Linear Technology DC1755A Demo Manual page 2

DEMO MANUAL DC1755A
QUICK START PROCEDURE
Demonstration circuit 1755A is easy to set up to evalu-
ate the performance of the LTC3860EUH. 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 supply to be 0V. Place jumpers in the following
IN
positions:
JP1 RUNA
JP2 RUNB
JP3 INT PWR BLK BIAS
2) Adjust the input voltage to be between 6V to 14V. V
should 1.5V ± 2%.
V should 1.2V ± 2%.
OUTB
3) Next, apply 50A load to each output and remeasure
V .
OUT
4) Once the DC regulation is confirmed, observe the output
voltage ripple, load step response, efficiency and other
parameters.
Note 1. No airflow is required at room temperature with
50A on both outputs. But for ambient temperatures higher
than 30°C, a cooling fan is recommended.
Note 2. Use the BNC connectors labeled V
to measure the output voltage ripple.
2
Note 3. Do not apply the load from the VOSA
the VOSA
turret. These turrets are only intended to monitor the
voltage across COUT3 and COUT13 respectively. Heavy
load currents applied across these turrets may damage
the converter.
DYNAMIC LOAD CIRCUIT (OPTIONAL)
Demonstration circuit 1755A provides a simple load step
ON
circuit consisting of a MOSFET and sense resistor for each
ON
rail. To apply a load step, follow the steps below.
ON
1) Preset the amplitude of a pulse generator to 0.0V and
OUTA
the duty cycle to 5% or less.
2) Connect the scope to the VOUT BNC connectors for
the rail under test with a coax cable. To monitor the
load step current, connect the scope probe across the
ISTEP
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
amplitude of the pulse generator output to provide the
desired load step pulse height. The scaling for the load
or V step signal is 10mV/A.
OUTA OUTB
–
turret or from the VOSB
+–
turrets for that rail.
+
turret to
+ –
turret to the VOSB
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