Note:1、12V input types have typically 3% less load regulation change.
Temperature Characteristics
Parameter
Specification
Storage
Case temperature
rise above ambient
Cooling
0305, 0309, 0315
0303, 0312, 0503, 0505, 0509, 0512C, 0515
0505, 1205
1209, 1212, 1215
Free air convection
Conditions
All output types
Min.
-40
-55
Typ.
Max.
85
125
Units
℃
℃
℃
℃
℃
℃
25
30
43
40
Technical notes
ISOLATION VOLTAGE
‘Hi
Pot Test’、“Flash Tested’、”Withstand Voltage“、‘Proof Voltage”、“Dielectric Withstand Voltage'&'Isolation Test Voltage”are all terms that relate to the same thing, a test voltage, applied for a speci
fied time, across a component designed to provide electrical isolation, to verify the integrity of that isolation.
Professional Power Module B-XT series of DC/DC converters are all 100% production tested at their stated isolation voltage. This is 1kVDC for 1 second.
A question commonly asked is,
“What
is the continuous voltage that can be applied across the part in normal operation?”
For a part holding no specific agency approvals, such as the B-XT series, both input and output should normally be maintained within SELV limits i.e. less than 42.4V peak, or 60VDC. The isolation test voltage
represents a measure of immunity to transient voltages and the part should never be used as an element of a safety isolation system. The part could be expected to function correctly with several hundred volts
offset applied continuously across the isolation barrier; but then the circuitry on both sides of the barrier must be regarded as operating at an unsafe voltage and further isolation/insulation systems must form a
barrier between these circuits and any user-accessible circuitry according to safety standard requirements.
REPEATED HIGH-VOLTAGE ISOLATION TESTING
It is well known that repeated high-voltage isolation testing of a barrier component can actually degrade isolation capability, to a lesser or greater degree depending on materials, construction and environment. The
B-XT series has toroidal isolation transformers, with no additional insulation between primary and secondary windings of enameled wire. While parts can be expected to withstand several times the stated test
voltage, the isolation capability does depend on the wire insulation. Any material, including this enamel (typically polyurethane) is susceptible to eventual chemical degradation when subject to very high applied
voltages thus implying that the number of tests should be strictly limited. We therefore strongly advise against repeated high voltage isolation testing, but if it is absolutely required, that the voltage be reduced by
20% from specified test voltage.
This consideration equally applies to agency recognized parts rated for better than functional isolation where the wire enamel insulation is always supplemented by a further
insulation system of physical spacing or barriers.
The minimum load to meet datasheet specification is 10% of the full rated load across the specified input voltage range. Lower than 10% minimum loading will result in an
increase in output voltage, which may rise to typically double the specified output voltage if the output load falls to less than 5%.
Capacitive loading and start up
Typical start up times for this series, with a typical input voltage rise time of 2.2μs and output capacitance of 10μF, are shown in the table below. The product series will start
into a capacitance of 47μF with an increased start time, however, the maximum recommended output capacitance is 10μF.
Start-up time
μs
B0303XT
B0305XT
B0309XT
B0312XT
B0315XT
B0503XT
B0505XT
B0505NXT
437
1359
3435
6590
7625
533
1368
721
B0506XT
B0509XT
B0512XT
B0515XT
B1205XT
B1209XT
B1212XT
B1215XT
Start-up time
μs
7200
3146
4960
7740
895
2150
3640
7180
Ripple & Noise Characterization Method
Ripple and noise measurements are performed with the following test configuration.
C1
C2
1μF X7R multilayer ceramic capacitor, voltage rating to be a minimum of 3 times the output voltage of the DC/DC converter
10μF tantalum capacitor, voltage rating to be a minimum of 1.5 times the output voltage of the DC/DC converter with an ESR of less
than 100mΩ at 100 kHz
C3
R1
R2
T1
RLOAD
100nF multilayer ceramic capacitor, general purpose
450Ω resistor, carbon fi lm,
±1%
tolerance
50Ω BNC termination
3T of the coax cable through a ferrite toroid
Resistive load to the maximum power rating of the DC/DC converter. Connections should be made via twisted wires
Measured values are multiplied by 10 to obtain the specified values.
By using the values of inductance and capacitance stated, the output ripple at the rated load is lowered to 5mV p-p max.
Component selection
Capacitor: It is required that the ESR (Equivalent Series Resistance) should be as low as possible, ceramic types are recommended.
The voltage rating should be at least twice (except for 15V output), the rated output voltage of the DC/DC converter.
Inductor: The rated current of the inductor should not be less than that of the output of the DC/DC converter. At the rated current, the DC resistance of the inductor should be
such that the voltage drop across the inductor is <2% of the rated voltage of the DC/DC converter. The SRF (Self Resonant Frequency) should be >20MHz.
Inductor
L,μH
B0303XT
B0305XT
B0309XT
B0312XT
B0315XT
B0503XT
B0505XT
B0505NXT
B0506XT
B0509XT
B0512XT
B0515XT
B1205XT
B1209XT
B1212XT
B1215XT
10
47
22
10
47
10
47
47
10
22
47
47
47
22
47
47
SMD
82103C
82473C
82223C
82103C
82473C
82103C
82473C
82473C
82103C
82223C
82473C
82473C
82473C
82223C
82473C
82473C
Through Hole
11R103C
11R103C
11R223C
11R103C
11R473C
11R103C
11R473C
11R473C
11R103C
11R223C
11R473C
11R473C
11R473C
11R223C
11R473C
11R473C
Capacitor
C,μF
4.7
4.7
2.2
1
1
4.7
4.7
4.7
4.7
2.2
1
1
4.7
2.2
1
1
Tolerance Envelopes
The voltage tolerance envelope shows typical load regulation characteristics for this product series. The tolerance envelope is the maximum output voltage variation due to
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