General Description

The MAX3679A is a low-jitter precision clock generator

with the integration of three LVPECL and one LVCMOS

outputs optimized for Ethernet applications. The device

integrates a crystal oscillator and a phase-locked loop

(PLL) clock multiplier to generate high-frequency clock

outputs for Ethernet applications.

Maxim’s proprietary PLL design features ultra-low jitter

minimizing design risk for network equipment.

Applications

Ethernet Networking Equipment

Features

♦ Crystal Oscillator Interface: 25MHz

♦ CMOS Input: 25MHz

♦ Output Frequencies for Ethernet

62.5MHz, 125MHz, 156.25MHz, 312.5MHz

♦ Low Jitter

♦ Excellent Power-Supply Noise Rejection

♦ No External Loop Filter Capacitor Required

+3.3V, Low-Jitter Crystal to LVPECL

Clock Generator

________________________________________________________________

Maxim Integrated Products

1

Ordering Information

Typical Application Circuit

19-4858; Rev 0; 8/09

For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,

or visit Maxim’s website at www.maxim-ic.com.

+

Denotes a lead(Pb)-free/RoHS-compliant package.

*

EP = Exposed pad.

EVALUATION

KIT

AVAILABLE

Pin Configuration appears at end of data sheet.

PART

TEMP RANGE

PIN-PACKAGE

MAX3679AETJ+

-40

°C to +85°C

32 TQFN-EP*

MAX3679A

MR

REF_IN

IN_SEL

QA_OE

QAC_OE

QB0_OE

QB1_OE

BYPASS

SELA1

SELA0

SELB0

RES1

SELB1

RES0

QA_C

X_OUT

X_IN

GNDO_A

GND

10.5

Ω

0.1

μF

36

Ω

Ω

ASIC

125MHz

QA

50

Ω

Ω

QA

Ω

ASIC

50

Ω

125MHz

QB0

50

Ω

Ω

QB0

Ω

ASIC

50

Ω

312.5MHz

QB1

50

Ω

Ω

QB1

Ω

ASIC

50

Ω

312.5MHz

10

μF

25MHz

33pF

27pF

0.01

μF

0.1

μF

0.1

μF

0.1

μF

0.1

μF

+3.3V

±5%