Interfacing to the line, Transmit driver monitor, Transmitter power-down – Rainbow Electronics DS3170 User Manual

Page 114: Transmitter jitter generation (intrinsic), Transmitter jitter transfer, Receiver, Table 9-33. transformer characteristics

DS3170 DS3/E3 Single-Chip Transceiver

114 of 233

9.12.4.3 Interfacing to the Line

The transmitter interfaces to the outgoing DS3/E3 coaxial cable (75

W) through a 2:1 step-down transformer

connected to the TXP and TXN pins.

Figure 1-1

shows the arrangement of the transformer and other

recommended interface components.

Table 9-33

specifies the required characteristics of the transformer.

9.12.4.4 Transmit Driver Monitor

If the transmit driver monitor detects a faulty transmitter, it sets the PORT.SR.TDM status bit. When the transmitter
is tri-stated, the transmit driver monitor is also disabled. The transmitter is declared to be faulty when the
transmitter outputs see a load of less than ~25

9.12.4.5 Transmitter Power-Down

To minimize power consumption when the transmitter is not being used, assert the PORT.CR1.PD configuration
bit. When the transmitter is powered down, the TXP and TXN pins are put in a high-impedance state and the
transmit amplifiers are powered down.

9.12.4.6 Transmitter Jitter Generation (Intrinsic)

The transmitter meets the jitter generation requirements of all applicable standards, with or without the jitter
attenuator enabled.

9.12.4.7 Transmitter Jitter Transfer

Without the jitter attenuator enabled in the transmit side, the transmitter passes jitter through unchanged. With the
jitter attenuator enabled in the transmit side, the transmitter meets the jitter transfer requirements of all applicable
telecommunication standards. See

Table 4-1

9.12.5 Receiver

9.12.5.1 Interfacing to the Line

The receiver can be transformer-coupled or capacitor-coupled to the line. Typically, the receiver interfaces to the
incoming coaxial cable (75

W) through a 1:2 step-up transformer.

Figure 1-1

shows the arrangement of the

transformer and other recommended interface components.

Table 9-33

specifies the required characteristics of the

transformer.

Figure 9-31

shows a general overview of the LIU block. The receiver expects the incoming signal to be

in B3ZS- or HDB3-coded AMI format.

Table 9-33. Transformer Characteristics

PARAMETER VALUE

Turns Ratio

1:2ct

±2%

Bandwidth 75

0.250MHz to 500MHz (typ)

Primary Inductance

mH (min)

Leakage Inductance

0.12

mH (max)

Interwinding Capacitance

10pF (max)

Isolation Voltage

1500V

RMS

(min)