dc dc converter




Input Range
The range of input voltage that the device can tolerate and maintain functional performance over the Operating Temperature Range at full load.
Load Regulation
The change in output voltage over the specified change in output load. Usually specified as a percentage of the nominal output voltage, for example, if a 1V change in output voltage is measured on a 12V output device, load voltage regulation is 8.3%. For unregulated devices the load voltage regulation is specified over the load range from 10% to 100% of full load.
Line Voltage Regulation
The change in output voltage for a given change in input voltage, expressed as percentages. For example, assume a 12V in-put, 5V output device exhibited a 0.5V change at the output for a 1.2V change at the input, line regulation would be 1%/1%.
Output Voltage Accuracy
The proximity of the output voltage to the specified nominal value. This is given as a tolerance envelope for unregulated devices with the nominal input voltage applied. For example, a 5V specified output device at 100% load may exhibit a measured output voltage of 4.75V, i.e. a voltage accuracy of –5%).
Input and Output Ripple and Noise
The amount of voltage drop at the input, or output between switching cycles. The value of voltage ripple is a measure of the storage ability of the filter capacitors. The values given in the datasheets include the higher frequency Noise interference superimposed on the ripple due to switching spikes.The measurement is limited to 20MHz Bandwidth.
Input to Output Isolation
The dielectric breakdown strength test be tween input and output circuits. This is the isolation voltage the device is capable of withstanding for a specified time, usually 1 se cond (for more details see chapter “Isolation Voltage vs. Rated Working Voltage”).
Insulation Resistance
The resistance between input and output circuits. This is usually measured at 500V DC isolation voltage.
Efficiency at FulI Load
The ratio of power delivered from the device to power supplied to the device when the part is operating under 100% load conditions at 25°C.
Temperature Drift
The change in voltage, expressed as a percentage of the nominal, per degree change in ambient temperature. This parameter is related to several other temperature dependent parameters, mainly internal component drift.
Switching Frequency
The nominal frequency of operation of the switching circuit inside the DC-DC converter. The ripple observed on the input and output pins is usually twice the switching frequency, due to full wave rectification and the push-pull configuration of the driver circuit.
No Load Power Consumption
This is a measure of the switching circuits power cunsumption; it is determined with zero output load and is a limiting factor for the total efficiency of the device.
Isolation Capacitance
The input to output coupling capacitance. This is not actually a capacitor, but the parasitic capacitive coupling between the transformer primary and secondary windings. Isolation ca pacitance is typically measured at 1 MHz to reduce the possibility of the on-board filter capacitors affecting the results.