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PDF MAX3679 Data sheet ( Hoja de datos )
| Número de pieza | MAX3679 | |
| Descripción | Low-Jitter Crystal to LVPECL Clock Generator | |
| Fabricantes | Maxim Integrated Products | |
| Logotipo |  |
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Hay una vista previa y un enlace de descarga de MAX3679 (archivo pdf) en la parte inferior de esta página. Total 11 Páginas | ||
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19-4374; Rev 0; 11/08
EVAALVUAAILTAIOBNLEKIT
+3.3V, Low-Jitter Crystal to LVPECL
Clock Generator
www.datasheet4u.com
General Description
The MAX3679 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
(0.36psRMS) and excellent power-supply noise rejection,
minimizing design risk for network equipment.
Applications
Ethernet Networking Equipment
Pin Configuration appears at end of data sheet.
Features
♦ Crystal Oscillator Interface: 25MHz
♦ CMOS Input: 25MHz
♦ Output Frequencies for Ethernet
62.5MHz, 125MHz, 156.25MHz, 312.5MHz
♦ Low Jitter
0.14psRMS (1.875MHz to 20MHz)
0.36psRMS (12kHz to 20MHz)
♦ Excellent Power-Supply Noise Rejection
♦ No External Loop Filter Capacitor Required
Ordering Information
PART
TEMP RANGE
PIN-PACKAGE
MAX3679CTJ+
0°C to +70°C
32 TQFN-EP*
+Denotes a lead-free/RoHS-compliant package.
*EP = Exposed pad.
Typical Application Circuit
10.5Ω
0.1μF
0.1μF
0.1μF
0.01μF
0.1μF
+3.3V ±5%
10μF
0.1μF
VCC
VCC
VCCA
MR
REF_IN
VCCO_A
VCCO_B
IN_SEL
QAC_OE
QA_OE
QB0_OE
QB1_OE
MAX3679
BYPASS
SELA1
SELA0
SELB1
SELB0
RES1
RES0
X_OUT
X_IN
25MHz
(CL = 18pF)
GND
VDDO_A
QA_C
125MHz
36Ω
QA Z0 = 50Ω
QA Z0 = 50Ω
125MHz
QB0 Z0 = 50Ω
QB0 Z0 = 50Ω
312.5MHz
QB1 Z0 = 50Ω
QB1 Z0 = 50Ω
312.5MHz
GNDO_A
33pF 27pF
Z0 = 50Ω
ASIC
ASIC
50Ω 50Ω
(VCC - 2V)
ASIC
50Ω 50Ω
(VCC - 2V)
ASIC
50Ω 50Ω
(VCC - 2V)
________________________________________________________________ Maxim Integrated Products 1
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.
1 page  
+3.3V, Low-Jitter Crystal to LVPECL
Clock Generator
www.datasheet4u.com
Typical Operating Characteristics
(Typical values are at VCC = +3.3V, TA = +25°C, crystal frequency = 25MHz.)
SUPPLY CURRENT
vs. TEMPERATURE
250
225
200
175 ALL OUTPUTS ACTIVE AND TERMINATED
150
125
100 ALL OUTPUTS ACTIVE AND UNTERMINATED
75
50
25
0
0 10 20 30 40 50 60 70 80
AMBIENT TEMPERATURE (°C)
DIFFERENTIAL OUTPUT WAVEFORM
AT 156.25MHz (LVPECL OUTPUT)
MAX3679 toc02
1ns/div
OUTPUT WAVEFORM AT 125MHz
(LVCMOS OUTPUT)
MAX3679 toc03
MEASURED USING 50Ω OSCILLOSCOPE INPUT
THROUGH NETWORK SHOWN IN FIGURE 1
1ns/div
-80
-90
-100
-110
-120
-130
-140
-150
-160
0.1
PHASE NOISE AT 312.5MHz
CLOCK FREQUENCY
1 10 100 1000 10,000 100,000
OFFSET FREQUENCY (kHz)
JITTER HISTOGRAM (312.5MHz OUTPUT,
40mVP-P SUPPLY NOISE AT 100kHz)
MAX3679 toc06
DJ = 5.0psP-P
5ps/div
-80
-90
-100
-110
-120
-130
-140
-150
-160
0.1
PHASE NOISE AT 125MHz
CLOCK FREQUENCY
1 10 100 1000 10,000 100,000
OFFSET FREQUENCY (kHz)
NOISE SPUR AMPLITUDE
vs. NOISE FREQUENCY
0
fC = 156.25MHz
-10 NOISE AMPLITUDE = 40mVP-P
-20
-30
-40
-50
-60
-70
-80
-90
10
100 1000
NOISE FREQUENCY (kHz)
10,000
_______________________________________________________________________________________ 5
5 Page 
www.datasheet4u.com
REF_IN
27pF
X_IN
25MHz
X_OUT
33pF
+3.3V, Low-Jitter Crystal to LVPECL
Clock Generator
IN_SEL
LVCMOS
0
CRYSTAL
OSCILLATOR
1
DIVIDERS:
NA = 2, 4, 5, 10
NB = 2, 4, 5, 10
Block Diagram
BYPASS
SELA[1:0]
0
625MHz
PFD
FILTER
VCO
1
÷25
MAX3679
DIVIDER
NA
LVCMOS
BUFFER
LVPECL
BUFFER
DIVIDER
NB
LVPECL
BUFFER
LVPECL
BUFFER
QAC_OE
QA_C
QA_OE
QA
QA
QB1_OE
QB1
QB1
QB0_OE
QB0
QB0
SELB[1:0]
Package Information
For the latest package outline information and land patterns, go to www.maxim-ic.com/packages.
PACKAGE TYPE
32 TQFN-EP
PACKAGE CODE
T3255+3
DOCUMENT NO.
21-0140
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are
implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 ____________________ 11
© 2008 Maxim Integrated Products
is a registered trademark of Maxim Integrated Products, Inc.
11 Page | ||
| Páginas | Total 11 Páginas | |
| PDF Descargar | [ Datasheet MAX3679.PDF ] | |
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