unr-3.3/3-d12 C&D Technologies., unr-3.3/3-d12 Datasheet - Page 5

• Manufacturer Part Number: unr-3.3/3-d12
• Description: Single Output, Non-isolated, 1.8/2.5/3.3vo U T 3.6-10w Dc/dc Converters
• Manufacturer: C&D Technologies.

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 appro-
priate). 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/Functional
Specifications Table.
Model
UNR-1.8/2-D5/-D5SM
UNR-2.5/2-D5/-D5SM
UNR-3.3/3-D5/-D5SM
UNR-3.3/3-D12/-D12SM
Figure 2. Driving the On/Off Control Pin
R
EP
Resistor (R
Internal
Pull-Up
10kΩ
1kΩ
1kΩ
1kΩ
+INPUT
ON/OFF
CONTROL
LOGIC GROUND
IP
)
Resistor (R
V
External
www.murata-ps.com
Pull-Up
IP
15kΩ
N.A.
N.A.
N.A.
R
IP
EP
)
Single Output, Non-Isolated, 1.8/2.5/3.3V
Voltage (V
Internal
Pull-Up
1.8V
2.5V
3.3V
V
IN
IP
)
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 conduction away from the
leads (into the encapsulated package) and shadowing effects.
"SM" modules do not currently withstand the standard solder-reflow process
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 soldering
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).
* PAD DIMENSION
** LEAD DIMENSION
0.015
(0.38)
0.130*
(3.30)
0.100**
(2.54)
Technical enquiries email: [e-mail], tel:
Figure 3. PC board Land Pattern
0.160*
(4.06)
out
3.6-10W DC/DC Converters
0.110**
(2.79)
UNR Series
MDC_UNR 3.6-10W_B01
[phone]
Page 5 of 7