging. These features and
the availability of the LTM4630-1EY in a compact 16mm
× 16mm × 5.01mm BGA package make it ideal for use in
many high-density point-of-load regulation applications.
The LTM4630-1 data sheet must be read in conjunction
with this demo manual for working on or modifying the
demo circuit DC2268A-E.
Design files for this circuit board are available at
http://www.linear.com/demo/DC2268A-E
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.
BOARD PHOTO
Figure 1. LTM4630-1/DC2268A-E Demo Board
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DEMO MANUAL DC2268A-E
PERFORMANCE SUMMARY
PARAMETER
Input Voltage Range
Output Voltage V
OUT1
Output Voltage V
OUT2
Per-Channel Maximum Continuous Output Current
Default Operating Frequency
Resistor Programmable Frequency Range
External Clock Sync. Frequency Range
Efficiency of Channel 1
Efficiency of Channel 2
Load Transient of Channel 1
Load Transient of Channel 2
V
IN
= 12V, V
OUT2
= 1.0V, I
OUT2
= 18A, f
SW
= 500kHz
V
IN
= 12V, V
OUT1
= 1.5V, I
OUT1
= 18A, f
SW
= 500kHz
V
IN
= 12V, V
OUT2
= 1.0V, I
STEP
= 0A ~ 4.5A
V
IN
= 12V, V
OUT1
= 1.5V, I
STEP
= 0A ~ 4.5A
V
IN
= 4.5V ~ 15V, I
OUT1
= 0A ~ 18A
V
IN
= 4.5V ~ 15V, I
OUT2
= 0A ~ 18A
Derating Is Necessary for Certain V
IN
, V
OUT
and Thermal
Conditions.
Specifications are at T
A
= 25°C
VALUE
4.5V ~ 15V
1.0V ±1.5% (0.985V ~ 1.015V)
1.5V ±1.5% (1.4775V ~ 1.5225V)
18A
500kHz
250kHz to 780kHz
400kHz to 780kHz
84.0% See Figure 3
87.9% See Figure 4
See Figure 5
See Figure 6
CONDITIONS
QUICK START PROCEDURE
Demonstration circuit DC2268A-E is easy to set up to
evaluate the performance of the LTM4630EY-1. It can
be easily inserted to an edge connector (SAMTEC MEC2-
20-01-L-DV--TR) for testing and debugging. Please refer
to Figure 2 for proper measurement setup and follow the
procedure below:
1. Pull up the RUN1 (J1 pin 22) and RUN2 (J1 pin 24)
between 1.4V to 5V or leave them floating.
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 12V.
3. Turn on the power supply at the input. The output
voltage in channel 1 should be 1.0V ± 1.5% (0.985V
~ 1.015V) and the output voltage in channel 2 should
be 1.5V ± 1.5% (1.4775V ~ 1.5225V),
4. 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 should be measured
at Co3 and Co4.
5. (Optional) LTM4630EY-1 can be synchronized to an
external clock signal. Remove R2 and apply a clock
signal (0~5V, square wave) to MODE-PLLIN pin.
6. (Optional) LTM4630EY-1 can be configured for a
2-phase single output at up to 36A on DC2268A-E.
Install 0Ω resistors on R26, R27, R28, R29, R32, and
remove R14, R18 R30. Output voltage is set by R7
based on equation V
OUT
= 0.6V(1 + 60.4k/R7).
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DEMO MANUAL DC2268A-E
QUICK START PROCEDURE
Table 2. DC2268A Demo Circuit
DEMO BOARD NUMBER
DC2268A-A
DC2268A-B
DC2268A-C
DC2268A-D
DC2268A-E
DC2268A-F
DC2268A-G
µMODULE REGULATOR ON THE BOARD
LTM4620
LTM4620A
LTM4628
LTM4630
LTM4630-1
LTM4630A
LTM4631
OUTPUT CURRENT
13A,13A
13A,13A
8A, 8A
18A,18A
18A,18A
18A, 18A
10A, 10A
Figure 2. Test Setup of DC2268A-E
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DEMO MANUAL DC2268A-E
QUICK START PROCEDURE
Efficiency, 1V
90
V
IN
= 12V
f
SW
= 500kHz
85.4
EFFICICENCY (%)
85
83.1
86.1 86.2 85.9
85.3
90
88.1
89 89.3 89.2 88.9
Efficiency, 1.5V
88.4
87.9
84
80
EFFICICENCY (%)
84.7
85
85.5
80
78.9
76.1
75
0
2
4
6
10 12
I
LOAD
(A)
8
14
16
18
75
0
2
4
6
V
IN
= 12V
f
SW
= 500kHz
8 10 12
I
LOAD
(A)
14
16
18
dc2268 F03
dc2268 F04
Figure 3. Measured Efficiency on Channel 1
(V
OUT1
= 1.0V, f
SW
= 500kHz, Channel 2 Disabled)
Figure 4. Measured Efficiency on Channel 2
(V
OUT2
= 1.5V, f
SW
= 500kHz, Channel 1 Disabled)
1V OUTPUT (20MHz BW) [50mV/DIV]
0A TO 4.5A LOAD STEP
dc2268 F05
Figure 5. Measured Channel 1 0A to 4.5A Load Transient (V
IN
= 12V, V
OUT1
= 1.0V)
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DEMO MANUAL DC2268A-E
QUICK START PROCEDURE
1.5V OUTPUT (20MHz BW) [50mV/DIV]
0A TO 4.5A LOAD STEP
dc2268 F06
Figure 6. Measured Channel 2 0A to 4.5A Load Transient (V
IN
= 12V, V
OUT2
= 1.5V)
Figure 7. Thermal Performance at V
IN
= 12V, V
OUT1
= 1.0V/14A,
V
OUT2
= 1.5V/14A, f
SW
= 500kHz, T
A
= 23°C, 200LFM Airflow
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