www.murata-ps.com
772 Series
Pulse Transformers
SELECTION GUIDE
Order Code
77203HVC
77205SC
77201C
77202C
77203C
77204C
77205C
77206C
77207C
77208C
Parameter
77209C
16.3
482
40
40
3.50
1.60
2.00
kVrms
Units
Turns ratio
Primary Inductance
(Min.)
Primary Et Constant
(Min.)
Leakage Inductance
(Max.)
Interwinding
Capacitance (Max.)
DC Resistance (Max.)
Primary winding
1:1
1.0
120
2.0
50
0.25
0.23
-
1:1:1 2:1:1 2:1:1
1.0
120
3.0
40
0.25
0.22
0.28
2.5
1.0
120
3.5
30
0.24
0.12
0.15
1.0
120
3.5
30
0.24
0.12
0.15
4.0
1:1
4.0
240
5.0
55
0.86
0.83
-
1:1:1 1:1:1 2:1:1
4.0
240
11
35
0.90
0.76
1.10
4.0
240
11
18
0.90
0.76
1.10
4.0
240
11
35
0.84
0.38
0.50
2.5
1:1
16.3
482
18
65
3.50
3.40
-
1:1:1 2:1:1
16.3
482
40
40
3.60
3.10
4.20
mH
Vμs
μH
pF
FEATURES
ATURES
compliant
RoHS
Inductance to 16.3mH
to 482 Vμs Et rating
Up
mounting
PCB
94 V-0 package materials
UL
to 4000Vrms isolation
Up
Backward compatible with
Sn/Pb soldering systems
DC Resistance (Max.)
Secondary1 winding
Ω
DC Resistance (Max.)
Secondary2 winding
DESCRIPTION
The 772 series of pulse transformers are intended
for medium power applications in switch mode
power supplies and thyristor/triac firing (e.g.
motor control applications). The standard turns
ratios may be modified on any transformer with
three windings by connecting any two windings
in series.
Isolation voltage (flash
tested for 1 second)
ABSOLUTE MAXIMUM RATINGS
Operating free air temperature range
Storage temperature range
Lead Temperature 1.5mm from case for 10 seconds
0°C to 70°C
-60°C to 125°C
300°C
SOLDERING INFORMATION
1
Peak wave solder temperature
Pin finish
Specifications typical at T
A
= 25°C
1 For further information, please visit www.murata-ps.com/rohs
300˚C for 10 seconds
Matte tin with nickel pre-plate
For full details go to
www.murata-ps.com/rohs
www.murata-ps.com/support
KMP_772C_B04
Page 1 of 3
772 Series
Pulse Transformers
PACKAGE SPECIFICATIONS
MECHANICAL DIMENSIONS
RECOMMENDED FOOTPRINT DETAILS
25.40 (1.00)
1
3
20.30 (0.799)
Ø1.20+0.15-0.00
(Ø0.472+0.006-0.000)
4
77202C
2
YYWW
5
6
2.54 (0.1)
2.54 (0.1)
12.30
(0.484)
5.92
(0.233)
12.5
(0.492)
Unless otherwise stated all dimensions in mm (inches) ± 0.25 (0.01).
TUBE DIMENSIONS
0.66 (0.026) Max.
2.53 (0.100)
5.08
(0.2)
15.24
(0.6)
5.08
(0.2)
3.05
(0.120)
20.32 (0.8)
13.30 (0.524)
0.75±0.12
(0.030±0.005)
11.50 (0.453)
Tube length: 530 (20.87) Max.
Unless otherwise stated all dimensions in mm (inches) ± 0.25 (0.01).
All dimensions in mm (inches) XX.X±0.50(0.02), XX.XX±0.25(0.01).
All pins on a 2.54 (0.1) pitch.
PIN CONNECTION STYLE - 8 PIN DIP (TOP VIEW)
Screen*
1
Secondary 1
3
4
Primary
5
Secondary 2
2
6
* Only on 77205SC
www.murata-ps.com/support
KMP_772C_B04
Page 2 of 3
22.50 (0.886)
772 Series
Pulse Transformers
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 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 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
voltage 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 correctly 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-accessible 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 environment. 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 applied 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 speci-
fied test voltage.
This consideration equally applies to agency recognized parts rated for better than
functional isolation where the wire enamel insulation is always supplemented by a
further insulation system of physical spacing or barriers.
Murata Power Solutions, Inc.
11 Cabot Boulevard, Mansfield, MA 02048-1151 U.S.A.
ISO 9001 and 14001 REGISTERED
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.
© 2011 Murata Power Solutions, Inc.
www.murata-ps.com/support
KMP_772C_B04
Page 3 of 3
