Datasheet

Remote On/Off Control
The OKL Series power modules can be specifi ed with either a positive or nega-
tive logic polarity. See Figures 7 and 8 for On/Off circuit control. In the positive
logic on/off option the unit turns on during a logic high on the On/Off pin and
turns off during a logic low. In a negative logic on/off option, the unit turns off
during logic high and on during logic low. The On/Off signal should always be
reference to ground. For positive or negative option, leaving then On/Off pin
disconnected will turn the unit on when input voltage is present.
Positive—Units are enabled when the on/off pin is left open or is pulled
high to +Vin. The On/Off circuit control is shown in fi gure 7. When the
external transistor Q1 is in the off state, the internal PWM enable pin is pull
high causing the unit to turn on. When Q1 is turn on, the On/Off pin is pulled
low and the units is off. Rp should be around 20K ohms.
Negative—Units are enabled when the ON/Off is open or brought to
within a low voltage (see specifi cations) with respect to –Vin. The unit is off
when the ON/Off is pulled high with respect to –Vin (see specifi cations). The
On/Off circuitry is shown in fi gure 8. The On/Off pin should be pulled high
with an external pull-up resistor (20K ohms). When Q1 is in the off state,
the On/Off pin is pulled high, transistor Q3 is turn on and the unit is off. To
turn on the unit, Q1 is turn on, pulling the On/Off pin low and turning Q3 off
resulting on the unit being on.
Dynamic control of the On/Off function should be able to sink the speci-
fi ed signal current when brought low and withstand appropriate voltage
when brought high. Be aware too that there is a fi nite time in milliseconds
(see specifi cations) between the time of On/Off Control activation and
stable, regulated output. This time will vary slightly with output load type
and current and input conditions.
Output Capacitive Load
These converters do not require external capacitance added to achieve
rated specifi cations. Users should only consider adding capacitance to
reduce switching noise and/or to handle spike current load steps. Install
only enough capacitance to achieve noise objectives. Excess external
capacitance may cause regulation problems, degraded transient response
and possible oscillation or instability.
Soldering Guidelines
Murata Power Solutions recommends the specifi cations below when installing these
converters. These specifi cations vary depending on the solder type. Exceeding these
specifi cations may cause damage to the product. Your production environment may differ
therefore please thoroughly review these guidelines with your process engineers.
Recommended Lead-free Solder Refl ow Profi le
Reflow Solder Operations for surface-mount products (SMT)
For Sn/Ag/Cu based solders:
Preheat Temperature Less than 1 ºC. per second
Time over Liquidus 45 to 75 seconds
Maximum Peak Temperature 260 ºC.
Cooling Rate Less than 3 ºC. per second
For Sn/Pb based solders:
Preheat Temperature Less than 1 ºC. per second
Time over Liquidus 60 to 75 seconds
Maximum Peak Temperature 235 ºC.
Cooling Rate Less than 3 ºC. per second
BOM  Rp  20K
BOM  Q1  Q SMT MOS P 30V
GND GND
+Vin +Vin
Rp
Q1
R1
E
PWM
OKL P Module
On/Off
Figure 6. On/Off Circuit Control for Using Positive On/Off Logic
BOM  Rp  20K
BOM  Q1  Q SMT MOS P 30V
GND GND
+Vin +Vin
Rp
Q1
Q3
E
GND
OKL N Module
On/Off
PWM
Figure 7. On/Off Circuit Control for Using Negative On/Off Logic
0
50
100
150
200
250
0 30 60 90 120 150 180 210 240 270 300
Time (sec)
Temperature (°C)
Preheating Zone
240 sec max
Soaking Zone
120 sec max
Reflow Zone
time above
217° C
45-75 sec
Peak Temp.
235-260° C
<1.5° C/sec
High trace = normal upper limit
Low trace = normal lower limit
Recommended Lead-free Solder Refl ow Profi le
OKL-T/1-W12 Series
Programmable Output 1-Amp iLGA SMT PoLs
MDC_OKL-T/1-W12 Series.B02 Page 17 of 18
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