XRT73LC00 datasheet(45/53 Pages) EXAR

45 / 53 page

áç

XRT73LC00

E3/DS3/STS-1 LINE INTERFACE UNIT

PRELIMINARY

REV. P1.0.1

The Transmit Drive Monitor feature performs monitor-

ing of the line in the Transmit Direction for the occur-

rence of fault conditions such as a short circuit on the

line or a defective Transmit Drive in the XRT73LC00.

The Transmit Drive Monitor is activated by connecting

the MTIP pin (pin 44) to the TTIP line through a 270

Ω

resistor connected in series and by connecting the

MRING pin (pin 43) to the TRING line through a 270

Ω resistor connected in series, as illustrated in

Figure 32.

When the Transmit Drive Monitor circuitry is connect-

ed to the line as illustrated in Figure 26, then it moni-

tors the line for transitions. As long as the Transmit

Drive Monitor circuitry detects transitions on the line

via the MTIP and MRING pins, it keeps the DMO

(Drive Monitor Output) signal “Low”. However, if the

Transmit Drive Monitor circuit detects no transitions

on the line for 128±32 TCLK periods, then the DMO

signal toggles “High”.

NOTES:

1. The Transmit Drive Monitor circuit does not have to

be used to operate the Transmit Section of the

XRT73LC00. This is purely a diagnostic feature.

2. The Transmit Drive Monitor feature can also be

used to monitor the Transmit Output Line Signal of

another LIU IC as illustrated in Figure 33.

FIGURE 32. THE XRT73LC00 EMPLOYING THE TRANSMIT DRIVE MONITOR FEATURES

R1 = 31.6

Ω

R2 = 31.6

Ω

TTIP

TRING

1:1

MTIP

MRING

R3 = 270

Ω

R4 = 270

Ω

R5 = 75

Ω

XRT73LC00 Datasheet(PDF) 45 Page - Exar Corporation

XRT73LC00 Datasheet(HTML) 45 Page - Exar Corporation

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53

Datasheet Download

Link URL