Feature highlights, General, Line interface – Rainbow Electronics DS21458 User Manual
Page 11: Clock synthesizer, Eneral, Nterface, Lock, Ynthesizer

DS21455/DS21458 Quad T1/E1/J1 Transceivers
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2. FEATURE HIGHLIGHTS
2.1 General
§ DS21455: 27mm, 1.27 pitch BGA, compatible replacement for the DS21Q55
§ DS21458: 17mm, 1.00 pitch CSBGA
§ 3.3V supply with 5V tolerant inputs and outputs
§ Evaluation kits
§ IEEE 1149.1 JTAG-boundary scan
§ Driver source code available from the factory
2.2 Line Interface
§ Requires a single master clock (MCLK) for both E1 and T1 operation. Master clock can be
2.048MHz, 4.096MHz, 8.192MHz, or 16.384MHz. Option to use 1.544MHz, 3.088MHz,
6.276MHz, or 12.552MHz for T1-only operation
§ Fully software configurable
§ Short- and long-haul applications
§ Automatic receive sensitivity adjustments
§ Ranges include 0dB to -43dB or 0dB to -12dB for E1 applications; 0dB to -36dB or 0dB to -15dB
for T1 applications
§ Receive level indication in 2.5dB steps from -42.5dB to -2.5dB
§ Internal receive termination option for 75Ω, 100Ω, and 120Ω lines
§ Monitor application gain settings of 20dB, 26dB, and 32dB
§ G.703 receive-synchronization signal-mode
§ Flexible transmit-waveform generation
§ T1 DSX-1 line build-outs
§ T1 CSU line build-outs of -7.5dB, -15dB, and -22.5dB
§ E1 waveforms include G.703 waveshapes for both 75Ω coax and 120Ω twisted cables
§ AIS generation independent of loopbacks
§ Alternating ones and zeros generation
§ Square-wave output
§ Open-drain output option
§ NRZ format option
§ Transmitter power-down
§ Transmitter 50mA short-circuit limiter with exceeded indication of current limit
§ Transmit open-circuit-detected indication
§ Line interface function can be completely decoupled from the framer/formatter
2.3 Clock Synthesizer
§ Output frequencies include 2.048MHz, 4.096MHz, 8.192MHz, and 16.384MHz
§ Derived from recovered line clock or master clock