BEL 0RSB

ISOLATED DC/DC CONVERTERS
18 Vdc - 75 Vdc Input, 12 Vdc/3.5 A Output
Bel Power, Inc. , a subsidiary of Bel Fuse, Inc.
Apr. 19, 2011
0RSB-40U12B
RoHS Compliant
PRELIMINARY Rev.A
Features

Isolated

Output Over-voltage Shut Down

High Efficiency

Over Temperature Protection

Fixed Frequency

OCP/SCP

High Power Density

Remote ON/OFF

Low Cost

Positive/Negative Remote Sense

Input Under-voltage Lockout

Basic Insulation

Output Voltage Trim

Class 1, Category 2, Isolated DC/DC Converter (refer to IPC-9592)
Applications

Networking

Computers and peripherals

Telecommunications
Description
The 0RSB-40U12B series is isolated dc/dc converter that operates from a nominal 24 Vdc or 48 Vdc source.
These units will provide up to 42 W of output power from an 18 - 75 Vdc wide input range. These units are
designed to be highly efficient and low cost. Features include remote on/off, over current protection and under
voltage lockout. These converters are provided in an industry standard sixteenth brick package.
Part Selection
Output Voltage
Input Voltage
12 Vdc
18 Vdc - 75 Vdc
Max. Output
Current
3.5 A
Max. Output
Power
42 W
Typical
Efficiency
85%
Model Number
Active Low
0RSB-40U12B
Notes: Add “G” suffix at the end of the model number to indicate Tray Packaging.
Part Number Explanation
0 R SB – 40 U 12 B
1 2
3
4
5
6
7
1---Through hole mount
2---RoHS 6, change “R” to “7” means RoHS 5
3---Series name, 1/16 Brick
4---Series code
5---Input range (18-75V)
6---Output voltage (12V)
7---Option, “x” of the model part number to be 0-9, A-Z, which will represent the special request of
customer.
Bel Fuse Inc. 206 Van Vorst Street, Jersey City, NJ 07302  Tel 201-432-0463  Fax 201-432-9542  www.belfuse.com
1
ISOLATED DC/DC CONVERTERS
18 Vdc - 75 Vdc Input, 12 Vdc/3.5 A Output
Bel Power, Inc. , a subsidiary of Bel Fuse, Inc.
Apr. 19, 2011
Absolute Maximum Ratings
Min
Typ
Max
Unit
-0.3
-
80
V
-
-
100
V
-0.3
-
18
V
-
-
1500
V
Ambient Temperature
-40
-
85
C
Storage Temperature
-55
-
125
C
Parameter
Continuous Input Voltage
Input Transient Voltage
Remote On/Off
I/O isolation voltage
Notes
100mS maximum
Note: Ratings used beyond the maximum ratings may cause a reliability degradation of the converter or may
permanently damage the device.
Input Specifications
Parameter
Operating Input Voltage
Min
18
Input Current (full load)
-
-
3.5
A
Input Current (no load)
-
60
120
mA
Remote Off Input Current
-
1
3
mA
Input Reflected Ripple Current
(rms)
-
3
7
mA
Input Reflected Ripple Current
(pk-pk)
-
20
50
mA
I t Inrush Current Transient
-
0.01
0.02
As
Input Over Voltage Lockout
78
-
82
V
Turn-on Voltage Threshold
16.6
17.2
17.8
V
Turn-off Voltage Threshold
16.2
16.8
17.4
V
2
Typ
48
Max
75
Unit
V
Notes
With simulated source impedance of
15uH, 5Hz to 20MHz. Use a
100uF/100V electrolytic capacitor with
ESR=1 ohm max, at [email protected]°C.
2
Note: All specifications are typical at 25 C unless otherwise stated.
Output Specifications
Parameter
Min
Typ
Max
Unit
11.75
12
12.25
V
Load Regulation
-
±9
±18
mV
Line Regulation
-
±6
±15
mV
Regulation Over Temperature
(-40deg.C-85deg.C)
-
±20
±35
mV
Output Ripple and Noise (pk-pk)
-
90
180
mV
Output Ripple and Noise (rms)
-
30
55
mV
Output Current Range
0
-
3.5
A
3.7
5
6
A
Short Circuit Surge Transien
-
0.5
1
As
Turn on Time
-
25
50
mS
Output Voltage Set Point
