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Murata Power Solutions |
78250 Series
MAX250 Compatible Converter Transformers
FEATURES
n RoHS compliant
www.DatanShMeeatx4iUm.cMomAX250 compatible
n Isolation to 4kVrms
n Industry-standard pinout
n Surface mount option
n UL 94 V-0 package materials
n Low profile
n Toroidal construction
n Fully encapsulated
n Industrial temperature range
DESCRIPTION
The 78250 series of converter transformers
are specifically designed for use with Maxim
chipsets to provide isolated RS232 interfaces.
Carefully controlled turns ratios ensure consistent
performance whilst a toroidal construction
minimises EMI.
For full details go to
www.murata-ps.com/rohs
CHARACTERISTICS 78250C/78250MC
Parameter
Conditions
Primary Inductance, LP
Leakage Inductance, LL
Interwinding Capacitance, CWW
Primary D.C. Resistance, RDC
Volt-time Product, Et
10kHz, 100mV
100kHz, 100mV
100kHz, 100mV
<0.1VDC
Pins1/2 or 2/3
Min. Typ. Max. Units
1.0 2.0 2.5 mH
2.0 3.0 μH
69 90 pF
1.0 2.0 Ω
50 Vμs
CHARACTERISTICS 78250VC/78250MVC
Parameter
Conditions
Primary Inductance, LP
Leakage Inductance, LL
Interwinding Capacitance, CWW
Primary D.C. Resistance, RDC
Volt-time Product, Et
10kHz, 100mV
100kHz, 100mV
100kHz, 100mV
<0.1VDC
Pins1/2 or 2/3
Min. Typ. Max. Units
1.0 2.0 2.5 mH
35 40 μH
9 12 pF
1.4 1.8 Ω
50 Vμs
ORDER CODE DETAILS
Order Code
78250C / 78250VC
78250MC / 78250MVC
78250MC-R / 78250MVC-R
Package Type
6 Pin DIL
6 Pin SM
6 Pin SM
Packaging Type
Tube
Tube
Tape & Reel
Quantity
50
50
500
ABSOLUTE MAXIMUM RATINGS
Operating free air temperature range
Storage temperature range
Lead temperature 1.5mm from case for 10 seconds
Peak current, IPK
Isolation voltage 78250(M)C (flash tested for 1 second)
Isolation voltage 78250V(M)C (flash tested for 1 second)
-40°C to 85°C
-50°C to 125°C
300°C
300mA
1.5kVrms
4.0kVrms
All specifications typical at TA=25°C
TECHNICAL NOTES
ISOLATION VOLTAGE
‘Hi Pot Test’, ‘Flash Tested’, ‘Withstand Voltage’, ‘Proof Volt-
age’, ‘Dielectric Withstand Voltage’ & ‘Isolation Test Voltage’
are all terms that relate to the same thing, a test voltage,
applied for a specified time, across a component designed
to provide electrical isolation, to verify the integrity of that
isolation.
All products in this series are 100% production tested at
their stated isolation voltage.
A question commonly asked is, “What is the continuous
voltage that can be applied across the part in normal opera-
tion?”
For a part holding no specific agency approvals both input
and output should normally be maintained within SELV limits
i.e. less than 42.4V peak, or 60VDC. The isolation test volt-
age 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 cor-
rectly 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-acces-
sible 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 environ-
ment. This 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 de-
pend 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 there-
fore 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 recog-
nized parts rated for better than functional isolation
where the wire enamel insulation is always supple-
mented by a further insulation system of physical
spacing or barriers.
www.murata-ps.com
KMP_78250C_C02 Page 1 of 3
78250 Series
MAX250 Compatible Converter Transformers
PACKAGE SPECIFICATIONS
MECHANICAL DIMENSIONS
6 Pin DIL
0.375
(9.52) MAX
0.354
(9.0) Max.
www.DataSheet4U.com
78250C
XYYWW
1 Primary Secondary 6
2
34
6 Pin SM
0.354
(9.0) Max.
0.5
(12.70)
0.375
(9.52) Max.
78250MC
XYYWW
1 Primary Secondary 6
2 5*
34
0.25
(6.35)
0.135±0.02
(3.44±0.50)
0.012(0.30)
0.008(0.20)
0.40
(10.16)
0.1
(2.54)
0.025 (0.63)
0.021 (0.53)
RECOMMENDED FOOTPRINT DETAILS
6 Pin DIL
0.10 (2.54) 0.10 (2.54)
0.10 (2.54) 0.10 (2.54)
0.25
(6.35)
0.012±0.30
(0.008±0.20)
0.035 (0.90)
0.1 (2.54)
0.025 (0.63)
0.021 (0.53)
Unless otherwise stated all dimensions in inches (mm) ±0.01 (0.25).
All pins on a 0.1 (2.54) pitch and within ±0.01 (0.25) of true position.
* Pin 5 is connected to secondary center tap. Package Weight 1.0g TYP.
6 Pin SM
0.06 (1.60) 0.06 (1.60)
Ø0.05
(1.20)
+Ø-000...00000560(1((00.2..10050) ))+-00..000060
(0.15)
(0.00)
0.04
(1.00)
0.04
(1.00)
0.45
(11.50)
0.45
(11.50)
0.10 (2.54) 0.10 (2.54)
Unless otherwise stated all dimensions in inches (mm)
±0.01 (0.25). All pins on a 0.1 (2.54) pitch and within
±0.01 (0.25) of true position.
TUBE OUTLINE DIMENSIONS
0.43
(10.95)
0.16 (4.00)
0.023±0.005
(0.60±0.15)
0.22 (5.50)
0.15
(3.80)
0.62 (15.70)
0.51
(12.95)
Unless otherwise stated all
dimensions in inches (mm)
±0.01 (0.25).
Tube length: 18.3±0.08 (465±2).
Tube material: Antistatic coated
clear pvc.
SOLDERING INFORMATION1
Pin finish
Peak wave solder temperature
Peak reflow temperature
Pure tin dip
300˚C for 10 seconds
220˚C
1 For further information, please visit www.murata-ps.com/rohs
www.murata-ps.com
KMP_78250C_C02 Page 2 of 3
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