841N4830 Datasheet, PDF (1/28 Pages) Integrated Device Technology – Fourth generation FemtoClock

FemtoClock® NG Crystal-To-HCSL
Frequency Synthesizer
841N4830
DATA SHEET
General Description
The 841N4830 is a 3 HCSL, 1 LVPECL and 2 LVCMOS output
Synthesizer optimized to generate PCI Express reference clock
frequencies. The device uses IDT’s fourth generation FemtoClock^®
NG technology for synthesis of high clock frequency at very low
phase noise. It provides low power consumption with good power
supply noise rejection. Using a 25MHz, 12pF parallel resonant
crystal, the following frequencies can be generated: 100MHz,
50MHz and 25MHz. Maximum rms phase jitter of 0.36ps, easily
meets PCI Express jitter requirements. The 841N4830 is packaged
in a small 32-pin VFQFN package.
Features
• Fourth generation FemtoClock^® Next Generation (NG) technology
• Three differential HCSL outputs, one differential LVPECL and
two single-ended LVCMOS/LVTTL outputs
• Crystal oscillator interface designed for a 25MHz, 12pF parallel
resonant crystal
• CLK/nCLK input pair can accept the following differential input
levels: LVPECL, LVDS, HCSL
• A 25MHz crystal generates output frequencies of: 100MHz,
50MHz and 25MHz
• VCO frequency: 2GHz
• RMS Phase Jitter @ 100MHz, (12kHz – 20MHz) using a 25MHz
crystal: 0.36ps (maximum)
• Power supply noise rejection PSNR: -45dB (typical)
• PCI Express Gen 2 (5 Gb/s) jitter compliant
• Full 3.3V supply mode
• -40°C to 85°C ambient operating temperature
• Available in lead-free (RoHS 6) package
Block Diagram
nOE_REF ^Pulldown
PLL_BYPASS ^Pulldown
nOEA ^Pulldown
XTAL_IN
25MHz
OSC 0
XTAL_OUT
CLK ^Pulldown
nCLK ^Pullup
1
CLK_SEL ^Pullup
IREF
DIV2_QB ^Pullup
nOEB ^Pulldown
PFD
&
LPF
FemtoClock® NG
VCO
2GHz
1
÷20
0
÷1 0
÷80
÷2 ¹
Pin Assignment
25MHz LVPECL
REF_OUT
nREF_OUT
100MHz HCSL
3QA[2:0]
3
nQA[2:0]
100MHz LVCMOS
QA3
32 31 30 29 28 27 26 25
PLL_BYPASS 1
24 QA1
nOE_REF 2
841N4830
23 nQA1
nOEB 3
32-Lead VFQFN
22 VDDO
DIV2_QB 4 ^{5mm x 5mm x 0.925mm} 21 QA2
VDDA 5
package body
20 nQA2
CLK 6
nCLK 7
K Package
Top View
19 GND
18 QA3
VDDO_REF 8
17 VDDO_QA3
9 10 11 12 13 14 15 16
100/50MHz
LVCMOS
QB
841N4830 Rev E 7/1/15
1
©2015 Integrated Device Technology, Inc.