High Speed Transmission Equipment
Additional T1 Design Considerations
A T1 application can be TIA-968 approved as two different possible device types. An XD
device means an external CSU is used and the unit does not have to meet the
TIA-968 environmental test conditions, but it must connect only behind a separately
registered DE device. This XD equipment does not have to meet the T1 pulse template
requirements. If not classified as an XD device, then typically the application must adhere to
TIA-968 environmental test conditions.
T3 Protection
The capacitance across the pair of wires = (D1 || D2) + P0640EC/SC. The diode
capacitance is approximately (10 pF || 10 pF) 20 pF. Then adding the capacitive effect of
the P0640EC/SCMC, which is typically 60 pF, the total capacitance across the pair of wires
is approximately 15 pF. The MUR 1100E diodes are fast-switching diodes that will exhibit
this level of capacitance. MURS160T3 is a surface mount equivalent. (Figure 3.18)
F1250T
D1
D2
P0640EC/SC MC or
P0720EC/SC MC
Figure 3.18 T3 Protection
Alternately, the advanced P0642SA exhibits very low capacitance and can be used as a
stand-alone device.
P0642SA
Figure 3.19 Alternate T3 Protection
http://www.teccor.com
+1 972-580-7777
3 - 16
© 2002 Teccor Electronics
SIDACtor Data Book and Design Guide
®
TECCOR [ TECCOR ELECTRONICS ]
