DEMO MANUAL DC1892A
LTM4630EV
High Efficiency, Dual 18A
Step-Down Power
µModule
®
Regulator
DESCRIPTION
Demonstration circuit 1892A features the
LTM
®
4630EV,
the high efficiency, high density, dual 18A, 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. DC1892A can deliver up to 18A maximum
in each channel. As explained in the LTM4630 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 effi-
ciency at low load currents, the MODE jumper (JP1) selects
pulse-skipping mode for noise-sensitive applications or
Burst Mode
®
operation 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. The output can be set
up to either coincidentally or ratiometrically track with
another supply’s output. Remote output voltage sens-
ing is available for improved output voltage regulation
at the load point. These features and the availability of
the LTM4630EV in a compact 16mm × 16mm × 4.41mm
LGA package make it ideal for use in many high density
point-of-load regulation applications. The LTM4630 data
sheet must be read in conjunction with this demo manual
for working on or modifying the demo circuit DC1892A.
Design files for this circuit board are available at
http://www.linear.com/demo/DC1892A
L,
LT, LTC, LTM, Linear Technology, Linear logo, μModule and Burst Mode are registered
trademarks of Linear Technology Corporation. All other trademarks are the property of their
respective owners.
BOARD PHOTO
Figure 1. DC1892A
dc1892afb
1
DEMO MANUAL DC1892A
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
= 5V, V
OUT1
= 1.5V, I
OUT1
= 18A, f
SW
= 500kHz
V
IN
= 5V, V
OUT2
= 1V, I
OUT2
= 18A, f
SW
= 500kHz
V
IN
= 12V, V
OUT1
= 1.5V, I
SETP
= 9 ~ 18A
V
IN
= 12V, V
OUT2
= 1V, I
SETP
= 9 ~ 18A
V
IN
= 4.5 ~ 15V, I
OUT1
= 0A ~ 18A, JP1: CCM
V
IN
= 4.5 ~ 15V, I
OUT2
= 0A ~ 18A, JP1: CCM
Derating Is Necessary for Certain V
IN
, V
OUT
and Thermal
Conditions. See the LTM4630 Data Sheet for Details
Specifications are at T
A
= 25°C
VALUE
4.5V ~ 15V
1.5V ± 1.5% (1.4775V ~ 1.5225V)
1V ± 1.5% (0.985V ~ 1.015V)
18A
500kHz
250kHz to 780kHz
400kHz to 780kHz
89.7%, See Figure 3
84.8%, See Figure 4
See Figure 5
See Figure 6
CONDITIONS/NOTES
QUICK START PROCEDURE
Demonstration circuit DC1892A is easy to set up to evalu-
ate the performance of the LTM4630EV. Please refer to
Figure 2 for proper measurement setup and follow the
procedure below:
1. Place jumpers in the following positions for a typical
application:
JP1
MODE
CCM
JP2
RUN1
ON
JP3
RUN2
ON
JP4
TRACK1
SEL.
SOFT-
START
JP5
TRACK2
SEL.
SOFT-
START
JP6
CLKOUT
PHASE
90°
5.
(Optional)
For optional load transient test, apply an
adjustable pulse signal between the IOSTEP CLK and
GND test points. Pulse amplitude (3V ~ 3.5V) sets the
load step current amplitude. The output transient current
can be monitored at the BNC connector J3 (15mV/A).
The pulse signal should have very small duty cycle
(< 10%) to limit the thermal stress on the transient load
circuit. Switch the jumper resistors R34 or R35 (on the
backside of boards) to apply load transient on channel
1 or channel 2, correspondingly.
6.
(Optional)
LTM4630 can be synchronized to an external
clock signal. Place the JP1 jumper on EXT_CLK and
apply a clock signal (0 ~ 5V, square wave) on the CLKIN
test point.
7.
(Optional)
The outputs of LTM4630 can track another
supply. The jumpers JP4 and JP5 allow choosing soft-
start or output tracking. If tracking external voltage is
selected, the corresponding test points, TRACK1 and
TRACK2, need to be connected to a valid voltage signal.
8.
(Optional)
LTM4630 can be configured for a 2-phase
single output at up to 36A on DC1892A. Install 0Ω
resistors on R14, R17, R28, R39 and remove R7, R19.
Output voltage is set by R25 based on the equation:
60.4k
V
OUT
=
0.6V •
1+
R25
dc1892afb
2. With power off, connect the input power supply, load
and meters, as shown in Figure 1. Preset the load to
0A and the V
IN
supply to 12V.
3. Turn on the power supply at the input. The output volt-
age in channel 1 should be 1.5V ± 1.5% (1.4775V ~
1.5225V) and the output voltage in channel 2 should
be 1V ± 1.5% (0.985V ~ 1.015V).
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 J1 and J2 with BNC cables. 50Ω termination should
be set on the oscilloscope or BNC cables.
2
京公网安备 11010802033920号
EEWORLD
