78250J Series
www.murata-ps.com
MAX250/MAX251 Compatible Converter SM Transformers
CHARACTERISTICS 78250JC
Parameter Conditions Min. Typ. Max. Units
Primary Inductance, L 10kHz, 100mV 1.0 2.0 2.5 mH
P
Leakage Inductance, L 100kHz, 100mV 0.6 3.0 H
L
Interwinding Capacitance, C 100kHz, 100mV 48 90 pF
WW
Primary D.C. Resistance, R <0.1VDC 0.7 2.0
DC
Volt-time Product, Et Pins1/2 or 2/3 50 Vs
Turns Ratio 1:1
FEATURES
CHARACTERISTICS 78250JVC
J-STD-020D reow
Parameter Conditions Min. Typ. Max. Units
RoHS compliant
Primary Inductance, L 10kHz, 100mV 1.0 2.0 2.5 mH
P
Leakage Inductance, L 100kHz, 100mV 35 40 H
Maxim MAX250/MAX251 compatible L
Interwinding Capacitance, C 100kHz, 100mV 4 10 pF
WW
Isolation to 4kVrms
Primary D.C. Resistance, R <0.1VDC 0.9 1.8
DC
Industry-standard pinout Volt-time Product, Et Pins1/2 or 2/3 50 Vs
Turns Ratio 1:1
Surface mount option
UL 94 V-0 package materials
ORDER CODE DETAILS
Order Code Package Type Packaging Type Quantity
Low prole
78250JC / 78250JVC 6 Pin SM Tube 50
Toroidal construction
78250JC-R / 78250JVC-R 6 Pin SM Tape & Reel 500
Industrial temperature range
ABSOLUTE MAXIMUM RATINGS
-40C to 85C
Operating free air temperature range
DESCRIPTION
-50C to 125C
Storage temperature range
300C
The 78250 series of converter transformers Lead temperature 1.5mm from case for 10 seconds
300mA
Peak current, I
are specically designed for use with Maxim
PK
1.5kVrms
Isolation voltage 78250(J)C (ash tested for 1 second)
chipsets to provide isolated RS232 interfaces.
4.0kVrms
Isolation voltage 78250V(J)C (ash tested for 1 second)
Carefully controlled turns ratios ensure consistent
performance whilst a toroidal construction
All specications typical at T =25C
A
minimises EMI.
TECHNICAL NOTES
For through hole versions see 78250 datasheet.
ISOLATION VOLTAGE REPEATED HIGH-VOLTAGE ISOLATION TESTING
Hi Pot Test, Flash Tested, Withstand Voltage, Proof Voltage, It is well known that repeated high-voltage isolation
Dielectric Withstand Voltage & Isolation Test Voltage are all testing of a barrier component can actually degrade
terms that relate to the same thing, a test voltage, applied for a isolation capability, to a lesser or greater degree
specied time, across a component designed to provide electri- depending on materials, construction and environ-
cal isolation, to verify the integrity of that isolation. ment. This series has toroidal isolation transformers,
with no additional insulation between primary and
All products in this series are 100% production tested at
secondary windings of enameled wire. While parts
their stated isolation voltage.
can be expected to withstand several times the stated
A question commonly asked is, What is the continuous volt-
test voltage, the isolation capability does depend on
age that can be applied across the part in normal operation?
the wire insulation. Any material, including this enamel
For a part holding no specic agency approvals both input
(typically polyurethane) is susceptible to eventual
and output should normally be maintained within SELV limits
chemical degradation when subject to very high ap-
i.e. less than 42.4V peak, or 60VDC. The isolation test volt-
plied voltages thus implying that the number of tests
age represents a measure of immunity to transient voltages
should be strictly limited. We therefore strongly advise
and the part should never be used as an element of a safety
against repeated high voltage isolation testing, but if it
isolation system. The part could be expected to function cor-
is absolutely required, that the voltage be reduced by
rectly with several hundred volts offset applied continuously
20% from specied test voltage.
across the isolation barrier; but then the circuitry on both
This consideration equally applies to agency recog-
sides of the barrier must be regarded as operating at an
nized parts rated for better than functional isolation
unsafe voltage and further isolation/insulation systems must
where the wire enamel insulation is always supple-
form a barrier between these circuits and any user-accessi-
mented by a further insulation system of physical
ble circuitry according to safety standard requirements.
For full details go to
spacing or barriers.
www.murata-ps.com/rohs
www.murata-ps.com/support
KMP_78250JC_A05 Page 1 of 378250J Series
MAX250/MAX251 Compatible Converter SM Transformers
PACKAGE SPECIFICATIONS
MECHANICAL DIMENSIONS
0.5
(12.70)
0.375
(9.52) Max.
Primary Secondary
1 6
0.354
2 5*
(9.0) Max.
78250JC
3 4
XYYWW
0.25
(6.35)
0.012 (0.30)
0.025 (0.63)
0.008 (0.20) 0.035 (0.90)
0.021 (0.53)
0.1 (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.
* Pin 5 is connected to secondary center tap. Package Weight 1.0g TYP.
RECOMMENDED FOOTPRINT DETAILS
0.06 (1.60)
0.10 (2.54)
0.04
(1.00)
0.45
(11.50)
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.
1
TUBE OUTLINE DIMENSIONS
SOLDERING INFORMATION
0.43
Pin nish Matte tin
(10.95)
Max. peak reow temperature 245C
2
Unless otherwise stated all
1
Moisture sensitivity level
0.16 (4.00)
dimensions in inches (mm)
0.01 (0.25). Max. time above liquidous (217C) 100s
0.0230.005
0.51
Tube length: 18.30.08 (4652).
1 For further information, please visit www.murata-ps.com/rohs
(0.600.15)
(12.95)
2 Representative samples of the product were subjected to the conditioning described in IPC/JEDEC
Tube material: Antistatic coated
clear pvc.
J-STD-020D and passed electrical testing, package coplanarity and visual inspection which
0.22 (5.50)
revealed no external cracks or changes in package body atness.
0.15
(3.80)
0.62 (15.70)
www.murata-ps.com/support
KMP_78250JC_A05 Page 2 of 3