78250 Series
MAX250 Compatible Converter Transformers
CHARACTERISTICS 78250C/78250MC
Parameter
Primary Inductance, L
P
Leakage Inductance, L
L
Interwinding Capacitance, C
WW
D.C. Resistance, R
DC
Volt-time Product, Et
Conditions
0kHz, 00mV
00kHz, 00mV
00kHz, 00mV
<0.VDC
5kHz, 5V
Min.
.0
Typ.
2.0
2.0
69
.0
Max.
2.5
3.0
90
2.0
Units
mH
μH
pF
Ω
Vμs
50
FEATURES
n
compliant
RoHS
n
Maxim MAX250 compatible
n
Isolation to 4kVrms
n
Industry-standard pinout
n
Surface mount option
n
94 V-0 package materials
UL
n
profile
Low
n
Toroidal construction
n
encapsulated
Fully
n
Industrial temperature range
CHARACTERISTICS 78250VC/78250MVC
Parameter
Primary Inductance, L
P
Leakage Inductance, L
L
Interwinding Capacitance, C
WW
D.C. Resistance, R
DC
Volt-time Product, Et
Conditions
0kHz, 00mV
00kHz, 00mV
00kHz, 00mV
<0.VDC
5kHz, 5V
Min.
.0
Typ.
2.0
35
9
.4
Max.
2.5
40
2
.8
Units
mH
μH
pF
Ω
Vμs
50
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 .5mm from case for 0 seconds
Peak current, I
PK
Isolation voltage 78250(M)C (flash tested for second)
Isolation voltage 78250V(M)C (flash tested for second)
All specifications typical at T
A
=25°C
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.
-40°C to 85°C
-50°C to 25°C
300°C
300mA
.5kVrms
4.0kVrms
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 00% 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.
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KMP_78250C.2
Page of 3
78250 Series
MAX250 Compatible Converter Transformers
PACKAGE SPECIFICATIONS
MECHANICAL DIMENSIONS
6 Pin DIL
0.375
(9.52) MAX
Primary
Secondary
6 Pin SM
0.5
(12.70)
0.375
(9.52) Max.
Primary
Secondary
0.35
(8.89) Max.
6
0.35
(8.89) Max.
6
5*
4
78250C
XYYWW
2
3
4
78250MC
XYYWW
2
3
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)
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) ±0.0 (0.25).
0.25).
All pins on a 0. (2.54) pitch and within ±0.0 (0.25) of true position.
0.25)
position
* Pin 5 is connected to secondary center tap. Package Weight .0g TYP.
RECOMMENDED FOOTPRINT DETAILS
6 Pin DIL
0.10 (2.54) 0.10 (2.54)
0.10 (2.54) 0.10 (2.54)
0.06 (1.60) 0.06 (1.60)
6 Pin SM
Ø0.05 (1.20) +0.006(1.20) +0.006 (0.15)
Ø0.05 (0.15)
-0.000 (0.00) -0.000 (0.00)
0.04
(1.00)
0.04
(1.00)
0.10 (2.54) 0.10 (2.54)
0.45
(11.50)
0.45
(11.50)
Unless otherwise stated all dimensions in inches (mm)
±0.0 (0.25). All pins on a 0. (2.54) pitch and within
0.25).
±0.0 (0.25) of true position.
0.25)
position
TUBE OUTLINE DIMENSIONS
0.43
(0.95)
0.6 (4.00)
0.023±0.005
(0.60±0.5)
0.22 (5.50)
0.5
(3.80)
0.62 (5.70)
0.5
(2.95)
Unless otherwise stated all
dimensions in inches (mm)
±0.0 (0.25).
0.25).
Tube length: 8.3±0.08 (465±2).
±0.08
±2).
).
Tube material: Antistatic coated
clear pvc.
RoHS COMPLIANCE INFORMATION
For through-hole products a peak wave
solder temperature of 300°C for 0 seconds
is permitted. The pin termination finish on
this product series is bright tin. All types are
backward compatible with Sn/Pb soldering
systems.
For further information, please visit www.cd4power.com/rohs
www.cd4power.com
KMP_78250C.2
Page 2 of 3
78250 Series
MAX250 Compatible Converter Transformers
TAPE & REEL SPECIFICATIONS
REEL OUTLINE DIMENSIONS
Ø15.039 (382) Max.
2.36 (60) Min.
0.94-1.08 (23.9-27.4)
*
Ø 0.53 (13.50)
0.50 (12.80)
Leader section
15.7 (400) Min.
3.9 (100)
Min.
0.059 (1.50)
Min.
1.20
(30.4) Max.
Goods
enclosure
section
0.96 (24.4)
1.04 (26.4)
Trailer section
6.3 (160) Min.
Unless otherwise stated all
dimensions in inches (mm) ±0.0(0.25).
* Includes flange distortion at outer edge.
Measured at hub.
Ø 0.80 (20.20) Min.
0.157
TAPE OUTLINE DIMENSIONS
(4.00)
0.069
(1.75)
0.069
(1.75)
0.157 (4.00)
2.00 (0.079)
0.079 (2.00)
0.059 (1.50) MIN
+0.004
0.059
(1.50+0.10 )
0.059 -0.000
-0.000 (1.50
-0.00
+0.004
+0.10
-0.00 )
0.217 (5.50)
+0.30
+0.012
0.945
0.945
+0.012
(24.00
+0.30
)
)
-0.10
(24.00
-0.10
-0.004
-0.004
0.453
(11.50)
0.453
(11.50)
3° MAX
Cover tape
COVER TAPE
3° MAX
0.369 (9.37)
0.369 (9.37)
0.472 (12.00)
0.024 (0.60) Max.
0.024 (0.60) MAX
0.283 (7.20)
0.283 (7.20)
0.240 (6.10)
Direction of unreeling
Unless otherwise stated all
dimensions in inches (mm) ±0.0(0.25).
0.472 (12.00)
R0.012 (R0.30) MAX
DIRECTION OF UNREELING
C&D Technologies (NCL) Limited reserve the right to alter or improve the specification, internal design or manufacturing
process at any time, without notice. Please check with your supplier or visit our web site to ensure that you have the
current and complete specification for your product before use.
© C&D Technologies (NCL) Limited 2005 KMP_78250C.4
No part of this publication may be copied, transmitted or stored in a retrieval system or reproduced in any way including,
but not limited to, photography, photocopy, magnetic or other recording means, without prior written permission from C&D
Technologies (NCL) Limited. Instructions for use are available from www.cd4power.com
C&D Technologies (NCL) Ltd
Tanners Drive, Blakelands North
Milton Keynes MK4 5BU, UK
Tel: +44 (0)908 65232
Fax: +44 (0)908 67545
email: mk@cdtechno.com
C&D Technologies, Inc.
Cabot Boulevard, Mansfield,
MA 02048-5 USA
Tel: + 800 233 2765
Fax: + 508 339 6356
email: sales@cdtechno.com
www.cd4power.com
KMP_78250C.2
Page 3 of 3
0.876 (22.25) MIN
0.518 (13.17)
DA103MC
78250C
XYYWW
XYYWW
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