QNT Triple Output DC-DC Series Data Sheet
80W • 48V Input • 0.95V to 5V Outputs
Feature Specifications
All specifications apply over input voltage, output load, and temperature range, unless otherwise noted.
Parameter
Remote Control (ON/OFF)
POSITIVE LOGIC
Converter OFF
Conditions/Description
Min
Nom
Max
Units
On/Off signal is low – converter is OFF
Shutdown pin is pulled low
Open circuit
3.6
0
20
0.8
Vdc
Vdc
Converter ON
Open Circuit
RC open
NEGATIVE LOGIC
Converter OFF
Converter ON
On/Off signal is low – converter is ON
Shutdown pin open circuit or voltage source
Shutdown pin is pulled low
2.4
-10
20
0.7
Vdc
Vdc
TTL output
Power Good
Disable output
Enable output
-5
2.5
0.6
5
Vdc
Vdc
Output Enable/Disable
Open circuit
The user must take care to ensure that the pin
reference for the control is connected close to the
Typical Application
This series of converters does not require any external
components for proper operation. However, if the
distribution of the input voltage to the converter contains
significant inductance, a capacitor across the input
terminals may be required to stabilize the input voltage.
A minimum of 1µF, quality electrolytic / ceramic
capacitor is recommended for this purpose.
For output decoupling it is recommended to connect a
2µF ceramic capacitor or higher value directly across
the output pins of the converter.
-VIN pin.
The control signal must not be
referenced ahead of EMI filtering, or remotely
from the unit.
Sequencing / Startup options
Start-up is defaulted to have no sequence but for
all outputs to typically start together and track
within 300mV of each other (similar load
conditions on each output).
More precise
tracking is possible using external components.
Remote Control Features:-
Power Good (Pgood)
A TTL level signal indicates that an individual
output has reached the correct voltage levels.
•
Standard Shutdown Feature (Positive Logic)
The remote control pin functions as a normal soft
shutdown. It is referenced to the -VIN pin. With positive
logic, when the remote control pin has a TTL voltage
applied, the output is turned off and the unit goes into a
very low input power mode.
Individual Output Enable/Disable
When this pin is pulled low (<0.6V), the individual
output is disabled. It should be used with an open
collector/drain signal.
Option “-N”
Any specific sequence can be configured by
connecting the Pgood of one output to the Enable
of another output. This causes approximately a
5ms startup delay between the first output and the
second output; the third output can be setup with
a similar method.
•
Inhibit Feature (Negative Logic)
This option reverses the logic required for Shutdown. It
is referenced to the –VIN pin. With negative logic, when
the remote control pin is pulled low, the output is turned
on (active low logic, failsafe).
Longer sequences are possible by individually
using the Enable inputs of each output or by
delaying the Pgood signal (via an RC network).
An open collector switch is recommended to control the
voltage between the remote control pin and the -VIN pin
of the converter. The remote control pin is pulled up
internally, so no external voltage source is required.
For more detail please refer to application notes
or design tool; contact factory for this information.
REV. JAN 31, 2005
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