MT9040

Data Sheet

9

Zarlink Semiconductor Inc.

Capture Range

Also referred to as pull-in range. This is the input frequency range over which the synchronizer must be able to pull

into synchronization. The MT9040 capture range is equal to

(OSCi). For example, a 32 ppm master clock results in a capture range of 198 ppm.

Lock Range

This is the input frequency range over which the synchronizer must be able to maintain synchronization. The lock

range is equal to the capture range for the MT9040.

Phase Lock Time

This is the time it takes the synchronizer to phase lock to the input signal. Phase lock occurs when the input signal

and output signal are not changing in phase with respect to each other (not including jitter).

Lock time is very difficult to determine because it is affected by many factors which include:

•

initial input to output phase difference

•

initial input to output frequency difference

•

synchronizer loop filter

Although a short lock time is desirable, it is not always possible to achieve due to other synchronizer requirements.

For instance, better jitter transfer performance is achieved with a lower frequency loop filter which increases lock

time. See AC Electrical Characteristics - Performance for Maximum Phase Lock Time.

MT9040 provides a fast lock pin (FLOCK), which, when set high enables the PLL to lock to an incoming reference

within approximately 500 ms.

MT9040 and Network Specifications

The MT9040 fully meets all applicable PLL requirements (intrinsic jitter, jitter/wander tolerance, jitter/wander

transfer, frequency accuracy and capture range for the following specifications.

1. Bellcore GR-1244-CORE June 1995 for Stratum 4

2. AT&T TR62411(DS1) December 1990 for Stratum 4

3. ANSI T1.101 (DS1) February 1994 for Stratum 4

4. ETSI 300 011 (E1) April 1992

5. TBR 4 November 1995

6. TBR 12 December 1993

7. TBR 13 January 1996

8. ITU-T I.431 March 1993

Applications

This section contains MT9040 application specific details for clock and crystal operation, reset operation, power

supply decoupling, and control operation.

Master Clock

The MT9040 can use either a clock or crystal as the master timing source.