bcp50w Murata Manufacturing Co., Ltd, bcp50w Datasheet - Page 5

• Manufacturer Part Number: bcp50w
• Description: 50 Watt Dc/dc Converters
• Manufacturer: Murata Manufacturing Co., Ltd

3.3V & 2.5V Outputs/Returns
The BCP Series outputs (pins 7 & 10) and returns (pins 6 & 9) are isolated
from the +V
transistors.
DC/DC converter. Though the returns are common within the DC/DC converter,
the regulating control loop for each output is sensed directly at its respective
output and return pins.To maintain optimum regulation when a ground plane is
not used, it is critical that PC board layouts return each output to its corre-
sponding return pin.
Filtering and Noise Reduction
All BCP DC/DC Converters achieve their rated ripple and noise specifi cations
using the external input and output capacitors specifi ed in the Performance/
Functional Specifi cations table. In critical applications, input/output noise may
be further reduced by installing additional external I/O caps. Input capacitors
should be selected for bulk capacitance, low ESR and high rms-ripple-current
ratings. Input capacitors serve as energy-storage devices to minimize varia-
tions in line voltage caused by transient IR drops in PCB conductors from
backplane to the DC/DC. Output capacitors should be selected for low ESR and
appropriate frequency response. All caps should have appropriate voltage rat-
ings and be mounted as close to the converters as possible.
of your particular load and layout conditions.
Input Fusing
Certain applications and/or safety agencies may require the installation of
fuses at the inputs of power conversion components. Fuses should also be
used if the possibility of sustained, non-current-limited, input-voltage polarity
reversals exists. For MPS BCP DC/DC Converters, you should use slow-blow
type fuses with values no greater than the following.
Fuses should be installed in the +Input line.
Input Overvoltage/Undervoltage Shutdown and Start-Up Threshold
Under normal start-up conditions, devices will not begin to regulate until the
ramping-up input voltage exceeds the Start-Up Threshold Voltage (35V for
"D48" models). Once operating, devices will not turn off until the input voltage
drops below the Undervoltage Shutdown limit (32V for "D48" models). Subse-
quent re-start will not occur until the input is brought back up to the Start-Up
Threshold. This built-in hysteresis prevents any unstable on/off situations from
occurring at a single voltage.
The 3.3V Return (pin 6) and 2.5V Return (pin 9) are connected internal to the
The most effective combination of external I/O capacitors will be a function
TECHNICAL NOTES
"D24" Models
"D48" Models
V
IN
IN
and –V
Range
IN
inputs (pins 4 & 1) via a transformer and opto-coupled
Fuse Value
6 Amps
3 Amps
www.murata-ps.com
listed in the Performance/Functional Specifi cations will cause the device to
shutdown. A built-in hysteresis (2V typical for "D24" models, 4V typical for
"D48" models) will not allow the converter to restart until the input voltage is
suffi ciently reduced.
Start-Up Time
The V
ing input voltage crosses the turn-on threshold point and the fully-loaded
output voltage enters and remains within its specifi ed accuracy band. Actual
measured times will vary with input source impedance, external input capaci-
tance, and the slew rate and fi nal value of the input voltage as it appears to the
converter.
input voltage applied but is turned off via the On/Off Control. The specifi cation
defi nes the interval between the time at which the converter is turned on and
the fully loaded output voltage enters and remains within its specifi ed accuracy
band.
On/Off Control (Standard feature)
The On/Off Control (pin 3) may be used for remote on/off operation. As shown
in Figure 1A, the control pin is referenced to the –Input (pin 1). The standard
BCP converter (no suffi x) is designed so that it is enabled when the control pin
is left open and disabled when the control pin is pulled low (to less than +0.8V
relative to –Input).
cal relay or an open-collector/open-drain drive circuit (optically isolated if
appropriate). The drive circuit should be able to sink approximately 1mA for
logic low.
disabled (pin 3 pulled low for no-suffi x models) while input power is ramping
up and then "released" once the input has stabilized.
added to part number), operation is opposite to that described above. The
converter is disabled when the On/Off Control pin is left open and enabled
when pulled low.
Input voltages exceeding the input overvoltage shutdown specifi cation
The On/Off to V
Dynamic control of the on/off function is best accomplished with a mechani-
The on/off control function is designed such that the converter can be
For BCP converters confi gured with a negative-polarity option ("N" suffi x
IN
to V
Figure 1A. No Suffi x
OUT
3
1
start-up time is the interval between the time at which a ramp-
ON/OFF
CONTROL
–INPUT
Dual Output BCP Models
OUT
Technical enquiries email: [e-mail], tel:
start-up time assumes the converter has its nominal
+13V
+3V
+Vcc
50 Watt DC/DC Converters
3.3 and 2.5V, Half-Brick
MDC_BCP Models.B03 Page 5 of 7
Figure 1B. "N" Suffi x
3
1
ON/OFF
CONTROL
–INPUT
[phone]
+Vcc