73M1822/73M1922 Data Sheet
DS_1x22_017
4.4 Isolation Barrier Pulse Transformer
The isolation element used by the 73M1x22 is a standard digital pulse transformer. Several vendors supply
compatible transformers with up to 6000 V ratings. Since the transformer is the only component crossing
the isolation barrier other than EMI capacitors that may be required, it solely determines the isolation
between the PSTN and the 73M1922 digital interface. This method of isolation is significantly superior to
other isolation techniques with major advantages in high common mode voltage operation, lower radiated
noise (EMI) and improved operation in noisy environments. Table 28 lists some pulse transformers
compatible with the 73M1x22. The table also includes lower-voltage transformers that offer low-cost
alternatives if such voltages are sufficient.
Table 28: Compatible Pulse Transformer Sources
Company
Number
Sumida
ESMIT 4180
750110001
TG-UTB01543S
PT79280
Wurth Electronics Midcom Inc.
UMEC
Datatronics
AAsupreme
P95003
Table 29 lists some of the typical transformer specifications used by the 731x22. Contact the manufacturer
directly for product information.
Table 29: Transformer Characteristics
Parameter
Test Condition
Min
54
–
Nom
60
Max
200
6
Tolerance
Unit
μH
Inductance
100 kHz, 10 mVAC, 1-2, Ls.
–
–
–
Interwinding
Capacitance
–
pF
Turn Ratio
–
–
–
–
1:1
–
–
–
±2 %
N/A
Ω
Ω
DC Resistance
Primary
Secondary
1 sec
0.25
0.25
–
–
–
–
Dielectric Breakdown
Voltage
2000
3750
Vrms
ET Constant
–
–
1.2
6000
–
–
–
–
–
–
Vμs
Vpeak
°C
Surge Test
1.2 x 50 μs
2800
-40
Operating Temperature
–
85
32
Rev. 1.6
TERIDIAN [ TERIDIAN SEMICONDUCTOR CORPORATION ]
