NB2779A

http://onsemi.com

2

Figure 1. Block Diagram

ModOUT

Crystal

Oscillator

Frequency

Divider

Feedback

Divider

Phase

Detector

Loop

Filter

XIN/CLKIN

XOUT

Modulation

Output

Divider

PLL

PD

Table 1. KEY SPECIFICATIONS

Description

Specification

Supply Voltages

Frequency Range

For 2.5 V Supply

For 3.3 V Supply

13 MHz < CLKIN < 30 MHz

13 MHz < CLKIN < 30 MHz

Cycle−to−Cycle Jitter

200 ps (maximum)

Output Duty Cycle

45/55% (worst case)

Modulation Rate Equation

Frequency Deviation

"1% (TYP) @ 16 MHz

1

2

3

6

5

4

XOUT

XIN/CLKIN

ModOUT

NB2779A

PD

Figure 2. Pin Configuration

Table 2. PIN DESCRIPTION

Pin #

Pin Name

Type

Description

1

PD

I

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.

5

ModOUT

O

Spread spectrum clock output.

6

P

Ground connection.