PRELIMINARY
3.3V and 2.5V, "Half-Brick"
50 Watt, DC/DC Converters
Dual Output
Mixed Voltage, BCP Models
Features
DATEL's BCP "half-brick" series has expanded to include dual-output, 3.3V and
2.5V DC/DC converters. The BCP-3.3/15-2.5/15-D24 (18-36V input) and BCP-3.3/15-
2.5/15-D48 (36-75V input) are fully isolated DC/DC converters housed in standard
"half-brick" packages (2.3" x 2.4" x 0.5"). These BCP's can support any combination
of 3.3V and 2.5V loading up to a combined total of 15 Amps. Both outputs are fully
isolated (1500Vdc) and independently line (0.2%) and load (0.5%) regulated.
Both BCP models feature input pi fi lters, input undervoltage and overvoltage shut-
down, input reverse-polarity protection, output overvoltage protection, current limiting,
and thermal shutdown. Each has an on/off control function (positive and negative
logic versions available), and both output voltages can be trimmed independently.
BCP Model DC/DC's deliver low noise (50mVp-p), effi ciency of 84% and are
fully specifi ed for 40 to +100C operation. Utilization of metal baseplate technology
with threaded inserts permits easy heat-sink attachment and/or pcb mounting. These
devices meet UL1950 and IEC/EN60950 safety standards, including BASIC insulation
requirements. CB reports are available on request. "D48" models are CE marked
(meet the requirements of LVD).
Figure 1. Simplifi ed Schematic
INNOVATION and EX C ELL E N C E
Independent 3.3V and 2.5V outputs
Up to 15 Amps per output
Each output fully regulated
No minimum load requirements
50 Watts total output power
Standard "half-brick" package
UL1950 and IEC/EN60950 safety
approvals (BASIC insulation)
Fully isolated, 1500Vdc guaranteed
18-36V or 36-75V input ranges
mark available (75V-input models)
Input under and overvoltage shutdown
Continuous short-circuit protection
Thermal shutdown
DATEL, Inc., Mansfi eld, MA 02048 (USA) Tel: (508)339-3000, (800)233-2765 Fax: (508)339-6356 Email: sales@datel.com Internet: www.datel.com
+INPUT
(4)
INPUT
(1)
SWITCH
CONTROL
+3.3V OUTPUT
(7)
+2.5V OUTPUT
(10)
3.3V RETURN
(6)
2.5V RETURN
(9)
2.5V TRIM
(8)
3.3V TRIM
(5)
REGULATOR
PWM
CONTROLLER
THERMAL
SHUTDOWN
OPTO
ISOLATION
ON/OFF
CONTROL
(3)
UV & OV
COMPARATORS
REFERENCE
& ERROR AMP
REFERENCE
& ERROR AMP
5 0 W , D U A L O U T P U T , M I X E D - V O L T A G E D C / D C C O N V E R T E R S
XCP Series
Performance Specifi cations and Ordering Guide
V
1
Nominal Output Voltage: 3.3 Volts
BCP
15
-
D48
-
Input Voltage Range:
D24 = 18-36 Volts (24V nominal)
D48 = 36-75 Volts (48V nominal)
I
1
Maximum Output Current: 15A
Dual Output/
Standard Half-Brick Package
P A R T N U M B E R S T R U C T U R E
2.5 15
/
-
N
V
2
Nominal Output Voltage: 2.5 Volts
I
2
Maximum Output Current: 15A
See Optional Functions
Optional Functions
BCP 50 Watt DC/DC's are designed with an On/Off Control function,
with either positive polarity (no suffi x) or negative polarity ("N"suffi x),
in the pin 3 position.
