PEB22554 SIEMENS [Siemens Semiconductor Group], PEB22554 Datasheet - Page 62

• Manufacturer Part Number: PEB22554
• Description: ICs for Communications
• Manufacturer: SIEMENS [Siemens Semiconductor Group]

Programmable Pulse Shaper
The analog transmitter includes a programmable pulse shaper to satisfy the
requirements of ITU-T I.431. The amplitude and shape of the transmit pulses are
completely programmable via registers XPM0-2 from the microprocessor interface.
The transmitter requires an external step up transformer to drive the line.
Transmit Line Monitor
The transmit line monitor compares the transmit line current on XL1 and XL2 with an
on-chip transmit line current limiter. The monitor detects faults on the primary side of the
transformer indicated by a highly increased transmit line current (more than 120 mA for
at least 3 pulses) and protects the device from damage by setting the transmit line driver
XL1/2 automatically in a high impedance state. Two conditions will be detected by the
monitor: transmit line ones density (more than 31 consecutive zeros) indicated by
FRS1.XLO and transmit line high currrent indicated by FRS1.XLS. In both cases a
transmit line monitor status change interrupt will be provided.
Figure 23
Transmit Line Monitor Configuration
Semiconductor Group
XL1
XL2
Monitor
62
Line
TRI
Shaper
Pulse
Functional Description E1
XDATA
ITS10936
PEB 22554
09.98