____________________________________________________ DS34T101, DS34T102, DS34T104, DS34T108
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Note 6:
The 1
F capacitor in series with TTIPn is only necessary in G.703 2048kHz mode (
LTISR.TXG703=1).
Note 7:
The 560pF on TTIPn/TRINGn must be tuned for your application.
Note 8:
Resistor RT is not necessary if receiver termination is internal. See LRISMR.RIMPM[2:0]. Table 10-60. Transformer Specifications
Specification
Recommended Value
Turns Ratio, 3.3V Applications
1:1 (Rx) and 1:2 (transmit) ±2%
Primary Inductance
600
H minimum
Leakage Inductance
1.0
H maximum
Intertwining Capacitance
40pF maximum
Transmit Transformer DC Resistance
Primary (Device Side)
Secondary
1.0
maximum
2.0
maximum
Rx Transformer DC Resistance
Primary (Device Side)
Secondary
1.2
maximum
1.2
maximum
10.13.1 LIU Operation
The incoming analog AMI/HDB3 waveform (E1) or analog AMI/B8ZS waveform (T1) is transformer coupled into the
RTIP/RRING pins of the LIU receiver. The LIU can be configured for internal termination (software selectable for
75
, 100, 110 or 120 applications) or external termination. The LIU receiver recovers clock and data from the
incoming analog signal and passes it through the jitter attenuation mux. The receiver contains an active filter that
reconstructs the analog received signal for the nonlinear losses that occur in transmission. The receiver circuitry is
configurable for various monitor applications. The device has a usable Rx sensitivity of 0dB to -43dB for E1 and
0dB to -36dB for T1, which allows the device to operate on 0.63mm (22AWG) cables up to 2.5km (E1) and 6k feet
(T1) in length. Data input to the LIU transmitter is sent via the jitter attenuation mux to the waveshaping circuitry
and line driver. The transmitter drives the E1 or T1 line from the
TTIP/TRING pins through a coupling transformer.
The line driver can handle both CEPT 30/ISDN-PRI lines for E1 and long-haul (CSU) or short-haul (DSX-1) lines for
T1. The configuration and status registers related to the LIU block are shown in the following table:
Register Name
Description
Functions
Page
Global Registers
Global Control Register 1
various
Global Transceiver Reset Register
LIU reset and soft reset bits
Global Transceiver Interrupt Status Register
LIU interrupt status bits (one per port)
Global Transceiver Interrupt Mask Register
LIU interrupt mask bits (one per port)
LIU Registers
LIU Transmit Rx Control Register
E1/T1 mode, LOS criteria, etc.
LIU Transmit Impedance Selection Register
Transmit impedance, LBO, 2048kHz
LIU Maintenance Control Register
Loopbacks, Tx/Rx power-down, Tx AIS
LIU Real-Time Status Register
Rx EQ status, Tx short/open, JA status
LIU Status Interrupt Mask Register
mask bits for bits in LLSR
LIU Latched Status Register
Rx EQ status, Tx short/open, JA status
LIU Rx Signal Level
Rx signal level in dB
LIU Rx Impedance and Sensitivity Monitor
Register
Rx impedance, sensitivity, monitor