Blank On/Off Control function (positive polarity) on pin 3
N On/Off Control function (negative polarity) on pin 3
L1 Pin length: 0.110 inches (2.79mm) 0.010
L2 Pin length: 0.145 inches (3.68mm) 0.010
BCP-3.3/15-2.5/15-D24
3.3 15 50 100 0.2% 0.5%
24 18-36 0.2/2.52 82% 84% C30, P39
2.5 15 50 100 0.2% 0.5%
BCP-3.3/15-2.5/15-D48
3.3 15 50 100 0.2% 0.5%
48 36-75 0.1/1.26 82% 84% C30, P39
2.5 15 50 100 0.2% 0.6%
Output
Input
R/N (mVp-p)
Regulation (Max.)
Effi ciency
Package
V
OUT
I
OUT
V
IN
Nom.
Range
I
IN
(Case,
Model
(Volts)
(Amps) Typ.
Max. Line
Load
(Volts) (Volts) (Amps) Min. Typ. Pinout)
Pin
Function P39
Pin
Function P39
1
Input
6
3.3V
Return
2 Case
(Baseplate) 7
+3.3V
Output
3 On/Off
Control
8
2.5V
Trim
4
+Input
9
2.5V
Return
5
3.3V
Trim
10
+2.5V
Output
M E C H A N I C A L S P E C I F I C A T I O N S
Optional Heat Sink (Part Number HS-CPLP2) *
I/O Connections
2.000
(50.80)
2.30
(58.42)
1.900
(48.26)
2.40
(60.96)
0.20
(5.08)
0.147 DIA. (3.734)
(4 PLACES)
0.20
(5.08)
0.50 (12.70) TYP.
051 (12.95) MAX.
0.10
(2.54)
TOP VIEW
MATERIAL: BLACK ANODIZED ALUMINUM
4 MOUNTING SCREWS AND 0.009 (0.229)
THICK THERMAL PAD INCLUDED
3.50
(88.90)
0.75
(19.05)
0.20
(5.08)
0.140 THRU AND COUNTERSINK
90 TO 0.26 (4 PLACES)
2.000
(50.80)
1.900
(48.26)
2.30
(58.42)
0.47
(11.94)
MATERIAL: BLACK ANODIZED ALUMINUM
2.48
(62.99)
0.16
(4.06)
Optional Heat Sink (Part Number HS-CP) *
2
0.30
(7.62)
0.400
(10.16)
1.000
(25.40)
1.400
(35.56)
2.40
(60.96)
1.000
(25.40)
1.900
(48.26)
2.30
(58.42)
1
2
3
4
9
10
8
7
6
5
2.000
(50.80)
(4) THREADED INSERTS
#M3 THD THRU
0.20
(5.08)
0.20
(5.08)
0.200
(5.08)
BOTTOM VIEW
0.300
(7.62)
0.600
(15.24)
1.300
(33.02)
1.600
(40.64)
METAL BASEPLATE
PLASTIC SHELL
0.20 MIN
(5.08)
0.50
(12.70)
0.040 0.002 DIA.
(1.016 0.051)
Case C30
3.3
-
Typical at T
A
= +25C under nominal line voltage and balanced "full-load" (3.3V @7.5A, 2.5V @ 7.5A)
conditions unless otherwise noted.
Ripple/Noise (R/N) measured over a 20MHz bandwidth. All models are specifi ed with 22F, low-ESR,
input capacitor and 10F tantalum in parallel with 1F ceramic output capacitors.
No load to 100% load, other output at no-load.
Nominal line voltage, no-load/3.3V at full-load condition.
Current from either output at maximum value, or both outputs to a combined total of 15 A.
3.3V at full-load condition.
* Note: When mounting the heat sink to the BCP converter:
1. Maximum applied torque is 6 in-lbs.
2. Minimum thread engagement of the mounting screws is 12mm deep.
LX
BCP Models
5 0 W , D U A L O U T P U T , M I X E D - V O L T A G E D C / D C C O N V E R T E R S
Performance/Functional Specifi cations
Typical @ T
A
= +25C under nominal line voltage, balanced "full-load" conditions, unless noted.
