NB2879A

http://onsemi.com

2

Figure 1. Block Diagram

ModOUT

Crystal

Oscillator

Frequency

Divider

Feedback

Divider

Phase

Detector

Loop

Filter

XINCLKIN

XOUT

REFOUT

Modulation

Output

Divider

PLL

Table 1. KEY SPECIFICATIONS

Description

Specification

Supply Voltages

Frequency Range

15 MHz < CLKIN < 30 MHz

Cycle−to−Cycle Jitter

300 ps (maximum)

Output Duty Cycle

40 / 60% (worst case)

Output Rise and Fall Times

1.1 ns (maximum)

Modulation Equation

Frequency Deviation

"1%

Figure 2. Pin Configuration

1

2

3

6

5

4

REFOUT

XOUT

XIN/CLKIN

ModOUT

NB2879A

Table 2. PIN DESCRIPTION

Pin #

Pin Name

Type

Description

1

REFOUT

O

Buffered output of the input frequency.

2

XOUT

O

Crystal connection. If using an external reference, this pin must be left unconnected.

3

XIN/CLKIN

I

Crystal connection or external reference frequency input. This pin has dual functions. It can be

connected either to an external crystal or an external reference clock

4

P

Power supply for the entire chip (3.3 V).

5

ModOUT

O

Spread spectrum clock output.

6

P

Ground connection.