LV12S28-150 Datasheet, PDF (4/15 Pages) Wall Industries,Inc. – Low Voltage DC-DC Converter 10-36 Vdc Input 28Vdc Output at 5.36A Half-Brick Package

Rev. C
TECHNICAL DATASHEET
LV12S28-150
DESIGN CONSIDERATIONS
Under Voltage Lock Out (UVLO)
The converter output is disabled until the input voltage exceeds the UVLO turn-on limit. The converter will
remain ON until the input voltage falls below the UVLO turn-off limit.
Over Current Protection
The converter is protected from short circuit and over current conditions. During these fault conditions, the
converter output will ‘hiccup’. The converter output will recover once the short or over current fault is removed.
Over Temperature Protection (OTP)
The converter has internal thermal protection that will shut the converter OFF once the case temperature exceeds
the OTP turn-off limit. The converter will resume operation when the case temperature has dropped below the
OTP turn-on limit.
Input Filter
It is recommended to bypass the +Vin and –Vin pins of the converter with a minimum of 680uF (50V minimum)
capacitor (UCC - SXE50VB681M12X35LL). No other bypassing is needed. However, to reduce the input ripple
beyond what is seen in Photo 1, larger values of capacitance may be used in conjunction with a ceramic capacitor.
Additionally, an inductor may be placed between the source and the previously mentioned capacitor. No inductor
should be placed between the capacitor and the input to the converter. It is important to note that placement of the
input filter must be as close as possible to the input pins of the converter to assure a low impedance at the pins.
Figure 2: Input Filter Setup
Low
Impedance
Source
+V_in
680 µF
electrolytic
capacitor
1 µF
ceramic
capacitor
-V_in
LV12S28-150
Output Filter
No additional output capacitor is needed for the power supply to operate. However, to reduce the ripple and noise
on the output, additional capacitance may be added. A low ESR Ceramic capacitor may be added across the +Vo
and –Vo pins to reduce the ripple and spike noise. Additional capacitance in the form of a tantalum or aluminum
electrolytic may also be placed across these pins in order reduce ripple and improve the transient peak-to-peak
voltage deviation.
Remote Sense
To improve the regulation at the load, route the connections from the -RS and the +RS pins to the –Vo and +Vo
connections at the load. This will force the converter to regulate the voltage at the load and not at the pins of the
converter (refer to Graph 6). If it is not desired to use the Remotes Sense feature, the –RS and +RS pins may be
left open or they may be shorted to the -Vo and +Vo pins respectively. Shorting the RS pins to the Vo pins will
reduce the voltage drops through the converter pins.
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