LSN16A-W3 Datasheet, PDF (7/8 Pages) Murata Manufacturing Co., Ltd. – Non-Isolated, 3-5.5VIN, 0.75-3.3VOUT 16 Amp DC/DC Converters

Single Output LSN-W3 Models
Non-Isolated, 3-5.5VIN, 0.75-3.3VOUT
16 Amp DC/DC Converters
LSN W3 DC/DC converters do not suffer from Output Reverse Conduction.
They employ proprietary gate drive circuitry that makes them immune to
moderate applied output overvoltages.
Thermal Considerations and Thermal Protection
The typical output-current thermal-derating curves shown below enable
designers to determine how much current they can reliably derive from each
model of the LSN W3 Series under known ambient-temperature and air-flow
conditions. Similarly, the curves indicate how much air flow is required to reli-
ably deliver a specific output current at known temperatures.
The highest temperatures in LSN W3’s occur at their output inductor, whose
heat is generated primarily by I²R losses. The derating curves were developed
using thermocouples to monitor the inductor temperature and varying the load
to keep that temperature below +110°C under the assorted conditions of air
flow and air temperature. Once the temperature exceeds +115°C (approx.), the
thermal protection will disable the converter. Automatic restart occurs after the
temperature has dropped below +110°C.
As you may deduce from the derating curves and observe in the efficiency
curves on the following pages, LSN W3’s maintain virtually constant efficiency
from half to full load, and consequently deliver very impressive temperature
performance even if operating at full load.
Lastly, when LSN W3’s are installed in system boards, they are obviously
subject to numerous factors and tolerances not taken into account here. If you
are attempting to extract the most current out of these units under demanding
temperature conditions, we advise you to monitor the output-inductor tempera-
ture to ensure it remains below +110°C at all times.
20 Amps Extended Operation
Under restricted conditions, the LSN W3 models with low output voltages
may produce up to 20 Amps of output current up to approximately +45°C
ambient temperature. There is no model number change. The Derating
curve illustrates typical performance. For this test, the converter was
mounted on a 12cm x12cm double-sided pc board with 2 ounce copper.
This 20 Amp operation is available with the following restrictions:
• Only 1.2 Volt and 1.5 Volt output models are verified for operation at
this time.
• The user must assure that there is adequate airflow at all times with
no airflow blockage by other large components. Make sure no adjacent
components have high temperatures. Be aware of systems using a
CPU temperature monitor to control the fan.
• Use only low to moderate ambient temperature.
• The user must assure that the total output power is not exceeded.
• This operation applies only to nominal input line voltage. Since effi-
ciency degrades at low line voltage, internal heat dissipation increases,
thereby exceeding the maximum output power.
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The Derating curve is drawn where the hot spot on the converter (usually
a power FET) reaches approximately +115°C. Although operation is possible
slightly beyond this point, DATEL strongly advises using this as the maxi-
mum temperature for greatest reliability.
Do not forget that a small overcurrent glitch while running 20 Amps output
could instantly shut down the converter using the Over Current sensor. This
margin of safety is considerably wider at 16 Amps maximum current. Make
sure your output current usage is smooth!! If you are in doubt, contact DATEL
to discuss your application.
www.murata-ps.com
Technical enquiries email: [e-mail], tel: [phone]
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