Output DC Current Limit
2
Notes
Vin=48V, Io=50% load
0-20MHz BW, with a 1µF
ceramic capacitor and a 10uF
Tantalum cap at output.
Hiccup mode, auto recovery
Bel Fuse Inc. 206 Van Vorst Street, Jersey City, NJ 07302  Tel 201-432-0463  Fax 201-432-9542  www.belfuse.com
2
ISOLATED DC/DC CONVERTERS
18 Vdc - 75 Vdc Input, 12 Vdc/3.5 A Output
Bel Power, Inc. , a subsidiary of Bel Fuse, Inc.
Apr. 19, 2011
Output Specifications (continued)
Parameter
Overshoot at Turn on
Output Capacitance
Transient Response
△V
Overshoot
25%~50%
of Max Load Settling Time
△V
Overshoot
50%~25%
of Max Load Settling Time
Vo=
12 V
Min
Typ
Max
Unit
-
0
5
%
10
-
220
uF
-
400
650
mV
-
150
300
uS
-
400
650
mV
-
150
300
uS
Notes
di/dt=0.1A/us, Vin=48Vdc, Ta=25°C,
with a 1µF ceramic capacitor and a
10uF Tantalum cap at output.
Note: All specifications are typical at nominal input, full load at 25°C unless otherwise stated.
General Specifications
Parameter
Efficiency
Switching Frequency
Min
Typ
Max
Unit
83
85
-
%
-
500
-
kHz
Over Temperature Protection
-
125
-
℃
Over Voltage Protection(Static)
-
130
160
%
Weight
-
14
-
g
Notes
Vin=48V, full load
The OTP threshold is set at 125°C in
non-latch mode, and the module will
restart automatically when
temperature falls down to 115°C.
This voltage is achieved by trimming
up output slowly.
Dimensions
Inches (L × W × H)
Millimeters (L × W × H)
1.30 x 0.90 x 0.46
33.02 x 22.86 x 11.69
-
-
-
1500
V
10M
-
-
Ohm
-
3900
-
pF
Isolation characteristics
Input to Output
Isolation Resistance
Isolation Capacitance
Note: All specifications are typical at 25 C unless otherwise stated.
Bel Fuse Inc. 206 Van Vorst Street, Jersey City, NJ 07302  Tel 201-432-0463  Fax 201-432-9542  www.belfuse.com
3
ISOLATED DC/DC CONVERTERS
18 Vdc - 75 Vdc Input, 12 Vdc/3.5 A Output
Bel Power, Inc. , a subsidiary of Bel Fuse, Inc.
Apr. 19, 2011
Efficiency Data
90%
85%
EFFICIENCY
80%
18V
24V
48V
75V
75%
70%
65%
60%
55%
50%
0.35
0.88
1.75
2.63
3.50
OUTPUT CURRENT (A)
Remote On/Off
Parameter
Signal Low (Unit On)
Signal High (Unit Off)
Active Low
Current Sink
Min
-0.3
Typ
-
Max
0.8
Unit
V
2.4
-
18
V
0
-
1
mA
Notes
Remote on/off pin open, Unit off.
Recommended remote on/off circuit for active low
Vin+
Vin+
On/off
On/off
Vin-
Vin-
Control with open collector/drain circuit
Control with photocoupler circuit
Vin+
Vin+
On/off
On/off
Vin-
Vin-
Vcc
Control with logic circuit
Permanently on
Bel Fuse Inc. 206 Van Vorst Street, Jersey City, NJ 07302  Tel 201-432-0463  Fax 201-432-9542  www.belfuse.com
4
ISOLATED DC/DC CONVERTERS
18 Vdc - 75 Vdc Input, 12 Vdc/3.5 A Output
Bel Power, Inc. , a subsidiary of Bel Fuse, Inc.
Apr. 19, 2011
Thermal Derating Curve
Maximum junction temperature of semiconductors derated to 120 degree C.
Vin=24V
Vin=48V
Bel Fuse Inc. 206 Van Vorst Street, Jersey City, NJ 07302  Tel 201-432-0463  Fax 201-432-9542  www.belfuse.com
5
ISOLATED DC/DC CONVERTERS
18 Vdc - 75 Vdc Input, 12 Vdc/3.5 A Output
Bel Power, Inc. , a subsidiary of Bel Fuse, Inc.
Apr. 19, 2011
Thermal Derating Curve (continued)
The OTP is achieved by thermistor R65 and it is in non-latch mode when the hottest component Q5 reaches
130°C with 100LFM air flow correspondingly. It will restart automatically when the temperature falls down to
110°C. The protecting point will be varied a little under different conditions (air flow, ambient temperature, input
