1)What is the working temperature range for DCDC Fixed input?

RE: Most of our DCDC fixed input can work under -40℃~+105 ℃ (Temperature ≥ 85 ℃ for derating); Details can see in the datasheet; 

2)How to use CS pin?

RE: The output CS pin only plays a filtering role. If the actual application is not under an occasion of the specific ripple requirements. The CS pin is not requested to connect. But if connected, it has a certain suppression effect on the output ripple noise.

3)Can DC-DC fixed input products be used in high magnetic field environments?

RE: The fixed input product is realized by the principle of alternating magnetic field direction conversion. If there is no shielding measure, the strong magnetic field makes the product work in a situation similar to short circuit, and the product is easy to damage.

4)What is the minimum starting current and input current of the module?

RE: The starting current of the module is generally about 1.4 ~ 1.6 times Iin-max; it is recommended to choose a slightly larger power supply; The minimum input current is in the case of no-load, refer to the indicator "No-load current" in the technical manual of the corresponding module.

5)How to select the input TVS tube and output capacitance for wide voltage products?

RE: TVS tube can be determined according to the input voltage, the general value is 1.2 to 1.5 times of the input voltage, the power is selected according to the surge protection voltage, and the output capacitor is generally selected according to the recommended value of the external capacitor in the technical manual.

6)Why is the power supply’s isolation voltage being not affected?

RE: The isolation voltage may not reach the target in some application or test. Most reasons are as below:

a)      The voltage tester has a boot overshoot;

b)      The value of isolation voltage is not enough;

c)       Reflow welding and hot air gun are used many times during maintenance

Solution: It can be improved by standardized testing and use. For example, the voltage is gradually increased during the isolation voltage test. The appropriate temperature is selected when welding the module to avoid repeated welding many times and damage to the module.

7)What is the role of the diode in the CTRL peripheral application circuit?

RE: This diode is mainly to prevent the reverse current backfilling, once the lack of diode, in the voltage feedback loop, there be a small signal current through the CTRL out of the module, which will make the module work abnormally.

8)How do modules implement negative input?

RE: When the negative voltage is -48V input, the input voltage "0V" is connected to Vin" of the module, and "-48V" is connected to the input "GND" to ensure the potential difference at the input end. When it is negative input, it is required that the direction of input current of the module is consistent with the positive input flow direction. It is best to series connect a diode at the input end to prevent reverse connection.

9) What causes the module boot protection?

 RE: The load carried by the module changes and jumps instantaneously and exceeds the overload requirements of the module, causing the boot protection.

 Solution: Choose the module with high power and meet the load requirements, and add buffer circuit to the output part of the module to reduce the instantaneous load current.

10) Can the input and output points of fixed input products be short-connected together?

RE: Yes, but the recommended capacitor must be added to the front and rear stages of the product. And the product no longer has isolation function after short-circuiting.