78250 SERIES
Converter Transformers
SELECTION GUIDE 78250/78250M
Parameter
Conditions
MIN
TYP
MAX
Units
Primary Inductance, L
P
Leakage Inductance, L
L
Interwinding Capacitance, C
WW
D.C. Resistance, R
DC
10kHz, 100mV
100kHz, 100mV
100kHz, 100mV
<0.1VDC
5kHz, 5V
1.0
2.0
2.0
69
1.0
2.5
3.0
90
2.0
mH
µH
pF
Ω
Vµs
FEATURES
s
Maxim Compatible
s
Isolation to 4kV
s
Surface Mount Options
s
Toroidal Construction
s
Standard Pinout
s
UL 94V-0 Package Material
s
Fully Encapsulated
s
Low Profile
s
Industrial Temperature Range
Volt-time Product, E
T
50
SELECTION GUIDE 78250V/78250MV
Parameter
Conditions
MIN
TYP
MAX
Units
Primary Inductance, L
P
Leakage Inductance, L
L
Interwinding Capacitance, C
WW
D.C. Resistance, R
DC
10kHz, 100mV
100kHz, 100mV
100kHz, 100mV
<0.1VDC
5kHz, 5V
1.0
2.0
35
9
1.4
2.5
40
12
1.8
mH
µH
pF
Ω
Vµs
DESCRIPTION
The 78250 series of converter transformers
are specifically designed for use with Maxim
chipsets to provide isolated RS232 interfaces.
Carefully controlled turns ratios ensur e
consistent performance whilst a toroidal
construction minimises EMI. The surface
mount devices are fully compatible with
CECC00802 to 280°C which allows them to
be placed and reflowed with IC’s thus
reducing time and cost in production.
Volt-time Product, E
T
50
ABSOLUTE MAXIMUM RATINGS
Operating free air temperature range
Storage temperature range
Lead Temperature 1.5mm from case for 10 seconds
Peak current I
PK
Isolation voltage 78250(M) (flash tested for 1 second)
Isolation voltage 78250V(M) (flash tested for 1 second)
All specifications typical at T
A
=25°C.
–40°C to 85°C
–50°C to 125°C
300°C
300mA
1500Vrms
4000Vrms
www.dc-dc.com
78250 SERIES
Converter Transformers
MECHANICAL DIMENSIONS
6 Pin DIP
9.52 max
Top View
Primary
Secondary
1
8.89 max
2
3
6
78250
XYYWW
4
6.35
3.44±0.50
0.30
0.20
10.16
2.54
0.63
0.53
6 Pin SM
12.70
9.52 max
Top View
Primary
Secondary
1
8.89 max
2
3
6
5*
4
78250M
XYYWW
6.35
0.30
0.20
0.90
2.54
0.63
0.53
* Pin 5 is connected to secondary centre tap.
All dimensions in mm XX.XX ±0.25mm. All pins on a 2.54mm pitch and within ±0.25mm of true position.
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 2000
NMP 78250.2
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.dc-dc.com
C&D Technologies (NCL) Ltd
Tanners Drive, Blakelands North
Milton Keynes MK14 5BU, England
Tel: +44 (0)1908 615232
Fax:+44 (0)1908 617545
email: info@cdtechno-ncl.com
www: http://www.dc-dc.com
C&D Technologies (NCL), Inc.
8917 Glenwood Avenue, Raleigh
NC 27612, USA
Tel: +1 (919) 571-9405
Fax: +1 (919) 571-9262
email: info@us.cdtechno-ncl.com
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