Data Sheet #: SG048

Page 2 of 16

Rev: P02

Date: 10 / 28 / 02

Functional Block Diagram

Figure 1

ALARM

DETECTION

Reference Input

(Pin 8)

DIVIDER

DPFD

ANALOG

FILTER

DIVIDER

FREE RUN

CONTROL

Free Run Enable

(Pin 5)

Input Freq. Select A

(Pin 14)

LOL Alarm Output

(Pin 7)

VCXO

LOR Alarm Output

(Pin 6)

Oscillator Output

(Pin 9)

Optional Oscillator Output

(Pin 1)

Reference Output

(Pin 1)

(Not available on

models with optional

oscillator output)

Input Freq. Select B

(Pin 13)

Tri-State Enable

(Pin 10)

with the 19.44 MHz model and 30 ppm accurate output with

the 125.0 MHz model. Additionally the Free Run mode may

be entered manually by asserting a high signal to the Free

Run Enable pin. The outputs, except the oscillator output,

may be put into the tri-state high impedance condition for

external testing purposes by asserting a high signal to the

Tri-State Enable pin.

The SCG2000i is 3.3 Volt components that typically

draw less than 100 mA. All models have an acquisition

time of approximately 1.0 second and can be used in

applications that require temperature rating of -40° to

85° C. All models have a 33

Ω resistor in series with the

oscillator output. The SCG2000i maximum package

dimensions are .78” x .83” x .35” on a six layer FR4 board

with surface mount pins. Parts are assembled using high

temperature solder to withstand surface mount reflow

process.

General Description

The SCG2000i provides high precision phase lock loop

frequency translation for the telecommunication applications. The

SCG2000i generates a CMOS output from an intrinsically low

jitter, voltage controlled crystal oscillator. while providing a jitter

attenuated, internal reference that is connected to a Reference

Output pin.

SCG2000i is well suited for use in line cards, service

termination cards and similar functions to provide reliable

reference, phase locked, synchronization for TDM, PDH, SONET

and SDH network equipment . The SCG2000i provides a low

phase gain (<0.2dB), jitter filtered, wander following output signal

synchronized to a superior Stratum or peer input reference

signal.

The SCG2000i include the following features: Free Run, Tri-

state and alarm outputs for Loss-of-Reference, (LOR), Loss-of-

Lock, (LOL). During the LOR alarm, the SCG2000i will also enter

a Free Run state which will guarantee a 20 ppm accurate output

Model Comparison Table

Table 1

Max

Model

Input

Duty

Reference Output

Oscillator Output

Notes

Ref Freq

Cycle

(Pin #1)

(Pin #9)

SCG2000

8-64 kHz

40/60

= Input Ref Freq.

1.544 MHz to 125.0 MHz

Basic Model

SCG2000i

8-16 kHz

45/55

= Input Ref Freq.

19.44 MHZ, 125.0 MHz

Industrial Temp. Range

SCG2010

19.44 MHz

40/60

8 kHz

19.44 MHz

SCG2020

19.44 MHz

40/60

19.44 MHz

77.76 MHz

SCG2030

8-64 kHz

45/55

= Input Ref Freq.

1.544 MHz to 125.0 MHz

Tight Duty Cycle

SCG2050

8-64 kHz

40/60

19.44 MHz

77.76 MHz

SCG2070

19.44 MHz

40/60

51.84 MHz, 77.76 MHz

51.84 MHz, 77.76 MHz

Ref Output = Osc Output

*Features which differentiate a model from the base model (SCG2000) are highlighted in boldface color and in the notes column.