Input
Input Voltage Range:
D24 Models 18-36 Volts (24V nominal)
D48 Models 36-75 Volts (48V nominal)
Overvoltage Shutdown:
D24 Models 40-43 Volts (41.5V typical)
D48 Models 77-80 Volts (78.5V typical)
Start-Up Threshold:
D24 Models 16.5-18 Volts (17.5V typical)
D48 Models 33.5-36 Volts (34.5V typical)
Undervoltage Shutdown:
D24 Models 15-17.5 Volts (16.5V typical)
D48 Models 30.5-33.5 Volts (32V typical)
Input Current:
Normal Operating Conditions See Ordering Guide
D24 Models 3.06 Amps maximum
D48 Models 1.53 Amps maximum
Standby Mode:
Off, OV, UV, Thermal Shutdown 10mA typical
Input Refl ected Ripple Current:
Source Impedance <0.1
22F Low-ESR Capacitor 88mArms, 250mAp-p maximum
Input Filter Type Pi (0.47F-4.7H-3.3F)
Reverse-Polarity Protection:
D24 Models 1 minute duration, 6A maximum
D48 Models 1 minute duration, 3A maximum
On/Off Control: (Pin 3)
D24 & D48 Models On = open or 13V - +V
IN
, I
IN
= 1mA max.
Off = 0-0.8V, I
IN
= 2mA max.
D24N & D48N Models On = 0-0.8V, I
IN
= 1mA max.
Off = open or 2.5 - +V
IN
, I
IN
= 50A max.
Output
V
OUT
Accuracy
3.3V Output 2% maximum
2.5V Output 2% maximum
Minimum Loading per Specifi cation No load
Ripple/Noise (20MHz BW)
See Ordering Guide
Line/Load Regulation See Ordering Guide
Effi ciency See Ordering Guide and Effi ciency Curves
Trim Range
5% independent
Isolation Voltage:
Input-to-Baseplate 1500Vdc minimum
Input-to-Baseplate 1000Vdc minimum
Output-to-Case 1000Vdc minimum
Isolation Capacitance 560pF
Isolation resistance 100M
Current Limit Inception:
3.3V @ 98% V
OUT
(2.5V @ no-load) 17-22 Amps
2.5V @ 98% V
OUT
(3.3V @ no-load) 17-22 Amps
Short Circuit Current Constant current 25A, indefi nite
Temperature Coeffi cient 0.02% per C
Overvoltage Protection: Comparator
3.3V Output 4.0 Volts
2.5V Output 3.25 Volts
Dynamic Characteristics
Dynamic Load Response:
3.3V (50-100% load step to 2% V
OUT
) 300sec maximum
2.5V (50-100% load step to 2% V
OUT
) 300sec maximum
Start-Up Time:
V
IN
to V
OUT
50 msec maximum
On/Off to V
OUT
25 msec maximum
Switching Frequency 300kHz (50kHz)
Environmental
MTBF Bellcore, ground fi xed, controlled
D24 Models TBD hours (case @ TBD C)
D48 Models TBD hours (case @ TBD C)
Operating Temperature (Ambient):
Case to Ambient, No heatsink TBD C/Watt
Without Derating 40 to +32C (without heat sink)
With Derating To +100C (See Derating Curves)
Case Temperature:
Maximum Allowable +100C
For Thermal Shutdown
+100C minimum, +110C maximum
Storage Temperature 40 to +120C
Physical
Dimensions 2.3" x 2.4" x 0.5" (58.4 x 61 x 12.7mm)
Case (Baseplate) Connection
Pin 2
Case/Pin Material Diallyl phthalate, UL94V-0 rated, aluminum
baseplate; solder-tinned brass pins
Weight 4.2 ounces (118 grams)
Primary to Secondary Insulation Level Basic
Absolute Maximum Ratings
Balanced, full-load = 3.3 @ 7.5A and 2.5V @ 7.5A. Models are specifi ed with an external 22F,
low-ESR, input capacitor and 10F tantalum in parallel with 1F ceramic output capacitors.
See Technical Notes for details.
