FBC DC/DC Series Data Sheet
500-Watt Full Brick,
48VDC Input, 12VDC @ 42A Output
Features
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High efficiency up to 94%
3
High power density - 91W/in
High current rating - 42A
Low profile – 12.7mm height
Input/output isolation: 1500VDC
Basic insulation
Start-up into high capacitive load
Low conducted and radiated EMI
Output overcurrent protection
Output overvoltage protection
Overtemperature protection
Remote sense
Remote on/off (primary referenced), positive
or
negative logic option
±10%
output voltage trim adjust
UL 1950 Recognition, CSA 22.2 No. 950-95
certification, TUV IEC950
Applications
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Intermediate Bus Architectures
Telecommunications equipment
LAN/WAN applications
Data processing applications
Description
The FBC Series of high density Bus Converters convert a worldwide telecom bus voltage of 36 to 75VDC to a 12V
bus at 42A. The output is ideal for powering non-isolated, point-of-load converters such as synchronous buck
converters used commonly in Intermediate Bus Architectures.
The unit's open-frame, two-board construction provides ideal thermal transfer for maximum reliability. Power
devices are mounted on an Insulated Metal Substrate (IMS) base plate with very low thermal impedance. The
control PCB is physically isolated from the hotter IMS board, providing lower overall component temperatures for
high reliability. The standard feature set includes remote on/off, remote output voltage sensing, positive output trim,
and input undervoltage lockout and overtemperature shutdown with hysteresis.
Selection Chart
Model
Input
voltage
(VDC)
36-75
Input
current,
Max, (ADC)
16
Output
voltage
(VDC)
12.0
Output rated
current
I
rated,
(ADC)
42
Output
Ripple/Noise
(mV p-p)
100
Typical
Efficiency
@ I
rated,
(%)
92.5
FBC42ZH
This product is intended for integration into end-use equipment. All the required procedures for CE marking of end-use
equipment should be followed
.
REV. MAY 23, 2003
Page 1 of 8
FBC DC/DC Series Data Sheet
500-Watt Full Brick,
48VDC Input, 12VDC @ 42A Output
Absolute Maximum Ratings
Stresses in excess of the absolute maximum ratings may cause performance degradation, adversely effect long-
term reliability, and cause permanent damage to the converter.
Parameter
Input voltage
Operating Temperature
Storage Temperature
ON/OFF Control Voltage
Conditions/ Description
Continuous
Transient, 100ms
Base Plate Temperature
Referenced to -Vin
Min
Max
75
100
110
125
7
Units
VDC
VDC
°C
°C
VDC
-40
-40
Environmental and Mechanical Specifications
All specifications apply over specified input voltage, output load, and temperature range, unless otherwise noted.
Parameter
Shock
Sinusoidal Vibration
Weight
Water Washing
MTBF
Conditions/Description
Halfsine wave, 3 axes
GR-63-CORE, Section 5.4.2
Standard process
Per Bellcore TR -NWT-000332
Min
50
1
Nom
Max
Units
g
g
Oz/gm
kHrs
5.2/145
Yes
1,000
Isolation Specifications
All specifications apply over specified input voltage, output load, and temperature range, unless otherwise noted.
Parameter
Insulation Safety Rating
Isolation Voltage
Isolation Voltage
Isolation Resistance
Isolation Capacitance
Conditions/Description
Input to output, input to base plate
Output to base plate
Min
1500
1500
10
1000
Nom
Basic
Max
Units
VDC
VDC
MOhm
pF
Input Specifications
All specifications apply over specified input voltage, output load, and temperature range, unless otherwise noted.
Parameter
Input Voltage
Turn-On Input Voltage
Turn-Off Input Voltage
Turn-On Time
Input Reflected Ripple Current
Inrush Transient
Conditions/Description
Continuous
Ramping Up
Ramping Down
To Output Regulation Band
100% Resistive Load
Full Load, 12uH source
inductance
Vin = Vin.max
Min
36
33
31.5
Nom
48
Max
75
35
33.5
5
60
0.1
Units
VDC
VDC
VDC
ms
mA p-p
A s
2
REV. MAY 23, 2003
Page 2 of 8
FBC DC/DC Series Data Sheet
500-Watt Full Brick,
48VDC Input, 12VDC @ 42A Output
Output Specifications
All specifications apply over specified input voltage, output load, and temperature range, unless otherwise noted.
Parameter
Output Voltage Setpoint Accuracy
Output Current
Line Regulation
Load Regulation
Total output voltage regulation
Remote Sense Headroom
Dynamic Regulation
Peak Deviation
Settling Time
Admissible Load Capacitance
Output Current Limit Threshold**
Switching Frequency
Overvoltage Protection,
Non Latching
Trim Range
Conditions/Description
Vin = Vin.nom, Full Load
See selection chart for I
rated
Vin.min to Vin.max, I
rated
Vin = Vin.nom, 10% to
100%I
rated
Over all input voltage, load,
and temperature conditions
50-75% load step change
to 1% error band
I
rated,
resistive load, Nom Vin
Vout = 0.97Vout.nom
Over all input voltage and
load conditions
I
rated
, Vin = Vnom
250
400
500
500
5,000
130
400
120
90
140
110
mV
µs
µF
%I
rated
kHz
%Vout
%Vout
Min
-2
10
Nom
Max
2
100
0.5
1.0
4
5%
Units
%Vout
%I
rated
%Vout
%Vout
%Vout
%Vout
-4
115
** Overcurrent protection is non-latching with auto recovery.
Feature Specifications
All specifications apply over specified input voltage, output load, and temperature range, unless otherwise noted.
