bcp-3.3-2.5 C&D Technologies., bcp-3.3-2.5 Datasheet - Page 5

• Manufacturer Part Number: bcp-3.3-2.5
• Description: 3.3v And 2.5v, Half-brick 50 Watt, Dc/dc Converters
• Manufacturer: C&D Technologies.

Output Overvoltage Protection
Each voltage output of the BCP Series converter is independently monitored
via an output comparator. If the output voltage should rise to a level
which could be damaging to the load circuitry (see Performance/Functional
Specifications for limits), the overvoltage circuitry will power down the PWM
controller causing the output voltages to collapse. Following a time out period
the converter will restart. If the fault condition persists the PWM will again
power down and the cycle will repeat. This on/off cycling is referred to as
a "hiccup-mode."
Case Connection
BCP DC/DC's do not connect the metal baseplate to an internal voltage. The
"uncommitted" baseplate is connected to pin 2 which, depending upon your
system configuration, should be connected to either +Input (pin 4), –Input (pin
1), Output Return (pins 6 & 9), or earth ground.
Thermal Shutdown
The BCP Series is equipped with Thermal Shutdown circuitry. If environmental
conditions cause the internal temperature of the DC/DC converter to rise
above the designed operating temperature (see Performance/Functional
Specifications), a precision temperature sensor will power down the unit.
When the internal temperature decreases below the threshold of the tem-
perature sensor the unit will self-start.
Input Reverse-Polarity Protection
Upon applying a reverse-polarity voltage to the DC/DC converter, an internal
diode will be forward biased and draw excessive current from the power
source. Therefore, it is required that the input current be limited be either an
appropriately rated input fuse or a current limited power source.
Threaded Inserts and Heatsink Installation
CAUTION: Do not use the threaded inserts to bolt the converter down to a
PC board. That will place unnecessary force on the mounting pins. Instead,
the converter is held securely by only soldering the mounting pins.
When attaching the heat sink from above the converter, use a maximum
torque of 2 inch-pounds (0.23 N-m) on the M3 bolts to avoid damaging the
threaded inserts. Use a tiny amount of fastener adhesive or M3 lockwashers
to secure the bolts.
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P O W E R E L E C T R O N I C S D I V I S I O N
Heat Sinks for BCP Series
DATEL offers two standard heat sinks that can be mounted to the half-brick
package to extend the converter's operating temperature range. Along with
the standard 2.3" x 2.4" x 0.5" (HS-CP) heat sink, DATEL has designed
a low-profile heat sink for height-restricted applications. This new heat sink
(HS-CPLP2) is designed with radiant fins that extend 0.51" beyond either
side of the 2.4" dimension of the BCP package. The convenience of this
design is that the finned extensions protrude only 0.31" below the top surface
of the DC/DC converter, allowing components with a profile height less than
0.2" to be mounted on the pc board below the heat sink. Therefore, while
the surface area of the low-profile heat sink measures 2.3" x 3.5", pcb real
estate is unaffected.
For optimum thermal performance in a natural convection application, the
low-profile heat sink should be mounted with the fins vertically oriented. Both
models are shipped with 0.009" self-adhesive thermal pad and mounting
screws.
Note: When mounting the heat sink to the BCP converter:
1. Maximum applied torque is 2 in-lbs.
2. Minimum thread engagement of the mounting screws is 12mm deep.
Figure 2. HS-CP and HS-CPLP2 Heat Sink Performance Vs. Air Flow
6
5
4
3
2
1
0
0
50W, Dual Output, Mixed-Voltage DC/DC Converters
100
200
HS-CP
AIR VELOCITY (FT./MIN.)
300
D C / D C C O N V E R T E R S
400
BCP Models
MDC_BCP50W_A01
HS-CPLP2
500
600
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