FEATURES
n Maxim Compatible
n BS EN 60950 Approved
n Isolation to 6kV
n Toroidal Construction
n Industry Standard Pinout
n UL 94V-0 Package Material
n Fully Encapsulated
DESCRIPTION
The 76250EN 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/XXEN converter transformers
are specifically designed for use with the
MAX253 chipset 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 bride or voltage doubling.
The devices are fully approved to BS EN
60950 for use in telecoms applications.
76250EN CHARACTERISTICS
Parameter Conditions MIN TYP MAX Units
Primary Inductance, LP 10kHz, 100mV 1.0 2.0 2.5 mH
Leakage Inductance, LL 100kHz, 100mV 35 40 µH
Interwinding Capacitance, CWW 100kHz, 100mV 5.0 10 pF
D.C. Resistance, RDC <0.1VDC 1.0 2.0 Ω
Volt-time Product, ET 5kHz, 5V 50 Vµs
76253/35EN CHARACTERISTICS
Parameter Conditions MIN TYP MAX Units
Primary Inductance, LP 100kHz, 250mV 53 92 120 µH
Secondary Inductance, LS 100kHz, 250mV 350 460 600 µH
Leakage Inductance, LL 100kHz, 250mV 1.5 3.6 µH
Interwinding Capacitance, CWW 100kHz, 250mV 1.80 3.00 pF
D.C. Resistance, RDC >0.1VDC 0.60 1.00 Ω
Volt-time Product, ET 5kHz, 5V 20 35 Vµs
76253/55EN CHARACTERISTICS
Parameter Conditions MIN TYP MAX Units
Primary Inductance, LP 100kHz, 250mV 120 205 250 µH
Secondary Inductance, LS 100kHz, 250mV 280 362 445 µH
Leakage Inductance, LL 100kHz, 250mV 3.90 5.00 µH
Interwinding Capacitance, CWW 100kHz, 250mV 1.20 3.00 pF
D.C. Resistance, RDC >0.1VDC 0.90 1.50 Ω
Volt-time Product, ET 5kHz, 5V 20 23 Vµs
ABSOLUTE MAXIMUM RATINGS
All specifications typical at TA= 2 5 ° C .
SELECTION GUIDE
Input Output Output Isolation Turns
Voltage Voltage Current Voltage Ratio
Order Code (V) (V) (mA Max) (VDC)
76250EN – – – 6000 1CT:1
76253/35EN 3.3 5.0 100 6000 1:√5
76253/55EN 5.0 5.0 200 6000 1:1.33
Operating free air temperature range 76250EN 0°C to 70°C
Operating free air temperature range 76253/XXEN –40°C to 85°C
Storage temperature range –50°C to 125°C
Lead Temperature 1.5mm from case for 10 seconds 300°C
Peak current IPK 76250EN 300mA
Peak current IPK 76253/XXEN 400mA
Isolation voltage (flash tested for 1 second) 6000VDC
76250EN, 76253/XXEN
EN Approved Converter Transformers
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