DS26528 Datasheet, PDF (76/269 Pages) Maxim Integrated Products – Octal T1/E1/J1 Transceiver

Register
LLSR LIU Latched Status Register
LRSL LIU Receive Signal Level
LRISMR LIU Receive Impedance and
Sensitivity Monitor Register
DS26528 Octal T1/E1/J1 Transceiver
10C4, 10E4
1005,1025,1045,1065,1085,10A5,
10C5, 10E5
1006,1026,1046,1066,1086,10A6,
10C6, 10E6
1007,1027,1047,1067,1087,10A7,
10C7, 10E7
Status Bits
LIU latched status bits related to loss,
Open circuit, etc.
LIU Receive Signal Level Indicator
LIU Impedance Match and Sensitivity
Monitor
9.11.2 Transmitter
NRZ data arrives from the framer transmitter; the data is encoded with HDB3 or B8ZS or AMI. The encoded data
passes through a jitter attenuator if it is enabled for the transmit path. A digital sequencer and DAC are used to
generate transmit waveforms complaint with T1.102 and G.703 pulse templates.
A line driver is used to drive an internal matched impedance circuit for provision of 75W, 100W, 110W, and 120W
terminations. The transmitter couples to the E1 or T1 transmit twisted pair (or coaxial cable in some E1
applications) via a 1:2 step-up transformer. In order for the device to create the proper waveforms, the transformer
used must meet the specifications listed in Table 9-34. The transmitter requires a transmit clock of 2.048MHz for
E1 or 1.544MHz for T1/J1 operation.
The DS26528 drivers have a short circuit and open circuit detection driver fail monitor. There is a TXEnable pin that
can High-Z the transmitter outputs for protection switching. The individual transmitters can also be placed in High-Z
through register settings. The DS26528 also has functionality for powering down the transmitters individually. The
relevant telecommunications specification compliance is shown in Table 9-33.
Table 9-33. The Telecommunications Specification Compliance for DS26528 Transmitters
TRANSMITTER FUNCTION
TELECOMMUNICATIONS COMPLIANCE
T1 Telecom Pulse Template Compliance
ANSI T1.403
T1 Telecom Pulse Template Compliance
ANSI T1.102
Transmit Electrical Characteristics for E1
Transmission and Return Loss Compliance
ITUT G.703
Table 9-34. Transformer Specifications
SPECIFICATION
Turns Ratio 3.3V Applications
Primary Inductance
Leakage Inductance
Intertwining Capacitance
Transmit Transformer DC Resistance
Primary (Device Side)
Secondary
Receive Transformer DC Resistance
Primary (Device Side)
Secondary
RECOMMENDED VALUE
1:1 (receive) and 1:2 (transmit) ±2%
600mH minimum
1.0mH maximum
40pF maximum
1.0W maximum
2.0W maximum
1.2W maximum
1.2W maximum
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