voltage, load...).
Temperature reference points on top side
Temperature reference points on bottom side
Ripple and Noise Waveform
48Vdc input, 12Vdc output
Note: Ripple and noise at full load, with a 1uF ceramic cap and a 10 uF Tantalum cap at output, Ta=25 deg C.
Bel Fuse Inc. 206 Van Vorst Street, Jersey City, NJ 07302  Tel 201-432-0463  Fax 201-432-9542  www.belfuse.com
6
ISOLATED DC/DC CONVERTERS
18 Vdc - 75 Vdc Input, 12 Vdc/3.5 A Output
Apr. 19, 2011
Bel Power, Inc. , a subsidiary of Bel Fuse, Inc.
Transient Response Waveforms
Vout= 12V 25%-50% Load Transients
Vout= 12V 50%-25% Load Transients
Note: Transient Response at Vin=48V, di/dt=0.1A/uS, with External 10uF Tantalum Cap and 1uF Ceramic Cap
at the output, Ta=25 deg C.
Startup & Shutdown
Rise Time
Vin=48V, Vout=12V, 100% Load
Startup time
Startup from Vin
Ch1: Vout
Ch2: Vin
Vin=48V, Vout=12V, 100% Load
Bel Fuse Inc. 206 Van Vorst Street, Jersey City, NJ 07302  Tel 201-432-0463  Fax 201-432-9542  www.belfuse.com
7
ISOLATED DC/DC CONVERTERS
18 Vdc - 75 Vdc Input, 12 Vdc/3.5 A Output
Bel Power, Inc. , a subsidiary of Bel Fuse, Inc.
Apr. 19, 2011
Output Trim Equations
Equations for calculating the trim resistor are shown below. The Trim Down resistor should be connected
between the Trim pin and Ground pin. The Trim Up resistor should be connected between the Trim pin and the
Vout. Only one of the resistors should be used for any given application.
Vout
Rtrimdown 
511
 10.22k 
delta
Module
Trim
GND
(100  delta)  Vo  5.11  626
Rtrimup 
 10.22k 
1 .225  delta
Rtrimdown
Vout
Module
Trim
Rtrimup
GND
Note:
delta 
Vo _ req  Vo   100 %
Vo
400
5000
360
4500
Trim resi stor value,Rtrim_up(KOhm)
Trim resi stor value Rtrim_down(KOhm)
Vo_req=Desired (trimmed) output voltage [V]
Output voltage Vo=12.007 V
320
280
240
200
160
120
80
3500
3000
2500
2000
1500
1000
500
40
0
4000
9.8
10.02 10.24 10.46 10.68 10.9 11.12 11.34 11.56 11.78
Adjusted output voltage Vo,adj (V)
12
0
12
12.12 12.24 12.36 12.48 12.6 12.72 12.84 12.96 13.08
Adjusted output voltage Vo,adj(V)
Bel Fuse Inc. 206 Van Vorst Street, Jersey City, NJ 07302  Tel 201-432-0463  Fax 201-432-9542  www.belfuse.com
8
13.2
ISOLATED DC/DC CONVERTERS
18 Vdc - 75 Vdc Input, 12 Vdc/3.5 A Output
Apr. 19, 2011
Bel Power, Inc. , a subsidiary of Bel Fuse, Inc.
Remote Sense
This module has remote sense compensation feature. It can minimize the effects of resistance between
module’s output and load in system layout and facilitates accurate voltage regulation at load terminals or
other selected point.
1. The remote sense lines carries very little current and hence do not require a large cross-sectional area.
2. This module compensates for a maximum drop of 10% of the nominal output voltage.
3. If the unit is already trimmed up, the available remote sense compensation range should be
correspondingly reduced. The total voltage increased by trim and remote sense should not exceed 10%
of the nominal output voltage.
4. When using remote sense compensation, all the resistance, parasitic inductance and capacitance of the
system are incorporated within the feedback loop of this module. It can make an effect on the module's
compensation, affecting the stability and dynamic response. A 0.1uF ceramic capacitor can be