Devices may be ordered with negative logic (pin 3 open = off). See Part Number Structure
and Technical Notes for additional information.
Output noise may be further reduced with the installation of additional external output
capacitors. See Technical Notes.
These signals must be referenced to the input return pin (V
IN
).
Demonstrated MTBF available on request.
Input Voltage:
Continuous:
D24 Models 43 Volts
D48 Models 87 Volts
Transient (100msec): D24 Models 50 Volts
D48 Models 100 Volts
Input Reverse-Polarity Protection Input Current must be limited. 1 minute
duration. Fusing recommended.
D24 Models
6 Amps
D48 Models
3 Amps
Output Overvoltage Protection
3.3V Outputs
4.0 Volts, comparator
2.5V Outputs
3.25 Volts, comparator
Output Current
Current limited. Devices can withstand
an indefi nite output short circuit.
Storage Temperature
40 to +120C
Lead Temperature (Soldering, 10 sec.) +300C
These are stress ratings. Exposure of devices to any of these conditions may adversely
affect long-term reliability. Proper operation under conditions other than those listed in the
Performance/Functional Specifi cations Table is not implied, nor recommended.
3
5 0 W , D U A L O U T P U T , M I X E D - V O L T A G E D C / D C C O N V E R T E R S
XCP Series
3.3V & 2.5V Outputs/Returns
The BCP Series outputs (pins 7 & 10) and returns (pins 6 & 9) are isolated
from the +V
IN
and V
IN
inputs (pins 4 & 1) via a transformer and opto-coupled
transistors.
The 3.3V Return (pin 6) and 2.5V Return (pin 9) are connected internal to
the 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 corresponding 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 volt-
age ratings and be mounted as close to the converters as possible.
The most effective combination of external I/O capacitors will be a function
of your particular load and layout conditions. Our Applications Engineers can
recommend potential solutions and can discuss the possibility of our modify-
ing a device's internal fi ltering to meet your specifi c requirements. Contact our
Applications Engineering Group for additional details.
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 DATEL BCP DC/DC Converters, you should use slow-
blow type fuses with values no greater than the following.
V
IN
Range Fuse Value
"D24" Models 6 Amps
"D48" Models 3 Amps
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).
Subsequent 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.
Input voltages exceeding the input overvoltage shutdown specifi cation listed
in the Performance/Functional Specifi cations will cause the device to shut-
down. 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
IN
to V
OUT
start-up time is the interval between the time at which
a ramping 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
capacitance, and the slew rate and fi nal value of the input voltage as it
appears to the converter.
The On/Off to V
OUT
start-up time assumes the converter has its nominal 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).
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 be able to sink approximately 1mA for
logic low.
The on/off control function is designed such that the converter can be dis-
abled (pin 3 pulled low for no-suffi x models) while input power is ramping up
and then "released" once the input has stabilized.
For BCP converters confi gured with a negative-polarity option ("N" suffi x
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.
T E C H N I C A L N O T E S
Figure 1A. No Suffi x
Figure 1B. "N" Suffi x
4
3
1
4
+INPUT
INPUT
ON/OFF
CONTROL
3
1
4
+13V
+3V
+INPUT
INPUT
ON/OFF
CONTROL
BCP Models
5 0 W , D U A L O U T P U T , M I X E D - V O L T A G E D C / D C C O N V E R T E R S
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
Specifi cations 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 confi guration, 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
Specifi cations), 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.
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-profi le heat sink for height-restricted applications. This new heat sink
(HS-CPLP2) is designed with radiant fi ns that extend 0.51" beyond either
side of the 2.4" dimension of the BCP package. The convenience of this
design is that the fi nned extensions protrude only 0.31" below the top surface
of the DC/DC converter, allowing components with a profi le height less than
0.2" to be mounted on the pc board below the heat sink. Therefore, while
the surface area of the low-profi le heat sink measures 2.3" x 3.5", pcb real
estate is unaffected.
