UHP28_2_12A Datasheet, PDF (7/9 Pages) Murata Manufacturing Co., Ltd. – Isolated, 12 Amp Half Brick, 48VIN/28.2VOUT DC/DC Converters

UHP-28.2/12-D48
Isolated, 12 Amp Half Brick, 48VIN/28.2VOUT DC/DC Converters
pins. Use of trim and sense functions can cause output voltages to increase,
thereby increasing output power beyond the converter's specified rating or
cause output voltages to climb into the output overvoltage region. Therefore:
(VOUT at pins) x (IOUT ) =< rated output power
TYPICAL PERFORMANCE CURVES
5(0  $
%FFICIENCYVS,INE6OLTAGEAND,OAD#URRENT —#

 _n).054
 _/./&&
#/.42/,

).054

/54054
3%.3% ^

42)-

n3%.3%

n/54054
K7
 
452.3
,/!$
Figure 6. Trim Connections Using A Trim Pot
1 _–INPUT
5
+OUTPUT



6).6

6).6

6).6

6).6


   

    
,OAD#URRENT!MPS
6
+SENSE
3 _ON/OFF
CONTROL
4
+INPUT
7
TRIM
8
–SENSE
RTRIM UP
9
–OUTPUT
LOAD
Figure 7. Trim Connections To Increase Output Voltages Using Fixed Resistors
1 _–INPUT
3 _ON/OFF
CONTROL
4
+INPUT
5
+OUTPUT
6
+SENSE
7
TRIM
RTRIM DOWN
8
–SENSE
9
–OUTPUT
LOAD
Figure 8. Trim Connections To Decrease Output Voltages Using Fixed Resistors
Trim Equations
1036
RTUP (k7) = 10 (
) + 936
$%
RTDOWN (k7) =
10 ( ¹⁰⁰
$%
)–2
where $% is the desired change of the output voltage in percent relative to VNOMINAL. Or,
±$% = ^{VOUT – VNOM} x 100
VNOM
UHP Converter Series Mounting
The UHP series include a multilayer planar-magnetic Printed Circuit Board
(PCB), high-current Input/Output pins, four removable brass mounting standoffs
and an optional machined aluminum baseplate. See Mechanical Specifications.
A user’s installation will normally have a host PCB to solder to the converter’s
I/O pins. To avoid placing the full mechanical mounting load on the I/O pins,
we recommend that the user’s PCB also includes bolts through the PCB to
assemble to the standoffs. Note the #M3 metric threading of the standoffs.
Avoid excessive torque assembling the bolts to the standoffs. Use lock wash-
ers or locking compound to avoid loosening of the mounting bolts.
The standoffs include machined shoulders so that mechanical force is not
placed against the converter’s power components. To avoid long-term oxida-
tion of the host PCB, be sure to accommodate the relatively high temperatures
of the power components adjacent to the user’s host PCB. Normally, a planar
grounded area of copper etch on the PCB surface will be sufficient to spread
the heat, reduce electrical noise and avoid hotspots. A relief dimension on the
standoffs floats the power components 0.02 inches minimum from the user’s
host PCB.
The baseplate is in thermal contact with the power components and practi-
cally all the converter’s internal heat dissipation is conducted away via the
baseplate. Users typically have two choices to remove this thermal load—
either an extruded aluminum finned heat sink or a thermal mounting surface
such as a chassis wall. The heatsink depends on ambient temperature, airflow
and total power extracted from the converter, depending on the input voltage
and converter efficiency. Do not attempt to conduct all baseplate heat solely
through the standoffs. Use either a thermal pad or thermal mounting com-
pound (“thermal grease”) when attaching the baseplate to its mounting sur-
face. Keep baseplate temperature below +110°C. Study the Derating Curve.
For chassis wall mounting, the user must consider the tolerance buildup—the
host PCB, mounting standoffs, thermal pad and placement of the chassis wall.
Measure carefully to avoid unwanted mechanical stresses.
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Technical enquiries email: [e-mail], tel: [phone]
UHP_28.2/12_D48.B02 Page 7 of 9