MC145572PB Freescale Semiconductor, MC145572PB Datasheet - Page 224

• Manufacturer Part Number: MC145572PB
• Manufacturer: Freescale Semiconductor

Specifications of MC145572PB

• Number Of Line Interfaces: 1
• Control Interface: HDLC
• Lead Free Status / Rohs Status: Not Compliant

E–4
E.4
2B1Q LINE INTERFACE
Figure E–5 shows the suggested 2B1Q interface networks for connection to the U–interface. The com-
ponent specifications are shown in Table E–5. Sources and specifications for the 2B1Q line interface
transformer can be found in Appendix B.
There are two basic topologies for the 2B1Q line interface. The first topology does not have resistors
between the transformer and Tip, and the transformer and Ring. The second topology does have these
resistors. By using positive temperature coefficient resistors on the line side of the transformer, electri-
cal safety design requirements may be more easily implemented. A positive temperature coefficient
resistor greatly increases its resistance value when it heats, up due to the application of external volt-
ages across Tip and Ring. Effectively, the positive temperature coefficient resistor creates a high imped-
ance, thereby limiting current flow between Tip and Ring when the protection diodes turn on.
Motorola continues to qualify several third party sources for the 2B1Q line interface trans-
former. Contact your local Motorola representative or Motorola factory applications staff
for the latest information regarding component sourcing.
MC145572
MC145572
RxP
RxN
Freescale Semiconductor, Inc.
TxP
TxN
RxP
RxN
TxN
TxP
For More Information On This Product,
Figure E–5. Typical 2B1Q Line Interface Schematic
Go to: www.freescale.com
C1
C1
R1
R2
R1
R2
MC145572
D3
D4
D3
D4
D2
V
V
D2
DD
V
DD
DD
V
NOTE
DD
(a)
D1
(b)
D1
PULSE PE68628
PULSE PE68628
1:1.25
1:1.25
C2
C2
D5
R3
R4
D5
RING
TIP
RING
TIP
MOTOROLA