PEB3081FV14XP Lantiq, PEB3081FV14XP Datasheet - Page 49

• Manufacturer Part Number: PEB3081FV14XP
• Manufacturer: Lantiq

Specifications of PEB3081FV14XP

• Number Of Line Interfaces: 1
• Control Interface: HDLC
• Lead Free Status / Rohs Status: Compliant

Preliminary
3.3.6
For both, receive and transmit direction a 1:1 transformer is used to connect the SBCX-
X transceiver to the 4 wire S/T interface. Typical transformer characteristics can be found
in the chapter on electrical characteristics. The connections of the line transformers is
shown in
Figure 23
For the transmit direction an external transformer is required to provide isolation and
pulse shape according to the ITU-T recommendations.
3.3.6.1
The ITU-T I.430 specification for both transmitter and receiver impedances in TEs results
in a conflict with respect to external S-protection circuitry requirements:
– To avoid destruction or malfunction of the S-device it is desirable to drain off even
– To meet the 96 kHz impedance test specified for transmitters and receivers (for TEs
This requirement results from the fact that this test is also to be performed with no supply
voltage being connected to the TE. Therefore the second reference point for
overvoltages V
greater than the combined forward voltages of the diodes, a current exceeding the
specified one may pass the protection circuit.
The following recommendations aim at achieving the highest possible device protection
against overvoltages while still fulfilling the 96 kHz impedance tests.
Data Sheet
small overvoltages reliably.
only, ITU-T I.430 sections 8.5.1.2a and
dimensioned such that voltages below 1.2 V (ITU-T I.430 amplitude) x transformer
ratio are not affected.
Figure
S/T Interface Circuitry
External Protection Circuitry
Connection of Line Transformers and Power Supply to the SBCX-X
DD
23.
10 µF
, is tied to GND. Then, if the amplitude of the 96 kHz test signal is
3.3 V
GND
VDD
VSS
SR1
SR2
SX1
SX2
49
Protection
Protection
Circuit
Circuit
8.6.1.1) the protection circuit must be
Description of Functional Blocks
1:1
1:1
Transmit
Receive
21150_05
Pair
Pair
PEB 3081
PEF 3081
2000-09-27