connected at the point of load to de-couple noise on the sense wires.
5. Recommend the connection of remote sense compensation as below figure. There are a resistor RS+
(100 ohm) from Vo+ to Sense+ and a resistor RS- (51 ohm)) from Vo- to Sense- inside of this module.
RS+
Vo+
Sense+
Load
RS-
Sense-
V o-
6. If not using remote sense compensation, please connect sense directly to output at module's pin, that is,
connect sense+ to Vo+ and sense- to Vo- at module's pin, the shorter the better. See below figure.
RS+
V o+
Sense+
Load
RS-
Sense-
Vo-
Bel Fuse Inc. 206 Van Vorst Street, Jersey City, NJ 07302  Tel 201-432-0463  Fax 201-432-9542  www.belfuse.com
9
ISOLATED DC/DC CONVERTERS
18 Vdc - 75 Vdc Input, 12 Vdc/3.5 A Output
Bel Power, Inc. , a subsidiary of Bel Fuse, Inc.
Apr. 19, 2011
Over Current Protection
To provide protection in a fault output overload condition, the module is equipped with internal current-limiting
circuitry and can endure current limiting for a few mili-seconds. If the over current condition persists beyond a few
milliseconds, the module will shut down into hiccup mode and restart once every 400mS. The module operates
normally when the output current goes into specified range. The typical average output current is 0.5A during
hiccup.
Vin=48V
Vin=24V
Input Under-voltage Lockout
Input Current
Under-voltage Lockout
Voltage Falling
V1=16.8V
V2=17.2V
Voltage Rising
V1
V2
Input Voltage (V)
Bel Fuse Inc. 206 Van Vorst Street, Jersey City, NJ 07302  Tel 201-432-0463  Fax 201-432-9542  www.belfuse.com
10
ISOLATED DC/DC CONVERTERS
18 Vdc - 75 Vdc Input, 12 Vdc/3.5 A Output
Bel Power, Inc. , a subsidiary of Bel Fuse, Inc.
Apr. 19, 2011
Mechanical Outline
Pin
Function
Dia.
Pin
Function
Dia.
1
Vin(+)
0.04’’
5
SENSE(-)
0.04’’
2
On/Off
0.04’’
6
TRIM
0.04’’
3
Vin(-)
0.04’’
7
SENSE(+)
0.04’’
4
Vout(-)
0.062’’
8
Vout(+)
0.062’’
Note: This module is recommended and compatible with Pb-Free Wave Soldering and must be soldered
using a peak solder temperature of no more than 260 ºC for less than 5 seconds.
Note:
1) All Pins: Material - Copper Alloy;
Finish – 3 micro inches minimum Gold over 50 micro inches minimum Nickel plate.
2) Undimensioned components are shown for visual reference only.
3) All dimensions in inches (mm); Tolerances: x.xx +/-0.02 in. (x.x +/-0.5mm) x.xxx +/-0.010 in. (x.xx +/-0.25mm).
Bel Fuse Inc. 206 Van Vorst Street, Jersey City, NJ 07302  Tel 201-432-0463  Fax 201-432-9542  www.belfuse.com
11
ISOLATED DC/DC CONVERTERS
18 Vdc - 75 Vdc Input, 12 Vdc/3.5 A Output
Bel Power, Inc. , a subsidiary of Bel Fuse, Inc.
Apr. 19, 2011
Revision History
Date
Revision
2011-04-19
PA
Changes Detail
Approval
First release
JZ Wang
RoHS Compliance
Complies with the European Directive 2002/95/EC, calling for the elimination of lead and
other hazardous substances from electronic products.
2011 Bel Fuse Inc. Specifications subject to change without notice. 041911
12
CORPORATE
FAR EAST
EUROPE
Bel Fuse Inc.
206 Van Vorst Street
Jersey City, NJ 07302
Tel 201-432-0463
Fax 201-432-9542
www.belfuse.com
Bel Fuse Ltd.
8F/ 8 Luk Hop Street
San Po Kong
Kowloon, Hong Kong
Tel 852-2328-5515
Fax 852-2352-3706
www.belfuse.com
Bel Fuse Europe Ltd.
Preston Technology Management Centre
Marsh Lane, Suite G7, Preston
Lancashire, PR1 8UD, U.K.
Tel 44-1772-556601
Fax 44-1772-888366
www.belfuse.com