78253 Series
www.murata-ps.com
MAX253 Compatible Converter Transformers
SELECTION GUIDE
Output
Voltage
Max. Output
Current
Isolation
Voltage
Input Voltage
Turns
Ratio
Package
Style
Order Code
V
V
mA
VDC
78253/35C
78253/35MC
78253/55C
78253/55MC
78253/35VC
78253/35MVC
78253/55VC
78253/55MVC
DIL
SM
DIL
SM
DIL
SM
DIL
SM
3.3
5.0
100
1500
1:2.27
1:1.31
1:2.14
1:1.33
5.0
3.3
5.0
5.0
5.0
5.0
200
100
200
1500
4000
4000
FEATURES
nRoHS compliant
nMaxim MAX253 compatible
n3.3V and 5V versions
nIsolation to 4kVDC
ORDER CODE DETAILS
Order Code
Package Type
Packaging Type
Quantity
78253/XXC
78253/XXMC
78253/XXMC-R
6 Pin DIL
6 Pin SM
6 Pin SM
Tube
Tube
50
50
nFrequency range to 500kHZ
nToroidal construction
nIndustry-standard pinout
nUL 94 V-0 package materials
nFully encapsulated
Tape & Reel
500
78253/35(M)C CHARACTERISTICS
Parameter
Conditions
Min.
0.30
1.60
Typ.
0.38
2.00
0.30
30
Max.
0.46
2.40
1.00
50
Units
mH
mH
μH
Primary Inductance, LP
Secondary Inductance, LS
Leakage Inductance, LL
Interwinding Capacitance, CWW
Primary D.C. Resistance, RDC
Volt-time Product, Et
100kHz, 250mV
100kHz, 250mV
100kHz, 250mV
100kHz, 250mV
>0.1VDC
pF
nLow profile
0.40
35
1.00
Ω
Vμs
nSurface mount option
nIndustrial temperature range
Pins 1/2 or 2/3
30
78253/55(M)C CHARACTERISTICS
Parameter
Conditions
Min.
0.60
1.10
Typ.
0.83
1.40
0.35
30
Max.
1.10
1.70
1.00
50
Units
mH
mH
μH
Primary Inductance, LP
Secondary Inductance, LS
Leakage Inductance, LL
Interwinding Capacitance, CWW
Primary D.C. Resistance, RDC
Volt-time Product, Et
100kHz, 250mV
100kHz, 250mV
100kHz, 250mV
100kHz, 250mV
>0.1VDC
DESCRIPTION
The 78253 series of converter transformers are
specifically designed for use with the MAX253
chip set to provide isolated power supplies. The
5V version can supply 1W and the 3.3V version
can supply 500mW. A centre tapped secondary
winding allows for full bridge, half bridge or
voltage doubling.
pF
0.70
50
1.50
Ω
Vμs
Pins 1/2 or 2/3
40
78253/35(M)VC CHARACTERISTICS
Parameter
Conditions
Min.
110
550
Typ.
142
710
3.00
4.20
0.30
22
Max.
185
Units
μH
Primary Inductance, LP
Secondary Inductance, LS
Leakage Inductance, LL
Interwinding Capacitance, CWW
Primary D.C. Resistance, RDC
Volt-time Product, Et
100kHz, 20mV
100kHz, 20mV
100kHz, 250mV
100kHz, 250mV
>0.1VDC
850
μH
Surface-mount parts
5.00
8.00
0.50
μH
pF
The surface-mount (M suffix) products are not
recommended for new designs. For existing designs,
however, Murata Power Solutions will continue to
manufacture and fully support these parts.
Ω
Vμs
Pins 1/2 or 2/3
18
78253/55(M)VC CHARACTERISTICS
For recommended alternatives please refer to the
78253J Series datasheet.
Parameter
Conditions
Min.
190
350
Typ.
240
444
5.20
4.20
0.40
28
Max.
310
Units
μH
Primary Inductance, LP
Secondary Inductance, LS
Leakage Inductance, LL
Interwinding Capacitance, CWW
Primary D.C. Resistance, RDC
Volt-time Product, Et
100kHz, 20mV
100kHz, 20mV
100kHz, 250mV
100kHz, 250mV
>0.1VDC
540
μH
8.00
8.00
0.60
μH
pF
Ω
Vμs
Pins 1/2 or 2/3
25
All specifications typical at TA=25°C
For full details go to
www.murata-ps.com/rohs
www.murata-ps.com/support
KMP_78253C_D04 Page 1 of 5