2
dc1453af
DEMO MANUAL DC1453A
V
IN
+
–
+
–
–
+
0A ~ 4A
+
–
–
+
LOAD
0A ~ 4A
–
+
–
+
LOAD
QUICK START PROCEDURE
Demonstration circuit 1453A is an easy way to evaluate the
LTM4619. If V
IN
is always below 5.5V, stuff a 0Ω resistor
at R16. Do not stuff R16 if V
IN
is higher than 5.5V. 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
3.3V and 1.8V application:
MODE/
CLK SEL.
RUN1
FREQUENCY
TRACK1
RUN2
TRACK2
CCM
On
500kHz
Soft-Start
On
Soft-Start
2. With power off, preset the loads to 0A and V
IN
supply
to be less than 28V. Connect the input power supply,
load and meters as shown in Figure 1.
3. Turn on the power at the input. The output voltage
between V
O1
+
and V
O1
–
should be 3.3V ±2%, and the
voltage between V
O2
+
and V
O2
–
should be 1.8V ±2%.
4. Once the proper output voltage is established, adjust
the load within the operating range and observe the
output voltage regulation, ripple voltage, effi ciency and
other parameters.
To measure input and output ripple, please refer to Fig-
ure 2 for proper setup. Keep in mind at high switching
frequencies and/or high input voltages, lower output
voltage may not regulate properly due to the minimum
on time of the regulator. Refer to the data sheet for more
details.
5. For output voltage tracking during start-up and shut-
down, set jumpers JP3 and JP4 to EXT SIGNAL and
apply a valid voltage signal to E8 and E10.
6. To synchronize the switching frequency to an external
clock set jumper JP2 in the EXT. CLK position and the
jumper JP1 in the BURST MODE / EXT. CLK position.
Apply a valid clock signal on the CLK SYNC test point.
Figure 1. Test Setup of DC1453A
Figure 2. Proper Scope Probe Placement
for Measuring Input or Output Ripple
INPUT OR OUTPUT CAPACITOR