UNR-1.8/2-D12SM データシートの表示（PDF） - Murata Power Solutions
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UNR-1.8/2-D12SM Datasheet PDF : 8 Pages
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UNR Series
Single Output, Non-Isolated, 1.8/2.5/3.3VOUT 3.6-10W DC/DC Converters
On/Off Control
The On/Off Control pin may be used for remote on/off operation. UNR
3.6-10W Series converters are designed so that they are enabled when the
control pin is pulled high or left open (normal mode) and disabled when the
control pin is pulled low (to less than +0.8V relative to Logic Ground). As
shown in the figure and table below, each device has an internal pull-up
resistor on its On/Off Control pin whose value and voltage vary with model.
Dynamic control of the on/off function is best accomplished with a
mechanical relay or an open-collector/open-drain drive circuit (optically
isolated if appropriate). The drive circuit should obviously be able to sink
appropriate current when activated and withstand appropriate voltage when
deactivated.
Applying an external voltage to the On/Off Control when no input power
is applied to the converter can cause permanent damage to the converter.
The on/off control function, however, is designed such that the converter
can be disabled (pin 2/3 pulled low) while input power is ramping up and
then "released" once the input has stabilized. The time duration between the
point at which the converter is released and its fully loaded output voltage
settles to within specified accuracy can be found in the Performance/Func-
tional Specifications Table.
SMT Solder Process for SM models
CAUTION — Avoid Reflow Ovens
For the surface-mount "SM" models of the UNR Series, the packages’
gull-wing leads are made of tin-plated (150 microinches) copper. The
gull-wing configuration, as opposed to “J” leads, was selected to keep the
solder joints out from under the package to minimize both, heat conduc-
tion away from the leads (into the encapsulated package) and shadowing
effects.
"SM" modules do not currently withstand the standard solder-reflow pro-
cess with its most common temperature profiles. In order to avoid damage
to the converter a selective solder process (i.e. hot air gun or a hand solder-
ing method) with the following parameters must therefore be chosen :
Pre-heat phase 30-60°C rise/minute to 150°C maximum.
Lead temperature 300°C for 10 seconds maximum.
As shown in Figure 3, our tests have determined the optimal landing-pad
size to be 160 mils by 130 mils (4 x 3.3 mm).
VIP
+INPUT
REP
RIP
ON/OFF
CONTROL
LOGIC GROUND
Figure 2. Driving the On/Off Control Pin
Model
Internal
Pull-Up
Resistor (RIP)
UNR-1.8/2-D5/-D5SM
UNR-2.5/2-D5/-D5SM
UNR-3.3/3-D5/-D5SM
UNR-3.3/3-D12/-D12SM
1k
1k
1k
10k
External
Pull-Up
Resistor (REP)
15k
N.A.
N.A.
N.A.
Internal
Pull-Up
Voltage (VIP)
1.8V
2.5V
3.3V
VIN
0.015
(0.38)
0.130* 0.100**
(3.30) (2.54)
* PAD DIMENSION
** LEAD DIMENSION
0.160*
(4.06)
0.110**
(2.79)
Figure 3. PC Board Land Pattern
www.murata-ps.com/support
MDC_UNR 3.6-10W.C01 Page 6 of 8
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