For optimum thermal performance in a natural convection application, the
low-profi le heat sink should be mounted with the fi ns vertically oriented. Both
models are shipped with 0.009" sellf-adhesive thermal pad and mounting
screws.
Note: When mounting the heat sink to the BCP converter:
1. Maximum applied torque is 6 in-lbs.
2. Minimum thread engagement of the mounting screws is 12mm deep.
6
5
4
3
2
1
0
0
100
200
300
400
500
600
700
AIR VELOCITY (FT./MIN.)
HS-CP
THERMAL RESIST
ANCE
C
WA
T
T
HS-CPLP2
Figure 2. HS-CP and HS-CPLP2 Heat Sink Performance Vs. Air Flow
5
5 0 W , D U A L O U T P U T , M I X E D - V O L T A G E D C / D C C O N V E R T E R S
XCP Series
+2.5V
LOAD
+2.5V OUTPUT
INPUT
+INPUT
2.5V TRIM
2.5V RETURN
+3.3V OUTPUT
3.3V TRIM
3.3V RETURN
10
8
1
4
9
7
5
6
20k
5-22
TURNS
+3.3V
LOAD
20k
5-22
TURNS
Output Trimming
Both the 3.3V and 2.5V outputs of the BCP Series can be independently
trimmed via a trimpot (Figure 3A) or a single fi xed resistor as shown (Figures
3B & 3C). The trimpot can be used to determine the value of a single fi xed
resistor. A single fi xed resistor can increase or decrease the output voltage
depending on its connection. Fixed resistors should have absolute TCR's
less than 100ppm/C to ensure stability.
Figure 3A. Trim Connections Using a Trimpot
Figure 3B. Increase Output Voltage Trim Connections Using a Fixed Resistor
A resistor connected from the Trim Pin (pin 5 for 3.3V trim, pin 8 for 2.5V
trim) to the appropriate Return (pin 6 for 3.3V trim, pin 9 for 2.5V trim) will
increase the output voltage.
A single resistor connected from the Trim Pin (pin 5 for 3.3V trim, pin 8 for
2.5V trim) to its appropriate +Output (pin 7 for 3.3V trim, pin 10 for 2.5V trim)
will decrease the output voltage.
Figure 3C. Decrease Output Voltage Trim Connections Using a Fixed Resistor
6
+2.5V
LOAD
+2.5V OUTPUT
INPUT
+INPUT
2.5V TRIM
2.5V RETURN
+3.3V OUTPUT
3.3V TRIM
3.3V RETURN
10
8
1
4
9
7
5
6
+3.3V
LOAD
+3.3V
TRIM
UP
+2.5V
TRIM
UP
+2.5V
LOAD
+2.5V OUTPUT
INPUT
+INPUT
2.5V TRIM
2.5V RETURN
+3.3V OUTPUT
3.3V TRIM
3.3V RETURN
10
8
1
4
9
7
5
6
+3.3V
LOAD
+3.3V
TRIM
DOWN
+2.5V
TRIM
DOWN
DATEL makes no representation that the use of its products in the circuits described herein, or the use of other technical information contained herein, will not infringe upon existing or future patent rights. The descriptions contained herein do
not imply the granting of licenses to make, use, or sell equipment constructed in accordance therewith. Specifi cations are subject to change without notice. The DATEL logo is a registered DATEL, Inc. trademark.
DATEL (UK) LTD. Tadley, England Tel: (01256)-880444
DATEL S.A.R.L. Montigny Le Bretonneux, France Tel: 01-34-60-01-01
DATEL GmbH Mnchen, Germany Tel: 89-544334-0
DATEL KK Tokyo, Japan Tel: 3-3779-1031, Osaka Tel: 6-6354-2025
DATEL, Inc. 11 Cabot Boulevard, Mansfi eld, MA 02048-1151
Tel: (508) 339-3000 (800) 233-2765 Fax: (508) 339-6356
Internet: www.datel.com Email: sales@datel.com
ISO 9001 REGISTERED
INNOVATION and EX C ELL E N C E
DS-0449 6/02
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