78250J Series
MAX250/MAX251 Compatible Converter SM Transformers
KMP_78250JC_A05 Page 1 of 3
www.murata-ps.com/support
www.murata-ps.com
For full details go to
www.murata-ps.com/rohs
FEATURES
J-STD-020D reflow
RoHS compliant
Maxim MAX250/MAX251 compatible
Isolation to 4kVrms
Industry-standard pinout
Surface mount option
UL 94 V-0 package materials
Low profile
Toroidal construction
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 through hole versions see 78250 datasheet.
CHARACTERISTICS 78250JC
Parameter Conditions Min. Typ. Max. Units
Primary Inductance, LP10kHz, 100mV 1.0 2.0 2.5 mH
Leakage Inductance, LL100kHz, 100mV 0.6 3.0 μH
Interwinding Capacitance, CWW 100kHz, 100mV 48 90 pF
Primary D.C. Resistance, RDC <0.1VDC 0.7 2.0 Ω
Volt-time Product, Et Pins1/2 or 2/3 50 Vμs
Turns Ratio 1:1
CHARACTERISTICS 78250JVC
Parameter Conditions Min. Typ. Max. Units
Primary Inductance, LP10kHz, 100mV 1.0 2.0 2.5 mH
Leakage Inductance, LL100kHz, 100mV 35 40 μH
Interwinding Capacitance, CWW 100kHz, 100mV 4 10 pF
Primary D.C. Resistance, RDC <0.1VDC 0.9 1.8 Ω
Volt-time Product, Et Pins1/2 or 2/3 50 Vμs
Turns Ratio 1:1
ORDER CODE DETAILS
Order Code Package Type Packaging Type Quantity
78250JC / 78250JVC 6 Pin SM Tube 50
78250JC-R / 78250JVC-R 6 Pin SM Tape & Reel 500
ABSOLUTE MAXIMUM RATINGS
Operating free air temperature range -40°C to 85°C
Storage temperature range -50°C to 125°C
Lead temperature 1.5mm from case for 10 seconds 300°C
Peak current, IPK 300mA
Isolation voltage 78250(J)C (flash tested for 1 second) 1.5kVrms
Isolation voltage 78250V(J)C (flash tested for 1 second) 4.0kVrms
All specifications typical at TA=25°C
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
specified time, across a component designed to provide electri-
cal 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 volt-
age that can be applied across the part in normal operation?”
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-accessi-
ble 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 depend on
the wire insulation. Any material, including this enamel
(typically polyurethane) is susceptible to eventual
chemical degradation when subject to very high ap-
plied 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 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.
78250J Series
MAX250/MAX251 Compatible Converter SM Transformers
KMP_78250JC_A05 Page 2 of 3
www.murata-ps.com/support
PACKAGE SPECIFICATIONS
MECHANICAL DIMENSIONS
RECOMMENDED FOOTPRINT DETAILS
0.354
(9.0) Max.
0.375
(9.52) Max.
0.5
(12.70)
0.025 (0.63)
0.021 (0.53)
0.035 (0.90)
0.012 (0.30)
0.008 (0.20)
0.25
(6.35)
0.1 (2.54)
78250JC
XYYWW
Primary Secondary
SOLDERING INFORMATION1
Pin finish Matte tin
Max. peak reflow temperature 245°C
Moisture sensitivity level21
Max. time above liquidous (217°C) 100s
1 For further information, please visit www.murata-ps.com/rohs
2 Representative samples of the product were subjected to the conditioning described in IPC/JEDEC
J-STD-020D and passed electrical testing, package coplanarity and visual inspection which
revealed no external cracks or changes in package body flatness.
6
5*
4
1
2
3
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.
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.
0.45
(11.50)
0.10 (2.54)
0.04
(1.00)
0.06 (1.60)
TUBE OUTLINE DIMENSIONS
0.023±0.005
(0.60±0.15)
0.16 (4.00)
0.22 (5.50)
0.43
(10.95)
0.51
(12.95)
0.15
(3.80)
0.62 (15.70)
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.
78250J Series
MAX250/MAX251 Compatible Converter SM Transformers
KMP_78250JC_A05 Page 3 of 3
www.murata-ps.com/support
Murata Power Solutions, Inc. 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. Specifications are subject to change without
notice. © 2018 Murata Power Solutions, Inc.
This product is subject to the following operating requirements
and the Life and Safety Critical Application Sales Policy:
Refer to: http://www.murata-ps.com/requirements/
TAPE & REEL SPECIFICATIONS
REEL OUTLINE DIMENSIONS
TAPE OUTLINE DIMENSIONS
1.20
(30.4) Max.
0.94-1.08 (23.9-27.4)
0.53 (13.50)
0.50 (12.80)
0.059 (1.50)
Min.
2.36 (60) Min.
0.80 (20.20) Min.
3.9 (100)
Min.
Leader section
15.7 (400) Min.
Goods
enclosure
section
Trailer section
6.3 (160) Min.
Ø15.039 (382) Max.
Ø
Ø
*
0.96 (24.4)
1.04 (26.4)
g
g
Unless otherwise stated all
dimensions in inches (mm) ±0.01(0.25).
* Includes flange distortion at outer edge.
g Measured at hub.
0.024 (0.60) Max.
0.283 (7.20)
0.369 (9.37)
Direction of unreeling
0.069 (1.75)
0.453 (11.50)
0.157 (4.00) 0.079 (2.00)
0.472 (12.00)
Cover tape
0.059 (1.50 )
+0.004
-0.000 +0.10
-0.00
0.945 (24.00 )
+0.012
-0.004
+0.30
-0.10
78250JC
XYYWW
Unless otherwise stated all
dimensions in inches (mm) ±0.01(0.25).
