DS_1x66B_001
73M1866B/73M1966B Data Sheet
4.3 Over-Voltage and EMI Protection
Over-voltage protection is required to meet worst-case conditions for target countries. UL1950,
EN60950, IEC 60950, ITU-T K.20/K.21 and GR-1089-CORE specifications define the protection
requirements for many countries. A single design can be implemented to meet all these requirements.
Figure 14 shows a recommended protection circuit topology. Fuse (F1) should be rated appropriately for
the country of operation, and the bidirectional thyristor (E1) should have a minimum break-over of 220 V,
a maximum break-over of 275 V and be able to survive a 100 A fast transient. In addition to over-voltage
and current protection, the 73M1x66B should make provisions to prevent EMI emissions and EMC
susceptibility. Figure 14 also illustrates how L1, L2, C35, C36 and C41can provide this suppression. The
ferrite beads, L1 and L2, should be capable of passing 150 mA and have an impedance of 2K Ω at 100
MHz. C35, C36 and C41 should be between 47pF and 220nF, and rated for a breakdown voltage greater
than the highest isolation voltage or line voltage that is required for country compatibility. C35 and C36
should be returned to an earth ground. EMI suppression is highly dependent on the physical design of
the overall circuit and not all the suppression components may be needed in every design and
application.
L1
2K Ohm @ 100MHz
F1
TR600-150
J1
T
6
5
4
3
2
1
C41
220pF, 300V
E1
L2
P3100SBRP
2K Ohm @ 100MHz
or equiv .
RJ-11
R
C36
220pF, 3kV
C35
220pF, 3kV
Figure 14: Suggested Over-Voltage Protection and EMI Suppression Circuit
Table 28: Reference Bill of Materials for Figure 14
Reference
Part Description
Bidirectional Thyristor
Source
Example MFR P/N
TB3100H-13-H,
TISP4290T3BJR-S
E1
Diodes Inc., Bourns
F1
PPTC Fuse
Tyco, Bourns
Steward, TDK
TDK
MF-R015/600 or equiv.
MPZ2012S601A
L1,L2
C35, C36
C41
2 KΩ @ 100 MHz, 150 mA min, 0805
220 pF, 3000 V
C4532COG3F221K
VJ1206Y221KXEAT5Z
220 pF, 300 V
Vishay
Rev. 1.6
31
TERIDIAN [ TERIDIAN SEMICONDUCTOR CORPORATION ]
