QTS48T67096 DC-DC Converter
485W at 48Vin Quarter-Brick Bus Converter
Preliminary Data Sheet
be capable of sinking up to 0.2mA at a low level
voltage of ≤ 0.8V. An external voltage source (±18V
maximum) may be connected directly to the ON/OFF
input, in which case it must be capable of sourcing or
sinking up to 1mA depending on the signal polarity.
Operations
Input and Output Impedance
These power converters have been designed to be
stable with no external capacitors when used in low
inductance input and output circuits.
Protection Features
In many applications, the inductance associated with
the distribution from the power source to the input of
the converter can affect the stability of the converter.
The addition of a 100 µF electrolytic capacitor with
an ESR < 1 ꢀ across the input helps to ensure
stability of the converter. In many applications, the
user has to use decoupling capacitance at the load.
The power converter will exhibit stable operation with
external load capacitance up to 5,000 µF on the
output.
Input Undervoltage Lockout
Input undervoltage lockout is standard with this
converter. The converter will shut down when the
input voltage drops below a pre-determined voltage.
The input voltage must be typically 35V for the
converter to turn on. Once the converter has been
turned on, it will shut off when the input voltage
drops typically below 32V. This feature is beneficial
in preventing deep discharging of batteries used in
telecom applications.
Additionally, see the EMC section of this data sheet
for discussion of other external components which
may be required for control of conducted emissions.
Output Overcurrent Protection (OCP)
The converter is protected against overcurrent or
short circuit conditions. Upon sensing an overcurrent
condition, the converter will latch off.
ON/OFF (Pin 2)
The ON/OFF pin is used to turn the power converter
on or off remotely via a system signal. There are two
remote control options available, positive and
negative logic, with both referenced to Vin(-). A
typical connection is shown in Fig. A.
Once the converter has shut down, input power must
be recycled or the enable pin must be toggled for the
unit to recover. Optional Hiccup mode overcurrent
protection is available.
Input Overvoltage Protection (OVP)
The converter will shut down if the input voltage
exceeds the threshold of the OVP circuitry. The
converter will automatically recover when the input
voltage is reduced below the turn on threshold
Overtemperature Protection (OTP)
The converter will shut down under an
overtemperature condition to protect itself from
overheating caused by operation outside the thermal
derating curves, or operation in abnormal conditions
such as system fan failure. After the converter has
cooled to a safe operating temperature, it will
automatically restart.
Fig. A: Circuit configuration for ON/OFF function.
The positive logic version turns on when the ON/OFF
pin is at a logic high and turns off when at a logic
low. The converter is on when the ON/OFF pin is left
open. See the Electrical Specifications for logic
high/low definitions.
Safety Requirements
The converters meet North American and
International safety regulatory requirements per
UL60950 and EN60950 (pending). Operational
Insulation is provided between input and output.
The negative logic version turns on when the pin is
at a logic low and turns off when the pin is at a logic
high. The ON/OFF pin can be hardwired directly to
Vin(-) to enable automatic power up of the converter
without the need of an external control signal.
To comply with safety agencies’ requirements, an
input line fuse must be used external to the
converter. A 20 Amp fuse is recommended for use
with this product.
The ON/OFF pin is internally pulled up to 5V through
a resistor. A properly debounced mechanical switch,
open-collector transistor, or FET can be used to
drive the input of the ON/OFF pin. The device must
The QTS48T67096 converter is UL approved
(pending) for a maximum fuse rating of 20 Amps. To
ZD-02069 REV. 1.0
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