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dc1626afa
DEMO MANUAL DC1626A
QUICK START PROCEDURE
Demonstration circuit 1626A is easy to set up to evalu-
ate the performance of the LTC3838EFE. Please refer to
Figure 1 for proper measurement equipment setup and
follow the procedure below.
1. With power off, connect the input supply, load and
meters as shown in Figure 1. Preset the load to 0A
and V
IN
supply to be 0V. Place jumpers in the following
positions:
JP4 RUN1 ON
JP1 RUN2 ON
JP3 MODE FCM
2. Adjust the input voltage to be between 4.5V to 26V.
V
OUT1
should 1.2V ±2%.
V
OUT2
should 1.5V ±2%.
3. Next, apply 15A load and recheck V
OUT
.
4. Once the DC regulation is confirmed, observe the output
voltage ripple, load step response, efficiency and other
parameters.
Note 1. Use the BNC connectors labeled V
OUT1
or V
OUT2
to measure the output voltage ripple.
Note 2. Do not apply the load from the turret
to the VO1_SNS– turret or from the VO2+ turret to the
VO2– turret. These turrets are only intended to monitor
the voltage across COUT1 and COUT5 respectively. Heavy
load currents applied across these turrets may damage
the converter.
Load Step Transient Testing
Demonstration circuit 1626A provides a simple load step
circuit consisting of a MOSFET and sense resistor for each
rail. To apply a load step, follow the steps below.
1. Preset the amplitude of a pulse generator to 0.0V and
the duty cycle to 5% or less.
2. Connect the scope to the V
OUT
BNC connectors for
the rail under test with a coax cable. To monitor the
load step current, connect the scope probe across the
/IOSTEP– turrets for that rail.
3. Connect the output of the pulse generator to the PULSE
GEN turret for the rail under test and connect the return
to one of the GND turrets.
4. With the converter running, slowly increase the ampli-
tude of the pulse generator output to provide the desired
load step pulse height. The scaling for the LOAD STEP
signal is 10mV/A.
