PM4354-PI datasheet(77/463 Pages) PMC

77 / 463 page

RELEASED

PM4354 COMET-QUAD

DATASHEET

PMC-1990315

ISSUE 6

FOUR CHANNEL COMBINED E1/T1/J1

TRANSCEIVER / FRAMER

PROPRIETARY AND CONFIDENTIAL TO PMC-SIERRA, INC. AND FOR ITS CUSTOMERS’ INTERNAL USE

Jitter Characteristics

The TJAT Block provides excellent jitter tolerance and jitter attenuation while generating minimal

residual jitter. It can accommodate up to 61 UIpp of input jitter at jitter frequencies above 5.7 Hz

(7.6 Hz for E1). For jitter frequencies below 5.7 Hz (7.6 Hz for E1), more correctly called wander,

the tolerance increases 20 dB per decade. In most applications the TJAT Block will limit jitter

tolerance at lower jitter frequencies only. For high frequency jitter, above 10 kHz for example,

other factors such as clock and data recovery circuitry may limit jitter tolerance and must be

considered. For low frequency wander, below 10 Hz for example, other factors such as slip buffer

hysteresis may limit wander tolerance and must be considered. The TJAT block meets the

stringent low frequency jitter tolerance requirements of AT&T TR 62411 and thus allows

compliance with this standard and the other less stringent jitter tolerance standards cited in the

references.

The corner frequency in the jitter transfer response can be altered through programming.

TJAT exhibits negligible jitter gain for jitter frequencies below 5.7 Hz (7.6 Hz for E1), and

attenuates jitter at frequencies above 5.7 Hz (7.6 Hz for E1) by 20 dB per decade. In most

applications, the TJAT block will determine jitter attenuation for higher jitter frequencies only.

Wander, below 10 Hz for example, will essentially be passed unattenuated through TJAT. Jitter,

above 10 Hz for example, will be attenuated as specified, however, outgoing jitter may be

dominated by the generated residual jitter in cases where incoming jitter is insignificant. This

generated residual jitter is directly related to the use of a 1/96 UI phase adjustment quantum.

TJAT meets the jitter attenuation requirements of AT&T TR 62411. The block allows the implied

jitter attenuation requirements for a TE or NT1 given in ANSI Standard T1.408, and the implied

jitter attenuation requirements for a type II customer interface given in ANSI T1.403 to be met.

Jitter Tolerance

Jitter tolerance is the maximum input phase jitter at a given jitter frequency that a device can

accept without exceeding its linear operating range, or corrupting data. For TJAT, the input jitter

tolerance is 61 Unit Intervals peak-to-peak (UIpp) with a worst case frequency offset of 354 Hz. It

is 80 UIpp with no frequency offset. The frequency offset is the difference between the frequency

of XCLK and that of the input data clock.

PM4354-PI Datasheet(PDF) 77 Page - PMC-Sierra, Inc