The analog AMI/HDB3 waveform off of the E1 line or the AMI/B8ZS waveform off of the T1 line is
transformer coupled into the RTIP and RRING pins of the DS21348. The user has the option to use
internal termination, software selectable for 75Ω/100Ω/120W applications, or external termination. The
device recovers clock and data from the analog signal and passes it through the jitter attenuation MUX
outputting the received line clock at RCLK and bipolar or NRZ data at RPOS and RNEG. The DS21348
contains an active filter that reconstructs the analog received signal for the nonlinear losses that occur in
transmission. The receive circuitry is also configurable for various monitor applications. The device has a
usable receive 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 at TPOS and
TNEG is sent via the jitter attenuation mux to the waveshaping circuitry and line driver. The DS21348
will drive the E1 or T1 line from the TTIP and TRING pins via 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.
DOCUMENT REVISION HISTORY
1) Datasheet for 3.3V only, 011801.
Added supply current measurements; added thermal characteristics of quad package, 092101.
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