2
dc1663af
DEMO MANUAL DC1663A
QUICK START PROCEDURE
PERFORMANCE SUMMARY
Demonstration circuit DC1663A is easy to set up to evalu-
ate the performance of the LTM4628EV. Please refer to
Figure 1 for proper measurement equipment setup and
the following the procedure:
1. Place jumpers in the following positions for a typical
application:
JP1
JP2
JP3
JP4
JP5
JP6
MODE
RUN1
RUN2
TRACK1
SEL.
TRACK2
SEL.
CLKOUT
PHASE
CCM
ON
ON
SOFT-
START
SOFT-
START
60°
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 volt-
age in channel 1 should be 1.5V ± 1.5% and the output
voltage in channel 2 should be 1.2V ± 1.5%.
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 SMA cables. 50Ω termination should
be set on the oscilloscope or SMA cables.
5. (Optional) For optional load transient test, apply an
adjustable pulse signal between IOSTEP CLK and GND
pins. Pulse amplitude (3V to 3.5V) sets the load step
current amplitude. The pulse signal should have very
small duty cycle (< 10%) to limit the thermal stress on
the transient load circuit. The output transient current
can be monitored at the SMA connector J3 (15mV/A).
Apply the jumper resistors R34 or R35 (on the back-
side of boards) to apply load transient on channel 1 or
channel 2 correspondingly.
6. (Optional) LTM4628 can be synchronized to an external
clock signal. Remove the jumper on JP1 and apply a clock
signal (0V to 5V, square wave) on the CLKIN test point.
7. (Optional) The outputs of LTM4628 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) LTM4628 can be configured for a 2-phase
single output at up to 16A on DC1663A. Refer to the
schematic for corresponding jumper resistor setup for
dual phase single output applications.
PARAMETER
CONDITION
VALUE
Input Voltage Range
4.5V to 26.5V
Output Voltage V
OUT1
V
IN
= 4.5 to 26.5V, I
OUT1
= 0A to 8A, JP1: CCM
1.5V ± 1.5% (1.4775V to 1.5225V)
Output Voltage V
OUT2
V
IN
= 4.5 to 26.5V, I
OUT2
= 0A to 8A, JP1: CCM
1.2V ± 1.5% (1.182V to 1.218V)
Per Channel Maximum Continuous Output Current Derating is Necessary for Certain V
IN
, V
OUT
and
Thermal Conditions, See Datasheet for Details.
8A
Default Operating Frequency
400kHz
External Clock Synchronous Frequency Range
400kHz to 780kHz
Efficiency of Channel 1
V
IN
= 5V, V
OUT1
= 1.5V, I
OUT1
= 8A, f
SW
= 400 kHz
87.7% See Figure 2
Efficiency of Channel 2
V
IN
= 5V, V
OUT2
= 1.2V, I
OUT2
= 8A, f
SW
= 400 kHz
85.5% See Figure 3
Load Transient of Channel 1
V
IN
= 12V, V
OUT1
= 1.5V, I
SETP
= 0A to 4A
See Figure 4
Load Transient of Channel 2
V
IN
= 12V, V
OUT2
= 1.2V, I
SETP
= 0A to 4A
See Figure 5
(T
A
= 25°C)
