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dc1477bfa
DEMO MANUAL DC1477B
Quick start proceDure
Demonstration circuit DC1477B is an easy way to evalu-
ate the performance of the LTM4609EV. 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
30V
OUT
application:
RUN
CLOCK
MODE
START
ON
PROG
CCM
SSO
2. With the power supply off, connect the input power
supply, load and meters as shown in Figure 1. Preset
the load to 0A and V
IN
supply between 10V to 36V.
3. Turn on the power at the input. The output voltage
should be 30V ± 2%.
4. Once the proper output voltage is established, adjust the
load within the operating range and observe the output
voltage regulation, ripple voltage, efficiency and other
parameters. A cooling fan and heat sink are necessary
for V
IN
<10V and I
OUT
= 3A.
5. To measure input and output ripple, please refer to
Figure 2 for proper setup.
6. To adjust the switching frequency turn off the power
supply and modify R6 and R7. Do not allow voltage at
pin PLLFLTR to exceed 2.4V.
7. Inductor and R
SENSE
should be modified to accom-
modate certain input and output condition. Refer to
the data sheet for details.
8. The input filter formed by CIN2, L2 and L3, CIN3 and
CIN4 is for the purpose of reducing the input voltage
ripple. The magnetic beads L2 and L3 are not necessary,
but they help to reduce the high frequency ringings on
the input supply significantly. See Figure 5 for details.
9. The optional components Rsnb1 and Csnb1, Rsnb2 and
Csnb2 can be used to form RC snubber circuits on the
switching nodes, which may help to reduce the output
ripple. Refer to the data sheet for details.
