IDT82V3155PVG【PDF 6/34 页】IC PLL WAN T1/E1/OC3 DUAL 56SSOP

收藏本站

您好，
买卖IC网欢迎您。
请登录
免费注册

买卖IC网

Sheet目录2000

2页 3页 4页 5页 [6页]7页 8页 9页 10页

Functional Description

February 20, 2009

IDT82V3155

ENHANCED T1/E1/OC3 WAN PLL WITH DUAL REFERENCE INPUTS

2.7

DPLL BLOCK

As shown in Figure - 7, the DPLL Block consists of a Phase Detector,

a Limiter, a Loop Filter, a Digital Control Oscillator and Divider.

2.7.1

PHASE DETECTOR (PHD)

In the Normal mode, the Phase Detector compares the virtual

reference signal from the TIE Control Circuit with the feedback signal

from the Frequency Select Circuit, and outputs an error signal

corresponding to the phase difference. This error signal is sent to the

Limiter circuit for phase slope control.

In the Freerun or Holdover mode, the Frequency Select Circuit, the

Phase Detector and the Limiter are inactive, and the input reference

signal is not used.

2.7.2

LIMITER

The Limiter is used to limit the phase slope. It ensures that the

maximum output phase slope is limited to 5 ns per 125 s for all input

transient conditions. This well meets the AT&T TR62411 and Telcordia

Figure - 7 DPLL Block Diagram

In the Normal mode, the Limiter receives the error signal from the

Phase Detector, limits the phase slope within 5 ns per 125 s and sends

the limited signal to the Loop Filter.

In the Fast Lock mode, the Limiter is disabled, and the DPLL locks to

the input reference within 500 ms, which is much shorter than that in the

Normal mode.

Dig

ital

Con

trol

Osci

llat

C32o

C16o

C8o

C4o

C2o

C3o

C6o

F0o

F8o

RSP

TSP

F16o

C1.5o

F32o

Output Interface

T1_Divider

E1_Divider

C6_Divider

Frequency

Selection

Circuit 1

Phase

Detector

Virtual Reference

Fraction_C6

Fraction_T1

24.704 MHz

32.768 MHz

25.248 MHz

Feedback Signal

Limiter

FLOCK

F1_sel1 F1_sel0

C19_Divider

155.52 MHz

F19o

C19o

APLL

19.44 MHz

Fraction_C19

C155NEG

C155POS

IN_sel

F0_sel1 F0_sel0

Frequency

Selection

Circuit 0

C2/C1.5

Loop Filter

Fx_sel1 Fx_sel0 (x = 0 or 1)

发布紧急采购，3分钟左右您将得到回复。

采购需求

(若只采购一条型号，填写一行即可)

*型号	*数量	厂商	批号	封装

添加更多采购

采购需求

发布成功！您可以继续发布采购。也可以进入我的后台，查看报价

发布成功！您可以继续发布采购。也可以进入我的后台，查看报价

我的联系方式