MT9040 데이터 시트보기 (PDF) - Zarlink Semiconductor Inc

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MT9040

T1/E1 Synchronizer

Zarlink Semiconductor Inc 

MT9040

Data Sheet

Pin Description (continued)

Pin #

45

46

47

48

Name

Description

TDI

TRST

TCK

TMS

Test Serial Data In (Input). JTAG serial test instructions and data are shifted in on this pin.

This pin is internally pulled up to VDD.

Test Reset (Input). Asynchronously initializes the JTAG TAP controller by putting it in the

Test-Logic-Reset state. If not used, this pin should be held low.

Test Clock (Input). Provides the clock to the JTAG test logic.

Test Mode Select (Input). JTAG signal that controls the state transitions of the TAP controller.

Functional Description

The MT9040 is a T1/E1 Trunk Synchronizer, providing timing (clock) and synchronization (frame) signals to

interface circuits for T1 and E1 Primary Rate Digital Transmission links. Figure 1 is a functional block diagram which

is described in the following sections.

Frequency Select MUX Circuit

The MT9040 operates on the falling edge of the reference. It operates with one of four possible input reference

frequencies (8kHz, 1.544MHz, 2.048MHz or 19.44MHz). The frequency select inputs (FS1 and FS2) determine

which of the four frequencies may be used at the reference input. A reset (RST) must be performed after every

frequency select input change. See Table 1.

FS2

FS1

0

0

0

1

1

0

1

1

Input Frequency

19.44MHz

8kHz

1.544MHz

2.048MHz

Table 1 - Input Frequency Selection

Digital Phase Lock Loop (DPLL)

As shown in Figure 3, the DPLL of the MT9040 consists of a Phase Detector, Loop Filter, Digitally Controlled

Oscillator and a Control Circuit.

Phase Detector - the Phase Detector compares the reference signal with the feedback signal from the Frequency

Select MUX circuit, and provides an error signal corresponding to the phase difference between the two. This error

signal is passed to the Loop Filter. The Frequency Select MUX allows the proper feedback signal to be externally

selected (e.g., 8kHz, 1.544MHz, 2.048MHz or 19.44MHz).

4

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