EN Approved MAX250/251/253 Compatible Converter Transformers
SELECTION GUIDE
Order Code
76250ENC
76253/35ENC
76253/55ENC
Input Voltage
V
-
3.3
5.0
Output
Voltage
V
-
5.0
5.0
Max. Output
Current
mA
-
100
200
Isolation
Voltage
V
DC
6000
6000
6000
Turns
Ratio
1CT:1
1:√5
1:1.33
FEATURES
RoHS compliant
Maxim MAX250/MAX251/MAX253
compatible
BS EN 60950 approved
Isolation to 6kV
DC
Toroidal construction
Industry-standard pinout
UL 94 V-0 package materials
Fully encapsulated
Compatible with RoHS soldering systems
Backward compatible with
Sn/Pb soldering systems
76250ENC CHARACTERISTICS
Parameter
Primary Inductance, L
P
(1&5)
Leakage Inductance, L
L
(1&5)
2
Interwinding Capacitance, C
WW
(1&2)
D.C. Resistance, R
DC
(1&5)
Volt-time Product, E
T
(1&5)
Conditions
10kHz, 100mV
100kHz, 100mV
100kHz, 100mV
<0.1V
DC
Min.
1.0
Typ.
2.0
35
1.5
1.0
Max.
2.5
40
3.0
2.0
Units
mH
μH
pF
Ω
Vμs
50
76253/35ENC CHARACTERISTICS
Parameter
Primary Inductance, L
P
(1&5)
Secondary Inductance, L
S
(2&6)
Leakage Inductance, L
L
(1&5)
2
Interwinding Capacitance, C
WW
(1&2)
D.C. Resistance, R
DC
(1&5)
Volt-time Product, E
T
(1&5)
Conditions
100kHz, 250mV
100kHz, 250mV
100kHz, 250mV
100kHz, 250mV
<0.1V
DC
Min.
140
700
Typ.
200
1000
5.0
2.7
0.4
Max.
Units
μH
μH
7.0
3.5
0.8
μH
pF
Ω
Vμs
25
35
76253/55ENC CHARACTERISTICS
DESCRIPTION
The 76250ENC converter transformer is
specifically designed for use with Maxim
chipsets to provide isolated RS232 interfaces. A
carefully controlled turns ratio ensures consistent
performance whilst a toroidal construction
minimises EMI.
The 76253/XXENC 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.
The devices are fully approved to BS EN 60950 for
use in telecoms applications.
Parameter
Primary Inductance, L
P
(1&5)
Secondary Inductance, L
S
(2&6)
Leakage Inductance, L
L
(1&5)
D.C. Resistance, R
DC
(1&5)
Volt-time Product, E
T
(1&5)
2
Conditions
100kHz, 250mV
100kHz, 250mV
100kHz, 250mV
100kHz, 250mV
<0.1V
DC
Min.
80
142
Typ.
Max.
150
267
Units
μH
μH
μH
pF
7.0
2.7
0.5
30
40
10.0
3.5
0.9
Interwinding Capacitance, C
WW
(1&2)
Ω
Vμs
ABSOLUTE MAXIMUM RATINGS
Operating free air temperature range 76250EN
Operating free air temperature range 76253/XXEN
Storage temperature range
Lead temperature 1.5mm from case for 10 seconds
Peak current, I
PK
76250EN
Peak current, I
PK
76253/XXEN
Isolation voltage (flash tested for 1 second)
0°C to 70°C
-40°C to 85°C
-50°C to 125°C
300°C
300mA
400mA
6000V
DC
SOLDERING INFORMATION
3
Peak wave solder temperature
Pin finish
All specifications typical at T
A
=25°C
1 Refer to mechanical dimensions for pin locations shown in brackets.
2 With pins 2 & 6 short circuited.
3
For further information, please visit www.murata-ps.com/rohs
300˚C for 10 seconds
Matte tin
For full details go to
www.murata-ps.com/rohs
www.murata-ps.com/support
KMP_7625XENC_B04
Page 1 of 4
76250ENC, 76253/XXENC
EN Approved MAX250/251/253 Compatible Converter Transformers
TYPICAL CHARACTERISTICS (VOLTAGE CURVES)
VOLTAGE CURVES
10
8
6
4
2
0
Output Voltage (V)
Output Voltage (V)
76253/35ENC
10
8
6
4
2
0
76253/55ENC
0
20
40
60
80
100
0
Output Current (mA)
100
200
300
Output Current (mA)
400
EFFICIENCY CURVES
100
80
60
40
20
0
76253/35ENC
100
80
60
40
20
0
76253/55ENC
Efficiency (%)
0
20
40
60
80
100
Efficiency (%)
0
100
200
300
400
Output Current (mA)
Output Current (mA)
VOLTAGE DEVIATION
110
76253/35ENC
110
76253/55ENC
Voltage deviation from nominal
25ºC output (%)
105
Voltage deviation from nominal
25ºC output (%)
-50
-25
0
25
50
75
100
105
100
100
95
95
90
90
-50
-25
0
25
50
75
100
Temperature (ºC)
Temperature (ºC)
All curves are derived from testing with the Maxim MAX235 IC using the circuit shown in application note MPAN-03 (download at http://www.murata-ps.com/data/apnotes/mpan-03.pdf).
www.murata-ps.com/support
KMP_7625XENC_B04
Page 2 of 4
76250ENC, 76253/XXENC
EN Approved MAX250/251/253 Compatible Converter Transformers
PACKAGE SPECIFICATIONS
MECHANICAL DIMENSIONS
15.00 (0.59)
1
15.00
(0.59)
2
3
5
76250ENC
XYYWW
12.50
(0.492)
12.00
(0.472)
2.54
(0.1)
4*
6
4.10
(0.161)
Ø0.56±0.05
(Ø0.022±0.002)
7.50
(0.295)
10.16 (0.4)
2.42 (0.095)
Pin Connections 76250EN (Top View)
Pin Connections 76253/XXEN (Top View)
1
Primary
Secondary
2
1
Primary
Secondary
2
3
3
4
* 76250EN Pin not fitted.
Unless otherwise stated all dimensions in mm (inches) ±0.25mm (±0.01).
All pins on a 2.54mm (0.1") pitch and within ±0.25mm (0.01") of true position.
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