DATA SHEET

843021 REVISION D 9/25/15

1

©2015 Integrated Device Technology, Inc.

FemtoClock® Crystal-to-3.3V LVPECL

Clock Generator

843021

General Description

The 843021 is a Gigabit Ethernet Clock Generator. The ICS84302

uses a 25MHz crystal to synthesize 125MHz. The 843021has

excellent phase jitter performance, over the 1.875MHz – 20MHz

integration range. The 843021is packaged in a small 8-pin TSSOP,

making it ideal for use in systems with limited board space.

Features

• One differential 3.3V LVPECL output

• Crystal oscillator interface designed for 22.4MHz – 28MHz, 18pF

parallel resonant crystal

• Output frequency range: 112MHz – 140MHz

• VCO range: 560MHz – 700MHz

• Output duty cycle range: 49% – 51%

• RMS phase jitter at 125MHz, using a 25MHz crystal

(1.875MHz – 20MHz): 0.650ps (typical)

Offset

Noise Power

100Hz ..............-94.2 dBc/Hz

1kHz ..............-122.8 dBc/Hz

10kHz ..............-132.2 dBc/Hz

100kHz ..............-131.3 dBc/Hz

• Full 3.3V supply mode

• 0°C to 70°C ambient operating temperature

• Available in lead-free (RoHS 6) package

• Industrial temperature information available upon request

Table 1. Frequency Table - Typical Applications

Inputs

Output Frequency Range (MHz)

Crystal Frequency (MHz)

25

125

26.6

133

Pin Assignment

843021

8 Lead TSSOP

4.40mm x 3.0mm x 0.925 package body

G Package

Top View

Block Diagram

OSC

Phase

Detector

VCO

÷5

÷25

(fixed)

Q0

nQ0

XTAL_IN

XTAL_OUT

25MHz

1

2

3

4

8

7

6

5

VCCA

VEE

XTAL_OUT

XTAL_IN

VCC

Q0

nQ0

nc