PSB3186FV14XP Lantiq, PSB3186FV14XP Datasheet - Page 47

• Manufacturer Part Number: PSB3186FV14XP
• Manufacturer: Lantiq

Specifications of PSB3186FV14XP

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

3.3.6
For both, receive and transmit direction a 1:1 transformer is used to connect the ISAC-
SX TE 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 22
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.
S/T Interface Circuitry
External Protection Circuitry
Connection of Line Transformers and Power Supply to the ISAC-SX
TE
DD
10 µF
, is tied to GND. Then, if the amplitude of the 96 kHz test signal is
3.3 V
GND
Figure
VDD
VSS
22.
SX1
SX2
SR1
SR2
47
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
ISAC-SX TE
PSB 3186
2003-01-30