Parameter
Shutdown (ON/OFF)
Negative Logic
Converter ON
Source Current
Converter OFF
Open Circuit Voltage
Positive Logic
Converter ON
Open Circuit Voltage
Converter OFF
Source Current
Overtemperature
Protection
Conditions/Description
On/Off signal is low – converter is ON
-0.5
ON/OFF pin is connected to -Vin
2.5
ON/OFF pin is floating
On/Off signal is low–converter is OFF
2.5
ON/OFF pin is floating
-0.5
ON/OFF pin is connected to -Vin
Baseplate temperature
120
0.8
1
7
5
7
5
0.8
1
130
VDC
mADC
VDC
VDC
VDC
VDC
VDC
mADC
°C
Min
Nom
Max
Units
REV. MAY 23, 2003
Page 3 of 8
FBC DC/DC Series Data Sheet
500-Watt Full Brick,
48VDC Input, 12VDC @ 42A Output
FBC42ZH
Characteristic Curves
100
Fuse
+Vi
+Vo
+Sense
C1
On/Off
Trim
C2
C2
C3
95
Efficiency (%)
90
85
80
36V
75
70
0%
20%
40%
60%
80%
100%
LOAD (%)
48V
75V
-Sense
-Vi
-Vo
Fig. 3. Typical Application of FBC Series
The FBC Series converter does not require any
external components for proper operation.
However, if the distribution of the input voltage to
the converter contains significant inductance, the
capacitor C1 may be required to enhance
performance of the converter. A minimum of a
100µF electrolytic capacitor with the ESR<0.7Ω is
recommended for the FBC Series.
Refer to the “Inrush Current Control Application
Note” on www.power-one.com for suggestions on
how to limit the magnitude of the inrush current.
For output decoupling we recommend to use a
10µF
low
ESR
tantalum
(AVX
TPSC106M025R0500 is used in our test setup)
and a 1µF ceramic capacitors. Note, that the
capacitors do not substitute the filtering required by
the load.
Fig. 1. FBC42ZH Efficiency vs. Output Load
18
16
14
12
Input Current (A)
10
8
6
4
2
0
20
30
40
50
60
70
80
Shutdown Feature Description
The ON/OFF pin in the FBC Series converter
functions as a normal soft shutdown.
It is
referenced to the –Vin pin (see Figure 3). With the
positive logic, when the ON/OFF pin is pulled low,
the output is turned off and the unit goes into a
very low input power mode.
With the negative logic, when the ON/OFF pin is
pulled low, the unit is turned on.
An open collector switch is recommended to
control the voltage between the ON/OFF pin and
the -Vin pin of the converter. The ON/OFF pin is
pulled up internally, so no external voltage source
is required.
Input Voltage (V)
Fig. 2. FBC42ZH Input Characteristic
Typical Application
Figure 3 shows the recommended connections for the
FBC Series converter.
REV. MAY 23, 2003
Page 4 of 8
FBC DC/DC Series Data Sheet
500-Watt Full Brick,
48VDC Input, 12VDC @ 42A Output
The user should avoid connecting a resistor between
the ON/OFF pin and the +Vin pin.
When the ON/OFF pin is used to achieve remote
control, the user must take care to insure that the pin
reference for the control is really the -Vin pin. The
control signal must not be referenced ahead of EMI
filtering, or remotely from the unit. Optically coupling
the information and locating the optical coupler directly
at the module will solve any of these problems.
65.68
Rup
=
1
−
(12 /
Vdesired
)
k
Ω
5.97
Rdown
=
(12 /
Vdesired
)
−
1
k
Ω
Notes:
Note:
If the ON/OFF pin is not used, it can be left floating
(positive logic), or connected to the -Vin pin (negative
logic).
1.
When the output voltage is trimmed up, the
output power from the converter must not
exceed its maximum rating. The power is
determined by measuring the output voltage on
the output pins, and multiplying it by the output
current.
In order to avoid creating apparent load
regulation degradation, it is important that the
trim resistors are connected directly to the
remote sense pins, and not to the load or to
traces going to the load.
The output voltage increase can be accomplished
by either the trim or by the remote sense or by
the combination of both. In any case the
absolute maximum output voltage increase shall
not exceed 10% of the nominal output voltage
Output Voltage Trim
Industry Standard Positive Trim (suffix –T)
The -T option units trim up with a resistor from the Trim
(#13) pin to the +Sense (#12) pin and trim down with a
resistor from the Trim (#13) pin to the –Sense (#11) pin
as shown in the Figure 4.
3.
2.
Safety Considerations
The FBC Series converter features 1500 Volt DC
isolation from input to output. The input-to-output
resistance is greater than 10MΩ.
These
converters are provided with Basic insulation
between input and output circuits according to all
IEC60950 based standards. Nevertheless, if the
system using the converter needs to receive safety
agency approval, certain rules must be followed in
the design of the system. In particular, all of the
creepage and clearance requirements of the end-
use safety requirements must be observed. These
documents include UL60950 - CSA60950-00 and
EN60950, although other or additional require-
ments may be needed for specific applications.
The FBC Series converter has no internal fuse.
The external fuse must be provided to protect the
system from catastrophic failure as shown in
Fig. 4. FBC Series Positive Trim Schematic
The equations below determine the trim resistor value
required to achieve the desired change in the output
voltage.
REV. MAY 23, 2003
Page 5 of 8
