DC/DC - Fixed Input

MORNSUN 0.2-3W fixed input DC DC converter features compact size and high power
density. It can be used in application where the voltage of the input MORNSUN
power supply is stable. The ultra-compact volume is an ideal solution for
communications, instrumentation and industrial electronics applications. And
the operating temperature range is -40°C to 85°C, even up to 105°C, which is
suitable for automotive industry. We hope that those high-efficiency,
excellent-quality, and cost-effective DC DC converter is an ideal fit for your
application needs.

Fixed Input-FAQs
How to meet the requirement for ripple & noise when using low cost dc dc
converter?
Low cost dc dc converters have a higher requirement for ripple & noise which
need further filtering. There are the following measures: (1) add a capacitor
at the output terminal (the function of the capacitor is to further lower
ripple & noise with a relatively low frequency); 2) add a PI
filter at the output terminal by filtering methods of capacitor + DM inductor +
capacitor  OR capacitor + CM inductor + capacitor (this method lowers ripple &
noise at the same time. If the frequency of the noise is high, it is
recommended to use the pattern of capacitor + CM inductor + capacitor); (3)
customers can choose a power module whose output voltage is one grade higher
and add an LDO to reduce ripple & noise (for instance, customers practically
need a 3.3V output
power module but there are demanding requirements for ripple & noise. Please
recommend customer to choose a 5V output power module and add an LDO to lower
it to 3.3V, and the LDO can lower ripple & noise).

What are the minimum starting current and input current of a module?
The starting current of a module is generally about 1.4-1.6 times that of the
Iin (max). The increase of capacitive load of the output terminal will also
increase the starting current value of the module. It is recommended to select
the forestage power supply with higher power. For the minimum input current in
the unloading condition, please check the ‘No-load current’ section in the
data sheet of the corresponding module.

The module fails to start up when the capacitive load is relatively large. How
to solve it?
In practical application, the capacitive load exceeds the maximum capacitive
load of operating module. In addition, when the output capacitance is extremely
large, large starting current is required at the moment of start-up, resulting
in the failure of starting the module.
It is recommended to decrease the connected capacitance of the output terminal
or add a buffer circuit at the output terminal to improve the capacity of the
module to withstand capacitive load

What problems will be caused and how to avoid them if a module starts up with
an input voltage lower than the minimum rated one?
The module may be damaged when it starts up at a voltage that is lower than
that of input voltage range. Because there is no under-voltage protective
circuits for the wide input voltage converters. 
The starting voltage should be determined on the basis of the threshold voltage
of MOSFET and soft starting circuit, and the starting voltage of the MOSFET is
2V or more lower than that of the minimum input voltage of the module.
In this circumstance, lower voltage input requires higher input current so as
to supply equal power; the power module is susceptible to damage in a higher
input current condition.
(1) It should be ensured that the actual input voltage is in the rated range
specified in the data sheet; 
(2) it is recommended to add an input under-voltage protective circuit on the
front-terminal of the module in accordance with the Wide Input Voltage DC/DC
Converter Application Guide.

Why is there high noise when the fixed input voltage product is used as the
power source of the relay?
There is high reflected ripple during the operation of the relay. 
It is recommended to implement some filtering measures or add a Y capacitor
between the input and output grounds.
As a dc dc converter manufacturers, we will make no spare efforts to help
consumers.

Minimum Order: 1 sets

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